The MPLS WG Archive

[Arumugam R <arumugamr@future.futsoft.com>]

Hi,
See inline comments.
Rajesh P Jain wrote:

>         Can someone clarify where should we store the Session Attribute Object ?

###  It is left to the implementation, but usually kept in the PSB.

> 
> 
>         Also, The draft tells that Session Attribute is an Optional Object. So,
> Let us consider a case where a Path Message is sent without a Session Attribute
> Object (As a result, the PSB is set up at all the nodes etc).

###  Eventhough it is optional, it is upto the implementation looking 
for it as a mandatory object.  Coming back to you question if you 
receive a Path message without a Session Attribute object, you have to 
allocate a FF style for the flow..

> 
> 
>         Now, If we send a Path Message (Of Course for Rerouting a Tunnel) with
> Session Attribute. So, How will the New Path Message compare Session Attribute
> Object Details (For the "Make Before Break" or Rerouting) the PSB of the Old
> Path Message.

###  So you can't reroute the traffic for an FF style flow

> 
> 
>             Does it mean that if we send a Path Message without a Session
> Attribute Object, some DEFAULT value of (Setup/ Holding Priority etc is stored).
> If yes, then what is the default value???

###  I think it should be your implementation's assumption. The default 
value can be 4.

Reg
Arumugam

> 
> TIA
>         Rajesh P Jain
> 
> 
> 
> "Feng, Mark" wrote:
> 
>> Also the "local protecion" flag is useful in term of re-routing LSPs in case
>> of downstream node failure. The resource affinity related vectors are useful
>> regarding constraint-based routing...
>> 
>> - Mark
>> 
>>> -----Original Message-----
>>> From: Khuzema Pithewan [mailto:khuzema@netbrahma.com]
>>> Sent: Thursday, July 19, 2001 1:49 AM
>>> Cc: 'mpls@uu.net'
>>> Subject: Re: Session Attributes
>>> 
>>> 
>>> SE Desired flag can be set in Session Attribute if Ingress is
>>> willing to
>>> use make-before-break of LSPs...
>>> 
>>> Khuzema.
>>> 
>>> 
>>> Rajesh P Jain wrote:
>>> 
>>>> "Hi",
>>>>                 I would also like to know if this Session
>>> 
>>> Attribute OBJECT
>>> 
>>>> anyway helpful in Rerouting Traffic Engineered Tunnels?? Is
>>> 
>>> the information
>>> 
>>>> present in this object anyway useful in "make-before-break" concept?
>>>> 
>>>> TIA
>>>>         Rajesh P Jain
>>>> 
>>>> "Feng, Mark" wrote:
>>>> 
>>>>> Ping,
>>>>> 
>>>>> I know the name implies the attributes belong to the
>>>> 
>>> session. But does it
>>> 
>>>>> mean all senders, i.e. ingress routers, need to have the
>>>> 
>>> same session
>>> 
>>>>> attributes? Should the transit nodes reject the new Path
>>>> 
>>> message, if the
>>> 
>>>>> session attributes are different from other senders of
>>>> 
>>> the same session,
>>> 
>>>>> because there is no rule on "merging" the session attributes?
>>>>> 
>>>>> Thanks.
>>>>> 
>>>>> - Mark
>>>>> 
>>>>>> -----Original Message-----
>>>>>> From: Ping Pan [mailto:pingpan@juniper.net]
>>>>>> Sent: Tuesday, July 17, 2001 9:37 PM
>>>>>> To: Khuzema Pithewan
>>>>>> Cc: rsvp@ISI.EDU
>>>>>> Subject: Re: Session Attributes
>>>>>> 
>>>>>> 
>>>>>> Khuzema,
>>>>>> 
>>>>>> First, this question should go to the mpls list. Please
>>>>> 
>>> forward the
>>> 
>>>>>> discussion to that list. Second, the question itself is
>>>>> 
>>> implementation
>>> 
>>>>>> dependent. Finally, since the Session Attribute object
>>>>> 
>>> is to describe
>>> 
>>>>>> the properties of a RSVP session, in a normal implementation,
>>>>>> it should
>>>>>> be kept where you keep the session.
>>>>>> 
>>>>>> - Ping
>>>>>> 
>>>>>> Khuzema Pithewan wrote:
>>>>>> 
>>>>>>> Hi,
>>>>>>> 
>>>>>>> Session Attribute Object in RSVP-TE contains some
>>>>>> 
>>> flags , setup and
>>> 
>>>>>>> holding priority and some session related info.
>>>>>>> 
>>>>>>>  My doubt is , if this object is per session or per LSP,
>>>>>> 
>>>>>> because name
>>>>>> 
>>>>>>> suggest
>>>>>>>  that it is per session, but holding/setup priorities are
>>>>>> 
>>>>>> the attributes
>>>>>> 
>>>>>>> of a LSP.
>>>>>>>  so basically where to keep this Object,?? in PSB or
>>>>>> 
>>> Session???
>>> 
>>>>>>> Khuzema.
>>>>>>