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RE: Is the advertisement (IGP) of available BW at each pre-emptio n le vel is a DS-TE- requirement ?
Neil,
At 23:05 13/11/2001 +0000, neil.2.harrison@bt.com wrote:
Francois,
I don't think its that simple.
Let me clarify :
The two scenarios below were just meant to be simple examples of what an
SP may want to do. It is not meant to restrict other scenarios in any
way. Text will be adjusted to make it clear that those are just
examples.
2nd,
largest BW packing of 'path entities' is the most efficient way to do
things if all path entities have the same survivability attribute.
I can imagine a case of large(r) L-LSP carrying BE traffic and a
small(er) E-LSP carrying VPN traffic.......if I have an availability SLA
to meet for the VPN LSP, then irrespective of the size of the BE LSP I
ought to restore the VPN traffic before I even consider the BE
traffic.
Perhaps, we could add a 3rd example based on your above scenario with
something like this.
"Yet another Service Provider may elect to configure the following
in order to (i) ensure that Premium Data LSPs are never driven away from
their shortest path because of Best-Effort LSPs while (ii) optimize
global network resource utilization by favoring placement of large LSPs
first:
- all
large size Premium Data LSPs to preemption priority 0
- all
small size Premium Data LSPs to preemption priority 1
- all
large size Best-Effort LSPs to preemption priority 2
- all
small size Best-Effort LSPs to preemption priority 3"
Is that in line with the scenario you described?
Thanks for your input
Francois
regards,
Neil
-----Original
Message-----
From: Francois Le Faucheur
[mailto:flefauch@cisco.com]
Sent: 13 November 2001 12:56
To: Choudhury, Sanjaya; Jim Boyle
Cc: te-wg
Subject: Re: Is the advertisement (IGP) of available BW at each
pre-emption le vel is a DS-TE- requirement ?
Choudhury,
At 20:17 09/11/2001 -0500, Jim Boyle wrote:
On Fri, 9 Nov 2001, Choudhury, Sanjaya
wrote:
>
Q3. In a DiffServ TE
domain, where the network administrator
> initiates the
creation the TE tunnels (using MPLS-TE-MIB ),
> when/how can he
take advantage of the following pre-emption
> scheme:
>
a)
Preemption within the same DiffServ traffic class
>
b)
Preemption across different DiffServ traffic classes
I'm not sure how people use the MPLS-TE-MIB to setup TE tunnels, so
I
can't help you there. I think you mean class-type above, so again,
that
is a specific proposal.
I am not sure I fully get the question (in particular I don't see the
relationship with the fact that you set up tunnels using MIB or not), but
let me quote some draft text from teh drafts we're working on as it may
help:
"
First, a Service Provider using two Class-Types (one for Voice and one
for Data), may elect to configure the following to ensure that Voice LSPs
are never driven away from their shortest path because of Data
LSPs:
-all
Voice LSPs to preemption priority 0
-all
Data LSPs to preemption priority 1
Another Service Provider may elect to configure the following in order to
optimize global network resource utilization by favoring placement of
large LSPs first:
- all
large size Voice LSPs to preemption priority 0
- all
large size Data LSPs to preemption priority 1
- all
small size Voice LSPs to preemption priority 2
- all
small size Data LSPs to preemption priority 3
"
Note that this is based on the observation that, today, a common use for
preemption is to give higher preemption to large LSPs in order to get
better global utilisation. You get a much better network utilisation by
fitting big things first and then small ones (just like filling up the
boot of the family car when going away on holidays, really).
Hope that helps.
Francois
>
> Thanks,
> sanjay
>
>
_________________________________________________________
Francois Le Faucheur
Development Engineer, IOS Layer 3 Services
Cisco Systems
Office Phone: +33 4
97 23 26 19
Mobile
:
+33 6 89 108 159
Fax:
+33 4 97 23 26 26
Email:
flefauch@cisco.com
_________________________________________________________
Cisco Systems
Domaine Green Side
400, Avenue de Roumanille
06 410 Biot - Sophia Antipolis
FRANCE
_________________________________________________________
_________________________________________________________
Francois Le Faucheur
Development Engineer, IOS Layer 3 Services
Cisco Systems
Office Phone:
+33 4 97 23 26 19
Mobile
:
+33 6 89 108 159
Fax:
+33 4 97 23 26 26
Email:
flefauch@cisco.com
_________________________________________________________
Cisco Systems
Domaine Green Side
400, Avenue de Roumanille
06 410 Biot - Sophia Antipolis
FRANCE
_________________________________________________________