RE: I-D ACTION:draft-shiomoto-ccamp-lsp-hierarchy-bis-01.txt

["Zafar Ali \(zali\)" <zali@cisco.com>]

Hi Dimitri, 

Please see reply in-lined. 

Thanks

Regards... Zafar  

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org 
> [mailto:owner-ccamp@ops.ietf.org] On Behalf Of dimitri papadimitriou
> Sent: Thursday, March 09, 2006 6:07 AM
> To: ccamp@ops.ietf.org
> Subject: Re: I-D ACTION:draft-shiomoto-ccamp-lsp-hierarchy-bis-01.txt
> 
> hi all, some comments on the problem statement of this doc:
> 
> "(2) How to identify the routing instance in which such an 
> advertisement should happen."
> 
> but by definition it is the same instance when speaking about 
> an FA (or are we not speaking about FA's only (?)

Correct, both FA and RA (Routing Adj). 

> the 
> previous paragraph seems to indicate this is not the case
> 
> "In order for the egress of an LSP to be able to advertise 
> the LSP as a TE link it needs to know that such an 
> advertisement is desirable, "
> 
> ok this is a trigger issue

Correct, to adv or not to adv. 

> 
> "and it also needs to know the TE Router ID of the ingress LSR.
> (Please recall that the Router ID of the other end of the 
> link is set in the Link-ID sub-TLV of the Link TLV of the TE 
> Opaque-LSA [RFC3630].)"
> 
> don't understand this; the Router ID is known and the TE 
> router ID is known as well (part of the TEDB) ... what's the 
> purpose of this new requirement (as there is no TE router ID 
> part of the corr. link TLV)
> 
> clarifications appreciated,

In the current signaling message, for numbered TE link it is NOT clear
where the Ingress/ Egress router-id-es are placed. Some implementation
use extended tunnel-id field for this but again this is not a must. So
please read the above as... 

"and (when LSP is signaled, Ingress/ Egress nodes ) also needs to know
the TE Router ID of the ingress LSR." 

Please also see related text in the ID related to how this help in
flooding.  

> 
> in general, if a clearer procedure for numbered FA signaling 
> could be devised that would be a good achievement, this said, 
> i am for inst. 
> unclear about these R and F bits ... where does numbered FA only adv.

A bi-directional LSP can be adv as an FA (only in MPLS TE topology) or
an RA (IP network) or both. These bits tells the Egress node on what
treatment is expected by the Ingress node. 
 
> per RFC4206 is reproduced here ? 

No, 

> what "adv. an FA in an IP network" 
> means ? 

The GMPLS bidirectional LSP is visible to IP topology for inclusion in
IP SPF. 

> why restrict adv. to MPLS-TE and IP networks only ? etc.

Can you please elaborate on this? 

> 
> imho, the issue of the trigger is part of a larger discussion 
> around FA policing ... in brief, providing a cleaner 
> procedure for numbered FA's is advisable but complexifying 
> procedures by incorporating policing related actions is not advisable
> 
> thanks,
> - dimitri.
> 
> Internet-Drafts@ietf.org wrote:
> 
> > A New Internet-Draft is available from the on-line 
> Internet-Drafts directories.
> > 
> > 
> > 	Title		: Advertisement of hierarchical and 
> stitchable Label Switched Paths as Traffic Engineering Links
> > 	Author(s)	: K. Shiomoto, et al.
> > 	Filename	: draft-shiomoto-ccamp-lsp-hierarchy-bis-01.txt
> > 	Pages		: 17
> > 	Date		: 2006-3-7
> > 	
> > This document addresses topics related to hierarchical and stitched 
> > Generalized Multiprotocol Label Switching (GMPLS) Label 
> Switched Paths 
> > (LSPs).  It describes extensions to allow an egress to 
> identify that a 
> > bi-directional LSP will be used as a dynamically signaled 
> Forwarding 
> > Adjacency LSP (FA-LSP) or Routing Adjacency (RA). In addition, the 
> > document also addresses the issue of how to indicate that an LSP 
> > should be advertised as a traffic engineering (TE) link into a 
> > different instance of the IGP and how to identify the instance that 
> > should be used.
> > 
> > A URL for this Internet-Draft is:
> > 
> http://www.ietf.org/internet-drafts/draft-shiomoto-ccamp-lsp-hierarchy
> > -bis-01.txt
> > 
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