[c-nsp] Error Msgs - SYS-4-CHUNKMALLOCFAIL - arp throttle

[Bob Tinkelman]

> Cisco 3825 showing the following errors - looking for input...

(your error log quoted below my signature)


We saw the same think on a cisco 7206-vxr with npe-t1 (1 gig memory)
running c7200-jk9su2-mz.124-16, and with lots of memory always available.

We found a reference to "arp throttle", which appears to be a method
to deal with a flood of packets to a non-existent address in a way
that keeps it from turning into a flood of ARP requests on a directly
connected net.

The error message line starting with "Total free: 0" makes it seem like
there is a hard limit of 500 "somethings".  It's not clear to me what
that is.  (Unanswered, not yet timed-out ARP requests?)

>From our router:
  | #sh mem summ | inc arp throttle
  | 0x6148AA98 0000002092 0000000001 0000002092    CEF: arp throttle chunk
  | 0x6148AA98 0000016000 0000000001 0000016000    CEF: arp throttle chunk

So there doesn't appear to be a lot going on there.

We'd guessed that we were seeing periods where there were a high number
of incoming probes trying to scan some of our directly attached LANs,
but we have not done any further investigation.  (Mostly, it hasn't
seemed to cause a problem yet, and so...)

I'd also be interested if anyone has any further insight.
--
Bob Tinkelman          <bob at tink.com>
ISPnet, Inc.  http://www.ispnetinc.net




> Aug 31 13:13:36: %SYS-4-CHUNKMALLOCFAIL: Could not allocate chunks for CEF:
> arp throt
> Total free: 0, Total inuse: 500, Cause : Not a dynamic chunk
>  -Process= "<interrupt level>", ipl= 1, pid= 87 -Traceback= 0x612B36C4
> 0x6002CA54 0x6002CAB8 0x615F1CD0 0x6005E8D8 0x60057CD0 0x60A15770 0x60A18448
> 0x602CD374 0x60AFD9B8
> Aug 31 13:15:35: %SYS-4-CHUNKMALLOCFAIL: Could not allocate chunks for CEF:
> arp throt
> Total free: 0, Total inuse: 500, Cause : Not a dynamic chunk
>  -Process= "<interrupt level>", ipl= 1, pid= 87 -Traceback= 0x612B36C4
> 0x6002CA54 0x6002CAB8 0x615F1CD0 0x6005E8D8 0x60057CD0 0x60A15770 0x60A18448
> 0x602CD374 0x60AFD9B8
> Aug 31 13:19:19: %SYS-4-CHUNKMALLOCFAIL: Could not allocate chunks for CEF:
> arp throt
> Total free: 0, Total inuse: 500, Cause : Not a dynamic chunk
>  -Process= "<interrupt level>", ipl= 1, pid= 87 -Traceback= 0x612B36C4
> 0x6002CA54 0x6002CAB8 0x615F1CD0 0x6005E8D8 0x60057CD0 0x60A15770 0x60A18448
> 0x602CD374 0x60AFD9B8