nanog mailing list archives

Re: iBGP next hop and multi-access media


From: Ralph Doncaster <ralph () istop com>
Date: Mon, 7 Oct 2002 00:11:26 -0400 (EDT)


On Sun, 6 Oct 2002, jlewis () lewis org wrote:

On Sun, 6 Oct 2002, Ralph Doncaster wrote:

As others are saying... it isn't "local".  It's not "local"
unless in the same subnet.  Physical topology often correlates
with higher layers, but it's not strictly 1:1.

Manually configuring a static route in router A would achieve the result:
ip route 172.16.16.0 255.255.255.0 fa0/0

Why are we doing basic IP routing 101 on NANOG?  

OK, since it's so basic why don't you explain how to have router A
dynamically learn from router B that there is a new subnet on the local
ethernet?

Don't route IP blocks to the ethernet.  That's using ARP as your routing
protocol and it's horribly fragile.  I've seen one ISP do that (they were
very technically challenged) and it's a setup that broke way too easily.

So then what do you call a connected route (for an ethernet interface on a
router)?  If you use ethernet, at the edges of your network you HAVE to
route IP blocks to the ethernet.

-Ralph



Current thread: