Re: [Lsr] Fwd: I-D Action: draft-ietf-lsr-isis-area-proxy-03.txt

[[e-mail]]

Hi Tony,

Please find below some nits/minor comments. Please feel free to silently discard.

1)

OLD: The
   advertisement in the Proxy LSP informs the remainder of the network
   that packets directed to the SID will be forwarded by one of the
   Inside Edge Nodes and the Area SID will be consumed.

NEW:

The

   advertisement in the Proxy LSP informs the outside area

   that packets directed to the SID will be forwarded to one of the

   Inside Edge Nodes and the Area SID will be consumed.

Motivation:

1)      More precise/descriptive and use the terminology defined in the draft

2)      The SID is a priori global in the outside area and hence will be forwarded by all nodes in the outside area (and not just by the Inside Edge Nodes). The destination is anycast to/toward any Inside Edge node.


2)
§ 4.3.2.  The Area SID Sub-TLV

The Area SID Sub-TLV allows the Area Leader to advertise a prefix and

   SID



§4.4.13.  The Area SID

  The Area Leader SHOULD advertise the Area SID information in the

   Proxy LSP as a Node SID as defined in [RFC8667] Section 2.1<https://tools.ietf.org/html/rfc8667#section-2.1>.


RFC8667 requires that for a Node SID, the prefix be an IP address (/32 or /138) (rather than an IP prefix of an arbitrary length) [1].
[1] https://tools.ietf.org/html/rfc8667#section-2.1.1.2

You may want to refer to this restriction when defining the Area SID Sub-TLV in section 4.3.2 . e.g. :s/advertise a prefix/advertise an IP address. Alternatively open the option to advertise a prefix SID without the N-Flag if this is a prefix.


3)
1 typo in -04 :s/ Inisde/ Inside

4)
OLD:
The Area Leader will generate a Proxy LSP that must be flooded across
   the Inside Area.  Inside Routers MUST ignore the contents of the
   Proxy LSP other than for flooding

My personal preference would be
NEW
The Area Leader will generate a Proxy LSP that will be flooded across
   the Inside Area.  Inside Routers MUST ignore the contents of LSP(s) originated with the Area Proxy System Identifier other than for flooding.

Motivation:

a)      Clarify that no new behavior is involved

b)      Specifies how the proxy LSP is to be identified as a proxy LSP.

5) Open question: is the Area Proxy LSP to be advertised/read from L1 or L2 LSP/LSDB or both?

"All routers within the Inside Area speak Level 1 and Level 2 IS-IS on all of the links within the topology."
OK.

"A node advertises the Area Proxy TLV in its L2 LSP"
So my reading/guessing is that the Area Proxy TLV is only sent in the L2 LSP of all Inside routers. (i.e. not in the L1 LSP).
If so:

-          Can you clarify the behavior when an Area Proxy TLV is received in an L1 LSP? (e.g. ignore, and if not, what is the behavior when the TLV is different in L1 and L2).

-          "they will advertise the Area Proxy TLV." May be adding "in their L2 LSP"

-          "All Inside Edge Routers learn the Area Proxy System Identifier from the Level 1 LSDB". I would have assumed  "from the Area Proxy TLV advertised in the level 2 LSDB.  So it may be a typo or I'm missing something, which is very possible.

o   "it MUST inject   the Area Proxy System Identifier into the Level 1 LSDB." Same comment.


Thanks,
--Bruno


From: Lsr [mailto:[e-mail]] On Behalf Of [e-mail]<mailto:[e-mail]>
Sent: Friday, September 4, 2020 2:29 PM
To: [e-mail]<mailto:[e-mail]>
Cc: [e-mail]<mailto:[e-mail]>
Subject: Re: [Lsr] Fwd: I-D Action: draft-ietf-lsr-isis-area-proxy-03.txt

Hi Tony,

I've read the diff for -03 and -04.
The new encoding of the Area SID is good for me.

And thank you for listening to my use case and suggestion.

Thanks,
--Bruno


From: Lsr [mailto:[e-mail]] On Behalf Of [e-mail]<mailto:[e-mail]>
Sent: Monday, August 24, 2020 7:02 PM
To: [e-mail]<mailto:[e-mail]>
Subject: [Lsr] Fwd: I-D Action: draft-ietf-lsr-isis-area-proxy-03.txt


Hi folks,

This updated draft has been published for a few weeks now.  We would like to solicit your opinion on this.  In particular, we have changed the encoding of the Area SID.  Do you find this encoding adequate and appropriate?

Thanks,
Tony



Begin forwarded message:

From: [e-mail]<mailto:[e-mail]>
Subject: I-D Action: draft-ietf-lsr-isis-area-proxy-03.txt
Date: August 5, 2020 at 1:17:39 PM PDT
To: <[e-mail]<mailto:[e-mail]>>
Cc: [e-mail]<mailto:[e-mail]>
Reply-To: [e-mail]<mailto:[e-mail]>, [e-mail]<mailto:[e-mail]>


A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the Link State Routing WG of the IETF.

       Title           : Area Proxy for IS-IS
       Authors         : Tony Li
                         Sarah Chen
                         Vivek Ilangovan
                         Gyan S. Mishra
        Filename        : draft-ietf-lsr-isis-area-proxy-03.txt
        Pages           : 19
        Date            : 2020-08-05

Abstract:
  Link state routing protocols have hierarchical abstraction already
  built into them.  However, when lower levels are used for transit,
  they must expose their internal topologies to each other, leading to
  scale issues.

  To avoid this, this document discusses extensions to the IS-IS
  routing protocol that would allow level 1 areas to provide transit,
  yet only inject an abstraction of the level 1 topology into level 2.
  Each level 1 area is represented as a single level 2 node, thereby
  enabling greater scale.


The IETF datatracker status page for this draft is:
https://datatracker.ietf.org/doc/draft-ietf-lsr-isis-area-proxy/

There are also htmlized versions available at:
https://tools.ietf.org/html/draft-ietf-lsr-isis-area-proxy-03
https://datatracker.ietf.org/doc/html/draft-ietf-lsr-isis-area-proxy-03

A diff from the previous version is available at:
https://www.ietf.org/rfcdiff?url2=draft-ietf-lsr-isis-area-proxy-03


Please note that it may take a couple of minutes from the time of submission
until the htmlized version and diff are available at tools.ietf.org.

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/


_______________________________________________
I-D-Announce mailing list
[e-mail]<mailto:[e-mail]>
https://www.ietf.org/mailman/listinfo/i-d-announce
Internet-Draft directories: http://www.ietf.org/shadow.html
or ftp://ftp.ietf.org/ietf/1shadow-sites.txt


_________________________________________________________________________________________________________________________



Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc

pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler

a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,

Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.



This message and its attachments may contain confidential or privileged information that may be protected by law;

they should not be distributed, used or copied without authorisation.

If you have received this email in error, please notify the sender and delete this message and its attachments.

As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.

Thank you.

_________________________________________________________________________________________________________________________

Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc
pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler
a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,
Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.

This message and its attachments may contain confidential or privileged information that may be protected by law;
they should not be distributed, used or copied without authorisation.
If you have received this email in error, please notify the sender and delete this message and its attachments.
As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.
Thank you.