Subject: Question on draft-ietf-tewg-qos-routing-01.txt

From: shen jing <[email-masked]>
Date: Tue, 06 Nov 2001 20:08:10 +0800

Hi :

I've read the draft draft-ietf-tewg-qos-routing-01.txt but met some
questions, is there anyone
would like to do me a favor to answer them ?

The following is the question I met:

1.  In Annex 2, it is stated EDR shows better performance than FR, TDR &

    SDR, and load state is  preferred to shortest path in  path
selecting(Annex 2, P13).
   But, How multi-path is tried in IP networks ? signalling with
   RSVP-TE or CR-LDP?
   If each connection is set up by this way,  will the signalling
   procedure bring much overhead ?
   If all paths failed , how to deal with the communication request ?
   drop or do with best-effort ?

2.  It is stated that Interdomain TE can be built as that in
     intradomain( Annex 2, P13), but there are protocols like BGP
    working in current IP networks which do not maintein any traffic
state and
     implements a business-relationship constrained  routing method.  Is

there
    any relationship  between EDR and BGP in internet ?

3.  In Annex3 P24,  it is stated that bandwidth reservation should be
     included in IP networks,  and per-VNET reservation is recommended,
but how is VNET defined in a network ?
     just by SN and DN?   MPLS  reservation prcedure and Diffserv is
recommended , but MPLS can implement QoS
     by using EXP bits , it does not need  Diffserv to set up Queueing
mechanism.

4. In Annex4 P13, it is stated "internetwork E can use various path
    selection methods in delivering connection/bandwidth-allocation
requests ", the example network
    give a interconnected networks with different routing methods. But,
if it is implemented in this way , should
    those nodes of internetwork E exchange serval types of routing
information ?

5.  How do you simulate such a large network ? I means which tools can
     be used to simulate TE & QoS algothrim in a multiservice network?
     How can I simulate a Gamma distributed traffic over a 132 nodes
network?

Thanks in advance

James Shen

---

From: "Ash, Gerald R (Jerry), ALCTA" <[email-masked]>
Date: Thu, 8 Nov 2001 18:58:05 -0500

Dear James Shen,

Thank you for your interest in the draft.  See below for brief responses.

Regards,
Jerry Ash
AT&T Labs

> -----Original Message-----
> From: shen jing [mailto:[email-masked]]
> Sent: Tuesday, November 06, 2001 7:08 AM
> To: [email-masked]
> Subject: Question on draft-ietf-tewg-qos-routing-01.txt

> selecting(Annex 2, P13).  But, How multi-path is tried in IP networks? 
> signalling with RSVP-TE or CR-LDP?

Yes multiple LSPs can be signaled with either RSVP-TE or CRLDP.

>  procedure bring much overhead?

No, especially if flows are routed according to an aggregated 
LSP-bandwidth allocation (denoted as a 'VNET' in the draft).

> If all paths failed, how to deal with the communication request?
> drop or do with best-effort?

Dropped, according to the CAC procedure discussed in the draft. 

> state and implements a business-relationship constrained  
> routing method.  Is there any relationship between EDR and 
> BGP in internet?

Not at this time although extensions could be proposed to do so 
or policies could be adopted to mimic EDR.

> but how is VNET defined in a network?

VNET is an aggregate of flows which are routed according to an aggregated 
LSP-bandwidth allocation.  This is analogous to the 'class type' concept 
in the MPLS-DiffServ-TE draft 
http://ietf.org/internet-drafts/draft-ietf-tewg-diff-te-reqts-01.txt.

> requests ", the example network give a interconnected networks with 
> different routing methods. But, if it is implemented in this way, 
> should those nodes of internetwork E exchange serval types of 
> routing information?

Yes, the details are spelled out in ANNEX 4 of the draft.

> be used to simulate TE & QoS algothrim in a multiservice network?

Service providers with large networks must have the ability to simulate
their networks.  In this case it is an in-house simulation model that is
used.