How to resolve "max_conn_overload" alarm from WAE-674 in WCCP mode?

Unanswered Question
Jun 15th, 2009

I have a WAVE-574 and a WAE-674 showing the minor alarm "max_conn_overload: The TFO accelerator is overloaded (connection limit)". Both are running WCCP redirection.

From CM GUI > Dashboard > Device > Monitor > Traffic Analysis > Connection Statistics, one device showed 175 connections and the other showed 864 connections. The alarm seems to say there's a limit of # of connections the TFO accerelator can handle. But how can I find the limit on the device? Is it configurable? What is the best practice to resolve this overload?

I have searched Cisco web sites for possible explanations, but couldn't find any.

Thanks in advance.

Gary

I have this problem too.
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dstolt Tue, 06/16/2009 - 05:17

Gary,

What version of WAAS are you running?

Thanks,

Dan

gwhuang5398 Tue, 06/16/2009 - 10:17

Hi Dan:

4.1.1c build 16 on all WAE and WAVE. All devices were ordered recently and shipped from Cisco within last a few weeks.

On the WAE, "sh statistics tfo" and "sh tfo detail" both show some numbers, but they don't seem to be corelated or match.

Thanks a lot

Gary

dstolt Thu, 06/18/2009 - 17:57

Gary,

There is a situation where routing loops can cause TFO overload and not show up in the stats (CSCsx68058). The stats/detection is fixed in 4.1.3, however the problems with routing loups still exist...

Look for errors in the syslog (opt_syn_rcv: Routing Loop

detected - Packet has our own devid. Packet dropped) or "sh stat TFO". See if you are seeing things like that which may be causing the TFO overload.

Dan

gwhuang5398 Fri, 06/19/2009 - 08:20

Hi Dan:

Thanks for the info. The TFO overload alarm was found on WCCP WAE and also Inline mode WAE. So probably not the routing loop issue. I looked at TFO stats, but not sure what numbers are good indications.

Can you take a look at the stats from the WCCP WAE-674?

Thanks a lot

Gary

WAE674-WCCP#sh stat tfo detail

Total number of connections : 10173

No. of active connections : 31

No. of pending (to be accepted) connections : 0

No. of bypass connections : 2216

No. of normal closed conns : 9587

No. of reset connections : 555

Socket write failure : 174

Socket read failure : 0

WAN socket close while waiting to write : 0

AO socket close while waiting to write : 0

WAN socket error close while waiting to read : 0

AO socket error close while waiting to read : 197

DRE decode failure : 0

DRE encode failure : 0

Connection init failure : 43

WAN socket unexpected close while waiting to read : 30

Exceeded maximum number of supported connections : 0

Buffer allocation or manipulation failed : 0

Peer received reset from end host : 106

DRE connection state out of sync : 0

Memory allocation failed for buffer heads : 0

Unoptimized packet received on optimized side : 5

Data buffer usages:

Used size: 0 B, B-size: 0 B, B-num: 0

Cloned size: 234 KB, B-size: 337 KB, B-num: 1230

Scheduler:

Queue Size: IO: 0, Semi-IO: 0, Non-IO: 0

Total Jobs: IO: 243894, Semi-IO: 215419, Non-IO: 29919

Policy Engine Statistics

-------------------------

Session timeouts: 0, Total timeouts: 0

Last keepalive received 00.1 Secs ago

Last registration occurred 7:22:30:06.9 Days:Hours:Mins:Secs ago

Hits: 4101731, Update Released: 67270

Active Connections: 2018, Completed Connections: 22638

Drops: 0

Rejected Connection Counts Due To: (Total: 4010359)

Not Registered : 0, Keepalive Timeout : 0

No License : 0, Load Level : 0

Connection Limit : 4010359, Rate Limit : 0

Minimum TFO : 0, Resource Manager : 0

Global Config : 0, TFO Overload : 0

Server-Side : 0, DM Deny : 0

No DM Accept : 0

Auto-Discovery Statistics

-------------------------

Connections queued for accept: 10146

Accept queue add failures: 0

AO discovery successful: 0

AO discovery failure: 0

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