[c-nsp] HSRP Groups on ASR1k

[Matthew Melbourne]

Interestingly, I've tried applying a similar config to a physical
built-in GE port on a lab ASR1k, and I don't see the same issue after
creating 25 sub-ifs, each using two HSRP groups. Therefore, I wonder
whether this is something specific to port-channels on this platform?

Cheers,

Matt

On 28 September 2010 21:17, Benjamin Lovell <belovell at cisco.com> wrote:
>
> On Sep 28, 2010, at 3:18 PM, Matthew Melbourne wrote:
>
>> Yes, I too expected the MAC to be the same to a given group number, unless
>> there are other factors at play here, e.g. per-VLAN/VRF/platform
>> limitations. I expected only two MACs to be used (one for each group).
>>
>> -----Original Message-----
>> Message: 1
>> Date: Tue, 28 Sep 2010 17:48:16 +0100
>> From: Phil Mayers <p.mayers at imperial.ac.uk>
>> To: cisco-nsp at puck.nether.net
>> Subject: Re: [c-nsp] HSRP Groups on ASR1k
>> Message-ID: <4CA21C50.9090209 at imperial.ac.uk>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> On 28/09/10 17:35, Benjamin Lovell wrote:
>>> I haven't looked into this on the ASR1K but what the message is
>>> telling you is that the NIC can only program 28 MAC addresses and you
>>> have used up the limit. If you add more sub-interfaces with HSRP then
>>> bad things will start to happen. Drops, punt to CPU, not sure as I
>>> have not looked into it on this platform but nothing good.
>>
>> Is this right?
>>
>> Isn't the HSRP MAC the same for a given group number, regardless of
>> which sub-int?
>>
>> We run all our interfaces (not ASR1k though) in "standby group 0"
>
> Yes but it's possible that sub-int requires a filter so 30 groups on 30 sub-ints require 30 MAC filters, etc. As I said this is all platform dependent stuff that I don't know for the AST 1K.
> If you want to keep adding sub-interfaces and HSRP group you really should have the TAC guys look into this. The platform may just reject with error anything over the limit but it may do worse things.
>
>>
>>>
>>> This could be a software limitation that was addressed or is planed
>>> to be addressed in later code releases or it could be a hard limit of
>>> the NIC used on the SPAs. I would open a case with the TAC to have
>>> them talk to the devs about this and see if it will be important to
>>> you.
>>>
>>> BTW - not clear on the part where you said you are using HSRP groups
>>> 1 and 2 on the customer sub-ints. You should use a unique standby
>>> group for each HSRP instance. If you are not this *may have something
>>> to do with your problem.
>>
>> Why? Using a different standby group per sub-int will surely definitely
>> run you over the mac receive filter size limit? What's the problem using
>> the same group number on different interfaces?
>
> Was an off hand thought, but if you really are using only two group IDs everywhere then the error message is proof that it's not as simple as number of MAC filters = number of HSRP group IDs.
>
>
>
>>
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>



-- 
Matthew Melbourne