Subject: [mpls-tp] PST terminology change

From: Dan Frost <[email-masked]>
Date: Wed, 05 May 2010 12:35:09 +0100

Due to confusion between the use of the term "tunnel" in MPLS today and
the term "Path Segment Tunnel" in the MPLS-TP Framework, the editors have
decided to adopt a new term for the latter.  This new term is "Sub-Path
Maintenance Element" (SPME).  Note that there are no RFCs using this term,
but drafts which currently use or refer to the term PST will need to be
updated accordingly.

- MPLS-TP Framework editors

---

From: David Allan I <[email-masked]>
Date: Wed, 5 May 2010 08:14:19 -0400

Does this replace the term PST as originially misconstrued, or is it the set of LSPs that implement the tunnel to monitor a portion of a transport path....?

My understanding was we needed a term for the latter and some variation of tunnel would be appropriate. 

FWIW Unfortunately the choice of "Element" actually sounds like it is some component of a MEG or ME..

Cheers
D

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Dan Frost
Sent: Wednesday, May 05, 2010 7:35 AM
To: [email-masked]
Subject: [mpls-tp] PST terminology change

Due to confusion between the use of the term "tunnel" in MPLS today and the term "Path Segment Tunnel" in the MPLS-TP Framework, the editors have decided to adopt a new term for the latter.  This new term is "Sub-Path Maintenance Element" (SPME).  Note that there are no RFCs using this term, but drafts which currently use or refer to the term PST will need to be updated accordingly.

- MPLS-TP Framework editors
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---

From: Dan Frost <[email-masked]>
Date: Wed, 5 May 2010 13:51:22 +0100

Hi David,

On Wed, May 05, 2010 at 08:14:19AM -0400, David Allan I wrote:
> Does this replace the term PST as originially misconstrued, or is it
> the set of LSPs that implement the tunnel to monitor a portion of a
> transport path....?

The former; it's just an LSP.

> My understanding was we needed a term for the latter and some
> variation of tunnel would be appropriate. 

This is a separate issue which still needs to be addressed.

> is some component of a MEG or ME..

Element is the thing itself (an LSP).  The E in SPME should become
entity (group) in the context of OAM terminology, I think.

-d

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From: Curtis Villamizar <[email-masked]>
Date: Thu, 06 May 2010 22:08:48 -0400

> - MPLS-TP Framework editors

Awful term but possibly an improvement over PST because it removes any
confusion with tunnel in the RFC3209 sense.

Would "working segement" and "protect LSP" be too simple and clear and
not result in a new TLA and therefore not be worth considering?

BTW in the data plane there is no difference between a single hop LSP
with PHP and a link with no LSP.  If you are not running a control
plane the former is a complete NOOP.  So a segment can be defined as a
single hop unsignaled LSP using PHP.  Then even at layer zero both the
working and protect are LSPs of sorts, just like all the other
layers.  It does remove a special case for layer zero.  :-)

Curtis