From: Scott Morris (swm@emanon.com)
Date: Wed Mar 14 2007 - 10:32:10 ART
If you are in the same subnet, you have to resolve down to layer2 addressing
(maps). If you are NOT in the same subnet, you could put up frame-relay
maps all you'd like, but it won't help you at all! Routing is the way to go
there!
Even with routing though, you still have SOME L3-L2 resolution. Namely in
order to route, you need your next hop. In order to get to your next hop
(on a local network) you need to know their physical address (L2) in order
to get there over whatever medium it happens to be!
IPv6 doesn't work any differently here than IPv4 does! The only difference
is that with IPv6, you need to map multiple addresses (anything you have
configured on the interface, including link-local, site-local, global
unicast, whatever). The big one is link local, and that's because all
packets sourced by your IGPs will show a source address of the FE80::xxxx.
That's your next hop and therefore needs to be reachable!
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Salau,Olayemi
Sent: Wednesday, March 14, 2007 8:41 AM
To: swm@emanon.com; Cisco certification
Subject: RE: IPv6 on Frame-Relay
Cheers Scott,
Your response on issue 2 is helpful; to be honest, just got to know that .0
is a valid address in ipv6 world. I understand the issue with eui-64, how it
works and I also comprehend your comment about point 1. So I'm left with
issue 3 now.
An excerpt from your reply:
"3. Same rules as IPv4. If you are on the same subnet, you'll want to have
Layer3 to Layer2 mapping (otherwise you'd get "encapsulation failed"
messages in "debug ipv6 packet") just like in Ipv4! The difference here is
that you have multiple addresses to use!"
... But we don't usually do remote addresses' layer3 to layer2 mapping in
IPv4. I thought Routing takes care of that (either static/dynamic).
Using Static Route within IPv6 domain usually don't need Layer3 to Layer2,
But for dynamic routing, you certainly do. I certainly understand the
concept of Layer3-2-Layer2 mapping else I wouldn't see myself prepared for
this exam by now, what I'm struggling with is why do
this(L3-to-L2 mapping) for remote addresses when using Dynamic RPs within
IPv6 domain.
Many Thanks
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