Skinny Keepalives - TCP out of order and duplicate ACKs

[mmedwid]

I am trouble-shooting a problem with phones rebooting at one of my sites.  There is plenty of bandwidth all along the path to the UCM 7.1 server.

I put a sniffer on the voice vlan to try and get a sense of what's going on at a packet level when phones boot.  Catching it in the act will take a day or two as the reboots are spurious happening sometimes once in a day to once every four days.  But straight off the bat I noticed these Skinny TCP out of order errors and duplicate ACKs in the trace.  Any thought what that would indicate?  See screen grab below.  Thank you.

[Imran Khan R]

Hi,

This looks like a network issue to me. Please check if everything is fine with your network configuration.

- Imran

[mmedwid]

Well there are no errors on any of the end station links or inter-switch links.  Pings between the publisher and any of the phones are loss-less and short..

From pub to phone:

--- 10.10.65.63 ping statistics ---

100 packets transmitted, 100 received, 0% packet loss, time 99129ms

rtt min/avg/max/mdev = 4.014/5.371/19.069/1.664 ms, pipe 2

From sub to phone:

--- 10.10.65.63 ping statistics ---

100 packets transmitted, 100 received, 0% packet loss, time 99129ms

rtt min/avg/max/mdev = 4.014/5.371/19.069/1.664 ms, pipe 2

[mmedwid]

The packet trace does show a lot of ICMP redirects so that the phones can get to the WAN/MPLS router.  Do the phones even respect ICMP redirects?  Perhaps we'd be better to just disable the redirects?