The MPLS WG Archive

["Philip Matthews" <philipma@nortelnetworks.com>]

Aditya:

Adrian beat me to the reply, but I agree with everything he said.
Does this answer your question?

- Philip

Aditya Chugh wrote:
> 
> Hello Philip,
>  Thanks for your mail.
> I recieved a reply from Adrian(enclosed below)......but I asked him a
> further question based on his answer(also enclosed below)...regarding which I am yet to hear
> from him. It would really help if you could shed some light on the matter !!!!
> 
> The question I had asked Adrian was:-- "Could you explain what you
> exactly mean by "state and information related to the previous incarnation of the session "
> 
> In section 3.4 of your draft you say that
> "If either LDP peer sets the FT Reconnect Flag to 0, or omits the FT
>    Session TLV, both LDP peers MUST release any state information and
>    resources associated with the previous instantiation of the LDP
>    session between the same LDP peers, including FT label state and
>    Addresses"
> 
> Could you please tell me as to what specifically constitutes the "state information and resources" ??
> 
> Secondly in Section 4.2 of your draft you write
>    "When an LDP Peer receives a message containing the FT Protection TLV,
>    it MUST take steps to secure this message (or the state information
>    derived from processing the message).  Once the message is secured,
>    it MUST be ACKed.  However, there is no requirement on the LSR to
>    send this ACK immediately."
> 
> What do you exactly mean by the term "SECURED".....obviously it does not mean "PROCESS" the message ?
> So what does "secure this message" mean ????
> 
> Looking forward to your reply.
> Thanks in Advance,
> Aditya
> 
> Dear Adrian,
>  Thanks for your reply.Could you kindly explain what you
> exactly mean by "state and information related to the previous incarnation of the session "
> 
> In section 3.4 of your draft you say that
> "If either LDP peer sets the FT Reconnect Flag to 0, or omits the FT
>    Session TLV, both LDP peers MUST release any state information and
>    resources associated with the previous instantiation of the LDP
>    session between the same LDP peers, including FT label state and
>    Addresses"
> 
> I broadly understand what you mean by  "state information and resources "..but could you
> give me the specifics as to what constitutes the "state information and resources" .
> Sorry for bothering you with the gory details...but I guess it is better to be safe rather than sorry
> Thanks for your help
> warm regards,
> Aditya
> 
> >>Hi again Aditya,
> >>Fair question.
> >>It's your choice whether you re-use the same session control block, but you should throw out state and information related >>to the previous
> incarnation of the session and only populate the new/re-used control block with information about the re-
> 
> >>established session.
> >>OK?
> >>Regards,
> >>Adrian
> 
> -----Original Message-----
> From: Philip Matthews [mailto:philipma@nortelnetworks.com]
> Sent: Tuesday, March 20, 2001 9:23 AM
> To: Aditya Chugh (Leela)
> Subject: Re: If we recieve FT reconnect Flag = 0...can we use same
> session ??
> 
> I saw this posted to the MPLS-OPS list run by the MPLS Resource Center....
> 
> If you have questions on our Fault Tolerance draft, it would be best to
> send them directly to the authors. Some of us are a little behind in our
> reading of various mailing lists ...
> 
> And don't send them to MPLS-OPS list, which is for operational questions,
> but to the MPLS WG list instead (mpls@uu.net).
> 
> Anyway, nice to see someone else implementing the draft.
> 
> - Philip
> 
> PS. Did Adrian every reply to your question??
> 
> "Aditya Chugh (Leela)" wrote:
> >
> > Dear Adrian,
> > I need to bother you again...!!!!!!
> >
> > If our FT-LDP implementation is to conform to your draft " draft-ietf-mpls-ldp-ft-00.txt "...then how should the following be handled ????
> 
> >
> > Consider the case when the TCP connection (of an FT session)  needs to be reestablished.
> > Before the Reconnection Timer Expires
> > if I recieve an Initialization message( with valid Session TLV)..
> > ....but FT reconnect flag set to 0( which means that peer has not preserved state info for previous instantiations of this LDP session )
> 
> >
> > I am supposed to release all the label state and resources associated with the previous instantiation of the LDP session.
> 
> >
> > this would mean that I release the Labels and the Control Blocks ( since Labels are stored in the Control Blocks).
> >
> > But do I need to tear down the session also ??...that is do I also need to
> > release the Session Block ...or I can use the same session block to establish a "Brand New" FT session.??
> >
> > Thanks in advance,
> > Aditya