# Network Cross-Traffic Questions



## CJTE (Sep 18, 2007)

I'm looking at changing my network infrastructure and wanted to check on some things.

Equipment:
Motorola Surfboard (HEREIN: Modem)
D-Link DIR-628 Wireless Router (HEREIN: Primary Router)
D-Link DGL-4300 Wireless Router/Gigabit LAN (HEREIN: Gigabit router)
Trendnet TEG-S80g Gigabit switch (HEREIN: Gigabit switch)
Some other misc. 10/100/Wireless routers/switches

Up until recently, I've always run 2 separate networks. One 'public' network with my roommates iPhone and another roommates Desktop, and another 'private' network with whatever other equipment I have.

This gives me a hard firewall between my roommates desktop (he's a big fan of illegal wares. I'm a big fan of not catching whatever his machine may be infected with at any given time), but also causes issues with stuff like the HD DVR's being double-natted.

Lately I've been considering putting the HR20's, XBox, and my roommates desktop on the same network (the "public" one) to access his media shares. This would solve the Double-NATting, But then HR20's wouldn't be able to connect to my media server. So then I have to put my media server on the "public" network. Not as big of a deal, because I can still see the "public" network from the "private" network, but the "public" network can't see me.

But the "public" network is on the primary router at 100mb/s. Whereas the rest of my equipment is on the "private" network at 1000mb/s. I push a lot of files around in the gigabyte range so the higher bandwidth is important to me. That means I would have to install a second NIC in my media server (one to run on the public network for the HR's and Xbox, and one to run on my network to push my files around).

Then I started thinking maybe it would just be easier to run everything on the one public network. That way I don't have to worry about daisy chaining routers, etc. I could put my machines on a gigabit switch.

But then I wonder what the cross-talk effects are going to be? If I initiate a file transfer from my laptop to my media server (both on the gigabit switch), what kind of latency issues am I going to hit being that I'm connected to everything else?


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## Grentz (Jan 10, 2007)

Nothing, a proper switch will work just fine like you stated at the end. Cross talk is a non issue unless those devices are actively talking with others (which is not cross talk, just standard talk  ). You should not be bottlenecked by the switch at all if it is a decent gigabit switch.

In any event, why worry about the HRs being behind double NAT? Functionally there should be no difference at this point. If you want to get the "ok" for network services, just port forward from your first router to your second router's "public" IP, and then from your second router to your HRs.


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## CJTE (Sep 18, 2007)

Grentz said:


> Nothing, a proper switch will work just fine like you stated at the end. Cross talk is a non issue unless those devices are actively talking with others (which is not cross talk, just standard talk  ). You should not be bottlenecked by the switch at all if it is a decent gigabit switch.
> 
> In any event, why worry about the HRs being behind double NAT? Functionally there should be no difference at this point. If you want to get the "ok" for network services, just port forward from your first router to your second router's "public" IP, and then from your second router to your HRs.


I don't know how "good" of a switch this is. It's a "green" switch (auto-senses power and turns off any ports that aren't in use) and I got it rather cheap so, we'll see over time.
In re: to the latter, Ive had problems (in general) trying to port forward from one router to another (to a device behind the second) and there were a few other people here who were having problems doing that for the HD DVRs. It sounds silly, but that's what it was.

What prompted my question is, in a corporate environment, when imaging over the network (with GHOST), we've (my old I/T boss and I) found that it's faster to let the machines get an IP, and then unplug the uplink before pushing out the image. If we leave the uplink plugged in, 10GB of data to 32 machines can take up to an hour longer (over a 100mb network), and that's with a Cisco smart switch.

But thanks for the reply.


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## Grentz (Jan 10, 2007)

That sounds like other issues at your office TBH. 

As far as port forwarding. Make sure you are forwarding to the correct IPs, it gets confusing, as it all has to be done perfectly. (make sure to forward from the first router to the second routers WAN IP (which will be one in the first routers private network range). Also make sure you don't have triple NAT (your modem, router 1, router 2).

I cannot imagine you are going to be moving enough to overload your network. Other things tend to bottleneck you way before you will get slowed by your network in a home environment. (Disks being one major one)


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## CJTE (Sep 18, 2007)

Grentz said:


> That sounds like other issues at your office TBH.
> 
> As far as port forwarding. Make sure you are forwarding to the correct IPs, it gets confusing, as it all has to be done perfectly. (make sure to forward from the first router to the second routers WAN IP (which will be one in the first routers private network range). Also make sure you don't have triple NAT (your modem, router 1, router 2).
> 
> I cannot imagine you are going to be moving enough to overload your network. Other things tend to bottleneck you way before you will get slowed by your network in a home environment. (Disks being one major one)


I'll take the hit on that one. The managed switches at the office I was referring to earlier are done at a higher corporate level so I have no control over whats going on inside...

In re: to port forwarding... I definetly understand.
Forward Port 80 from (primary routers IP) to (Secondary Routers IP)
Forward Port 80 from (Secondary Routers IP) to (Client Device)
Open firewall on client device.

In theory it should work. Sometimes it just *doesnt*. :lol:


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## Grentz (Jan 10, 2007)

and Directv Network Services is definitely not the best to try it with. It is unreliable at best 

I have one receiver that works 100% with it and one that is on and off, even though both are setup identical (just different port numbers)


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## CJTE (Sep 18, 2007)

Grentz said:


> and Directv Network Services is definitely not the best to try it with. It is unreliable at best
> 
> I have one receiver that works 100% with it and one that is on and off, even though both are setup identical (just different port numbers)


and just out of curiosity...
Did you try reversing the port numbers?
:lol:


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## funhouse69 (Mar 26, 2007)

Sorry I'm late to this question but I agree with everything that has been said. Obviously a single switch will be easier but completely understand the two networks as I've always done that for my wireless devices and VPN in if needed. 

I don't know what type / size files you move around your network but I am moving around full video files which are many GB in size along with thousands of 25MP Digital Files all the time and I have no issue. I am however copying these files to and from Client Machines to 10TB+ RAID Boxes which can pump out some serious bandwidth. 

As mentioned the only time you are going to see issues is when you are doing multiple copies from the same systems and that is just the way it goes because the system can't keep full bandwidth going to each device. This can be improved in various ways like faster disk subsystems and more memory for cache but each can be somewhat costly.

Sure there are differences between switches but in a home network are you really going to notice? I guess that depends... I bought a used 24 Port Dell Managed Gig Switch off e-bay and I also have a Netgear GS108T 8 Port Managed Switch in my Entertainment Center that is connecting my HTPC, My Livingroom PC and my 2 HR-20's.

Are switches of this caliber needed in a home? Of course not but I did put a Netgear 5 Port Gig Switch in my Entertainment Center before the Netgear one and it had many issues where traffic just seemed to drop off for no apparent reason. I replaced it and it did the same thing, hasn't happened once with my Netgear and its been in place for almost 2 years now (been up for 188 days since I last powered it off). 

I specifically went with Managed Switches so I could see what was going on in my network, I have SNMP Running on all of my network switches and firewalls so I can do just that. 

Yup I'm a network guy and that is just what we do isn't it


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## Grentz (Jan 10, 2007)

CJTE said:


> and just out of curiosity...
> Did you try reversing the port numbers?
> :lol:


Yup, still finicky :lol:


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