[c-nsp] BGP re-announcement question

[Pete Templin]

On 7/29/13 4:06 PM, Arie Vayner (avayner) wrote:
> The best route is through your upstream (I guess), so you are not
> advertising it back... You could increase the local-pref for routes
> you receive from your customers as compared to routes you receive
> from your upstreams. In this way you would always prefer the local
> path to your customer (not sure they would like you to do that...)

+10000 on this.  They are your customer, so it's safe to presume that 
they want you to carry their traffic (they send you a check every month 
in exchange for this service), and in turn you (might) send a check 
elsewhere to continue the process.  It's not an easy thing to roll out 
en masse, but I'd argue that it needs to be done.

I normally use 400 for customer routes, 300 for routes from peers (I've 
been known to use transit providers as peers; accept only their routes 
and their customer routes, and advertise out with no-export or their own 
'peer' community), 200 for routes from transits.  One benefit is that an 
"unconfigured" router with LP=100 won't get any traffic, so it'll make 
the lack of proper configuration obvious.

As others suggested, a community to override this might be appreciated 
by your customers, if they have enough clue to use it. Be warned that 
since "everyone else" (or at least everyone else upstream of you) does 
this same sort of preference, so if they request a low LP in your 
network, they're going to want a low LP in subsequent networks until 
they get to the peered-only networks.

pt