Re: [nsp] BGP Migration

From: Niels Bakker (niels@euro.net)
Date: Wed Aug 16 2000 - 11:38:14 EDT


andy nwebube <andynwebube@hotmail.com> writes:

> I wonder if anybody in this community can give me some advice. I am working
> on migrating an AS to an already existing one. I have an idea of what I want
> to do but I would love to hear from you guys.
>
> The situation is the AS call it B that I am migrating is connected to the
> main AS (A) at two places running 100Mb FE connections (with eBGP). Maximum
> traffic on both lines are about 50Mb. AS B is also connected to another
> telco that also provides internet access. the line is clocked at 18Mb. and
> finally AS B has a connection to an Internet Exchange BW is 100Mb.
> Apart from peering with the Telco and AS A, the only other peering is at the
> Internet Exchange. (~50 peerings).

Hmmm. Do you happen to work for my previous employer, by any chance?

> My question is how would you go about this without loosing much connectivity
> to the internet and carry out the migration seamlessly.
>
> Secondly, does anybody know where I could get information on the internet
> with regards to case studies of AS migrations.

First of all, you should check whether your peers see the announcements
done by AS A of AS B. Some probably offer looking glasses. Then, decide
whether you want to keep AS B's router alive at the exchange (of course
not as AS B but under AS A). If so, tell your peers that on a certain day
it'll move to another AS, and will they please reconfigure their routers
on that day. You can only do this if that router is actually directly
connected to AS A.

Then, do the same trick will all other routers in AS B, including the one
to the external ISP. (This will probably require some coordination. If
they want to impose their planning on you, dump them.) You'll probably
want to originate the networks currently in AS B on a core router
somewhere in AS A.

Don't forget to update the RIPE database - probably best to do this a few
days in advance so people building automatic filters have a bit more time
to adjust to the new situation.

Merging the two IGPs will be a seriously more... interesting undertaking.

If you work for my previous employer: don't forget to tell them from whom
you got the advice.

TIE,

        -- Niels.



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