Subject: Comments on draft-jounay-pwe3-leaf-initiated-p2mp-pw-01

From: [email-masked]
Date: Wed, 15 Apr 2009 13:50:12 +0800

Hi, Frederic,

I have read draft-jounay-pwe3-leaf-initiated-p2mp-pw-01 and have some 
comments. please see below:

1、section 5.4. Configuration 
 
   After configuring on each T-PE the attached AIIs, it is assumed that 
   all the PEs (Ingress/Egress T-PEs and all S-PEs) maintain an AII PW 
   routing table which gives for each AII as entry the "next hop" to 
   reach that AII. This AII routing table can be filled manually or 
   updated dynamically by means of some extended routing protocol like 
   proposed in [DYN MS-PW]. The construction of the table is out of 
   scope of the present document. 
 
   Each PE relies on its AII PW routing table to select the next hop PE 
   (S-PE or T-PE) to reach a given AII. 

>1  Does this AII routing table include both TAII and SAII?
>2  In S-PE, this AII routing table includes all the AII, or just part of 
the AII( e.g. which are in its dowstream)?

2、Section 5.7. Using TAII Leaf Sub-TLV 
 
   Section TBD 
 
   The TAII Leaf sub-TLV MAY be optionally used when a leaf joins the PW 
   tree to announce to the source that it is part from the PW tree. If 
   this option is chosen, the Egress T-PE adds to the FEC Element this 
   TAII sub-TLV in the Label Map message. As soon as in the source 
   direction a Label Map is not required since for instance a S-PE 
   already maintains a state for this MS-PW tree, the information 
   related to the Leaf TAIIs is retrieved from the TAII Leaf sub-TLV and 
   is propagated by means of a LDP Notification message up to the 
   corresponding Ingress T-PE. 
> I am not sure about the propagation of TAII Leaf sub-TLV. Is it sent to 
ingress T-PE directly, or to the upstream S-PE(if there exists such S-PE 
in the upstream direction)?

Best Regards!

Xinquan Zhang

2009/4/15

---

From: <[email-masked]>
Date: Mon, 20 Apr 2009 14:55:50 +0200

Hi Xinquan,
 
Please see my answer inline [FJ]
 
Best Regards,
Fred

________________________________

De : [email-masked] [mailto:[email-masked]] 
Envoyé : mercredi 15 avril 2009 07:50
À : JOUNAY Frederic RD-RESA-LAN
Cc : [email-masked]; [email-masked]
Objet : Comments on draft-jounay-pwe3-leaf-initiated-p2mp-pw-01

Hi, Frederic, 

I have read draft-jounay-pwe3-leaf-initiated-p2mp-pw-01 and have some comments. please see below: 

    

>1  Does this AII routing table include both TAII and SAII? 
[FJ] Yes, the AII routing table dynamically populated (BGP, OSPF, IS-IS or LDP) should maintain both. The Egress T-PE joins the PW tree by initiating a Label Map whose the FEC contains the SAII, the PW tree source. Hence upon receipt of the message the S-PE does a lookup to select the NH to reach this SAII.      
>2  In S-PE, this AII routing table includes all the AII, or just part of the AII( e.g. which are in its dowstream)? 
 [FJ] the AII routing table should be used also for VPWS or VPLS, so bidirectional PW. Therefore the AII routing table must reflect all the AII configured on T-PEs. Of course agregate AII format (i.e. w/o ACID info) as defined in [DYN MS-PW] must be used to optimize the AII routing table

   Section TBD 
    
> I am not sure about the propagation of TAII Leaf sub-TLV. Is it sent to ingress T-PE directly, or to the upstream S-PE(if there exists such S-PE in the upstream direction)?  
[FJ] The Notification message can not be directly sent to the Ingress T-PE if there is not direct T-LDP session to reach the Ingress T-PE, i.e. S-PE in between. That's the reason why the message should be propagated hop by hop (i.e. S-PE by S-PE) up to the Ingress T-PE.
 I agree with you that's worth clarifying this section. 

Best Regards! 

Xinquan Zhang 

2009/4/15

---

From: [email-masked]
Date: Tue, 21 Apr 2009 09:22:53 +0800

Hi Frederic, 

Thanks for your clarificaton.

You have two drafts about P2MP PW signaling, one is leaf-initiated mode 
and the other is source-initiated mode. In my opinion, your original 
intention is to propose leaf-initiated mode as a solution for inter-domain 
scenario, and source-initiated mode for intra-domain scenario. Am I right? 
Or your have other considerations?

Best regards!

Xinquan Zhang

2009/4/21

<[email-masked]> 
发件人:  [email-masked]
2009-04-20 20:55

收件人
<[email-masked]>
抄送
[email-masked], [email-masked], [email-masked]
主题
RE: Comments on draft-jounay-pwe3-leaf-initiated-p2mp-pw-01

Hi Xinquan,

Best Regards,
Fred

Hi, Frederic, 

 

>1  Does this AII routing table include both TAII and SAII? 
[FJ] Yes, the AII routing table dynamically populated (BGP, OSPF, IS-IS or 
LDP) should maintain both. The Egress T-PE joins the PW tree by initiating 
a Label Map whose the FEC contains the SAII, the PW tree source. Hence 
upon receipt of the message the S-PE does a lookup to select the NH to 
reach this SAII.      
the AII( e.g. which are in its dowstream)? 
 [FJ] the AII routing table should be used also for VPWS or VPLS, so 
bidirectional PW. Therefore the AII routing table must reflect all the AII 
configured on T-PEs. Of course agregate AII format (i.e. w/o ACID info) as 
defined in [DYN MS-PW] must be used to optimize the AII routing table

   Section TBD 
 
ingress T-PE directly, or to the upstream S-PE(if there exists such S-PE 
in the upstream direction)?  
[FJ] The Notification message can not be directly sent to the Ingress T-PE 
if there is not direct T-LDP session to reach the Ingress T-PE, i.e. S-PE 
in between. That's the reason why the message should be propagated hop by 
hop (i.e. S-PE by S-PE) up to the Ingress T-PE.
 I agree with you that's worth clarifying this section. 

Best Regards! 

Xinquan Zhang 

2009/4/15

---

From: <[email-masked]>
Date: Tue, 21 Apr 2009 16:54:35 +0200

Hi Xinquan,
 
"In my opinion, your original intention is to propose leaf-initiated mode as a solution for inter-domain scenario, and source-initiated mode for intra-domain scenario. Am I right?" 
 
not really, actually both procedures (leaf or source initiated)  are not limited in their operating principles and as such could be used  to cover SS-PW and MS-PW configuration.  
For the standardization work we propose to focus first on P2MP SS-PW  as it is the simplest configuration, to agree on the required new  building blocks : FEC element, signaling procedures etc...   
The part related to P2MP SS-PW setup in the leaf-initiated draft and the part related to P2MP MS-PW setup in the source-initiated draft should be added asap or considered in a separate document.
 
Regarding their network applicability the choice between both approaches will have to be made on a case by case basis, driven by architectural and operational constraints. For the moment we felt the need to investigate both solutions in parallel.
 
Do you have any comment on the applicability of the two approaches ?  Or any specific requirement that would need to be included in the requirements draft on P2MP PW ?
 
Best Regards,
 
Fred

De : [email-masked] [mailto:[email-masked]] De la part de [email-masked]
Envoyé : mardi 21 avril 2009 03:23
À : JOUNAY Frederic RD-RESA-LAN
Cc : [email-masked]; [email-masked]; [email-masked]
Objet : 答复: RE: Comments on draft-jounay-pwe3-leaf-initiated-p2mp-pw-01

Hi Frederic, 

You have two drafts about P2MP PW signaling, one is leaf-initiated mode and the other is source-initiated mode. In my opinion, your original intention is to propose leaf-initiated mode as a solution for inter-domain scenario, and source-initiated mode for intra-domain scenario. Am I right? Or your have other considerations? 

Best regards! 

Xinquan Zhang 

2009/4/21 

2009-04-20 20:55 

收件人

Hi Xinquan, 

Best Regards, 
Fred 

Hi, Frederic, 

   

   
  Section TBD 

Best Regards! 

Xinquan Zhang 

2009/4/15