[nsp] "ignore" on PA-FE-TX, 12.2(18)S4

[Scott Madley]

On a 7200 'ignores' are caused when IOS can't replenish the rx ring's
particle buffers (private/public).  You'll also see 'throttles' when this
happens.  I don't know if the 'ignore' counter gets incremented when IOS
can't coalesce  a contigious buffer for a packet that needs to be process
switched (although it will increment the 'throttle counter').

SPD will only help in insuring that packets set to IP-Prec 6/7 (OSPF,
HDLC/PPP Keepalives, etc) get placed in the priority queue to be processed
by the RP.  Assuming that your 'ignored' counter increments are caused by
OSPF/BGP flaptastic fun, SPD will help.

I don't think it's a problem with SPD queue sizes, rather just bursty
traffic.  Here's to hoping that increasing your input buffer helps you!

Cheers!
-SM


-----Original Message-----
From: Gert Doering [mailto:gert at greenie.muc.de]
Sent: Tuesday, June 15, 2004 5:56 AM
To: Scott Madley
Cc: sabt at sabt.net; lee.e.rian at census.gov; Gert Doering;
cisco-nsp at puck.nether.net
Subject: Re: [nsp] "ignore" on PA-FE-TX, 12.2(18)S4


Hi,

On Tue, Jun 15, 2004 at 04:54:55AM -0400, Scott Madley wrote:
> Ignores are incremented on a VIP-PA when there are insufficient particle
> buffers in the global pool to replace the interface rx ring buffers.
> Ignores are also incremented when a packet arrives on an interface and
there
> a no available MEMD buffers in an interface pool.

Thanks for that hint.  I forgot to mention that the router in question is
a 7200VXR/NPE-400, so "no MEMD or VIP" here.

Ytti suggested that the problem might actually been caused by me
incrementing the input queue size to 500 without adapting the SPD queue
parameters (which would explain the high number of flushes but no
input drops).  I have now increased the SPD thresholds as well, and am
observing the box's behaviour.

In the last 30 minutes, no flushes and no ignores... - but then, the
ignores didn't increment "all the time" but usually in bursts every now
and then.  So I'll need to wait for a few days to judge the effect.

Thanks for all the suggestions so far!

gert

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