Re: draft-gan-fast-reroute-00.txt

[Ping Pan <pingpan@juniper.net>]

Curtis Villamizar wrote:
> 
> Please consider merging this capability with the bandwdith sharing
> capability described in draft-kini-*.  This would allow the bandwidth
> on backup paths to be shared where possible.  See additional comments
> on this below.
> 

Sure. I have read the INFOCOM papers before. Let me take a look at them
again. Just curious, has anyone implemented the proposed routing
(OSPF/ISIS) extensions?

> > 3.2 DETOUR Object
> >
> >              0             1              2             3
> >         +-------------+-------------+-------------+-------------+
> >         |       Length (bytes)      |  Class-Num  |   C-Type    |
> >         +-------------+-------------+-------------+-------------+
> >         |                   Source ID                           |
> >         +-------------+-------------+-------------+-------------+
> >         |                   Downstream Node ID                  |
> >         +-------------+-------------+-------------+-------------+
> >
> This seems to assume node disjoint paths.  A more general approach
> would be to provide a list of SRLG that the detour need to avoid.
>
> A special case is one where an SRLG contains all links terminated at a
> given node, which covers the node disjoint case above.
> 

My editing goof: the downstream node ID is the first downstream router
to avoid. It is used in the CSPF computation, which is to provide the
shortest detour path between the current router to a downstream merging
router. We will consider your comment of having a list for protecting
nodes.

> It should be fine to provide a object that names a specific node as a
> special case of the detour object, and may be (is) needed to
> accommodate existing code.  It might be useful to have a form of the
> detour object that covered the link disjoint special case.  There
> should also be a form of the detour object that allows the more
> general list of SRLG.
> 
> SRLG should also be considered in the "Detour Path Computation
> Algorithm" section.
> 

Sure. Thanks!

> 
> > 6 Intellectual Property Considerations
> >
> >    Juniper Networks, Inc. is seeking patent protection on technology
> >    described in this Internet-Draft. If technology in this Internet-
> >    Draft is adopted as a standard, Juniper Networks agrees to license,
> >    on reasonable and non-discriminatory terms, any patent rights it
> >    obtains covering such technology to the extent necessary to comply
> >    with the standard.
> 
> Could you please point out exactly what you think is new and unique
> about this proposal?

It's up to the lawyers to decide. ;-) Look, it seems everyone has used
the similar paragraph for their restoration mechanism. We really have no
choice. BTW, what's the status of that restoration patent application
from Bell Labs which your drafts are based on? ;-)

Take care and thanks!

- Ping