iBGP next hop and multi-access media

Mon Oct 7 04:11:26 UTC 2002

On Sun, 6 Oct 2002, jlewis at 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