The client has a normal tcp connection to server via ACE. if network interrupt occured (link up-down ) the client send SYN packet with same source port number what was used in the previously session between them. The ACE send the SYN to server but the server respond ACK packet only and not SYN,ACK packet because the TCP session is live for server. The client send the rst packet after syn but the ACE drops it.
The show conn shows the in and out sessions which were originaly betwen client and server.
Lajos-ACE/Admin# sho np 1 me-stats "-stcp" | i dow
Segs outside window: 0
Connection shutdown FIN: 0
Connection shutdown RST: 0
We disabled the normalization without results.
The idle timeout does not help because the ACE
feels that client and server continue the old session. !!!!
the show conn output shwos the following while the client send the SYN and RST and the server send the ACK only.
8 2 in TCP 73 10.46.2.2:12346 192.168.37.221:1072 ESTAB
[ idle time : 00:00:01, byte count : 2049 ]
[ elapsed time: 00:12:41, packet count: 41 ]
90 2 out TCP 75 192.168.37.217:1072 10.46.2.2:12346 ESTAB
[ conn in reuse pool : FALSE]
[ idle time : 00:00:01, byte count : 2319 ]
[ elapsed time: 00:12:41, packet count: 46 ]
My opinion the ACE try to make a new ,second connection before SYN . The RST packet resets the second session and the first session unchanged. ( but the idle timer is not increasing )The server respond in the frisst session.
Unfortunetly the client uses the same source and destination TCP ports in every session. :-)
Moquery is the command line cousin of Vizore, it's very helpful and efficient sometimes during the troubleshooting. This article aims to provide moquery cheat sheet to the users for some most common seen scenarios.
Here is the checklist before customers/partners contact Cisco TAC:
Firmware Version of APIC and Switch
Download Switch and APIC techsupport logs
Problem description (Symptoms with details)
Business impact (eg, what kind of services...
moquery usageAPIC moquerySwitchmoquery
This document discuss a common issue observed during the VMM integration & VM workload migration to ACI fabric.
VMware Virtual machines are hosted in Cisco UCS-B seri...