Subject: [PWE3] Comments to draft-cao-pwe3-mpls-tp-pw-over-bidir-lsp-00

From: Greg Mirsky <[email-masked]>
Date: Mon, 26 Jul 2010 20:10:42 -0700

Dear Authors,
please find my comments to very interesting and timely proposal:

   - Section 2, third paragraph discusses signaling ow PW-to-LSP mapping in
   absence of LDP. MPLS-TP Control Plane framework listed four possible
   combination of LSP and PW control planes. Though your suggestion to use
   G-ACh in absence of LDP is valid I'd consider use of RSVP-TE signaling as
   alternative to G-ACh.
   - proposed formats, as I understand them expected to bind context of PW
   to identified MPLS-TP tunnel. If LDP is not used to signal PW I don't see
   that PW is being properly identified. According to MPLS-TP Identifiers, AGI,
   Src-AC_ID and Dst-AC_ID, in combination with already listed IDs, will
   establish PW's context.

Regards,
Greg

---

From: Mach Chen <[email-masked]>
Date: Tue, 27 Jul 2010 22:44:34 +0800

Hi Greg,

Thanks for your comments!

For the suggestion on using RSVP-TE signaling as an alternative in absence of LDP, since RSVP-TE is signaling protocol of tunnel LSP but not of PW, and IMHO, tunnel LSP is better transparent to its clients(e.g., PWs),  I not sure we could use RSVP-TE to signal this PW to PSN Tunnel binding. Of cause, theoretically, RSVP-TE may be used to do this.

As to your second comment, if we use GACh-based solution to do the PW to PSN tunnel association, since this association messages are send along the PW, the PW label could be used to demultiplex the proper PW, seems there is no need to add extra IDs, am I correct?

Best regards,
Mach 

From: Greg Mirsky 
Sent: Tuesday, July 27, 2010 11:10 AM
To: Mach Chen ; [email-masked] ; Attila Takacs ; pwe3 
Subject: Comments to draft-cao-pwe3-mpls-tp-pw-over-bidir-lsp-00

Dear Authors,

  a.. Section 2, third paragraph discusses signaling ow PW-to-LSP mapping in absence of LDP. MPLS-TP Control Plane framework listed four possible combination of LSP and PW control planes. Though your suggestion to use G-ACh in absence of LDP is valid I'd consider use of RSVP-TE signaling as alternative to G-ACh. 
  b.. proposed formats, as I understand them expected to bind context of PW to identified MPLS-TP tunnel. If LDP is not used to signal PW I don't see that PW is being properly identified. According to MPLS-TP Identifiers, AGI, Src-AC_ID and Dst-AC_ID, in combination with already listed IDs, will establish PW's context. 

Regards,
Greg

---

From: Greg Mirsky <[email-masked]>
Date: Tue, 27 Jul 2010 08:55:18 -0700

Dear Mach,
thank you for taking time to respond to my notes. Please see newer in-lined
and tagged GIM.

Best regards,
Greg

On Tue, Jul 27, 2010 at 7:44 AM, Mach Chen <[email-masked]> wrote:

> For the suggestion on using RSVP-TE signaling as an alternative in absence
> of LDP, since RSVP-TE is signaling protocol of tunnel LSP but not of PW, and
> IMHO, tunnel LSP is better transparent to its clients(e.g., PWs),  I not
> sure we could use RSVP-TE to signal this PW to PSN Tunnel binding. Of cause,
> theoretically, RSVP-TE may be used to do this.
>
GIM>> Perhaps I'm overextending but, especially with all the gaps in LDP
identified in MPLS-TP Control Plane Framework, RSVP-TE might be well
extended to signal PW. Thus the rationale. Besides, we'd like to signal
mapping between tunnel and PW before PW enabled.

>
> As to your second comment, if we use GACh-based solution to do the PW to
> PSN tunnel association, since this association messages are send along the
> PW, the PW label could be used to demultiplex the proper PW, seems there is
> no need to add extra IDs, am I correct?
>
GIM>> If we to use ACH over PW wouldn't that mean that the PW is already
mapped to the particular tunnel? What if signaled information is different
from the existing mapping? Signaling along signaling of PW works well
operationally but using PW ACH/VCCV, in my view, does not. That is why I've
suggested to add PW IDs.

>
> Best regards,
> Mach
>
>  *From:* Greg Mirsky <[email-masked]>
> *Sent:* Tuesday, July 27, 2010 11:10 AM
> *To:* Mach Chen <[email-masked]> ; [email-masked] ; Attila Takacs<[email-masked]>;
> pwe3 <[email-masked]>
> *Subject:* Comments to draft-cao-pwe3-mpls-tp-pw-over-bidir-lsp-00
>
> Dear Authors,
>    - Section 2, third paragraph discusses signaling ow PW-to-LSP mapping
>    in absence of LDP. MPLS-TP Control Plane framework listed four possible

---

From: Mach Chen <[email-masked]>
Date: Wed, 28 Jul 2010 16:34:08 +0800

Hi Greg,

Thanks for your prompt reply forgive me this delayed reply for the crazy 
network in the hotel :(

Please see inline...

--------------------------------------------------
From: "Greg Mirsky" <[email-masked]>
Sent: Tuesday, July 27, 2010 11:55 PM
To: "Mach Chen" <[email-masked]>
Cc: "Attila Takacs" <[email-masked]>; "pwe3" <[email-masked]>
Subject: Re: Comments to draft-cao-pwe3-mpls-tp-pw-over-bidir-lsp-00

> mapping between tunnel and PW before PW enabled.
If RSVP-TE could be extended to signal PW, yes, it could be extended do 
this. And the current LDP-based procedures defined in this draft can make 
sure that the PW is not enabled before the mapping.

> operationally but using PW ACH/VCCV, in my view, does not. That is why 

My original thought about this is that the PW may map to any PSN tunnel at 
first and then use the PW to associate the desired binding, and then both 
ends change to the agreement tunnel. This is just a minutes thought. And 
since the current draft is now limited to discuss LDP-based solution, we are 
open to discuss GACh-based solution or other solutions. I agree that if a 
different connection other than the PW is used to communicate the mapping, 
the PW IDs are required.

Best regards,
Mach