Subject: Query regarding loopback interface

From: "Ramakrishnan" <[email-masked]>
Date: 12 Feb 2002 06:12:55 -0000

Dear sir/madam,
   Please answer the following question so that I can proceed further.

Q) if we have any virtual link (ex. loopback) it will have a loopback address. Other than that, should we need to have any link local address for that interface. ?

Anticipating your reply...

regards,
Ramakrishnan. 

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From: Steve Deering <[email-masked]>
Date: Thu, 14 Feb 2002 07:47:11 -0800

>Q) if we have any virtual link (ex. loopback) it will have a loopback address. Other than that, should we need to have any link local address for that interface. ?

Ramakrishnan,

The loopback link does not require a link-local address.  If you have
virtual links that can have more than one node attached (e.g., some
people refer to an IP tunnel as a virtual link), those links will
need link-local addresses for the (virtually) attached nodes.

Steve

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From: JINMEI Tatuya / 神明達哉<[email-masked]>
Date: Thu, 21 Feb 2002 17:39:51 +0900

>>>>> On Thu, 14 Feb 2002 07:47:11 -0800, 
>>>>> Steve Deering <[email-masked]> said:

> need link-local addresses for the (virtually) attached nodes.

This is quite reasonable, but seems to contradict a requirement in the
address architecture draft:

   All interfaces are required to have at least one link-local unicast
   address (see section 2.8 for additional required addresses).
(draft-ietf-ipngwg-addr-arch-v3-07.txt, Section 2.1)

We may have to clarify this point before the draft is in an RFC
status.

					JINMEI, Tatuya
					Communication Platform Lab.
					Corporate R&D Center, Toshiba Corp.
					[email-masked]
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From: Steve Deering <[email-masked]>
Date: Thu, 28 Feb 2002 10:47:40 -0800

>(draft-ietf-ipngwg-addr-arch-v3-07.txt, Section 2.1)

In the scoped addresss architecture draft, we say:

   The IPv6 unicast loopback address, ::1, is treated as having link-
   local scope within an imaginary link to which a virtual "loopback 
   interface" is attached. 

effectively saying that the ::1 loopback address is a special-case
link-local address.

>We may have to clarify this point before the draft is in an RFC

I agree.

Steve