Local networks and the 3800-HGV

[Computer-Joe ACE - Master]

I hope someone will find this useful or informative. 

My LAN/DSL setup before U-VERSE, consisted of a non-wireless router with 4 port switch behind the SBC/ATT DSL modem in bridge mode in my office on the second floor.  I ran an all hardwired network (didn't trust wireless way back then and yes I made my wife plug here laptop in all the time). The router fed a 5 port switch in my office plus a feed that went all the way to the basement to another switch. The switch in my office fed my main computer, my graphics/printserver computer, and up to 2 more "Guest" computers on the work bench (I build, upgrade and repair computers to help supplement my disability). The switch in the basement fed a couple of wall jacks in living and dining rooms (for laptop), another switch in my wife's first floor office, and another switch out in the garage (underground feed). The switch in my wife's first floor office is for a plug-in for her laptop and a Lan based printer which is controlled by the printserver/graphics computer on second floor. The switch in the garage (my wife's quilting studio) is for a plug-in for her laptop and a computer that runs her CNC-based quilting machine. All switch interconnects were done using the MDI ports for proper up-linking. The router's switch and all other switches (not hubs) were/are Linksys 10-100 full duplex.

Every thing hummed along smoothly (internet, cross-network backups, streaming, Lan based printing) until I removed my router and modem (during the UV install) and up-linked my basement switch (they stuck my RG in the basement) in to one of the 3800's UTP ports, then all hell broke loose. The first and most apparent thing I noticed was that every live port on every switch on my LAN started flashing like crazy. I figured, OK that must be the DHCP on the RG giving out addresses, but the traffic never stopped so the installer called T2 and let me talk to them. After explaining what the problem was and describing my network setup, the T2 tech said that my network (referring to my 4 switches) was, and I quote, "scary" and that they only support one computer and no networking. So after the install I have IPTV (and that's a whole other can of worms) and a home network that's too busy to do any networking. Backups choked, streaming stuttered, print jobs timed out, and internet was slow (and no help from UV techs).

So, here's what I've learned. The 3800-HGV is at it's best a (H)ome (G)ateway for (V)ideo/(V)oip. IPTV and VOIP are what it routes best and what it gives priority to. Home computer networks are always secondary. If you already have a large network (more than 1 computer and Lan based printer) DO NOT rely on the 3800 for switching or routing duties for your network.

TCPIP is what your computers use to communicate with each other and the internet. HPNA is the technology (protocol) used by the UV service for IPTV. It appears to be a broadcast and respond technology using ICMP or IGMP to ensure Quality Of Service (like a keep-alive ping for your old dialup connection). The 3800 not only broadcasts this excessive amount of traffic over the coax connections (for coax connected STBs) but the UTP connections as well (for CAT5 connected STBs). So with the RG and the STBs chattering away in HPNA over your local network, your computers can hardly get a byte in edgewise in TCPIP.

I think the only connections with the RG that are free of HPNA traffic are the USB connection, a wireless connection, or a UTP connection set to DMZ in the RG.

With this in mind, I went out and purchased my own 54G (wireless security has improved and I was tired of my wife complaining) router with 4 port switch, plugged its WAN port to a UTP port on the RG and set it to DMZ and hung the rest of my network off the new router with a different IP range than the RG and the STBs. This cleared every thing up for my local network and improved internet access as well.

P.S.. IMHO Those of you who think your saving money or getting away with something by plugging a computer or game console into the UTP port on the STB which is connected to the RG by coax, and calling it a network extender, instead of buying another switch or running some more CAT5 are just degrading the communications for both devices.

[callmeox ACE - Professor]

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Computer-Joe wrote:

I hope someone will find this useful or informative. 

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How about neither? 

I'm not going to go line by line in your post to refute what you have stated as many people use the wired side of the RG successfully. Flashing ports don't necessarily indicate that the switch can't handle anyone else's traffic. I have more than one computer as well as a LAN based printer and I've had zero connectivity issues between nodes.

What the tech should have told you is that the video portion of Uverse is multicast and this is how the RG can feed multiple TV's the same video signal concurrently.  Yeah, multicast is chatty, but it doesn't overwhelm the network one bit.

http://en.wikipedia.org/wiki/Multicast 

Ethernet and TCP/IP were devised as a way to allow multiple nodes to communicate on the same wire and this is exactly what is going on with your internal network.   The RG includes a 100 megabit wired switch and even with the entire 7 streams available to Uverse subscribers with HD and THDVR, you're not approaching the capacity limits of the wire.  HPNA has even more bandwidth available, so there's even less potential for capacity issues there.

You can't judge the efficiency of your network solely on flashing lights on your equipment. 

[Computer-Joe ACE - Master]

 "I'm not going to go line by line in your post to refute what you have stated as many people use the wired side of the RG successfully."

 Well OX, I'm glad for you to have been included in the "many" who didn't have problems and not the "few" who have.

"Flashing ports don't necessarily indicate that the switch can't handle anyone else's traffic."

I guess I should have used better termonology. The lights were almost solid on almost 100% of the time with all computers turned off.

 "Ethernet and TCP/IP were devised as a way to allow multiple nodes to communicate on the same wire and this is exactly what is going on with your internal network."

Yes, but it was aslo devised to communicate on the same wire without collisions or dropped packets due to a computer not waiting for the lull to send it's data. But the RG doesn't appear to follow those rules to the letter.

 "The RG includes a 100 megabit wired switch and even with the entire 7 streams available to Uverse subscribers with HD and THDVR, you're not approaching the capacity limits of the wire."

Yes, it has a 100 Mbps switch (no 100 Mbps switches actually hit more than 85-90 Mbps of actual data throughput) but that switch is controlled by the RG and it gives priority to IPTV and VIOP to the extent of delaying or dropping packets for local computer use and this was what was causing network tasks to fail in my situation.

 And though it might be enough bandwidth for 4 HD streams (2 coming in to be recorded and 2 being sent out for thdvr) and 4 SD streams (2 coming in to be recorded and 2 being sent out for thdvr if I get another STB) that leaves very little overhead for local computer use and what little is left gets stomped on by the RG's heavy-handed QOS.

"You can't judge the efficiency of your network solely on flashing lights on your equipment."

And if you had actually paid attention to what you were reading you would know that I was not judging my network solely by the flashing lights.

[callmeox ACE - Professor]

Putting your personal attack aside, don't you find it odd that with the multitudes of Uverse subs here with wired networks that you are the only one thus far to complain about it being overloaded?

I doubt that it was as an issue with the RG not giving your traffic priority, but most likely you asking 100 megabit ethernet to do more than it is able.

[Computer-Joe ACE - Master]

My personal attack. Sounds to me like you just can't see past your own ego.

[callmeox ACE - Professor]

And again your comment has nothing to do with an overloaded 100 megabit network connection. Computer networks aren't unlimited resources. Perhaps adding Uverse to a very busy 100 megabit network pushed it past it's capacity limit, but that's hardly the fault of AT&T.

[Computer-Joe ACE - Master]

Geez, you sound like tech support. My big scary, "overloaded" network (which is not supported) must have confused the poor little blameless RG.

Like I said before ox, READ THE POST.

I thought I stated pretty clearly that:

1) Before UV install, I had a perfectly functional "non-overloaded" network.

2) After UV install, number 1 above was no longer true.

3) What I found to be the cause.

4) What I did that solved the problems.

Part of that rosy world that is UV, that the salesman on the phone promised me, was that none of my existing computers or network would be affected by the UV service.

I posted my experiences in the spirit of what I thought was a SUPPORT forum and that if someone has had, is having, or will have similar problems, they will find it usefull.

OX, If you have not had the same problems, and you did not find it usefull, and you aren't go to offer any ACTUAL support (other than for AT&T), why the hell did you even reply.

[callmeox ACE - Professor]

Just fighting misinformation.

It's my job, though the pay stinks.

[gtwendt]

were you using a managed switch or just a switch?  I was thinking if you used a managed switch you could just block the multicast traffic from those ports and free up the "computer" side...

Just a thought.

Message Edited by gtwendt on 09-29-2008 08:59 AM

[Computer-Joe ACE - Master]

That's what I would have to do to block it, but managed switches are fairly expensive and I would still have to get a wireless access point to keep all computers on "my" side of the network. The 54g router was only 40 bucks and handles the blocking and wireless duties. It was an easy setup. I set the new router to use DHCP for the WAN address, plugged it in to the RG, let the RG assign a local address to the new router and then set that address to the DMZ. When I go to the new router it shows as having the same WAN, gateway, and DNS addresses that the RG uses. I set the new router to assign addresses to "my" side of the network in a different IP range than what the RG uses (192.168.2.* instead of 192.168.1.*) but using the same subnet mask. My internet works fine with no interuptions and local network tasks (back ups, streaming, etc.) work as expected. I can also still access the RG from "my "side of the network when I need to without having to change any network settings.

[Computer-Joe ACE - Master]

Sorry OX, it's a dirty job, but someone has to do it.

[gtwendt]

Cool - just a thought.  Dell has some great 1 gig managed business class switches starting at 73 for 8 ports.  Not bad at all.  I have a gaming router that I was using just like you did here, but did not like the extra hop on the 360.  I might go back to it since I need it for the NAS and printers anyway and just live with it. 

[Computer-Joe ACE - Master]

I havn't done any online gaming yet with UV, but when I run speed tests (http://www.speakeasy.net/speedtest/ just did one) from within my nested router domain I consistantly get better than 2.80 Mbps down and 0.95 up and I have the 3/1 package. If I check my desktop bandwidth widget (which reads my network adapters actual throughput) I often see some bursts to 3.2 down and 1.1 up when I run the speed tests with the only activity showing on my internal router being my port and the WAN port. That one thing I like about UV, I kept the same speed package I had with DSL but went from 568k up to 1M up.

[gtwendt]

I have the max package and yes the internet side of uverse is great.  The issue is latency increased from point to point, so ping rates jumped from 15ms to 30+ms to some locations, which for gaming can suck big time.  I have noticed I host a lot of games though with this package, so my complaint does drop a little.

[Koolkid1935]

The problem here IMO is that your switches, unlike the RG, do not support IGMPv3 snooping and filtering thus treating the multicasted video traffic as broadcasts.  Had they have all supported IGMPv3 snooping and filtering, this would not be a problem.  If you plug another computer straight into the RG, you should notice no traffic on it that isn't supposed to be there.

I fail to see how this is AT&T's problem unless you can prove through a throughput monitor on your computer that your NIC was being pushed to it's limits.  I should mention that ARP packets are sent out about every second and the more devices you have there will be more ARP messages on your network.  ARP packets are small though and should not be able to bring down an entire 100Mb/s network.  You either didn't mention or I didn't see it if any of your STBs are on your Ethernet network.  The IGMPv3 snooping/filtering in the RG should be active on all local interfaces (HPNA, USB, Wi-Fi, and Ethernet).  HPNA is just an interface much in the same way Ethernet or Wi-Fi are.  All of the LAN interfaces are also bridged, so a broadcast packet on one interface gets sent to all interfaces, while multicast traffic should only go out to the interface/port that it needs it on.

Message Edited by Koolkid1935 on 09-30-2008 05:30 PM

[Computer-Joe ACE - Master]

Initial install was all coax for TVs, nothing but my computer network on the RG's 4 port switch (only 1 port, the rest distributed through my switches). As for the switches, is that an issue with all switches? I use all identical Linksys(CISCO) EZXS55W 5 port with uplink (MDI). A later tech tried using an AT&T supplied switch (Netgear GS108) and it had the same problem. I guess I did not express my self correctly. I don't think the network was at it's bandwidth/throughput capacity. What it seemed like to me was that the RG would preempt (interrupt) my computer traffic to give full priority to any IPTV traffic no matter how small. That interruption seemed to manifest itself in delays or dropped packets or collisions on my computer network (stuttering streaming, corrupted or failed cross-network saves or backups, email timeouts). None of which was happening before connecting to the RG.

[bsdsmb]

That Linksys model is a fairly no-frills switch. 

It sounds like you likely have a broadcast storm starting when you introduce your RG to your greater network.  Based upon your description, I could not understand your entire network, but your described results sounds like you have a loop in there somewhere.  Or, as mentioned prior, it could be multi-cast packets getting bounced around between your switches.  Either way ... your config is a-typical and is causing your results.  It is not really a fault or problem with the Uverse gear and its performance - per se.

With these inexpensive consumer switch devices like you are doing (especially if you then introduce multiple WLAN gizmos) it is not uncommon to get a loop introduced in your network - and broadcast storms that result.  More expensive switches often support 802.1w or Spanning Tree protocol (http://en.wikipedia.org/wiki/Spanning_tree_protocol) to avoid loops or shut down multiple data paths through the network.

It might be worth tracing every wire in your network to make sure you don't have a loop, or if sticking a router in there as you described fixed your problem, consider it fixed!

The 2Wire 3800 device Uverse is using is a sophisticated and very capable device for their services.  It should provide a platform for anyone to base a network on.  However, if you are going to try to stick more than 4 hosts (IPTVs or computers) into it ... you need to carefully consider what you are doing, and purchase equipment suited to the task.

[Computer-Joe ACE - Master]

Here is a diagram of my network: http://comp-joe.sewnicequilting.com/network_map

The black is before UV. The red shows cabling changes after removing the router/switch and modem and installed the RG. That's when I experienced the problems. What solved the problem for me was inserting my own router between the RG and switch B.

The modem, router/switch and switch A were in second floor office. Switch B is in basement. Switch C is in first floor office. Switch D is in garage. "Computer" designates stationary resident desktops. "Wall Jack" and "Spare" are for our two laptops (I did not use wireless before UV) and any "Guest" computers. I ran this topology by the tech support at Linksys and they approved it.

[bsdsmb]

The diagram leaves me a little uncertain.  I assume you are suggesting you moved the Switch A uplink and the Switch B uplink both directly into the RG.  The prior modem and router/firewall were totally removed?  Again, I thought you suggested the RG was placed in an entirely separate room than the original CPE devices.  Just trying to understand here...

And do you have any wireless enabled?  In other posts I thought you mentioned using wireless in some capacity.

And where did you stick your new router/firewall to create the fix?

[Koolkid1935]

The diagram leads me to believe the switches are all connected to switch B which in turn uplinks to the RG, now the third party router then RG.

[Computer-Joe ACE - Master]

After UV install, moved Switch A uplink to Switch B and Switch B uplink to RG, which was installed in basement. Yes, Original modem and router were removed. The new router is now between Switch B and the RG. I did not use wireless when I first had UV installed, although I do use wireless now, but I use the wireless from my new router and disabled the RG wireless.

[Computer-Joe ACE - Master]

yes koolkid

[djmegahertz_1]

I know I brought this up in another thread, but what Joe described here is very accurate. I had the same problem and after I separated my pc network away from the TVIP network all had cleared.

You might not even know if you just do some general browsing and email, but if you do some intensive UDP traffic, you will be in trouble.

I use a Netopia with VPN and it works great.

Just be sure to use a different subnet.