RE: Two Drafts for Resilience of Control Plane

[ibryskin@movaz.com]

Hi,

Here is one of the problems that I?ve been thinking for a while ? control
plane partitioned LSPs. Suppose one or more signaling controllers managing
some LSP went out of service leaving the LSP?s data plane intact. As far
as the user is concerned such LSP is perfectly healthy and operational.
Such situation could last for a considerable period of time. Do we need to
manage such LSP via control plane? Sure, we must be capable to tear down
such LSP, perform mb4b rerouting, distribute alarms between operational
controllers, signal data plane faults and perform recovery switchover,
modify LSP status, etc. Can we do this today? No, but with some
(signaling) extensions the problem I believe is solvable. Is this some
artificial, ?fabricated? problem? No, I think it is real. Does it fall
under the control plane resilience problem space? I believe it does.

Igor

> I agree with Zafar and Dimitri.  If someone wanted to document the GMPLS
> control plane resiliency features, as was done for GMPLS addressing,
> that might be a useful activity.
>
>> -----Original Message-----
>> From: dimitri papadimitriou [mailto:dpapadimitriou@psg.com]
>> Sent: Friday, October 28, 2005 9:56 AM
>> To: Igor Bryskin
>> Cc: Zafar Ali (zali); Kim Young Hwa; ccamp@ops.ietf.org
>> Subject: Re: Two Drafts for Resilience of Control Plane
>>
>> igor -
>>
>> over time CCAMP came with a set of mechanims to improve control plane
>> resilience (RSVP and LMP GR upon channel/node failure) other WG
> protocol
>> work are also usable used here OSPF GR, etc. ... on the other side,
>> mechanism such as link bundling have built-in resilience capabilities
>> and most GMPLS control plane capabilities have been designed such as
> to
>> be independent of the control plane realisation (in-band, out-of-band,
>> etc.)
>>
>> so indeed i share the concern of Zafar what could we do more here than
>> document these tools and provide our experience in using them;
>>
>> now, before stating there are (potential) problems(s) arising - would
>> you please be more specific on what are these potential issue(s)
> and/or
>> problems ? (not related to policy/config. - note: all the issues you
>> have pointed here below are simply policy/config specific but none of
>> them highlights a missing IP control plane resiliency feature)
>>
>> thanks,
>> - dimitri.
>>
>>
>> Igor Bryskin wrote:
>>
>> > Zafar,
>> >
>> > The problem arises when the control plane is decoupled
>> > from the data plane. The question is do we need such
>> > decoupling in IP networks? Consider, for example, the
>> > situation when several parallel PSC data links bundled
>> > together and controlled by a single control channel.
>> > Does it mean in this case that when the control
>> > channel fails all associated data links also fail? Do
>> > we need to reroute in this case LSPs that use the data
>> > links? Can we rely in this case on control plane
>> > indications to decide whether an associated data link
>> > is healthy or not (in other words, can we rely on RSVP
>> > Hellos or should we use, for example, BTD)? Should we
>> > be capable to recover control channels without
>> > disturbing data plane? I think control plane
>> > resilience is important for all layers. You are right,
>> > Internet does work, however, we do need for some
>> > reason TE and (fast) recovery in IP as much as in
>> > other layers,don't we?
>> >
>> > Cheers,
>> > Igor
>> >
>> > --- "Zafar Ali (zali)" <zali@cisco.com> wrote:
>> >
>> >
>> >>Hi All,
>> >>
>> >>I am unable to understand the problem we are trying
>> >>to solve or
>> >>fabricate. My control network is IP based and IP has
>> >>proven resiliency
>> >>(Internet *does* work), why would I like to take
>> >>control plan resiliency
>> >>problem at a layer *above-IP* and complicate my
>> >>life. Did I miss
>> >>something?
>> >>
>> >>Thanks
>> >>
>> >>Regards... Zafar
>> >>
>> >>
>> >>________________________________
>> >>
>> >>	From: owner-ccamp@ops.ietf.org
>> >>[mailto:owner-ccamp@ops.ietf.org]
>> >>On Behalf Of Kim Young Hwa
>> >>	Sent: Friday, October 28, 2005 6:04 AM
>> >>	To: ccamp@ops.ietf.org
>> >>	Subject: Two Drafts for Resilience of Control Plane
>> >>
>> >>
>> >>	Dear all,
>> >>
>> >>	I posted two drafts for the resilience of control
>> >>plane.
>> >>	One is for requirements of the resilience of
>> >>control plane, the
>> >>other is for a protocol specification as a solution
>> >>of that .
>> >>	These are now available at:
>> >>
>> >>
>> >
>> > http://www.ietf.org/internet-drafts/draft-kim-ccamp-cpr-reqts-01.txt
>> >
>> >>
>> >>
>> >
>> >
> http://www.ietf.org/internet-drafts/draft-kim-ccamp-accp-protocol-00.txt
>> >
>> >>
>> >>	I want your comments.
>> >>
>> >>	Regards
>> >>
>> >>	Young.
>> >>
>> >>	===================================> >>	Young-Hwa Kim
>> >>	Principal Member / Ph.D
>> >>	BcN Research Division, ETRI
>> >>	Tel:     +82-42-860-5819
>> >>	Fax:    +82-42-860-5440
>> >>	e-mail: yhwkim@etri.re.kr
>> >>	===================================> >>
>> >>
>> >
>> >
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>> >
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>> >>
>> >
>> >
>> >
>> >
>> >
>> >
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