Subject: RE: [NSIS] I-D ACTION:draft-vandenbosch-nsis-resilience-00.txt

From: "Georgios Karagiannis (ELN)" <[email-masked]>
Date: Wed, 3 Jul 2002 17:28:07 +0200

Hi Sven

I will only reply to one of your statements/remarks, that is mainly
representative also for some of the other statements/remarks that
you have sent in your previous e-mail.
Note that I am open on discussing and contributing to your draft.

[georgios-first]>> I will only comment your draft starting from Section 5.
[georgios-first]>> Main comment that I have is related to the fact  that you somehow
[georgios-first]>> emphasise that the per-class states complicate the failure notification
[georgios-first]>> and recovery issues, while I think that failure notification and recovery
[georgios-first]>> issues are independent of the type of these states.

[sven] In general, per-class state has the effect of losing the link
between a certain initiator and its associated reservation. As such, it
causes an issues for failure notification because of the absence of state
information on where to send the notification.

[georgios] well, in both approaches (when a node uses a per flow state 
or a per class state), a failure can be notified to either another NF (NSIS Forwarder)
or to a NSIS Initiator (NI).
In the per-class state approach the failure can be notified to a NF (NSIS Forwarder) 
located at an edge node that can relate the per class 
state with a per flow state. This NF can subsequently notify the NSIS Initiator (NI)
when needed.
In the per flow state approach the failure can be notified to an NF (edge)
or to an NI when needed.

Best Regards,
Georgios

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---

From: [email-masked]
Date: Thu, 4 Jul 2002 08:19:29 +0200

Hi Georgios,

Thanks for your comments. I think you are making two important assumptions,
that may be specific to a particular scenario:
1. Some of the NFs keep per-flow state, some do not (the 'edges' as you
call them)
2. The NF that detects the failure and the NF that needs to be informed see
the same network (otherwise, how will the per-class NF know which other NFs
to contact)
Now there are three possibilities:
1. The scenario you have in mind does not have some the issues described in
the draft. They can, however, remain valid for other scenarios.
2. The scenario you have in mind can have some of the issues described in
the draft. In that case, it is covered.
3. The scenario you have in mind has issues that are not mentioned in the
draft. In that case, of course, we should add them.
We might try to link specific issues to scenarios (like we discussed for
the requirements draft).

What do you think?
Sven.

"Georgios Karagiannis (ELN)" <[email-masked]>
@ietf.org on 03/07/2002 17:28:07

Sent by:  [email-masked]

To:   Sven VAN DEN BOSCH/BE/ALCATEL@ALCATEL
cc:   [email-masked]
Subject:  RE: [NSIS] I-D ACTION:draft-vandenbosch-nsis-resilience-00.txt

Hi Sven

[georgios-first]>> I will only comment your draft starting from Section 5.
[georgios-first]>> Main comment that I have is related to the fact  that
you somehow
[georgios-first]>> emphasise that the per-class states complicate the
failure notification
[georgios-first]>> and recovery issues, while I think that failure
notification and recovery
[georgios-first]>> issues are independent of the type of these states.

[georgios] well, in both approaches (when a node uses a per flow state
or a per class state), a failure can be notified to either another NF (NSIS
Forwarder)
or to a NSIS Initiator (NI).
In the per-class state approach the failure can be notified to a NF (NSIS
Forwarder)
located at an edge node that can relate the per class
state with a per flow state. This NF can subsequently notify the NSIS
Initiator (NI)
when needed.
In the per flow state approach the failure can be notified to an NF (edge)
or to an NI when needed.

Best Regards,
Georgios

---

From: "Georgios Karagiannis (ELN)" <[email-masked]>
Date: Thu, 4 Jul 2002 14:10:07 +0200

Hi Sven

What I tried to say in the previous e-mail is that 
the resilience issues that will have to be taken into consideration 
in NSIS are failure notification and for some extend
failure recovery!
Now these are resilience issues that have to be covered by NSIS anyway, 
independently if a NF is using a per flow state or a per class
state. The way (i.e., the solution) of how the failure notification 
and failure recovery is done is different for these two cases, but the 
issues that are relevant for NSIS and have to be considered by NSIS 
are the same.

Best Regards,
Georgios

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]]
Sent: Thursday, July 04, 2002 8:19 AM
To: Georgios Karagiannis (ELN)
Cc: [email-masked]
Subject: RE: [NSIS] I-D ACTION:draft-vandenbosch-nsis-resilience-00.txt

Hi Georgios,

What do you think?
Sven.

Hi Sven

Best Regards,
Georgios