Subject: RE: Last call on LSP Ping

From: Shahram Davari <[email-masked]>
Date: Wed, 18 Dec 2002 13:12:31 -0800

Cusrtis,

For point (5) I already suggested (in previous emails) a change to the Downstream mapping TLV as following:

To support ATM (28-bit VPI/VCI) and FR (10-bit or 23-bit DLCI)
may I suggest changing the size of the Downstream label to 28 bits and 
right justifying any ATM/FR/MPLS label in this field as following:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Downstream IPv4 Router ID                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               MTU             | Address Type  |  Reserved     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Interface Address                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               Downstream Label                        |Protoco|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                                                               .
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               Downstream Label                        |Protoco|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

For point (1) I suggested adding the inner label to the echo-request:

 0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Route Distinguisher                      |
      |                          (8 octets)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         IPv4 prefix                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Prefix Length |                 Must Be Zero                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  PW/PSN  Label                |  Must be Zero |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Route Distinguisher                      |
      |                          (8 octets)                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         IPv6 prefix                           |
      |                                                               |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Prefix Length |                 Must Be Zero                  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  PW/PSN  Label                | Must be Zero  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

-Shahram

> > 
> > > 5) How are the ATM/FR labels supported in Label-mapping TLV?
> > 
> > barf.^h^h^h^r  Yes - good point.
> > I don't care^h^h^r I don't know.
> > 
> > The amount of thought put into this seems proportional to 
> the deployed
> > base of MPLS over ATM/FR in ISPs.
> > 
> > Someone who cares^h^h^r Someone who knows more about this 
> may have to
> > pointlessly beat their head against the wall ^r contribute.
> > 
> > :-)		       [ just kidding - sort of ]
> > 
> > > I think it is more constructive to answer protocol 
> > impacting questions
> > > rather than leave them unanswered and wait for the 7th 
> > version (4 versions un
> > > der draft-pan-lsp-ping and 3 versions under name 
> > draft-ietf-mpls-lsp-ping) of
> > >  the draft.
> > 
> > OK.  I still owe you an answer on point 4 and something 
> intellegent on
> > point 5.
> 
> OK.
> 
> Yours,
> -Shahram
> 
> > 
> > > Yours,
> > > -Shahram
> > 
> > Thanks for the reminders on these points.
> > 
> > Curtis
> > 
>

---

From: Curtis Villamizar <[email-masked]>
Date: Wed, 18 Dec 2002 17:07:33 -0500

In message <[email-masked]
>, Shahram Davari writes:

That doesn't help if the ATM LSRs don't decrement TTL.  Did this
change?  Are ATM LSR decrementing TTL these days?

The people most interested in MPLS-ping are those people operating
networks.  The intersection of the set of people operating networks
and the set of people interested in ATM LSR might be the null set.

But if adding this TLV makes satisfies the set of people interested in
ATM LSR, then its fine with me to add this as the Downstream ATM
Mapping TLV.

> For point (1) I suggested adding the inner label to the echo-request:

IMHO - That wasn't necessary and its redundant since the next label is
on the label stack and there is an entry on the FEC stack as well.

Curtis