ECMP group limits

[otn-cco]

Hi,

I understand from Cisco that the NCS 5k platform has an ECMP group limit of 4096.   I'm struggling to determine what limits there might be for other platforms such as an ASR 1k for example.   Has anyone run into this before ?

Thanks.

Matt.

[Georg Pauwen]

Hello,

stupid question maybe, but what do you mean by group limit ? The Nexus 5000 support 16 paths for load balancing, but that is probably not what you mean ?

[otn-cco]

Hi,

Here is what Cisco TAC has told us.

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Following is more detail about ECMP group:
 
ECMP object is used by an IPv4 route/IPv6 route/MPLS entry when there are multiple paths corresponding to that prefix. ECMP object consists of an ECMP group object which points to an array of member paths. Each member path corresponds to a specific path through which the packet can be forwarded.
When there is only a single path to forward the packet, ECMP object will not be used.
Each ECMP object uses entries from the member path table. The number of entries used is equal to the number of paths in ECMP. If either of the resources run out, we will hit OOR condition and this will result in not programming rest of the route updates.

Matt