RE: comments on draft-ietf-tewg-diff-te-reqts-06.txt

["Francois Le Faucheur (flefauch)" <flefauch@cisco.com>]

>> I now see why I did not understand. When you say "TE-LSPs are routed"
>> then I think of "routing happens all the time for all packets".
>> From what you suggest to add, it sounds as if you mean that at the
>> time a TE-LSP is configured, that that is the time when bandwidth
>> is reserved. So I guess you mean
>>      - in which order the different TE-LSPs are configured
>>        (or established or created) 
>> 
>> Did I get that? If so, then my text if probably even better.
>> 

Alright then let's go for:
"      - in which order the different TE-LSPs are configured
        (or established)
"

(as I couldn't explain the difference between "created".


>> So can you tell me (I am thick, sorry) what means:
>>   - {TA}PSC
>>   - <FEC/{TA}/PSC>
>> 
>> Maybe once you explain it to me I will get it and maybe 
>> there is an Aha
>> 

How about an example:

Say SP supports a class of service C1 with committed/excess concepts
using the AF11 and AF12 PHBs.

Diff-Serv has defined a convenient term to designate all the packets of
the DS domain whose DSCP correspond to AF11 . It is called a Traffic
Aggregate. Let me call it, loosely, the AF11 TA.
Clearly we also have the AF12 TA.

We look at the packets belonging to AF11 TA and AF12 TA as the ones
forming the C1 class of service. To indicate that the reason those two
are grouped together is because they "share a ordering constraints" (ie
they MUST not be reordered) we call this set a {TA}PSC.
The PSC is an existing Disff-Serv concept that precisely designates the
set of PHBs sharing the "same ordering constraint".
Hence the notation of "{TA}PSC" to suggest that it is a set of several
TA whose relationship is that their PHBs belong to the same PSC.
In brief it is really nothing else that the set of all packets in that
domain which belong to a given "class of service".

Now clearly, depending on their destination, packets of a given class of
service (ie packets from a given {TA}PSC ) will be transported on
different TE tunnels. FEC is an MPLS term that sort of designate the set
of packets that are "going on the same path from MPLS perspective".  The
set of packets of a given class of service which are transported on a
given tunnel are called a  <FEC/{TA}/PSC> to indicate it is basically
the intersection of a FEC and a {TA}/PSC. 

Aha?

>> > So how about breaking this up into something like :
>> > 
>> > "
>> > The solution developed to address the requirements defined in this
>> > document must address security aspects. DS-TE does not raise any
>> > specific additional security requirements beyond the 
>> existing security
>> > requirements of MPLS TE and Diff-Serv. The solution must 
>> > ensure that the
>> > existing security mechanisms of MPLS TE and Diff-Serv are not
>> > compromised by the solution protocol/procedure extensions 
>> or otherwise
>> > must provide security mechanisms to address this. 
>> > "
>> > 
>> That sounds much better to me. 
>>

Will update.
 
>> Pls check that you also addres the comments about DoS attacks as
>> reaided by David Meyer.
>> 

Discussed separately.

Francois

>> Bert
>> > Thanks 
>> > 
>> > Francois
>> > 
>> 
>>