TCP reassembly queue overflow on Cisco 877 VPN router

whiteford · ‎10-22-2007

I keep getting this error on my syslog server from one of my Cisco 877 VPN ADSL routers:

60: Dropping TCP Segment: seq:3959461132 1420 bytes is out-of-order; expected seq:3959437672. Reason: TCP reassembly queue overflow - session 172.19.10.18:2293 to 80.67.87.174:80

What does it mean?

owillins · ‎10-26-2007

Can you please verify the "show ip inspect statistics" and the version of IOS in use? You will likely need to up the out-of-order max queue length.

Would it be possible to increase the queue size for out of order packets

#ip inspect tcp reassembly queue Length 64

Syntax:

ip inspect tcp reassembly {[queue length packet-number] [timeout seconds] [memory limit size-in-kb] [alarm {on | off}]}

whiteford · ‎10-26-2007

Hi,

It's IOS version c870-advipservicesk9-mz.124-15.T1.bin

show ip inspect statistics

Packet inspection statistics [process switch:fast switch]

tcp packets: [1712052:14818230]

udp packets: [191:42150]

packets: [182:30946]

http packets: [41279:273990]

Interfaces configured for inspection 1

Session creations since subsystem startup or last reset 70271

Current session counts (estab/half-open/terminating) [2:0:0]

Maxever session counts (estab/half-open/terminating) [95:14:9]

Last session created 00:01:01

Last statistic reset never

Last session creation rate 0

Maxever session creation rate 255

Last half-open session total 0

TCP reassembly statistics

received 10063 packets out-of-order; dropped 708

peak memory usage 37 KB; current usage: 0 KB

peak queue length 16

let me know if i need to change anything