How to enable " ipv6 unicast-routing" to permit traceroute from 6PE to ipv6-cloud
mtinka at globaltransit.net
Wed Sep 7 04:43:26 CEST 2011
On Tuesday, August 09, 2011 06:36:27 PM Herlianto wrote:
> Dear IPv6 Expert,
Very late response...
> We are on development IPv6 over MPLS using 6PE schenario.
> Our P using CRS-1 (IOS-XR).
> I Would like to know how to ensure/to test using
> traceoute from one of 6PE to IPv6 Internet cloud?
> Traceroute not permit because of TTL , but there are
> suggest to permit traceroute at P can be enable " ipv6
> but that command is only for IOS, not for IOS-XR.
> I need your advice how to ensure using traceoute from one
> of PE or CE to the IPV6 internet cloud with our P using
> IOS-XR (CRS-1)
Well, first things first, IOS XR is unlike IOS/IOS XE. In
IOS XR, the v6 stack is enabled by default (or what I really
mean is - you don't need to manually turn it on). The only
thing you need to do is assign an interface a v6 address and
you're good to go.
Regarding why traceroute fails in your scenario - well, with
the way traceroute works in MPLS, when an MPLS label's TTL
is decremented to 0 during transit, the router on which the
TTL expires needs to generate the ICMP Unreachable message,
which should be sent down the original LSP along which the
MPLS frame was received.
In your scenario, your core router should generate an ICMPv6
Unreachable message toward the source, but since your router
isn't running v6 (which is the whole point of 6PE), this
will not work, and you'll just see [* * *] in that portion
of the traceroute output.
There has been mention of enabling v6 in IOS (don't know
about IOS XR) and using v4-mapped v6 address to source
ICMPv6 Unreachable messages in a 6PE topology; but if you
ask me, it will be far easier to simply turn on v6 inside
your core and be done with it :-).
Hope this helps.
Mark <= who doesn't believe in 6PE :-).
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Size: 836 bytes
Desc: This is a digitally signed message part.
Url : http://lists.cluenet.de/pipermail/ipv6-ops/attachments/20110907/9475af8f/attachment.bin
More information about the ipv6-ops