Last Call Review of draft-ietf-mpls-tp-shared-ring-protection-05

Request Review of draft-ietf-mpls-tp-shared-ring-protection
Requested rev. no specific revision (document currently at 06)
Type Last Call Review
Team General Area Review Team (Gen-ART) (genart)
Deadline 2017-05-12
Requested 2017-04-28
Other Reviews Rtgdir Last Call review of -04 by Mach Chen (diff)
Secdir Last Call review of -05 by Paul Hoffman (diff)
Review State Completed
Reviewer Christer Holmberg
Review review-ietf-mpls-tp-shared-ring-protection-05-genart-lc-holmberg-2017-05-17
Posted at
Reviewed rev. 05 (document currently at 06)
Review result Ready with Nits
Last updated 2017-05-17


I am the assigned Gen-ART reviewer for this draft. For background on
Gen-ART, please see the FAQ at

Document:		draft-ietf-mpls-tp-shared-ring-protection-05.txt
Reviewer:		Christer Holmberg
Review Date:		17 May 2017
IETF LC End Date:	12 May 2017
IETF Telechat Date:	N/A
Summary:		The document is well written, but there are a few issues I¹d
like the authors to address.

Major Issues: None

Minor Issues:

Section 4.1.3:

The text says:

    "When an MPLS-TP transport path, such as an LSP, enters the ring,Š²

The ³such as an LSP² statement is confusing. Could there be something else
than LSP?

Section 4.4:

Would it be useful to say that, for a given ring, an interconnect node
acts as an egress node for that ring, meaning that all LSPs using the
interconnect node will use the same tunnel within the ring?

Section 4.4.2:

The text says:   

                  "The service LSPs that traverse the interconnected rings
use separate
                  ring tunnels on each ring, and the LSPs on different
rings are
                  stitched by the interconnection node.²

It¹s unclear to me what ³separate tunnels² mean. As there are two
different rings, there will obviously be separate tunnels. Or, do you mean
to say something else?

Section 5.1:

The first sentence says:

                 "The MSRP protection operation MUST be controlled with
the help of the
                  Ring Protection Switch protocol (RPS).²

I think it would be good to have a few introduction sentences of the RPS
protocol, before mandating the usage of it.

The text says:   

                 "The RPS protocol MUST carry the ring status information
and RPS
                  requests, either automatically initiated or externally
                  between the ring nodes.²

This text is a little confusing. Is this a protocol requirement, or a
protocol usage requirement? Similar to my previous comments, a generic
introduction to the protocol, and the requirements it has to fulfil, would
be useful. In addition, that text should reference to section 5.3
for the justification of defining a new protocol in the first place.

Editorial Issues:


In the document you use both ³ring node² and ³ring-node² terminology.
Unless there is a reason for that, please use consistent terminology.

Section 1:

The text says:

    "As described in [RFC5654], MPLS-TP requirements, section"

Šand later:

    "described in section of [RFC5654]."

Please use consistent wording.

Section 3:

I like the way the section describes how the requirements have been met.
As I assume most of the solutions are described more in detail elsewhere
in the document, I wonder whether it would be possible to add references?

Something like:

"For detailed information, see section x.x.x.x."

Section 4.1:

The text says:

   "A port can carry multiple ring tunnels, and a ring tunnel can carry
multiple LSPs."

I think it would be good to add a picture showing a port carrying multiple
ring tunnels, carrying multiple LSPs.