# DECA vs Ethernet



## pjschwartz

I've got a HR20-700 and HR22-100 connected via ethernet to support multi room viewing. What would be the advantage of upgrading my system with SWMs, DECA adapters, etc to move to DirecTVs "supported" configuration for multi room viewing? Is it worth making the hardware investment ?


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## Stuart Sweet

The advantage would be the relatively bulletproof nature of SWiM networking, plus the ability to add service to any room with only one wire. 

DIRECTV's latest (non-DVR) receiver doesn't work without a SWiM and neither does its upcoming HR34 DVR. SWiM is "where it's going" and at some point without it, you'll be locked out.

Personally I think it's well worth it.


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## veryoldschool

pjschwartz said:


> I've got a HR20-700 and HR22-100 connected via ethernet to support multi room viewing. What would be the advantage of upgrading my system with SWMs, DECA adapters, etc to move to DirecTVs "supported" configuration for multi room viewing? Is it worth making the hardware investment ?


"Tough call"
If it's working fine now, it may not [will not] work any better.
I have DECA and it works fine, but then it did when I used ethernet.

Single wire has some pluses, as does not having a bunch of cables, but "function wise" if it's working fine now, then nothing is going to change by upgrading.


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## DarkLogix

From the posts I've read the only Deca only one is the H25
the HR34 disables deca if an ethernet cable is plugged in

so the advantage would be D*'s support and easier CSR calls
I would upgrade to SWM just because it'll be easier
though for Deca if you already have ethernet cable in place and its working then there isn't an ROI


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## veryoldschool

DarkLogix said:


> From the posts I've read the only Deca only one is the H25
> *the HR34 disables deca if an ethernet cable is plugged in*
> 
> so the advantage would be D*'s support and easier CSR calls


Nope, that's the H/HR24 that does.


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## DarkLogix

veryoldschool said:


> Nope, that's the H/HR24 that does.


then why does the HR34 even have a ethernet port?


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## Carl Spock

My contract was up last month so when I feel strong enough to tackle DirecTV and dicker with them over my renewal, I am going to go from a perfectly functioning unsupported Ethernet WHDVR system to DECA and SWiM, but only if they give it to me for free. I think I'll win that argument. I've gotten free hardware before at contract renewal time.


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## Drucifer

pjschwartz said:


> I've got a HR20-700 and HR22-100 connected via ethernet to support multi room viewing. What would be the advantage of upgrading my system with SWMs, DECA adapters, etc to move to DirecTVs "supported" configuration for multi room viewing? Is it worth making the hardware investment ?


The advantage of DECA over Ethernet is that it takes MRV off your home LAN.


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## veryoldschool

DarkLogix said:


> then why does the HR34 even have a ethernet port?


Why? :shrug: but from what I've heard, connecting the ethernet port doesn't disable the internal DECA.


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## DarkLogix

veryoldschool said:


> Why? :shrug: but from what I've heard, connecting the ethernet port doesn't disable the internal DECA.


ok, I had seen a post to the contrary but maybe its just a programing oversight


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## Stuart Sweet

DarkLogix said:


> then why does the HR34 even have a ethernet port?


The HR34 has an ethernet port because if it's used as an RVU server, and there are no other receivers in use, it can provide on demand and other services to the clients by connecting directly to a router. It's just one option.


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## Sixto

DarkLogix said:


> ok, I had seen a post to the contrary but maybe its just a programing oversight


It doesn't disable the Ethernet, at least presently.

But it is not recommended to use the Ethernet connection as a Broadband DECA, but it does seem to work, but again not recommended.

Also, "taking MRV off the home LAN" seems to be somewhat a myth. A robust Switch already does point-to-point, with virtually zero impact on the home LAN. But obviously, DECA is king and preferred for the typical home.


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## DarkLogix

Drucifer said:


> The advantage of DECA over Ethernet is that it takes MRV off your home LAN.


However you're likely to be connecting the Deca system to your network for VOD and such so that negates it for the most part

but it does give you a single point of contact which can be easier to manage


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## DarkLogix

Sixto said:


> It doesn't disable the Ethernet, at least presently.
> 
> But it is not recommended to use the Ethernet connection as a Broadband DECA, but it does seem to work, but again not recommended.
> 
> Also, "taking MRV off the home LAN" seems to be somewhat a myth. A robust Switch already does point-to-point, with virtually zero impact on the home LAN. But obviously, DECA is king and preferred for the typical home.


Ya
assuming they have a switch and not a hub (I've seen a few consumer routers with hubs listed as switches)(an easy way to tell is to use a computer with wireshark and plug it into an unused port, if you see data addressed for another device and not a broadcast packet then you have a hub, ok maybe not easy for others)

but from D*'s perspective its easier to support it, they don't have to train their people on RJ45 or run more cables through the home and they don't have to worry that someone is using a junky hub


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## Sixto

DarkLogix said:


> Ya
> assuming they have a switch and not a hub (I've seen a few consumer routers with hubs listed as switches)(an easy way to tell is to use a computer with wireshark and plug it into an unused port, if you see data addressed for another device and not a broadcast packet then you have a hub, ok maybe not easy for others)
> 
> but from D*'s perspective its easier to support it, they don't have to train their people on RJ45 or run more cables through the home and they don't have to worry that someone is using a junky hub


Correct, DECA is mature, and the recommended and preferred approach.


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## DarkLogix

I know I hate using consumer routers and if I ran a company I wouldn't want to put people in a place that they might have to troubleshoot some random crappy consumer router that isn't worth its weight in paper

so Deca has a nice ROI for D* I can't argue that, no added cable, no added training, and in time no extra devices

maybe they're leaving the ethernet on the HR34 on so it can take the place of the CCK/CCK-W's


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## Stuart Sweet

Sorry, that's not it. It's more for its use as a server in an environment where there are no traditional receivers.


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## Sixto

Was thinking the same as Stuart ... maybe an HR34 with a few Smart TVs, all Ethernet connected.


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## DarkLogix

I know if I was D* that I'd want to simplify MRV setup
possibily have the HR34 replace the CCK/CCK-W when its used (ie if you have a HR34 maybe you can get rid of the CCK

but also have the ethernet link for use with the C30 type devices

why not kill 2 birds with one stone

maybe someone with a HR34 could test this (connect ethernet to the rj45 port and remove thier CCK)


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## dsw2112

DarkLogix said:


> I know if I was D* that I'd want to simplify MRV setup
> possibily have the HR34 replace the CCK/CCK-W when its used (ie if you have a HR34 maybe you can get rid of the CCK
> 
> but also have the ethernet link for use with the C30 type devices
> 
> why not kill 2 birds with one stone
> 
> maybe someone with a HR34 could test this (connect ethernet to the rj45 port and remove thier CCK)


I don't think anyone said it won't work (it will); it was mentioned that this wasn't the intended usage. I'm sure there will be stories of setups as you describe.


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## DarkLogix

Ya I just hope that D* planned for it when they built the HR34 as if not then the Deca to eth link via a HR34 might be sub-par but then it might be better than the CCK (any word on the HR34's eth port speed? I guess its likely only 100)


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## Sixto

100Mbps.


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## DarkLogix

argg why couldn't they get with it and put in a gig link
with Deca being over 200Mbps a gig link should allow for faster access and lower latency (although then ethernet would have something noticeable over deca)


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## Stuart Sweet

DarkLogix said:


> Ya I just hope that D* planned for it when they built the HR34 as if not then the Deca to eth link via a HR34 might be sub-par but then it might be better than the CCK (any word on the HR34's eth port speed? I guess its likely only 100)


That is not, will not, cannot, etc. be the plan. I understand what you're saying but please move on.


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## pjschwartz

So is the "latency" issue (when issuing DVR commands . . . FF, pause, etc) eliminated with DECA?


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## DarkLogix

From what I've read a good eth network doesn't have latency issues with MVR and nether does deca


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## veryoldschool

pjschwartz said:


> So is the "latency" issue (when issuing DVR commands . . . FF, pause, etc) eliminated with DECA?


I don't have those problems, but there are times starting a recording, that I'm waiting [too long], which I think is more due to the DVR being "busy".


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## lugnutathome

pjschwartz said:


> So is the "latency" issue (when issuing DVR commands . . . FF, pause, etc) eliminated with DECA?


I've heard yes and no to that question but having 11 receivers on some LOOOONG runs (nearly 200ft in one case), I see latency as being relative to the distances between the client server pairing. Closer (in line feet) boxes are more "localized" in the responses whereas the longer line units seem slower and a more predictable back run so you don't miss programming using visual "oh it's on now" cues and response times.

My workout room "Bat Cave" HR24-500 is 191 feet from the Ethernet backbone switch and my master bedroom's "Sleepy Hollow" HR23-700 145. Physically these units are about 50 feet apart.

I have several H25s on DECA bridged via an "ICK" so to be fair all my servers use the Ethernet backbone so I cannot say for certain DECA would improve things. But from a viewer's perspective the two infrastructures are transparent to one another in my implementation.

If what you have works changing things out might not be anything you would note as being different. OTOH, having single lines to a DVR does allow DVR placement in rooms that prior could only use a standard receiver.

SWM also has AGC (Automatic Gain Control) so is a bit less weather affected.

Converting to DECA and having VOD requires a few of "stems and pieces" (if you've the older non internal DECA equipment) and another wall wart for your Internet connectivity.

But it does get you "support", frees up your existing LAN for downloading the newest:dance01: Lady Gaga stuff, and is conceptually "future proof". But given RVU and it's standards are for Ethernet, I'm thinking a well oiled LAN is perfectly serviceable too. But as the receivers evolve that Ethernet port may go the way of the Dodo.

Then again non WWDVR subscribers still may need VOD so for the DVR's it is conceivable that the Ethernet port may in fact remain.

It's anybodies guess.

Don "unless you need to add receivers or get support, you may be just fine as you are" Bolton


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## poppo

Drucifer said:


> The advantage of DECA over Ethernet is that it takes MRV off your home LAN.


With a Ethernet switch, it's not on your LAN any more than DECA is.



lugnutathome said:


> But it does get you "support", frees up your existing LAN for downloading the newest:dance01: Lady Gaga stuff, and is conceptually "future proof".


I fail to see how it frees up your LAN for downloading. The data still has to come through your router, and as noted above, with a switch it doesn't use any LAN BW other than what comes though the router just like DECA.


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## dennisj00

I think what everyone is saying - or mostly everyone - is that MRV traffic stays on the DECA cloud. VOD and the other miscellaneous traffic - TVApps, etc. - does have to get back to your router and then the internet.

A well designed LAN can do the same thing. But how many joe customers have a well designed home LAN. 

And Directv installers know coax connectors, not rj45s.


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## lugnutathome

poppo said:


> With a Ethernet switch, it's not on your LAN any more than DECA is.
> 
> I fail to see how it frees up your LAN for downloading. The data still has to come through your router, and as noted above, with a switch it doesn't use any LAN BW other than what comes though the router just like DECA.


Just a humorous tone about a possible positive side effect of having the DECA "subnet" running mainly isolated from your primary network except for VOD or Utoob traffic that has to bubble out through the router.

Reality is a well implemented LAN is just fine even a mere 10/100 one.

In the case of the OP they have a suitable infrastructure in place and no immediate need to change.

Don "just tryin to interject some levity into what has been a touchy subject in the past" Bolton


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## poppo

dennisj00 said:


> But how many joe customers have a well designed home LAN.


Well designed?  Connect equipment to switch - done. How hard is that? As long as all receivers are connected to the same switch, it is no different then the 'DECA cloud'.


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## lugnutathome

poppo said:


> Well designed?  Connect equipment to switch - done. How hard is that? As long as all receivers are connected to the same switch, it is no different then the 'DECA cloud'.


Actually it is different (Ethernet) in that it is SWM independent and scales out to allow more devices over greater physical distances than DECA was engineered for. In normal home installations they would operate identically however (from a viewers perspective).

As to well designed and the simple explanation you offer, the average "Joe" can conceivably find ways to stack switches off switches and make internal switch routing confined to one or 2 ports on the main backbone and that could get f'ugly.

But yeah if everything goes through a good quality centralized backbone switch each client has a private line to its server whereas DECA has a "party line" which uses "channels" to permit a single client to connect to a single server in amidst the swirl of all the traffic.

In the broad sense DECA is more limited but it's limits were designed to function in nearly all of their residential base installations and it simplifies Direct TVs management, and maintenance of the service.

So while it might not scale to MDU "sized" installations it has a great sweet spot for the vast majority of subscribers.

Don "how did that horse get back in here?" Bolton


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## poppo

I just don't see anything complicated about using Ethernet with zero impact on the LAN until it comes to Internet traffic or other traffic that goes though the router (i.e. nomad to iPad via wireless). And that will be the same if using DECA. I'm sitting here looking at my switch passing MRV traffic between 2 switch ports while I stream a movie from my server to my TV via two other ports. For all practical purposes, they are on separate networks as far as LAN traffic is concerned. This is not rocket science. 

Of course for someone that does not already have network cable in place, DECA is the way to go. But there is absolutely no issue concerning LAN traffic using Ethernet. If anyone has a complicated enough LAN that requires multiple switches, etc., the odds are they have the smarts to do it right (or have paid someone to set it up).


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## dennisj00

poppo said:


> Well designed?  Connect equipment to switch - done. How hard is that? As long as all receivers are connected to the same switch, it is no different then the 'DECA cloud'.


Maybe 'Well designed' should be replaced by 'poorly implemented'. . .

Read thread after thread of 'my ipad won't find my dvr . . .' or 'my dvr drops off the network' of why does this dvr have a 192.168.2.x address and this one has a 192.168.1.x address . . .

Some people think one router is good, two must be better!

Another reason they have 'supported' vs. non-supported'. Armed with only a coax tool, the DECA dvrs will find each other until thrown into the poorly implemented local LAN!

I visited a friend a few months ago that paid to have his network setup -- he is an engineer by trade and you would think might know better?? I believe quoting you *'the odds are they have the smarts to do it right (or have paid someone to set it up)'*.

So he should have the smarts or paid (drum roll here. . )the GEEK squad. . .

His wireless was using his neighbors router! And he had paid the GEEK squad!!


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## DarkLogix

lugnutathome said:


> Just a humorous tone about a possible positive side effect of having the DECA "subnet" running mainly isolated from your primary network except for VOD or Utoob traffic that has to bubble out through the router.


I know you put subnet in quotes but still from a network perspective subnet is not applicable here (a subnet mask when binary ANDed with an ip address results in the network ID which looks like an IP but its not a usable IP address when that mask is used but it defines the network)

sorry I just don't like it when people use subnet or vlan wrong, it comes from actually using VLSM to make differant size subnets applied to vlans


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## lugnutathome

DarkLogix said:


> I know you put subnet in quotes but still from a network perspective subnet is not applicable here (a subnet mask when binary ANDed with an ip address results in the network ID which looks like an IP but its not a usable IP address when that mask is used but it defines the network)
> 
> sorry I just don't like it when people use subnet or vlan wrong, it comes from actually using VLSM to make differant size subnets applied to vlans


No problem. I'm a DBA not a network guy. I know just enough to do what I need to here at home. At work I use the networking group.

Don "so how does that new hair net thingamabob connect up anyhow?" Bolton


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## DarkLogix

No worries I'm horrible with DB's (Sure I can manage but DB's aren't my strong suit) I know alot of the concepts but its the fine details of DB's that I don't


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## lugnutathome

DarkLogix said:


> No worries I'm horrible with DB's (Sure I can manage but DB's aren't my strong suit) I know alot of the concepts but its the fine details of DB's that I don't


I wouldn't call the details "fine" More like obstacles and traps:grin:

Don "knot rely and Eye Tee perfeshinal eye jest plaa won at werk" Bolton


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## gio12

pjschwartz said:


> So is the "latency" issue (when issuing DVR commands . . . FF, pause, etc) eliminated with DECA?


No. I matter of fact, I say the same if not better performance using a wireless connection for MRV. I played the CSR roulette for weeks to get DECA installed, hoping for better performance. Nope. Almost a waste of my time and D* time/money. Luckily it was FREE!


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## DarkLogix

gio12 said:


> No. I matter of fact, I say the same if not better performance using a wireless connection for MRV. I played the CSR roulette for weeks to get DECA installed, hoping for better performance. Nope. Almost a waste of my time and D* time/money. Luckily it was FREE!


I have an idea that might help with lag on long runs but it would have costs that might not be acceptable

basicly put a gig switch at each reciver
then connect using a short ethernet cable
then link all the switches in a star configuration with a central gig switch

the benefit of this is gig ethernet has lower latency than 100mbit and you'd be sending data over the bulk of the distance at gig even though the reciver is only talking to the switch at 100


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## schwefel

DarkLogix said:


> I have an idea that might help with lag on long runs but it would have costs that might not be acceptable
> 
> basicly put a gig switch at each reciver
> then connect using a short ethernet cable
> then link all the switches in a star configuration with a central gig switch
> 
> the benefit of this is gig ethernet has lower latency than 100mbit and you'd be sending data over the bulk of the distance at gig even though the reciver is only talking to the switch at 100


That is just not a good idea. Latency will be affected, just not decreased.

Yes, gig Ethernet is FASTER, in terms of throughput. Comparing gig to fast ethernet is like a 2 lane free way to a 20 lane freeway, not increasing the speed limit.

Latency is a function of several different factors.
1. Processing Delay
2. Queueing Delay
3. Serialization Delay
4. Propegation Delay

Some of these are more pronounced on a router than on a switch and vise-versa. Consumer grade switches(1) and routers(2) will also not be as robust of have the advanced features that real, business grade (Cisco [and I mean real Cisco, not their consumer grade Linksys or Valet], Junier, HP, etc) equpment will have.

Without further ado, onto what each of the delays are and what they mean for you.

*Processing Delay -* Processing delay is the delay that is induced by the device examining the frame(3). Whenever an active network device recieves a frame, it has to do several things to it. If it is a switch, it has to examine the destnation MAC(4) address, then it looks up to see which port that MAC is on. If it is a router and/or itself is the destination, it has to reassemble the packet(5) if it was fragmented and then examine the destination IP address, then it can determine where the packet needs to go. Device load (not necessarily the amount of data) and the quality of the device is the determining factor In the car/highway anaology, this would be determining where you want to go, more or less.

*Queueing Delay -* Queueing delay is nothing more than waiting at "exit door" for your turn to go. Generally this is minimal. However, if your are pushing a lot of data, queueing delay can be significant. This would be waiting in line on a metered on ramp.

*Serialization Delay -* Serialization delay, unlike the first two, does not vary based on device load. It only varies inversely based on link speed. A gig Ethernet link will have 1/10th the serialization delay of a fast Ethernet link. Think of this as the acceleration of your car.

*Propegation Delay -* Propegation delay is the amount of time it takes for the frame to go from one end of the link to the other. Propegation delay varies directly baseed on the length of the link. This is the speed limit. It is a hard speed limit. In copper it is ~2/3 the speed of light, in fiber it is just below the speed of light(6). Using copper as the link medium, the propegation delay is 10 ft/0.000000015 sec. (I hope I got my math right.)

What does all this mean?

In your scenario, I see 5 devices: 
R(eceiver)a ---- G(ig switch)a ---- M(ain switch) ---- Gb ---- Rb

(Assumptions are being made from the moment the frame is placed on the link from Ra, until it is processed by Rb) The frame will encounter roughly the same propegation delay, but it will have additional processing, queueing and serialization delays at Ga and Gb. These can be significant.

The two biggest things you can do to reduce delay is to have each receiver plugged directly in to the main switch and use a quality switch. To go a step further, you could use QoS(7) or create a seperate network segment (that is what DECA is) and that would isolate the rest of your network from the recievers.

Going wireless presents a whole additional set of variable and other fun stuff that I am not going to get in to. (At least not tonight, if you want I will add another post to describe that.)

Definintions:
1 - Switch: A switch is an active device that operates sort of like an old telephone switch board. When network devices send data, they send it to the MAC address of the end device if it local or the default router [gateway] if it not local. While this is an oversimplification, if the sending and receiving device have IP addresses of X.X.X.y where the X's match, they are local. If the X's do not match, they are not local. The switch learns which MAC address(es) are on each port and direct the frames only the port that has the that MAC address. If it has not learned the MAC address yet, it will flood it (send it to all ports) until it learns which port the MAC is on.

2 - Router: A router is kind of like a swich, except it is slower and know where no local devices live. It takes more time/processing power for a router to do its job than a switch. (This is an EXTREME oversimplication.)

3 - Frame: A frame is the unit of data that is actually sent across the link. It encapuates the packet (or part of the packet) that is being sent. A frame will never have more than one packet. You can think of a frame as a motorcycle, car, van, bus, etc.

4 - MAC: A media access control (MAC) address is globally unique id used by Ethernet network devices. It is 48 bits long and commonly seen in the form of 0123.4567.89ab or cd:ef:01:23:45:67. Frames are addressed by the MAC address.

5 - Packet: A packet is the "useful" information that is being transmitted. If we are using a similar anaology as we did in #2, a packet would be family that is going somewhere in the minivan. A packet (because of frame size maximums) has maximum size of 1500 bytes. If the packet's size exceeds 1500 bytes, it will get fragmented (split) in to multiple frames and need to be reassembled at the destination. Think of it like there is a family of 10, but the minivan only holds 6. Six would go in once minivan, the other 4 would have to go in another.

6 - Speed if Light: In a vaccume, the speed of light is (almost) 300,000,000m/s that everyone remember. In other substances (air, glass, water, diamond, etc) it slows down ever so slightly.

7 - QoS: Quality of Service (QoS) is way of prioritizing certain (important) traffic over other (non-important) traffic. It is a mechanism to reduce queueing delay only.

In summay, if you want the best performance, have a minimun nuber of switches between your receivers. To go a step further, get business grade switches. If you really want to do all that you can, configure QoS.

You can purchase business grade switches for a reasonable price on eBay, as long as you do not insist on the most current model. A few months ago, I bought a Cisco 3550 24 port PoE (Power over Ethernet) switch for $135. Granted, I did not purchase it for my AV setup (I am VoIP/call center architecht and it is for my home lab) the reasons why I bought it include the above.

If anyone wants to go the route of bussiness grade network gear, or if you want to know me, let me know. Always happy to help.

p.s. It is 2:00 am. All of this seems coherant to me right now. Whether it is or not may change in the morning. That and spelling, too.


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## Sixto

Thanks for the very informative post. Excellent reading.


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## schwefel

Sixto said:


> Thanks for the very informative post. Excellent reading.


My pleasure.

If anyone is interested I could do a more complete write up (sticky candidate?) comparing Ethernet, Wi-Fi and MoCA. (DECA, as understand it, being MoCA operating on a different freq band so that it is compatable with DTV's freqs.)

They all have their pros/cons.

In just the few threads I have looked it, there seems to be some mis-information out there.


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## DarkLogix

although you have some good points you also made a number of mistakes

1. switches have nothing to do with IP's (IP's are layer 3, switches work at layer 2)
a switch looks only at the destination MAC address

the only way to remove that processing delay (extremely minimal) is to use a hub but then a hub will greatly hurt the available bandwidth

The use of QoS doesn't isolate but rather prioritizes data but adds more proccessing delay than anything else thus requires more PCU power to handle and few devices have good layer2 QoS, most QoS is done at layer 3 but doing it at layer 3 doesn't help a lan thats only working at layer 2 (exept at the end points)

Deca offers a Stop gap of using QoS

yes a signal over copper has a speed limit but theres more to it than that the length of the ones/zeros (ie the amount of time sending a one in 100 vs gig is differant so it takes less time to send even a very small frame) think about it like painting lines on a road and with 100 its 10ft long for a 1 but on gig its 1ft long

the proseccing delay caused by a switch is extremely minimal, and once the switch has learned all the existing mac addresses (done when a device first becomes active) (the programing for this is very simple and theres hardware switching that can do it extremely fast) but if you add in Layer2 QOS you have to do more than just dest mac send to port x

most of your post was good but you mentioned IP addresses with switches which isn't accurate as a switch doesn't interact with IP addresses but only with MAC addresses (yes there are "layer3" switches that are actually hybrid switch/routers but the switch part still doesn't work with IP's)

btw of course you want to minimize the number of switches and any that you do have need to be uplinked via a proper link (ie don't make bottle necks)
and a media converter would be the best way to lower propogation lag (ie convert to light then convert back though that takes some processing too)


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## schwefel

DarkLogix said:


> although you have some good points you also made a number of mistakes
> 
> 1. switches have nothing to do with IP's (IP's are layer 3, switches work at layer 2)
> a switch looks only at the destination MAC address


I never said that switches look at the IP. What I said was: (emphasis added)



schwefel said:


> 1 - Switch: A switch is an active device that operates sort of like an old telephone switch board. When network devices send data, they send it to the MAC address of the end device if it local or the default router [gateway] if it not local. *While this is an oversimplification, if the sending and receiving device have IP addresses of X.X.X.y where the X's match, they are local. If the X's do not match, they are not local.* The switch learns which MAC address(es) are on each port and direct the frames only the port that has the that MAC address. If it has not learned the MAC address yet, it will flood it (send it to all ports) until it learns which port the MAC is on.


I was stating what is considered local, albeit a little over simplified.



DarkLogix said:


> the only way to remove that processing delay (extremely minimal) is to use a hub but then a hub will greatly hurt the available bandwidth


Yes, using a hub will remove almost all processing delay. While hub does not "remove" bandwidth, it nonetheless can have a detrimental effect on the performance of the network.



DarkLogix said:


> The use of QoS doesn't isolate but rather prioritizes data but adds more proccessing delay than anything else thus requires more PCU power to handle and few devices have good layer2 QoS, most QoS is done at layer 3 but doing it at layer 3 doesn't help a lan thats only working at layer 2 (exept at the end points)


Ok, you got me on that one. I started with one thought, ended with another. eh, it was 2:00 am after all.

You are correct, QoS does introduce more processing delay. As with everything there is a trade off. Processing delay is, typically, very minimal. Queueing delay, however, can be much more impactful. With QoS enabled, a small increase in processing delay is more than offset by the significant reduction in queueing delay.



DarkLogix said:


> Deca offers a Stop gap of using QoS


Yes, but as far as I know, DECA QoS is nothing mroe than a black box. What does the QoS mark, how are the different queues set up, etc.

I have been looking (not that hard or spending much time) for tech specs related to DECA/MoCA. If anyone has more detailed info, I would love to have it passed on.



DarkLogix said:


> yes a signal over copper has a speed limit but theres more to it than that the length of the ones/zeros (ie the amount of time sending a one in 100 vs gig is differant so it takes less time to send even a very small frame) think about it like painting lines on a road and with 100 its 10ft long for a 1 but on gig its 1ft long


Yes, the amount of time it takes to put the data on the wire is less with gig than with fast. That is the serialization delay. As I said, it is inversely proportional to the speed of the link. Serialization delay will be 10x less with gig than it will be with fast.

However, once it is on the wire, it does not matter. Propegation delay is purely a function of the transport medium and distance. If I have 2 identical length networks, simple ones with 2 PCs each connected directly by an ethernet cable, and one is gig and the other is fast, and a packet is sent from the source PC on each network at the EXACT same time, they will arrive at the destination PC at the EXACT same time. Yes, I can send more data over a give time period with gig, but it will still take the same amount of time to from Point A to Point B no matter what the speed.

It is like a bus vs a van on the freeway. They both start at the same point and drive the same speed. One just has more bandwidth (passengers) than the other.



DarkLogix said:


> the proseccing delay caused by a switch is extremely minimal, and once the switch has learned all the existing mac addresses (done when a device first becomes active) (the programing for this is very simple and theres hardware switching that can do it extremely fast) but if you add in Layer2 QOS you have to do more than just dest mac send to port x
> 
> most of your post was good but you mentioned IP addresses with switches which isn't accurate as a switch doesn't interact with IP addresses but only with MAC addresses (yes there are "layer3" switches that are actually hybrid switch/routers but the switch part still doesn't work with IP's)


I never said that switches look at the IP. What I said was: (emphasis added)



schwefel said:


> 1 - Switch: A switch is an active device that operates sort of like an old telephone switch board. When network devices send data, they send it to the MAC address of the end device if it local or the default router [gateway] if it not local. *While this is an oversimplification, if the sending and receiving device have IP addresses of X.X.X.y where the X's match, they are local. If the X's do not match, they are not local.* The switch learns which MAC address(es) are on each port and direct the frames only the port that has the that MAC address. If it has not learned the MAC address yet, it will flood it (send it to all ports) until it learns which port the MAC is on.


I was stating what is considered local, albeit a little over simplified.



DarkLogix said:


> btw of course you want to minimize the number of switches and any that you do have need to be uplinked via a proper link (ie don't make bottle necks)
> and a media converter would be the best way to lower propogation lag (ie convert to light then convert back though that takes some processing too)


----------



## hasan

Carl Spock said:


> My contract was up last month so when I feel strong enough to tackle DirecTV and dicker with them over my renewal, I am going to go from a perfectly functioning unsupported Ethernet WHDVR system to DECA and SWiM, but only if they give it to me for free. I think I'll win that argument. I've gotten free hardware before at contract renewal time.


While not at renewal time, when WHDVR upgrades were first being offered, I called up and got the full setup, including new dish and required DECAs, plus install for all of $25.00.

I had a perfectly functioning ethernet setup (with one issue that was caused by wireless issues). I really like having the SWiM/DECA setup.

I'm actually running a hybrid setup...there is one dvr on its own dish, that is not SWiM, but it sees the network and mrv works fine (within the limits of the wireless connection that gets it to the network).

While I liked the performance of my hardwired non-supported system, when I got the chance to upgrade for such a low cost, I jumped at it. We don't know if home networking will remain "functional" for a long time, or not. I also liked taking all that traffic off the home network)

If you can get the DECA setup at an affordable cost, I would recommend it.


----------



## Diana C

Seems to me that the major advantage of DECA over Ethernet is that you MUST use DECA with the H25, and presumably any future receivers, when part of a MRV installation.


----------



## poppo

hasan said:


> I also liked taking all that traffic off the home network)


Ugh!! Why do people keep saying this? There is no more/less traffic on the LAN then using Ethernet and a switch.


----------



## dsw2112

poppo said:


> Ugh!! Why do people keep saying this? There is no more/less traffic on the LAN then using Ethernet and a switch.


Several of the folks I know use a single ethernet run to the entertainment center, and a switch to "break-out" and attach peripherals (D* receiver, Blu Ray, Xbox, etc.) Should they switch to DECA then the MRV traffic would no longer be on that LAN ethernet run.


----------



## veryoldschool

This "debate" will go on and on.
When I only had ethernet [pre DECA] it worked fine, and wiring it through a switch wasn't a problem.

I moved recently and so I have a fresh start.
Boxes of networking cables & parts, that I don't need now.
DirecTV came in and setup coax for my receivers.
Since they all have internal DECAs, I simple added my wireless CCK behind the receiver, in the same room as the router, and "I'm done". 
The only thing I needed out of my networking boxes was an ethernet cable to string between two rooms to get this PC connected to my U-verse router.


----------



## MizzouTiger

poppo said:


> Ugh!! Why do people keep saying this? There is no more/less traffic on the LAN then using Ethernet and a switch.


All I can say is that I recently added a switch to connect my 3 networked receivers to and then connected the switch to my router. I have noticed a vast improvement in MRV performance since. I haven't gotten a single freeze-up when viewing a remotely recorded program and trick play performance is much faster.

It is my understanding that using a switch will indeed remove the MRV traffic off of your router traffic as the switch is directing the MRV data from one MAC address to another specific MAC address and none of this data is having to go through the router. The only time any receiver "data" would go through the router is when a receiver had to access the internet for VOD downloads or for an App.


----------



## heaphus

So, my wife really wants MRV, but we don't currently have DECA or SWM. I have called and played CSR twice and, despite being a fifteen year subscriber that's not under contract, $199 is the best they have been able to come up with to come install the equipment. I really don't want to pay that much. Now, I can either continue to try to get a deal, or it looks as though I can get the equipment and do it myself for about $100. If I go the self-installation route, will I have any trouble getting them to activate MRV, and will it be supported? Thanks.


----------



## veryoldschool

heaphus said:


> So, my wife really wants MRV, but we don't currently have DECA or SWM. I have called and played CSR twice and, despite being a fifteen year subscriber that's not under contract, $199 is the best they have been able to come up with to come install the equipment. I really don't want to pay that much. Now, I can either continue to try to get a deal, or it looks as though I can get the equipment and do it myself for about $100. If I go the self-installation route, will I have any trouble getting them to activate MRV, and will it be supported? Thanks.


I was in the test group for this and when it came time to pay for the service, I had no problem getting it activated as supported. I had told them that I had DECA in place already.

What is your hardware now?
"Sometimes" the $200 is cheap for what you get, or you can leverage a receiver upgrade at the same time.


----------



## lugnutathome

Titan25 said:


> Seems to me that the major advantage of DECA over Ethernet is that you MUST use DECA with the H25, and presumably any future receivers, when part of a MRV installation.


The major advantage is really the full support of Direct TV. It's an architecture *they* control and understand.

With the wireless CCK, an Etherenet cable, and a band stop filter one can adapt an H25 to an Ethernet set up quite easily and judging by the HR34 having an Ethernet port and the RVU alliance using Ethernet as the standard I would almost guess that the future dual tuner DVR will still have an Ethernet port aboard. (again that is just a guess).

But while the Ethernet vs DECA war keeps flaring up it's really moot.

If you have a typical residence and you are a typical person you likely do not have a hard wired LAN and your wiring length requirements do not force limits beyond DECA's engineered service parameters. So then using DECA should be a no brainer. It works, has full support, and takes problem resolution away from you.

I'm still stuck on Ethernet primarily because I have absurdly long cable runs and span several SWM units. Eventually as DECA matures I'm expecting I can take advantage of it myself. Till that time comes I've a hybrid beast that works seamlessly but I have to handle all the problem resolution and engineer (as well as implement) any of the changes to my infrastructure myself.

Don "watching TV should not have to be work" Bolton


----------



## heaphus

veryoldschool said:


> I was in the test group for this and when it came time to pay for the service, I had no problem getting it activated as supported. I had told them that I had DECA in place already.
> 
> What is your hardware now?
> "Sometimes" the $200 is cheap for what you get, or you can leverage a receiver upgrade at the same time.


Thanks. We currently have (2) HR20-100, one in the living room and one in the master bedroom. However, we have two kids that are just about ready to have TV in their bedrooms. Maybe I should wait a bit, and try to package MRV and some HR34/RVU goodness for a new contract.


----------



## veryoldschool

heaphus said:


> Thanks. We currently have (2) HR20-100, one in the living room and one in the master bedroom. However, we have two kids that are just about ready to have TV in their bedrooms. Maybe I should wait a bit, and try to package MRV and some HR34/RVU goodness for a new contract.


There needs to be a special configuration for DECA and the HR20-100, which is shown in a sticky at the top of this forum.

Also you may want to have/get one or more DVRs for the kids recording.
I wouldn't want to be sharing a HR34 with "my kids" [if I had any], as Sponge Bob, etc., isn't my cup of tea. :lol:


----------



## Rtm

veryoldschool said:


> There needs to be a special configuration for DECA and the HR20-100, which is shown in a sticky at the top of this forum.
> 
> Also you may want to have/get one or more DVRs for the kids recording.
> I wouldn't want to be sharing a HR34 with "my kids" [if I had any], as Sponge Bob, etc., isn't my cup of tea. :lol:


Wont they still show up in the playlist and sponge bob is usually on when other prime time type events aren't.


----------



## veryoldschool

Rtm said:


> Wont they still show up in the playlist and sponge bob is usually on when other prime time type events aren't.


You can select sharing or not sharing with each DVR, or you can block a DVR completely with a bandstop filter [which you'd need if you don't use a DECA on a receiver]. Depending on how the coax is connected and the type of splitters used, you can separate DVRs between locations too.


----------



## heaphus

veryoldschool said:


> There needs to be a special configuration for DECA and the HR20-100, which is shown in a sticky at the top of this forum.
> 
> Also you may want to have/get one or more DVRs for the kids recording.
> I wouldn't want to be sharing a HR34 with "my kids" [if I had any], as Sponge Bob, etc., isn't my cup of tea. :lol:





Rtm said:


> Wont they still show up in the playlist and sponge bob is usually on when other prime time type events aren't.





veryoldschool said:


> You can select sharing or not sharing with each DVR, or you can block a DVR completely with a bandstop filter [which you'd need if you don't use a DECA on a receiver]. Depending on how the coax is connected and the type of splitters used, you can separate DVRs between locations too.


Good stuff. I hadn't thought that much about unified playlist/sharing issues when adding the kids to the mix. How granular is the sharing control? For example, is it possible to have the master bedroom receiver see the playlists of all other receivers, but to not share it's playlist back to those other receivers? Can it be one way like that? Or, is the sharing all or nothing, so to speak?


----------



## veryoldschool

heaphus said:


> Good stuff. I hadn't thought that much about unified playlist/sharing issues when adding the kids to the mix. How granular is the sharing control? For example, is it possible to have the master bedroom receiver see the playlists of all other receivers, but to not share it's playlist back to those other receivers? Can it be one way like that? Or, is the sharing all or nothing, so to speak?


Within the menu options, it's limited to share or not & remote delete or not.
This is where with some tweaking of the coax connections and a filter, you can separate the coax network into two. "Kids world, and your world".


----------



## harsh

DarkLogix said:


> then why does the HR34 even have a ethernet port?


Because none of the available RVU client devices feature DECA?


----------



## DarkLogix

dsw2112 said:


> Several of the folks I know use a single ethernet run to the entertainment center, and a switch to "break-out" and attach peripherals (D* receiver, Blu Ray, Xbox, etc.) Should they switch to DECA then the MRV traffic would no longer be on that LAN ethernet run.


well most entertainment devices only have a 100mbit connection so if a gig switch is used (or atleast one with 1 gig port for uplink) then if the number of 100mbit devices is less than 10 then there isn't a bottle neck there (ie no congestion trying to get in the uplink)

now if a crappy 100mbit uplink is used then its possible that congestion might occure, though many entertainment devices I've seen don't max out a 100 link


----------



## sunking

Oddly enough, the defenders of ethernet are in reality backing the reason that deca is being pushed. How many posts have been in here saying basically, "if you upgrade to giga, or add a switch, or properly configure your network, etc, etc" (all paraphrases). The point of deca is you plug them all in, turn them all on, and in golf terms, grip it and rip it.

In reality, ethernet as a protocol is a poor choice for MRV in a typical household environemnt. The only reason we can use it at all is because hardware can be added to help it through its short comings, namely its lack of being able to guarantee any sort of scheduling. In the end all you can do is assume that things will get there in a timely fashion because we've spent money to try to do so.

We can get this with deca, but in doing so we restrict our maximum bandwidth between nodes and have a max number of nodes we can communicate with. But we guarantee latency and throughput between nodes.


----------



## dsw2112

DarkLogix said:


> well most entertainment devices only have a 100mbit connection so if a gig switch is used (or atleast one with 1 gig port for uplink) then if the number of 100mbit devices is less than 10 then there isn't a bottle neck there (ie no congestion trying to get in the uplink)
> 
> now if a crappy 100mbit uplink is used then its possible that congestion might occure, though many entertainment devices I've seen don't max out a 100 link


These threads often get sidetracked on semantics, or context; I think that you missed the fact that I was replying to this:



hasan said:


> ...I also liked taking all that traffic off the home network





poppo said:


> Ugh!! Why do people keep saying this? There is no more/less traffic on the LAN then using Ethernet and a switch.


The point of my previous post is that DECA can take MRV traffic off of a LAN (in specific situations,) not that entertainment devices can max out a 100Mb ethernet segment. Whether taking MRV traffic off a segment (that's also used for other devices) is important is entirely dependent on the network infrastructure and the devices being used.


----------



## poppo

sunking said:


> Oddly enough, the defenders of ethernet are in reality backing the reason that deca is being pushed. How many posts have been in here saying basically, "if you upgrade to giga, or add a switch, or properly configure your network, etc, etc" (all paraphrases). The point of deca is you plug them all in, turn them all on, and in golf terms, grip it and rip it.


Ummm...Anyone with even the simplest LAN will have a switch. So 'you plug them all in, turn them all on, and in golf terms, grip it and rip it'. Zero difference in ease if you already have Cat5 cable to the DVRs.



sunking said:


> In reality, ethernet as a protocol is a poor choice for MRV in a typical household environemnt.


Huh? That makes zero sense and is absoluty false. DECA or not, the units are still using TCP/IP.



sunking said:


> We can get this with deca, but in doing so we restrict our maximum bandwidth between nodes and have a max number of nodes we can communicate with. *But we guarantee latency and throughput between nodes.*


Huh? If I'm using a switch (as 99.999% of people using Ethernet would), there is no more latency than with DECA. And with units that don;t have built in DECA, there is yet another conversion layer to add latency. I would say Ethernet actually has less latency than DECA. and throughput is a non issue with a switch.


----------



## veryoldschool

poppo said:


> I would say Ethernet actually has less latency than DECA.


It does, but latency isn't an issue with or without DECA.


----------



## poppo

veryoldschool said:


> It does, but latency isn't an issue with or without DECA.


Agreed. But someone else seems to think it matters, or is somehow more significant with Ethernet.


----------



## DarkLogix

poppo said:


> Ummm...Anyone with even the simplest LAN will have a switch. So 'you plug them all in, turn them all on, and in golf terms, grip it and rip it'. Zero difference in ease if you already have Cat5 cable to the DVRs.
> 
> Huh? That makes zero sense and is absoluty false. DECA or not, the units are still using TCP/IP.
> 
> Huh? If I'm using a switch (as 99.999% of people using Ethernet would), there is no more latency than with DECA. And with units that don;t have built in DECA, there is yet another conversion layer to add latency. I would say Ethernet actually has less latency than DECA. and throughput is a non issue with a switch.


well technicaly Ethernet is not TCP/IP
but does almost always have TCP/IP over top

ethernet defines the most common layer 2 communication
the most common the layer 1 is UTP (unshielded twisted pair) cable (but Coax was used for 10Base networking way back when)
and TCP/IP is the most common layer 3

but all 3 can be used with different tech, ethernet can run over fiber, TCP/IP can run over setups that don't use ethernet for Layer2, and tons of things use UTP for non-ehternet applications, and then sometimes people use STP cable instead of UTP

some forms of fiber don't use ethernet for layer2 communication as removing it can lower the lag on really long hauls (on such setups the interfaces don't have MAC addresses as that is part of ethernet)

sorry for going OT its just starting to annoy me that people think ethernet = UTP-Ethernet-TCP/IP when its only a part of it (and Cat7 cable is actually S/STP cable not UTP)


----------



## veryoldschool

poppo said:


> Agreed. But someone else seems to think it matters, or is somehow more significant with Ethernet.


"Or some" simply want to argue "numbers" that are meaningless to this.
Good ethernet and DECA both work well.
DECA can be easier [as I posted], but if you already have ethernet, "use it". :lol:


----------



## sunking

poppo said:


> Ummm...Anyone with even the simplest LAN will have a switch. So 'you plug them all in, turn them all on, and in golf terms, grip it and rip it'. Zero difference in ease if you already have Cat5 cable to the DVRs.


That's interesting as by definition the simplest lan does not have a switch. The main advantage of DECA for directv is that they start at the lowest common denominator and can assume nothing.



poppo said:


> Huh? That makes zero sense and is absoluty false. DECA or not, the units are still using TCP/IP.


The bane of ethernet is collision management. No matter what you do you can always get a denial of service due to flooding. And this can happen in a way that is completely legitimate as far as protocols are concerned. For this to happen with DECA you need to break protocol.


poppo said:


> Huh? If I'm using a switch (as 99.999% of people using Ethernet would), there is no more latency than with DECA. And with units that don;t have built in DECA, there is yet another conversion layer to add latency. I would say Ethernet actually has less latency than DECA. and throughput is a non issue with a switch.


I'd actually take that bet that 1 in 10,000,000 people have just a hub and not a switch or maybe just go directly into their modem, whether they know it or not. To be frank I think that many if not most households spend extra money for switches that really aren't needed.

Ethernet may have less latency. Or it may not. I'll even say that it most certainly does under normal conditions in a typical environment. But it can not guarantee anything. And from a customer support stand point it's a nightmare.

I'm not trying to advocate not using it. If you've got the wires go for it. You'll probably see no difference. But I will say that DECA is a better fit.


----------



## DarkLogix

sunking said:


> The bane of ethernet is collision management. No matter what you do you can always get a denial of service due to flooding. And this can happen in a way that is completely legitimate as far as protocols are concerned. For this to happen with DECA you need to break protocol.


a DOS attack is not a layer2 attack (short of a Layer2 loop, ie pluging a switch into itsself and that can occur with 2 Decas)(and it would require them having access to your network physically and would have instant issues)

internet based (D)DOS attacks are layer3 and collisions aren't a layer3 occurance they're a layer2 occurance and can't happen on a full duplex switch

many (D)DOS attacks are a form of exploiting TCP/IP such as SYN floods which cause issues as the device is trying to reply to them and small packets take more CPU per bit to deal with than large packets and syn packets are very small but are also a normal part of TCP but not normally the only packet a client device is sending

there are allso buffer aimed attacks which fill the transmit buffers on an interface (but is still not a collision)

a collision is when 2 devices are sending data on the same pair of wires, in full duplex 1 pair is for sending and 1 pair for receiving (unless its gig then all 4 pairs are used 2/send 2/receive) and as a switch handels the crossover a device will not receive on the send pair

in a hub network if 2 devices send at the same time then they will collide on the hub but hubs should be outlawed and used as shooting clays

in a half duplex switched network collisions can occue if a device is sending to another device thats also sending something

but in a full duplex switched network collisions are impossible as when device 1 sends it can receive on the other pair and the switch will handle all the crossover

ok by definition the absolute simpilest network would be a 1 pair crossover cable linking 2 computers, and in such a network collisions would be common, but as things are now it would be very odd to have a 1 pair twisted pair crossover cable and if you tried to make such a cable many devices wouldn't even accept it aswell as you would likely have lots of NEXT (near end cross talk) as you'd have to remove the 1 pair from the others and if you weren't cerfull you'd untwist it to much although then there wouldn't be another pair to get the cross talk

but yes csma/cd is a very crappy collision handling method but luckily it isn't even needed in a full duplex switched network, TDMA is better but lowers the bandwidth per device


----------



## veryoldschool

Maybe we should find a networking forum for all of this nonsense. :nono:


----------



## lugnutathome

veryoldschool said:


> Maybe we should find a networking forum for all of this nonsense. :nono:


Aside from the decaying equine carcass that is the basis of the thread, much of the content (once past the various personal feather ruffling moments) is enlightening and informative.

Before this round of D vs E I had a fairly high level understanding of networking and not all I thought was exactly correct. Through this thread much has become clear and though I wouldn't cut it as a network engineer now I feel far better informed on how networking functions with respect to my needs in my infrastructure.

Interestingly there has been far more detail conveyed on Ethernet than on DECA so I can see where it may seem bothersome in what should be DECA "world" but as Direct TV has chosen to implement a technology that doesn't scale out for some of us, knowing and fully understanding what our options are is very helpful. Especially given we have to support our own.

Don "learning is always a good thing" Bolton


----------



## veryoldschool

lugnutathome said:


> Aside from the decaying equine carcass that is the basis of the thread, much of the content (once past the various personal feather ruffling moments) is enlightening and informative.


While it may be that for some, it is getting way beyond the needs of a "Connected Home", and almost should be spun off into its own forum.


----------



## DarkLogix

veryoldschool said:


> While it may be that for some, it is getting way beyond the needs of a "Connected Home", and almost should be spun off into its own forum.


But one thread does not a forum make


----------



## veryoldschool

DarkLogix said:


> But one thread does not a forum make


And shouldn't that be a clue? !rolling


----------



## DarkLogix

veryoldschool said:


> And shouldn't that be a clue? !rolling


Its close enough to fit in connected home and hopefully draw the ethernet questions away from forming other threads but its not enough to form another sub forum imo


----------



## veryoldschool

DarkLogix said:


> Its close enough to fit in connected home and hopefully draw the ethernet questions away from forming other threads but its not enough to form another sub forum imo


"My point is"...
The detail of ethernet protocol, layer control, stacks, etc., isn't anything we have control over, or could make changes to.

The thread topic/title is DECA vs Ethernet, so this becomes one sided. DECA information is limited and ethernet is kind of pointless.

What has been stated many times is:


Switches for ethernet work better then [evil] hubs.
Don't overload any segment of your ethernet.
A good working ethernet works as well as DECA.
If you don't have either in place to start with, DECA may be simpler/easier and is supported by DirecTV.


----------



## DarkLogix

ya well knowledge is almost never a bad thing
Knowledge is power ecept when it scares you.


----------



## veryoldschool

DarkLogix said:


> ya well knowledge is almost never a bad thing
> Knowledge is power ecept when it scares you.


The same thing could be said about _quantum mechanics_, but it would have little to do with a connected home.

This just seems to have turned into a geek fest by the ethernet experts.


----------



## lugnutathome

veryoldschool said:


> While it may be that for some, it is getting way beyond the needs of a "Connected Home", and almost should be spun off into its own forum.


And now I see your point!

Don "mine is atop me head" Bolton


----------



## Spanky_Partain

So far the only complaint I have about DECA is that I have replaced two DECA boxes in my environment. Even with that said I have had to replace one 5 port Gb switch as well.

At least the DECA boxes were free!

Think I will go back to a rotary phone and then all worries will be resolved. :lol:


----------



## lugnutathome

DarkLogix said:


> ya well knowledge is almost never a bad thing
> Knowledge is power ecept when it scares you.


Nobody is scared here as far as I can see. I for one have truly appreciated your knowledge on the subject but the problem is we keep weighing "one vs the other" when unless we had a solid hard wired infrastructure in place for other reasons it's moot.

In that context I get where the details of Ethernet should be in their own forum. Some of us in the group share many complex concepts and ideas and sometimes we get ahead of where the bulk of the group is, or where a person whom had asked a question really wanted to go. It confuses the question for many.

I have no doubt that Ethernet's scalable and "tunable" infrastructure offers a superior technical solution however it is to a problem in this context a very few of us have. DirectTV came up with a controlled infrastructure which within it's boundaries is simple and transparent to the consumer.

There are those very few of us that have infrastructure requirements that exceed the boundaries engineered into Direct TV's DECA and since in the end we're just talking IP packet transferring here, Ethernet is gold in those instances cause gee well that is what it was made for.

I truly thank you for sharing your knowledge on the subject and think your idea of a sticky is an excellent one! There is much knowledge here for those of us that need it (I have been one).

There are many here whom could care less and have grown irritated at this recurring topic when logically (to them) DECA handles nearly everyone's needs so moving this to it's own forum should stop the "well if you had DECA you wouldn't need to deal with that" (paraphrased) and we might lose some of the emotionally charged posts.

Again I think what you have said is incredibly valuable.

Don "Ethernet is superior in it's flexibility but in this context it's self service and that's problematic for most everyone" Bolton


----------



## dpeters11

"veryoldschool" said:


> [*]Switches for ethernet work better then [evil] hubs.


I wouldn't use one in this case, but hubs aren't always evil. I use one myself in my setup.


----------



## veryoldschool

dpeters11 said:


> I wouldn't use one in this case, but hubs aren't always evil. I use one myself in my setup.


Well if not "evil", they're not the best to stream MRV through, since they can swamp the network needlessly.


----------



## dpeters11

"veryoldschool" said:


> Well if not "evil", they're not the best to stream MRV through, since they can swamp the network needlessly.


Agreed, I wouldn't use them in the majority of situations.


----------



## harsh

sunking said:


> That's interesting as by definition the simplest lan does not have a switch. The main advantage of DECA for directv is that they start at the lowest common denominator and can assume nothing.


Regrettably, DECA does make some assumptions about wiring. The worst one may be that all existing outlets are home run and/or all existing splitters are easily found and replaced.


> The bane of ethernet is collision management. No matter what you do you can always get a denial of service due to flooding. And this can happen in a way that is completely legitimate as far as protocols are concerned. For this to happen with DECA you need to break protocol.


This is a pretty thin stretch of reality. Unless you've got some manner of high zoot client-server data processing or video production activity going on with your home network, there's little chance of anything resembling flooding.

DECA has limitations because every node uses the entire network to communicate with any other node and the other node must use the same path to communicate back. In switched Ethernet, it is entirely possible (even likely) that you have a full bandwidth path both to and from each and every node (in the classic MRV sense where one client is having a conversation with exactly one server).

It is not all that difficult to figure out if there are any hubs in the LAN and it is cheaper than a DECA adapter to replace each one.

MoCA/DECA is a nifty way of using coax to do something that it wasn't particularly well suited for otherwise. It has decided limitations in order to make this happen and for many, those limitations are survivable. Surely the greatest advantage is getting around having to qualify techs for LAN wiring but that's certainly no recommendation for its use otherwise.

Ethernet is ultimately a more flexible solution for the home theater where you're going to need at least one other LAN connection at each TV anyway as streaming content becomes more popular. I've got five hardwired devices in my main TV setup and I suspect that some people have more than that. My bedroom setup has three devices (not including the computer that is also wired in).


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## veryoldschool

harsh said:


> DECA has limitations because every node uses the entire network to communicate with any other node and the other node must use the same path to communicate back.


Are you ever going to get off your soapbox? You know SO little about DECA. :nono:
Will you only get off it when your service provider starts using MoCA?


The MoCA 1.0 offers greater than 100 Mpbs MAC rates and 270 Mbps PHY rate.
MoCA 1.1 is an extension to MoCA 1.0 and offers 175 Mpbs MAC rates (PHY rate remains the same), parameterized quality of service (PQoS) for provisioning and bandwidth management of real time data requests for video applications, and 16 node network extension.
The MoCA 2.0 specification is available to all members and provides the following:
Two performance modes, Basic and Enhanced, with 400 Mbps and 800 Mpbs, MAC or actual throughput rates, respectively;
PHY rates for each mode are 700 Mbps and 1.4 Gbps, respectively;
Improved reliability with one packet error in 100 million packets, and a lower latency of 3.5ms;
Backward interoperability with 1.0 and 1.1 devices. MoCA 2.0 will recognize 1.0/1.1 devices on the network, and vica versa, without any impairment or degradation to performance.


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## poppo

veryoldschool said:


> "What has been stated many times is:
> 
> 
> Switches for ethernet work better then [evil] hubs.
> Don't overload any segment of your ethernet.
> A good working ethernet works as well as DECA.
> If you don't have either in place to start with, DECA may be simpler/easier and is supported by DirecTV.


I agree 100%.

The only disagreement I have with anyone is with those who claim that DECA somehow frees up your LAN more than Ethernet which is a false statement. And in my case where I have a nomad in the mix attached to the the same switch as my DVR's, they all talk happily between themselves and have zero impact on any other LAN traffic. At least until the point that that the nomad sends data to the iPad via the wireless router. But the same would hold true in a DECA world.


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## DarkLogix

dpeters11 said:


> I wouldn't use one in this case, but hubs aren't always evil. I use one myself in my setup.


Hubs are evil scum of the earth

the only use for a hub is for packet sniffing


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## Rtm

If got a H25 could I hook it up to my unsupported setup with a deca in the wiring closet one to the switch and one cable to the satellite coming off the coax that feeds to the H25?


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## harsh

veryoldschool said:


> Are you ever going to get off your soapbox? You know SO little about DECA. :nono:


If you have issue with something I said, address it. If not, be bitter on your own time.


> Will you only get off it when your service provider starts using MoCA?


My opinion of MoCA won't change based on who does or doesn't offer it (unless so few providers offer it that it doesn't reach critical mass). The importance of critical mass is whether or not any RVU or Sling clients arrive with DECA/MoCA out of the box.

Many of those features you list are comparable with HomePlug or HomePNA. Few, if any, come anywhere close to Gigabit Ethernet. If you're considering installing one or the other, why go with the one that is limited in the way that MoCA is?

Pity the soul that doesn't have an HR24 to analyze their DECA network.


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## sigma1914

harsh said:


> ...
> 
> Pity the soul that doesn't have an HR24 to analyze their DECA network.


Ironic...coming from a non DirecTV sub who doesn't have a HR24, DECA, or any DirecTV stuff to analyze yet ALWAYS has a comment on it.


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## harsh

Rtm said:


> If got a H25 could I hook it up to my unsupported setup with a deca in the wiring closet one to the switch and one cable to the satellite coming off the coax that feeds to the H25?


Are you looking to connect your existing DECA network to the Internet or just connect an H25 to the Internet?

Either way, you'll need to pop for a Internet Connection Kit.


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## bjamin82

Personally I think DECA is way more reliable for MRV than the home network. My old house I had wires everywhere, no wireless and it dropped on occasion in the middle of a show... with DECA, its flawless.


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## Sixto

I had 7 receivers and nomad all attached to a Gig Switch, all was fine.

With the success of DECA, and possibly the trend to DECA-only devices such as the H25 (I now have one), I decided that it was probably a good time to transition to DECA.

I picked up a CCK from Solid Signal and made the switch to DECA (already had a SWiM-16 and cascaded SWiM-8).

Have been DECA for about a week now, and all is great, no issue that I've noticed, and alot less wires at the Switch.  (No longer a real need for the 24-port Gig Switch, all could easily now fit in a 16 port).

I've especially enjoyed the comfort of the DECA diagnostic screens on the H24/H25/HR24/HR34 to show the signal levels and bandwidth between devices. Besides DECA, it's been nice to be able to judge the quality of the cabling between devices.

While I already was somewhat networking knowledgeable, I've also enjoyed the details discussed in this thread, some good stuff.


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## veryoldschool

harsh said:


> Many of those features you list are comparable with HomePlug or HomePNA. Few, if any, come anywhere close to Gigabit Ethernet.


What a nit wit.
HomePlug, by it's nature isn't even using twisted pair, but uses the power lines within the home, to carry the RF signals. Because of this it's completely dependent on a wiring structure that was never intended to be used this way and may not work between two outputs in the SAME ROOM, if they're on two different circuit. Even when on the same circuit, they don't have much range.
DECA doesn't suffer this, since it's used on cables intended for RF, and therefore has range that HomePlug can't even dream of.

We could run fiber in our home too, which would exceed "your precious" Gigabit Ethernet, but this would far exceed then need for MRV, just like Gigabit Ethernet.


> Pity the soul that doesn't have an HR24 to analyze their DECA network.


 Pity the fool that doesn't know what they're posting about.
ALL DECAs have the means to know the status of the DECA. Receivers with in internally can show more information, while each external DECA reports its status through LEDs and their color.
"Of course I know this", because I have this, while you just post crap about things you have no clue of or experience with.
"nit wit"


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## dpeters11

"DarkLogix" said:


> Hubs are evil scum of the earth
> 
> the only use for a hub is for packet sniffing


I am one port short on my WNDR3800. Rather than buying a switch, I plugged a hub into it for my PS3 and Roku. Only one of which is used at a time.


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## dpeters11

"Rtm" said:


> If got a H25 could I hook it up to my unsupported setup with a deca in the wiring closet one to the switch and one cable to the satellite coming off the coax that feeds to the H25?


The H25 requires SWM and has the DECA functionality built in.


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## DarkLogix

veryoldschool said:


> We could run fiber in our home too, which would exceed "your precious" Gigabit Ethernet, but this would far exceed then need for MRV, just like Gigabit Ethernet.


Well if you ran fiber unless you did some harder to make use of implementation of it (harder becase most fiber transivers that would not require 5-6 figure cost equ still use the ethernet protocal) you'd still be using ethernet

and you can do 10Gbase-T over copper but finding a 10Gbase-T switch is still hard to find as 10Gbase-X is much easier to find.

I wouldn't run fiber to a enduser device simply because its less resistant to damage and copper patch cables are cheaper

one day I will however run 10Gbase-T via Cat7 cable in my home but not till cisco has a SFP+ for 10Gbase-T, or a 2900 model that has 20+ 10Gbase-T ports


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## veryoldschool

DarkLogix said:


> Well if you ran fiber unless you did some harder to make use of implementation of it (harder becase most fiber transivers that would not require 5-6 figure cost equ still use the ethernet protocal) you'd still be using ethernet
> 
> and you can do 10Gbase-T over copper but finding a 10Gbase-T switch is still hard to find as 10Gbase-X is much easier to find.
> 
> I wouldn't run fiber to a enduser device simply because its less resistant to damage and copper patch cables are cheaper
> 
> one day I will however run 10Gbase-T via Cat7 cable in my home but not till cisco has a SFP+ for 10Gbase-T, or a 20600 model that has 20+ 10Gbase-T ports


The point I was trying to make:
Currently the Bugatti Veyron is the world's fastest street car at 267 MPH. If I needed to pick up a quart of milk, driving a Bugatti wouldn't make the trip any quicker to the corner 7/11.

A Gigabit ethernet is the same for MRV.
DECA is fast enough for the task it's made for. It doesn't require additional wiring.
It isn't going to replace ethernet for computers, nor be used in a business environment for networking.

For "the Basset" to barf HomePlug as a comparison to DECA is nonsense.


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## harsh

veryoldschool said:


> HomePlug, by it's nature isn't even using twisted pair, but uses the power lines within the home, to carry the RF signals.


Do they not offer comparable performance?

Theorizing about why a technology must be inferior doesn't change what has been measured.

I think you'll find that Gigabit fiber is not decidedly better performing than Gigabit Ethernet and Gigabit Ethernet has a much bigger bang for the buck while still meeting the need for networking the entire home; something that MoCA/DECA cannot claim.


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## DarkLogix

veryoldschool said:


> The point I was trying to make:
> Currently the Bugatti Veyron is the world's fastest street car at 267 MPH. If I needed to pick up a quart of milk, driving a Bugatti wouldn't make the trip any quicker to the corner 7/11.
> 
> A Gigabit ethernet is the same for MRV.
> DECA is fast enough for the task it's made for. It doesn't require additional wiring.
> It isn't going to replace ethernet for computers, nor be used in a business environment for networking.
> 
> For "the Basset" to barf HomePlug as a comparison to DECA is nonsense.


Ya I was only mentioning it as I'm growing more annyoed by people thinking that ethernet is only on twisted pair

But driving the Bugatti to get milk would be more fun


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## veryoldschool

harsh said:


> Do they not offer comparable performance?


No they don't!!!!!!
You pick the worst solution out there for home networking and then equate it to DECA. :nono:
"If you had a clue" about what you're posting, you would know this.

Gigabit ethernet will handle more than DECA, "no question".
If I had to use/install only one network in my home, I would use ethernet and switches.
Since I don't need to, I use ethernet for my computer(s) as I can transfer large files quicker, and I use DECA between all my receivers for MRV, since my cabling is already there and functions "just as well" as ethernet would.


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## veryoldschool

DarkLogix said:


> But driving the Bugatti to get milk would be more fun


While I haven't driven one, when I used to have my Lotus, a trip to get a quart of milk, sometimes would take longer than it should, as I'd needed to have "a discussion with local law enforcement" along the way.


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## DarkLogix

veryoldschool said:


> While I haven't driven one, when I used to have my Lotus, a trip to get a quart of milk, sometimes would take longer than it should, as I'd needed to have "a discussion with local law enforcement" along the way.


Well thats driver error
just be cause you can do 100+MPH doesn't mean you should nor does it mean you can't have fun wile not angering local enforcement
when I get milk in my mustang I don't have to have a chat with local law enforcement unless I'm being foolish


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## veryoldschool

DarkLogix said:


> Well thats driver error
> just be cause you can do 100+MPH doesn't mean you should nor does it mean you can't have fun wile not angering local enforcement
> when I get milk in my mustang I don't have to have a chat with local law enforcement unless I'm being foolish


What I found wasn't that I was speeding, but that I was quicker off the line than they "thought" I should be, and half the time, they simply wanted to know what I was driving, as it was a very uncommon model [one of less than 350 exported into the states].
When you get close to 10 LBs/horsepower, you "tend to standout".


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## DarkLogix

veryoldschool said:


> What I found wasn't that I was speeding, but that I was quicker off the line than they "thought" I should be, and half the time, they simply wanted to know what I was driving, as it was a very uncommon model [one of less than 350 exported into the states].
> When you get close to 10 LBs/horsepower, you "tend to standout".


well if we use manufacture specs then 10LB/HP isn't that raddical
2006 Mustang GT 300HP 3500LB so about 11.67 LB/HP
but yes I know the lotus is an awsome car

so now we've gone from networking to cars

now the ariel atom 500 thats LB/HP that will be unavoidable (500HP and maybe 1000LB)


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## veryoldschool

And now maybe it's time for:

:backtotop

Since this started with using a network that had enough bandwidth to handle the tasks, and "faster" isn't always "better".


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## zx10guy

DarkLogix said:


> Well if you ran fiber unless you did some harder to make use of implementation of it (harder becase most fiber transivers that would not require 5-6 figure cost equ still use the ethernet protocal) you'd still be using ethernet
> 
> and you can do 10Gbase-T over copper but finding a 10Gbase-T switch is still hard to find as 10Gbase-X is much easier to find.
> 
> I wouldn't run fiber to a enduser device simply because its less resistant to damage and copper patch cables are cheaper
> 
> one day I will however run 10Gbase-T via Cat7 cable in my home but not till cisco has a SFP+ for 10Gbase-T, or a 2600 model that has 20+ 10Gbase-T ports


You can actually run 10Gbase-T over Cat6a and even Cat6 with distance constraints.

Per my other post in the MRV sticky in reply to your post, you cannot get a 10Gbase-T SFP+. The power demands for 10GBase-T on an SFP+ port precludes this.

What Cisco 2600 model are you referring to? 2600s are routers. And the only models I know of that have 10G ports that are not uplinks are the Nexus line of switches (ie Nexus 5000).


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## DarkLogix

zx10guy said:


> You can actually run 10Gbase-T over Cat6a and even Cat6 with distance constraints.
> 
> Per my other post in the MRV sticky in reply to your post, you cannot get a 10Gbase-T SFP+. The power demands for 10GBase-T on an SFP+ port precludes this.
> 
> What Cisco 2600 model are you referring to? 2600s are routers. And the only models I know of that have 10G ports that are not uplinks are the Nexus line of switches (ie Nexus 5000).


that was a typo I ment 2900 I thought I had corrected the typo, and yes I know 2600's are routers and are over 3 generations old

but in that part of the post I was refering to a switch that does not yet and might not for a long time exist

and yes you "can" run 10Gbase-T on cat6a and cat6(not to full spec) but to be proper you should use cat7 as cat6a was only added as a lesser way than using cat7
by full spec I mean upto full distance thats in the spec, ie 100m


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## zx10guy

DarkLogix said:


> that was a typo I ment 2900 I thought I had corrected the typo, and yes I know 2600's are routers and are over 3 generations old
> 
> but in that part of the post I was refering to a switch that does not yet and might not for a long time exist
> 
> and yes you "can" run 10Gbase-T on cat6a and cat6(not to full spec) but to be proper you should use cat7 as cat6a was only added as a lesser way than using cat7
> by full spec I mean upto full distance thats in the spec, ie 100m


Well, definition of proper is subjective. If you're talking about typical datacenter deployments, the connection lengths are far less than the 100M spelled out as the full distance spec. So you would be able to use Cat6/6a within a rack between device and the 10 Gig top of rack switch. You can even run uplinks between switches down the row of racks or even from rows to the aggregation/core switching depending on how spread out the racks are.

So the implication of "proper" as you have used is misleading.

As far as the 2960 series seeing 10 GigE for access ports instead of just for uplinks, you'll be waiting a very long time. I would see Cisco pushing the 3750Xs to have this way before the 2960s. The 4900Ms do have 10GigE capability for both fiber and copper. But you're dealing with oversubscription with the 10GbE copper module to the tune of I think 2:1. So in the traditional Catalyst line, the 4900M is the only non-chassis based switch to have 10GigE non-uplink ports. If you want multiple 10GigE access ports, you'll have to go to the Nexus line for top of rack switching.

ETA: In home environments, I would be highly suprised to see full 100M cabling supporting 10GigE. Just can't see this even for uber geek home deployments. I've got 10GigE running on three servers in my home network on a single 10GigE switch all within my "server" room. Granted, I'm not running any category cabling as I'm connecting the servers to the 10GigE switch with 3M passive twinax cabling.


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## zx10guy

Something else I wanted to add to this discussion of DECA vs Ethernet. I haven't done a deep dive into how the MRV protocol works between DVRs. But if it's multi-cast/broadcast based, then there can be advantages of isolating the MRV traffic from the rest of the LAN. Multicast traffic can easily bring a network to its knees depending on the frequency of the broadcasts along with other traffic running on the LAN. As many here are probably of the uber home user type, there may be other types of multicast traffic running on the network such as media/music servers.

Managed switches would be a solution to help with this type of broadcast traffic by using VLANs to isolate the traffic or the use of IGMP.


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## veryoldschool

zx10guy said:


> Managed switches would be a solution to help with this type of broadcast traffic by using VLANs to isolate the traffic or the use of IGMP.


Which was posted at least 100 replies back in this thread.

This thread seems to have simply turned into a place for anyone with networking experience to come in and pontificate, with little to do with the original topic, or for that matter this sub forum, being a "Connected Home".
Few homes are going to have the hardware/network that is currently being posted about.


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## Stuart Sweet

I have to completely agree. This thread is closed; if you have specific technical questions please start a new thread.


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