[frr] 2 MPLS Questions

[David Ahern]

On 4/6/17 11:24 AM, Olivier Dugeon wrote:
> Hi David,
> 
> 
> Le 06/04/2017 à 16:14, David Ahern a écrit :
>> On 4/6/17 10:12 AM, Donald Sharp wrote:
>>> I'm not sure I would call it 'waste'.  The solution, as I understand
>> There is no waste.
>>
>>> it, allocates the appopriate amount of memory to handle the # of
>>> labels handed to it with a *limit* of 4k bytes to the size that is
>>> alloc'ed internally to the kernel.  This way they are keeping the data
>>> structure limit to the maximum size of a page on some platforms at
>>> worse case.
>> exactly.
> So, if I correctly understand, this means that we could manage for
> example 136 segment paths of 30 labels each, 256 segment paths of 16
> labels each, 1024 segment paths of 4 labels, ... In other words, the sum
> of all label stacks of all segment paths must fit under the 4k bytes
> limit. I understand that we must put a limit, but 4k bytes is short.
> Very short. At the maximum it only authorizes 4k connexions with only
> one label i.e. only 4K LDP, RSVP-TE or MP-BGP paths.
> 
> So, is there a possibility to request another chunk of 4k bytes to
> increase the number of managed paths ? or this limit is hard coded at
> the compilation ?

Before I respond, let me make sure I understand your question.

The 4k limit is for a single route. A route is nexthops + labels per
nexthop. for example:

ip -f mpls route add 100 \
    nexthop as to 101/102/.../130 via inet 172.16.1.1 \
    nexthop as to 201/202/.../230 via inet 172.16.2.1 \
    ...
    nexthop as to 3001/3002/.../3030 via inet 172.16.30.1 \

Are you saying you want more than 30ish nexthops in a single multipath
route?