[52616] in North American Network Operators' Group
Re: iBGP next hop and multi-access media
daemon@ATHENA.MIT.EDU (alex@yuriev.com)
Mon Oct 7 10:09:20 2002
Date: Mon, 7 Oct 2002 10:13:43 -0400 (EDT)
From: alex@yuriev.com
To: Ralph Doncaster <ralph@istop.com>
Cc: "jlewis@lewis.org" <jlewis@lewis.org>,
"E.B. Dreger" <eddy+public+spam@noc.everquick.net>,
"nanog@merit.edu" <nanog@merit.edu>
In-Reply-To: <Pine.LNX.4.21.0210070006230.1709-100000@ns.istop.com>
Errors-To: owner-nanog-outgoing@merit.edu
> > > 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?
It cannot. IP works on layer 3. Ethernet is layer 2. Your local grouping
happens on layer 2. Layer 3 does not know about it unless you TELL it about
it.
> 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.
A connected route is installed only when you *CONFIGURE* it, something that
you are refusing to do.
Configure the connected route by assigning a secondary to the interface and
your router will *know* that it can reach that subnet directly.
If you do not want to do that, configure a dynamic routing protocol or
insert a static route pointing to a router which knows how to reach that
network directly.
Alex
