[j-nsp] Limit on the number of BGP communities a route can be tagged with?

[James Bensley]

On 23 August 2016 at 13:40, Olivier Benghozi
<olivier.benghozi at wifirst.fr> wrote:
> And about a limitation to 10 communities:
> I've seen that on SEOS (Redback/Ericsson OS for SmartEdge routers) when using "set community" in a route-map. This is a ridiculous arbitrary limitation, of course.
>
> Hopefully the limitation was only in the CLI, not in the BGP code itself. So the workaround was to use the route-map "continue" command like in a BASIC GOTO structure to add more communities in additional route-map entries (with set community additive - these are Cisco-like commands).
>
>> Le 23 août 2016 à 14:03, Alexander Arseniev <arseniev at btinternet.com> a écrit :
>>
>> In BGP messages, a regular community is encoded in 7 bytes, and extended one in 11 bytes.
>>
>> Max BGP message size is 4096 bytes - this sets a limit for regular communities number to about 4K/7=570, and for extended communities to about 4K/11=360, if You consider the minimal mandatory information that has to be there apart from communities.
>>
>>
>> On 23/08/2016 03:18, Huan Pham wrote:
>>>
>>> I remember hitting a limit on a number of communities (something like 10 or
>>> so) on a platform (can not remember which one from which vendor). So I
>>> believe that there is a hard limit a platform or OS can support.
>>>
>>> I test this in the lab and found no problem with tagging 100 communities.
>>>
>>> Is there a maximum number of communities that Junos can tag to a route? If
>>> yes, then what it is?  Thanks.


Hi,

Hopefully not completely hijacking this thread; I'm interested to know
if there is a way I can limit a peer to a maximum number of
communities?


Cheers,
James.