nanog mailing list archives

Re: IPv6 questions


From: snort bsd <snortbsd () yahoo com au>
Date: Tue, 29 Jan 2008 13:55:46 -0800 (PST)


It does make sense though. Say one megabits interface with 20 VLANs. In that scenario, every VLAN, usually has own 
link-local address. It is more practical than "multiple interfaces with same link-local address."

I found this on Juniper router and now assume it is Juniper specific implementation.

Thanks all

----- Original Message ----
From: Scott Morris <swm () emanon com>
To: Erik Nordmark <erik.nordmark () sun com>; snort bsd <snortbsd () yahoo com au>
Cc: nanog () merit edu; juniper-nsp <juniper-nsp () puck nether net>
Sent: Tuesday, 29 January, 2008 12:36:55 PM
Subject: RE: IPv6 questions


And unless you are on only certain particular devices (e.g. L3
 switches)
then the end device won't necessarily have any relevant clue what VLAN
 it's
on.

I have never seen/heard of an RFC for it either and would certainly
 wonder
"WHY?".  :)

Scott 

-----Original Message-----
From: owner-nanog () merit edu [mailto:owner-nanog () merit edu] On Behalf Of
 Erik
Nordmark
Sent: Tuesday, January 29, 2008 1:44 PM
To: snort bsd
Cc: nanog () merit edu; juniper-nsp
Subject: Re: IPv6 questions


snort bsd wrote:
Never mind

it is the VLAN number. But which RFC define this? 

I've never seen an IPv6 RFC specify to put the VLAN number in the
 link-local
address.
Thus this must be an (odd) choice made by some implementation. Perhaps
 the
implementation somehow requires that all the link-local addresses for
 all
its (sub)interfaces be unique, even though the RFCs assume that the
implementation should be able to deal with multiple interfaces with
 same
same link-local address.

    Erik

Thanks all

Dave

----- Original Message ----
From: snort bsd <snortbsd () yahoo com au>
To: nanog () merit edu; juniper-nsp <juniper-nsp () puck nether net>
Sent: Monday, 28 January, 2008 3:05:59 PM
Subject: IPv6 questions


Hi All:

With link-local IPv6 address, the converting from MAC-48 to EDU-64  
address format (FF FE stuffing). How does the VLAN tags affect the  
conversion?

With the rule of FF FE stuffing, I can see clearly work on the ptp  
interfaces. But on those Ethernet based VLANs, it doesn't seem to 
follow  that pattern:

Current address: 00:90:69:4a:b9:5d, Hardware address: 
00:90:69:4a:b9:5d

well, i assume the link-local should be fe80::290:69ff:fe4a:b95d/64.
 actually, it shows:

Destination: fe80::/64, Local: fe80::290:6903:94a:b95d

how does the router get this 03 09 instead of ff fe?

Thanks all








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