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The FRRouting Protocol Suite
https://frrouting.org/
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FRR suddenly stops seeing packets in BGP TCP session #2361

Closed ossark closed 5 years ago

ossark commented 6 years ago

Hello,

I am running FRR 4.04 on Ubuntu 18.04. I am using BGP multihop to connect to a peer (Microsoft Azure). All works well until suddenly FRR stops "seeing" packets from the Azure side.

I see them with tcpdump on the machine that runs FRR but FRR acts as if it cannot see them. Attached is a pcap that shows this.

172.29.253.78 is FRR. 10.47.0.254 is Azure.

I am aware that this may not even be an FRR issue but maybe someone can enlighten me on how to rule out FRR in that case.

frr.pcap.zip

donaldsharp commented 6 years ago

This is not FRR. The pcap is clearly showing a l2 issue that needs to be resolved before FRR can be expected to work reliably. I would work on the connectivity issue first.

ossark commented 6 years ago

Hello,

How is it that you suspect an L2 issue? Do you mean the re-transmits in TCP? How is this indicative of an L2 issue?

On 4 juni 2018, at 14:28, Donald Sharp notifications@github.com wrote:

This is not FRR. The pcap is clearly showing a l2 issue that needs to be resolved before FRR can be expected to work reliably. I would work on the connectivity issue first.

— You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub, or mute the thread.

donaldsharp commented 6 years ago

We see retransmissions when 1 side does not acknowledge the received tcp/ip packet. If we see large swaths of packets being retransimitted this typically means we have a connectivity issue that needs to be fixed before we worry about higher levels