Subject: [nemo] Answers to the questions at IETF SF

From: Ryuji Wakikawa <[email-masked]>
Date: Sat, 03 May 2003 16:50:25 +0900

Hi All.

>Basic Network Mobility Support - draft-wakikawa-nemo-basic-00.txt 
>================================================================== 
>The draft was presented by Thierry Ernst as Ryuji Wakikawa could not be present. 
>All technical questions should be directed to Ryuji via email or on the
>mailing list. 

I was really sorry that I could not attend the NEMO meeting. 
I did not reply to the questions which were made at NEMO meeting in SF.
Thanks Thierry for your kindly offer to make presentation instead of me.

>How does this implementation hand more than one prefix for your mobile
>network? 

If MR has multiple prefixes, then MR basically configures multiple
addresses for all prefixes. 
If the prefixes are aggregated to send BU, then MR configures only single address
for aggregated prefix.

For example, if MR has P-1::/64 and P-2::/64.
MR assigns two addresses as MR-A to send two separate BU for P-1 and
P-2.

If MR decide to manage both prefixes equally, it assigns an address
which is P::/63 and sends single BU for P::/63 to HA.

> There appears to be a restriction to using only one prefix. Thus, how
> do you create routes at the home agent for both prefixes? instead of
> having a prefix suboption? 

MR can take care of multiple prefixes. There is no restriction.

> Question - Does one always have to maintain a binding cache entry on
> the home agent, even when you're at home? 

Management of BC is always required at HA, but the optimization such as
not using tunnel is provided. 
See my former mail posted to NEMO ML (4/30, Subject: Multiple Egress vs multihoming)

> There was a comment that deregistration is easy with implementation.
> However it is unclear as to why this would be. 

For example, ND operations. (Stop Proxy NDP, Re-registraion MN's NDP
entry.) I remembered related discussion at MIP6 ML to let draft simple
and easy. MIP6 does not have alternative solution for returning home,
but our draft proposes the solution to provide advantages of returning
home without deregistration procedures.

regards,
ryuji

---

From: Alexandru Petrescu <[email-masked]>
Date: Sat, 03 May 2003 20:11:33 +0200

Hi Ryuji, just a quick note here.

Ryuji Wakikawa wrote:
>> How does this implementation hand more than one prefix for your 
>> mobile network?
> 
> 

In my view, if MR has two prefixes P-1 and P-2 for the mobile network it
is presumably in order to assign prefix P-1 on the first subnet of the
mobile network (the one that is attached directly to MR) and prefix P-2
to another subnet of the mobile network deeper below MR, like directly
attached to a Fixed Router.  In that case, it is not very natural, in my
oppinion, to assign an address derived from P-2 on any of the MR's
interfaces.

Or maybe you assume (or the questioner assumed) that the two prefixes
are both assigned to the same subnet immediately below MR?

Alex
GBU