H21 Network Problem taking over network

[srrudin]

I have (2) HR21's and (2) H21-100 running the lated CE code. I have enabled the network on the H21's and am able to use the MRV. The MRV works very nice when available. I am having a problem about every 4 hours.

The best term I can come up with is that they "scream" on the network after a while so nothing else can access the network. The link lights on the switch of the connected H21's are flashing rapidly with nothing going on. If I disconnect the H21's from the switch, everything frees up and my other network devices can access the network again.

The only way to stop the network from "screaming" on the H21-100 is to red button reset the H21.

Network is Linksys WRT310N connected to 16port Netgear Gigabit switch. Reseting the Router and switch would last about 5 seconds. The only way to clear "screaming" was to disconnect the H21's or red button reset.

I anxoiusly await the next release to get this issue stabilized and am curious if anyone else is experiencing similar problems.

 

[jds7801]

As mentioned in my reply to your other post, I have seen the exact problem that you describe above. I am using an 8 port Aopen Ethernet switch. I was not using MRV when the problem occurred here.

 

[pmcode]

The best term I can come up with is that they "scream" on the network

I am pretty sure the term you guys are looking for is "flooding the network"

I am going to assume a couple of things here, and give you a couple of things to try to verify if this is actually happening.

1. You have a simple private IP network set-up, either 192.168.x.x or 10.x.x.x.
2. You have your network opened to the entire subnet. 255.255.255.0
3. You are using your WRT310N to provide IP addresses. (DHCP on).

The best thing to do to verify the H21 is the problem is to load wireshark Wireshark: Download , and set it up to perform a capture on the interface with the same IP (range) as the H21 while the network appears to be busy. You should see a ton of traffic (probably UDP based) with a source address the same as your H21.

If you do, it means the traffic is possibly being repeatedly "bounced" around. If you select one of the UDP packets, in the bottom half of the wireshark screen, you'll see the packet broken down into segments. One of those segments (Internet Protocol) should say what the TTL is for the packet. Directv probably went with a default TTL of 128, which could be causing the problem.

One possible fix action is to try plugging the H21s and HR21s into the router without the Gig switch. This will probably take all the ports on your router, so start with one of each H21/HR21.

One other fix action I can see would be to set up a sub network for only the D* boxes. Unfortunately, this requires you to run the DD-WRT firmware on your router, enabling you to setup 2 vlans. You could then use the built in IPtables to restrict the UDP traffic to only that vlan (may kill DIRECTV2PC if you use it, may not).

Hope fully that helps, if not, please disregard, or proceed to verbally smack me down

PmCode

 

[srrudin]

Thank you for the response. I am curious about setting the devices directly into the router. Would it make sense to add a 4 port switch into the router and plug all the DirecTV equipment into that? That way I use only one port on router. Would the router prevent the DirecTV for interfering with any other ports on the router or anything else attached to router?

I have another port on router going to 16 port GB switch and 3rd port to Vonage.

Thank you again.

 

[pmcode]

If I am not wrong, you described your network as being:

internet ----> WRT310N ---> 16port Gig Switch ---> D* equipment

The switch may not (actually should not) be passing the packets to the router, so the TTL flag may not be getting lowered. (TTL just means how many hops across routers the packet can take before it dies and is re-requested). If the switch sees the same network address in the source and destination portion of the packet, it will/should keep the packet within itself, since it knows what devices are plugged into it. Assuming this switch isn't ancient, or a REALLY cheap.

I am not entirely sure how DirecTV is doing their MRV, so I am assuming it is through what is called Multicast. One host (H21) makes a request, and the HR21 sends a response (the video feed requested) across the entire network (sort of a broadcast).

They could be using unicast, which would make more sense, though if you are seeing a major network "bogdown", then I think it more likely to be a multicast implementation.

You could plug your D* devices into their own switch, without plugging it into your router, and see if MRV works as it should. You would have to set the devices' IP addresses manually, though, and only plug the switch with the D* stuff into your router when doing upgrades. This doesn't sound like a good solution, however, as you also wouldn't know if it is "bogging down" unless it gets so bad as to effect video.

I would like to see what hapens if you plug only one H21 and one HR21 directly into the router, along with a single PC (or laptop). Start the MRV from one to another while surfing the web and see if anything happens.

PmCode

 

[jds7801]

OK I had another "Network Flood" today. I started Wireshark and it showed no packets at my PC Interface. I could see the lights blinking on my Ethernet Switch between the H21 and the HR21 so whatever is happening doesn't appear to be Broadcast Packets. The problem went away as soon as I unplugged the H21-100 receiver. I will look around and see if I can find an old Ethernet Hub. I will capture the Non Broadcast traffic from the H21 the next time it happens..

 

[JAG72]

Even if you have a large amount of traffic on your local network it should not be impacting other devices if you are using switches. It should be isolated to just the HR21 port and what ever it is talking to. The only thing that might flood is the uplink between the switches. If the switches are only 100MB I could possibly see that happen but if they are gig I don't see how it would be possible. Very good thought about getting an old hub and giving that a try to get a capture.

 

[stonecold]

NVM miss read.

 

[pmcode]

OK I had another "Network Flood" today. I started Wireshark and it showed no packets at my PC Interface. I could see the lights blinking on my Ethernet Switch between the H21 and the HR21 so whatever is happening doesn't appear to be Broadcast Packets. The problem went away as soon as I unplugged the H21-100 receiver. I will look around and see if I can find an old Ethernet Hub. I will capture the Non Broadcast traffic from the H21 the next time it happens..

Sorry to get back on this thread so late...

When you say no packets at your PC interface, do you mean none whatsoever, or just none relating to broadcast stuff?

You should have captured at least a few packets, of something your pc was doing at the time, I would think. Are you sure you selected the correct interface to capture? My PC, for example, has 6 interfaces to choose from. Don't get me wrong, I would think you would have something running, either program wise, or in the taskbar that would send/receive something during your capture.

As far as not seeing anything D* related that could be a unicast issue with the way D* MRV operates. You may never see those packets with wireshark if D* addreses them directly from one unit to the other. That is one of the downfalls of wireshark. The only way to get around that is to put two extra ethernet cards in your PC, and set your machine up as a "true" packet sniffer. More info available if you are interested.

Hey, I've got an idea! Send ME your H21 and I'll troubleshoot the issue. It may, unfortunately take a few months (years).

You are correct, though, if you can find an old hub, it should allow you to capture all traffic, just make sure your PC and all of your D* gear is attached to that hub. Otherwise, purchase a switch with an actual monitor port.

 

[jds7801]

I was seeing no Broadcast traffic. The Ethernet Switch was not passing any traffic to the PC that I have WireShark on. It was like the Ethernet Switch was too busy to pass any traffic. My laptop that is connected via Wireless to a Router that is upstream from the Ethernet Switch was still working. I haven't seen the problem with the past two CE updates so maybe they fixed it.