[j-nsp] Least impactful way to migrate from private ASN to public ASN

[Andy Litzinger]

We have two MX80 routers that currently each have an eBGP neighbor to the
same upstream ISP and are iBGP neighbors.  We are using the same internal
ASN for both iBGP and eBGP.  It's the autonomous-system number defined
under routing-options.  We're adding a second peer and have recently
received our public AS from RIPE.

Currently we are only receiving default routes from our upstream ISP.  The
new peer will only be advertising a small section of their space to us.

With respect to configuration changes on the MX80s, what is the least
impactful way to move from the private ASN to the public?

since we're only receiving default routes is it enough to simply change the
ASN on one router at a time while coordinating the change with the ISP at
the same time?  I presume my iBGP session will break until i replicate the
same change on the other side, but will that really impact anything in this
case?

thanks!
 -andy