Hi Piotr,
There isn't a known issue in this respect. Can you please run "dropstats"
on the destination compute node to see if any error counters are going up
inside vrouter?
Also, can you please run "flow -l" on the destination compute node to see if
the flow action for the relevant flow is set to F (forward).
Raja
From: Users
<[email protected]<mailto:[email protected]>>
on behalf of Piotr P <[email protected]<mailto:[email protected]>>
Date: Monday, October 12, 2015 at 7:39 AM
To: "<[email protected]<mailto:[email protected]>>"
<[email protected]<mailto:[email protected]>>
Subject: [Users] Drops of the first SYN packet
Hi All,
We are experiencing problem with missing packets between Virtual Machines
located within the same Virtual Network.
Our setup Contrail 2.20 (buld 64), Priority of encapsulation: VxLAN, MPLSoUDP,
MPLSoGRE
The effect is visible during each new transmission/flow. There is missing first
syn packet or first icmp ping.
This affect each tcp session, it's delayed for syn retransmission time.
Drops occurs for each subsequent new tcp session between VM's. We can repeat
tcp connection between VM and first syn will be missing all the time.
It's not visible in all Virtual Networks. There are some other Virtual Networks
that works correctly.
We can reproduce this behaviour with creating new networks with even only 2
virtual machines.
Those networks differs only by other routing-target value.
This effect
does not appear when we have transmission outside VN (eg through physical
gateway)
it's only correlated when traffic stays within network.
Tcpdump on compute nodes shows that:
- All packets are visible on incoming tap interface (from source VM)
- all packets are visible on bond interfaces on both compute nodes (vrouter)
with VMs (bond active-passive toward physical switch )
Computer nodes are located on the same physical switch (no visible errors on
switch ports)
- first packet/syn from transmission is missing on a tap interface toward
destination VM
Please let know if this is some known behaviour. What could be the steps to
troubleshoot this issue?
Kind Regards
Piotr Pieprzycki
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