Subject: [mpls-tp] Question on scope of draft-frost-mpls-loss-delay-00

From: Greg Mirsky <[email-masked]>
Date: Sun, 19 Dec 2010 19:34:51 -0800

Dear Dan and Stewart,
bullet two in Introduction and Section 2.7.1 Type of Channels list only link
(section, LSP or a PW as channels over which LM and DM could be conducted.
But the Section 2.7.4 Intermediate Nodes describes operation of LM and DM by
using TTL exception method. Though LM and DM operation does not
differentiate whether querier and addressee are MEP or MIP reference to use
of TTL implies to LM/DM directed at MIP. I view it as case of Segment. Do
you see that querier might be MIP as well or LM/DM on generic Segment can be
performed only with SPME?

Regards,
Greg

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From: Stewart Bryant <[email-masked]>
Date: Mon, 20 Dec 2010 14:29:41 +0000

On 20/12/2010 03:34, Greg Mirsky wrote:
> Dear Dan and Stewart,
> bullet two in Introduction and Section 2.7.1 Type of Channels list 
> only link (section, LSP or a PW as channels over which LM and DM could 
> be conducted. But the Section 2.7.4 Intermediate Nodes describes 
> operation of LM and DM by using TTL exception method. Though LM and DM 
> operation does not differentiate whether querier and addressee are MEP 
> or MIP reference to use of TTL implies to LM/DM directed at MIP. I 
> view it as case of Segment. Do you see that querier might be MIP as 
> well or LM/DM on generic Segment can be performed only with SPME?
>
> Regards,
> Greg
In MPLS  I can see no reason why one could not make the measurement 
between any two nodes on the LSP using the TTL method.

Within the MPLS-TP of this, the convention is to only initiate the OAM 
exchange at an LSP endpoint, thus requiring an SPME to monitor the 
traffic between a pair of midpoint LSRs. We may need to add some text on 
this in the MPLS-TP for loss-delay.

- Stewart