From: i2rs [mailto:[email protected]] On Behalf Of Russell Harrison
Sent: 09 January 2014 15:26
To: Guanxiaoran
Cc: [email protected]
Subject: Re: [i2rs] TED extension in topology info model

Looks ok in concept, but there's a great deal of redundancy in the performance 
info you describe. It seems that only one of the residual/available/utilized 
fields would be needed.
[DD] Hmmm I disagree.
All 3 fields maybe used as they have subtle differences.

Residual BW =  Maximum Bandwidth minus the bandwidth currently *allocated* to 
RSVP-TE LSPs.
Available BW = Residual bandwidth minus the measured bandwidth *used* for the 
actual forwarding of non-RSVP-TE LSP packets.
BW Utilization = the actual utilization of the link (i.e.: as measured in the 
router including both RSVP and non-RSVP)

The other two could be calculated (not to mention, in this context residual and 
available probably mean he same thing.
[DD] "residual and available" are different, as above!

THe delay and loss fields are also interesting, assuming good methods to 
measure same are in place...

-rh

Sent from my iPhone
On Jan 9, 2014, at 3:19 AM, Guanxiaoran 
<[email protected]<mailto:[email protected]>> wrote:
Hi ,

[draft-medved-i2rs-topology-im-01] defines a TED (Traffic Engineering Data) 
component ([RFC5305], [RFC3630]):
<ted-link> ::= <COLOR>
                     <MAX_LINK_BANDWIDTH>
                     <MAX_RESV_LINK_BANDWIDTH>
                     (<UNRESERVED_BANDWIDTH>...)
                     <TE_DEFAULT_METRIC>
                     [<srlg-attributes>]

Besides the factors proposed in that document, other factors such as latency, 
limited bandwidth, packet loss, and jitter 
([draft-ietf-isis-te-metric-extensions-01], 
[draft-ietf-ospf-te-metric-extensions-05], [draft-wu-idr-te-pm-bgp-03]), are 
all important that need to be taken into account in the topology info model.

For example, shall we extend the TED component (i.e. including network 
performance information ) as follows:
<ted-link> ::= <COLOR>
                     <MAX_LINK_BANDWIDTH>
                     <MAX_RESV_LINK_BANDWIDTH>
                     (<UNRESERVED_BANDWIDTH>...)
                     <TE_DEFAULT_METRIC>
<TE_Performance_Info>
                     [<srlg-attributes>]

<TE_Performance_Info> ::= <Unidirectional Link Delay>
                                                   <Min/Max Unidirectional Link 
Delay>
                                                   <Unidirectional Delay 
Variation>
                                                   <Unidirectional Packet Loss>
                                                   <Unidirectional Residual 
Bandwidth>
                                                   <Unidirectional Available 
Bandwidth>
<Unidirectional Utilized Bandwidth>

What do you think?
[DD] Maybe we should have -  [<TE_Performance_Info>] making it optional?

Regards,
Dhruv


Regards,
Ran
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