Subject: RE: [Fwd: I-D ACTION:draft-pan-rsvp-te-restart-01.txt]

From: "David Allan" <[email-masked]>
Date: Wed, 15 Aug 2001 15:03:00 -0400

Ping:

Comments in line....

<snip>
	> You (and others, my 
	> point is not specific to this I-D) are eliminating all forms of
fate 
	> sharing between the control and data planes, despite (in the MPLS
case 
	> vs. GMPLS) the use of common resources in the control and data
plane 
	> adjacencies.

	David,

	What has been proposed in all forms of graceful restart is the
message 
	format on the wire. How you implement the routers to support these 
	messages is totally up to the developers.

Seems to me that interoperability and overall network survivability would
mandate at least some agreement on the semantics associated with this
stuff.... 

	> This may suggest that control plane failure is today significantly
more 
	> frequent than data plane or link failure and there is a real
problem to 
	> solve, but adding restart mechanisms to everything in the control
plane 
	> is not the complete answer.

	You are right. There are several solutions to help routers/networks
in 
	case of failure condition. Graceful restart is to solve the problem
when 
	control plane dies, but data forwarding is up. Fast reroute is to
solve 
	the problem when data forwarding is in trouble. LSP-ping (please
don't 
	start all those architectural beatification argument again) is to
detect 
	data plane black-hole problem....

Secular issues aside ;-), what you describe above is a pragmatic response to
improving the reliability of a particular application of MPLS, and that's
OK, but I trust you aren't suggesting that the above is a complete
solution....

cheers
Dave

---

From: Ping Pan <[email-masked]>
Date: Wed, 15 Aug 2001 14:14:23 -0700

David Allan wrote:

> 
> Secular issues aside ;-), what you describe above is a pragmatic 
> response to improving the reliability of a particular application of 
> MPLS, and that's OK, but I trust you aren't suggesting that the above is 
> a complete solution....
> 

Dave,

You are right. We are not solving all the problems in the MPLS world. In 
fact I doubt anybody knows all the problems.  :-)

Base on our (both vendors and providers) experience, we will solve the 
problems as they come up. I hope this is a reasonable approach.

Best regards,

- Ping