Re: [Teas] AD review of draft-ietf-teas-lsp-attribute-ro

Hi Lou, 

Thanks a lot for providing the suggested description. I think it specifies a reasonable rule of using the ERO Hop Attributes subobject in the loopback scenario. 

Adrian, if you also like it, I can update the draft accordingly.

Many thanks,
Jie

> -----Original Message-----
> From: Teas [mailto:teas-bounces@ietf.org] On Behalf Of Lou Berger
> Sent: Thursday, January 22, 2015 3:17 AM
> To: adrian@olddog.co.uk; 'Cyril Margaria'; teas@ietf.org
> Cc: draft-ietf-teas-rsvp-te-li-lb@tools.ietf.org;
> draft-ietf-teas-lsp-attribute-ro.all@tools.ietf.org;
> draft-ietf-ccamp-wson-signaling@tools.ietf.org
> Subject: Re: [Teas] AD review of draft-ietf-teas-lsp-attribute-ro
> 
> [ccamp dropped response doesn't concern the WSON draft] On 1/21/2015 6:57
> AM, Adrian Farrel wrote:
> >> For draft-ietf-teas-rsvp-te-li-lb this could be (restricting the TLV
> >> to
> >> > explicit nodes, precluding link ids):
> >> > The Attribute Flags TLV with Loopback Attribute Flag set MUST be
> >> > present after an explicit Hop addressing an TE Router ID
> >> > identifying a specific node or a Link ID identifying an incoming TE
> >> > link.  it MUST NOT be present after a loose,  abstract node, Link
> >> > ID identifying an outgoing TE link, Component Interface ID or Label.
> > Ah, joy!
> > Yes. This needs another fix to draft-ietf-teas-rsvp-te-li-lb.
> > I've made a note in the data tracker and marked that I-D as needing a
> > new revision.
> >
> I think this phrasing is too restrictive as it may be possible to put some of the
> identified items into loopback in some technologies, e.g., an output interface.
> How about:
> 
> after:
>     The mechanism defined in [I-D.ietf-teas-lsp-attribute-ro] is used to address
> the loopback request
>      to the particular node.
> add:
>      The ingress MUST ensure that the desired  loopback mode is strictly
> identified in the ERO.
> and
> OLD:
> 
>    If the bit is set, the node SHOULD try to put the LSP into loopback mode.
> NEW
>     If the bit is set, the node MUST check that the desired loopback is strictly
>     identified by verifying that the L bit is set to 0 in both the ERO Hop
>     Attributes subobject and the prior subobject. The prior subobject
>     MUST also be checked to ensure that it provides strict identification.
>     Currently, the type value MUST be verified to be less than 32, and
>     for type values 1 and 2 the prefix length MUST be 32 and 128 respectively.
>     If the desired loopback is not strictly identified the request MUST be
> ignored
>     and a "Bad EXPLICIT_ROUTE object" error SHOULD be generated.
> 
>      Otherwise, the node SHOULD try to put the LSP into loopback mode.
> 
> 
> Lou
> 
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