iBGP next hop and multi-access media

Mon Oct 7 14:13:43 UTC 2002

> > > 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