iBGP next hop and multi-access media

Mon Oct 7 12:38:18 UTC 2002

On Mon, 7 Oct 2002, Ralph Doncaster wrote:

> When you setup a secondary ip on an interface
>  int fa0/0
>    ip address a.b.c.d e.f.g.h secondary
> 
> How does it determine where to send the packets?  ARP.
> Which is the same as adding the route described above.

>From what I've read so far, it looks like you're asking for is more like
automatic discovery of new subnets local to a given segment, followed by
preferential route selection similar to HSRP.  

Except above, you're claiming that adding a secondary interface is the
same as adding a route.  It's not, as adding the secondary interface
provides a logical link between a layer 3 address and a layer 2 address,
so that ARP is not needed to find the next-(layer 3)-hop, only to find the
next layer 2 hop.

Again, let's move routing 101 to different venue.

Pete

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Peter J. Templin, Jr., CCNP, CCDP
Networking Consultant

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