Subject: Re: [NSIS] Feedback from the "mobility in NSIS" meeting

From: "Sung-Hyuck Lee" <[email-masked]>
Date: Mon, 10 Nov 2003 13:20:44 -0600

Hi  Jukka and Marcus,

my comments inline:

Regrads,

Sung-Hyuck
----------------------------------------------------------------------------------

Jukka wrote:

>> > Basic Issues
>> > ------------
>> 
>> > - How to discover crossover router, when
>> 
>> First question: what do you need the crossover router for? What 
>> functionality is special on the crossover router?

>[JM] Read the line in paranthesis... when you are the receiver and you 
>move, the new path starts at the cross-over router. This is where the 
>local repair starts.

[S-H] Yes, in addition to the initiation of the state update on the common path 
afther handover,  the crossover router may need to have the functionality of 
the NI, NR, and NF.

>> >   a) the cross-over router exists by the definition in RSVP, that is, the
>> > same       session is identified on a new interface
>> >   b) the cross-over router does not exist in the previous way, that is,
>> > new       messages for an existing session arrive from a new peer through
>> > the old       interface
>> >   c) other nodes than the cross-over router affect the signaling
>> > (The cross-over router discovery is most important when the mobile node
>> > is receiver)
>> >
>> > - State update on the common path after handover
>> >
>> 
>> I would assume this is NSLP dependent

>[JM] May be, may be not... don't know the clear answer, yet

>> 
>> > - Interactions with mobility protocols such as MIP and LMM protocols
>> >
>> 
>> IMHO there is no interworking needed with MIP except that MIP might want to 
>> use NSIS.

>[JM] To me NSIS and MIPv6 and Fast Handovers have something in common, as 
>CARD and CT have. Also, how would MIPv4 work with NSIS with CoAs and 
>CCoAs, tunneling, and possible triangular routing. What if CN and MN are 
>actually in the same network? Any changes to make things more efficient 
>aka. optimize? (yes, I know, someone will soon tell not to focus on 
>optimizations at this stage... but it might we worthwhile to at least 
>document some 
>ideas?)

[S-H] IMHO, it may be one of the important issues that we need to discuss at the 
analysis statge as well as at the future optimization stage to support fast 
re-establishment after handover. For example, an MN (as a sender) or a crossover 
router (when an MN is a receiver) may be able to initiate the re-establishment of the 
QoS-NSLP state in a fast manner as soon as the MN or crossover router receives 
a mobility information message (e.g., Binding Update message). 

>> > - Dependencies between the NTLP and NSLP and split of functionality
>> > between    layers
>> >
>> 
>> Can you an example where the split might be different when looking into 
>> mobile versus static networks.

>[JM] No, not yet. Probably some issues related to who triggers who and
>when and why and what messages are then send, when a mobility event occurs
>and states need to be managed.
 
[S-H] Basically, there may not be a big difference. But, at least we can
identity that certain triggering events are related to mobility or non-mobility.
One example could be 'last node detection'. Specifically, when a route change 
occurs due to handover, the NTLP of the old AR will find that its peer (i.e., MN) 
is not alive any longer since it will not receive any acknowledgement from the MN 
in response to a peer discovery request message. However, in this case, the 
NSLP of the old AR should not generate any error message to avoid teardown of 
existing states before the crossover router initiates a teardown message on the 
obsolete path. This case may also be considered as a special case of dead
peer discovery of the NTLP.