Subject: [mpls] Proposed response to the liaison from ITU-T SG13

From: Loa Andersson <[email-masked]>
Date: Wed, 26 Mar 2008 09:48:50 +0100

Working Group,

we have received a liaison from ITU-T SG13.
https://datatracker.ietf.org/liaison/417/
Below a proposed response is included. Please send comments
to the working group mailing list no later than April 2.

/Loa

------  proposed liaison response  ---------------------

Thank you for your liaison from your Seoul meeting on
Y.RACF-DistribMPLS "Distributed RACF Architecture for
MPLS Networks".

This work is of interest to the MPLS Working
Group.  Please keep us informed as the work progresses.

Upon a cursory review we have identified some points where
clarification would be beneficial to our understanding.

Our reading is that ITU-T 4/13 has defined and Session
Border Controller Connection Admission Control function
as a gateway connected with an MPLS LER and in the so called
distributed environment it appears that this function is
embedded in the ingress MPLS LER.

There are several points where we would greatly appreciate your
clarification:

1. Describe the process by which the SBC gateway determines
    QoS and priority requirements by the so called "Policy
    Decision and Functional Entity" [PD-FE]?

2. Once the PD-FE QoS and priority requirements have been established
    by the PD-FE, what is the process by which they are then
    communicated to the MPLS LER?

3. Describe the expected behavior by the MPLS LER, e.g.
    the actual mechanism for tunneling.

4. What is meant by a PE-FE function as pointed out on
    page 4 of this document, eg. that an Ingress LER will also
    possess SBC gateway capabilities?

5. What extensions of DS-TE do you expect to have
    if any to support the PE-FE capability?

We look forward to your reply.

Thank you,

[To be signed by the wg chairs]

-- 
Loa Andersson

Principal Networking Architect
Acreo AB                           phone:  +46 8 632 77 14
Isafjordsgatan 22                  mobile: +46 739 81 21 64
Kista, Sweden                      email:  [email-masked]
                                            [email-masked]
_______________________________________________
mpls mailing list
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https://www.ietf.org/mailman/listinfo/mpls

---

From: "Adrian Farrel" <[email-masked]>
Date: Wed, 26 Mar 2008 10:27:35 -0000

Hey Loa,

Thanks for the work. I know how exciting it is to prepare a liaison 
response.

Can you add:

a. Reference 7 (RFC2702) is incorrectly named. It should be "Requirements 
for Traffic Engineering Over MPLS". Further, where RFC2702 is cited in the 
text, it is probable that RFC3209 is intended.

b. It is noted in Section 6.1 that the LERs include the role of TRE-FE as 
they have the "capability to establish TE tunnels and reserve bandwidth". 
Yet at the top of Section 6 you state "...Label Edge Routers are assumed to 
be connected via pre-provisioned ... or Traffic Engineering (TE) tunnels." 
"Pre-provisioned" is obviously a relative term, but it would be helpful to 
clarify that TRE-FE has some dynamic role in the provisioning of TE tunnels, 
and that those tunnels are not a priori pre-provisioned.

c. As and when the LERs (TRE-FEs) trigger TE tunnel establishment or 
modification they will be required to perform path computation for those 
tunnels. Have you examined how the functional component of the Path 
Computation Element (RFC4655) fits into your architecture?

d. Figure 1 usefully shows a concatenation of core MPLS networks connected 
at edge routers. TE tunnels run only across single domains. What analysis 
have you done of the benefits of TE tunnels that cross multiple domains? You 
may want to refer to RFC4726 and RFC4655 in this context.

Thanks,
Adrian

----- Original Message ----- 
From: "Loa Andersson" <[email-masked]>
To: <[email-masked]>; "Ross Callon" <[email-masked]>; "David Ward" 
<[email-masked]>
Sent: Wednesday, March 26, 2008 8:48 AM
Subject: [mpls] Proposed response to the liaison from ITU-T SG13