Subject: RE: [Forces-protocol] topic 2:: HA

From: "Khosravi, Hormuzd M" <[email-masked]>
Date: Mon, 26 Apr 2004 09:00:24 -0700

Hi Weiming,

Thanks for your comments. I am fine with your 1st 2 comments, I had a
question on the 3rd.
Why does TML configuration affect the association between the Primary CE
and FE ? I must be missing something here. Pls do clarify this.

BTW, to answer your question...
"Is the TML only allowed to be statically configured, or can be
configured dynamically by CEM/FEM?"

I don't think we need to define this, the TML can be either statically
configured or dynamically configure. BTW, what configuration are you
referring to ? Also, I think we should have less dependence on CEM/FEM
since this is not something in our scope either, otherwise it will be
difficult to get a working implementation. So static configuration might
be the best.

Hope this helps,

regards
Hormuzd

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Weiming Wang

Here is my attempt to start some discussion on topic 2, we just have 1
week to complete All discussions so we need to move fast!

Based on our discussions on TML and PL as well as the 3 schemes proposed
by Jamal, here is my suggestion for HA scheme...

At any time there is one Primary CE controlling the FE and there can be
multiple secondary Ces. The FE PL is aware of the primary and secondary
Ces. Only the primary CE is sending Control messages to the Fes. The FE
may choose to send its events, redirection packets to all the Ces or
only Primary CE (we need to decide one or keep this configurable ?). A

[Weiming] Based on the fact that ForCES requirements and framework have
explicitly defined CE-CE and FE-FE being out of scope of ForCES
architecture
(not only out of the ForCES protocol), and CE-CE syncronization should
surely be
supplied (by any means) by custumers when multi CEs are used, I suggest
we limit
FE to only be responsible for one CE at a time so as to simplify the
case.
Partial information like events, redirection packets in this case
actually is of
little use for the redundant CEs.

[HK] Ok, I am fine with this

CE-to-CE synchronization may be needed, however that is out of our
current scope for ForCES PL.
[Weiming] As I said above, this is even out of the scope of ForCES
architecture,
according to RFC3654.

[HK] Agreed

The association between the FE and primary
CE may change based on the Connection State (triggered by TML) or an
explicit message (such as Move, described by Jamal) from the primary CE.

[Weiming] Regarding this, I strongly ask to let us answer the questions
first
"Is the TML only allowed to be statically configured, or can be
configured
dynamically by CEM/FEM?" If it is a static one, we then definitely need
PL to
have TML configuration ability (as I have posted for several times, and
also Ram
proposed), or else, if TML can be dynamically configured by CEM/FEM all
the time
during the protocol runtime, we then do not need to have the PL to do
this.
This rule also applies to CE change or failover, connection link
failure, etc.
From the TML-PL interface discussion and the HA discussion, I have a
strong
feeling that some TML configuration from PL layer based on, as Ram said,
sessions are  also in great demand as well as per message based implicit
signaling.  Hormuzd &Jamal, I hope you can give some comments on this.
[/Weiming]

Best regards,
Weiming

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---

From: "Weiming Wang" <[email-masked]>
Date: Tue, 27 Apr 2004 00:34:54 +0800

Hi Hormuzd,

Thank for your immediate reply. pls see more inline.

BR,
weiming

----- Original Message -----
From: "Khosravi, Hormuzd M" <[email-masked]>

[Weiming] My understanding of the re-association process of CE-FE is  actually
to re-configure the TML in some way. Of course, you may call it just a state
change  or a 'move' action,  or whatever, which actually does not matter too
much.  What I actually mean is this process may then be able to be controlled by
PL if we do not want CEM/FEM to do this (I'm actually still not clear if CEM/FEM
may always be uprunning along with the protocol running, or just run for one
time only when CE/FE starts). For e.g., we may setup some policies in advance to
FE TML to let it know what to do when some CE fails. This is what I mean TML
configuration here. My idea (I suppose also Ram's ) is such configuration may be
necessary, not just for the HA policy.
[/Weiming]

Hope this helps,

regards
Hormuzd

-----Original Message-----

[HK] Agreed

Best regards,
Weiming