[c-nsp] Operational impact of switching from ingress to egress replication mode

[John Neiberger]

Sorry.  I also meant to say it's a Sup 720-3BXL. Based on what I can
see on CCO, that thing can forward 400 Mpps of ipv4 traffic. Does that
mean that I can set a rate limit of, say, 300 Mpps and somewhat guard
the CPU from meltdown for a few moments?


On Tue, Sep 21, 2010 at 2:52 PM, John Neiberger <jneiberger at gmail.com> wrote:
> Are you all referring to "mls ip cef rate-limit"? If so, what do you
> think would be a good value to use on a Sup 720? We'd like to set it
> so that the CPU isn't overloaded so much that routing protocols drop
> and we don't lose our SSH sessions. That way we can monitor it and
> watch to see when the CPU drops back down to normal.
>
> Thanks!
> John
>
> On Tue, Sep 21, 2010 at 2:16 PM, John Neiberger <jneiberger at gmail.com> wrote:
>> Thanks. I've never used the MLS limiters before, so I'll look into how
>> they're configured in case we decide to use them. But we also have the
>> option of moving most of our production traffic away from these boxes
>> temporarily, so we may be able to just deal with the temporary chaos.
>>
>> John
>>
>> On Tue, Sep 21, 2010 at 2:04 PM, Benjamin Lovell <belovell at cisco.com> wrote:
>>> Excellent point and suggestion. This should prevent punts from smashing your control plane and causing a cascading effect like the one I described.
>>>
>>> -Ben
>>>
>>>
>>> On Sep 21, 2010, at 3:47 PM, Phil Mayers wrote:
>>>
>>>> On 09/21/2010 08:27 PM, Benjamin Lovell wrote:
>>>>> The primary thing to worry about here is the mcast packet rate not
>>>>> number of mroutes. Replication change will cause all mcast packets to
>>>>> be punted to CPU for a short period(few 100 msec or so).
>>>>
>>>> Remember you can rate-limit this with the MLS limiters. Whilst they defaults are (very) high, lowering it for the duration of this change could ease the problems.
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>>
>