Questions on GMPLS ASON OSPF-TE ID

["Bardalai, Snigdho" <Snigdho.Bardalai@us.fujitsu.com>]

Hi Dimitri,

 

As mentioned in today's meeting I have the following questions on this

ID:

 

1. The Addressing Draft requires that the TERouterID to be an addressable IP

    address i.e. one can ping this address.

 

    The ID needs to clearly state what is the requirement for ASON.

 

2. Upward / downward LSA transformation

 

    When LSAs are exported from one level to another then these LSAs need to be

    transformed. The ID does not clearly specify how the transformation takes place.

 

    The specific scenarios are:

    + Upward LSA transformation - what values are used for the adv Router ID, Router Address

       and LINK ID ?

    + Downward LSA transformation - what values are used (for above mentioned fields) ?

 

3. TE Links LSAs

 

    From reading the ID I can infer that every TE link advertised at a particular level

    needs to be a link between 2 routers i.e. Router ID, because the LINK ID MUST

    be set to the neighboring router's Router ID as per RFC 3630.

 

    In that case when there is only one router for a set of TE nodes then how will

    the TE link LSAs look like when they get advertised by that single router. Or is it

    expected that these TE link LSAs never get advertised by that single router

    (i.e. all TE nodes must get represented as an abstract node) ?

 

4. Upward / downward discovery and selection

 

   The ID describes a procedure by which routers can automatically discover and select

   the upward and downward speaker router.

 

   It is quite clear that when the current speaker sees a router with a router ID larger than

   its own and the U or D bit set it will stop importing or exporting LSAs. 

 

   What is not clear is that how does the router with the highest router ID know when to

   start importing or exporting LSAs, because it has no knowledge which is the current

   speaker and there is no clear way to figure out when it has stopped importing or exporting

   LSAs.

 

   Could you please explain how this works ?

 

Thanks,

Snigdho