Hi,

On Wed, Sep 21, 2016 at 11:14:06AM +0200, Robert Raszuk wrote:
> Let me provide an example:
> 
> ???I have 400 PEs and I want to do 10 different length of prepends depending
> on the peering AS.
> 
> So today when I advertise the prefix I need 10 different communites for it
> and 10 different policies on each out of my 399 egress PEs to translate
> such magic number into an action.
> 
> While injecting 10 communities is not a big deal maintaining 10 different
> policies across all 399 PEs adds-up and this is what makes the current BGP
> policies very long and difficult to maintain.
> 
> And if we just add simple integer which will indicate the size of prepend
> and within given AS make one magic number to indicate this is prepend
> request we are neatly done.

This is a very poor example for encoding such complexity into the *protocol*.

An implementation could easily do this in their route-policy language

  if ( community in ( MYAS:PEERAS:([1-9]) ) ) then
      set as-path prepend MYAS times $1 
  endif

with "MYAS" and "PEERAS" properly pre-defined in route-policy context.

Gert Doering
        -- NetMaster
-- 
have you enabled IPv6 on something today...?

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