RE: [mpls] For your review - Issues/errors/clarifications in RFC3 036

neil.2.harrison@bt.com Fri, 08 October 2004 11:04 UTC

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Subject: RE: [mpls] For your review - Issues/errors/clarifications in RFC3 036
Date: Fri, 08 Oct 2004 11:57:03 +0100
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Thread-Topic: [mpls] For your review - Issues/errors/clarifications in RFC3 036
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To: loa@pi.se
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Thanks Loa,

I think there are 2 separate issues here:

-	whether the LDP signalling protocol has the right exception
handling;

-	how *any* control-plane protocols should behave in the face of
data-plane defects.....and in general it is not a good idea to take
actions in the control-plane unless the nature of the defect is
understood 1st in the data-plane.  That is why I asked the question
about issuing a withdraw on getting unexpected labelled pkts.

Thanks.....regards, Neil

> -----Original Message-----
> From: Loa Andersson [mailto:loa@pi.se] 
> Sent: 08 October 2004 11:33
> To: Harrison,N,Neil,IKR2 R
> Cc: ewgray@GraIyMage.com; Nick.Weeds@dataconnection.com; mpls@ietf.org
> Subject: Re: [mpls] For your review - 
> Issues/errors/clarifications in RFC3 036
> 
> 
> Neil,
> 
> guess that tht is a fair question, it should be looked into, 
> but I guess that it is out of scope for an update of the LDP 
> spec. (I didn't say "implemenation specific :) ). For 
> communication between LDP peers it is my take that we can 
> trust TCP, after all that was one of the reasons chosing TCP.
> 
> Now, if the protocol exchange information in a correct
> manner, but one implementation creates a label mapping
> that is errornous, this is not something we can address
> in the protocol specification, is it?
> 
> /Loa
> 
> neil.2.harrison@bt.com wrote:
> 
> > Loa,
> > 
> > I was meaning in general, ie labelled pkts.  Just want to check 
> > nothing is being overlooked here.
> > 
> > regards, Neil
> > 
> > 
> >>-----Original Message-----
> >>From: Loa Andersson [mailto:loa@pi.se]
> >>Sent: 08 October 2004 11:19
> >>To: Harrison,N,Neil,IKR2 R
> >>Cc: ewgray@GraIyMage.com; Nick.Weeds@dataconnection.com; 
> mpls@ietf.org
> >>Subject: Re: [mpls] For your review - 
> >>Issues/errors/clarifications in RFC3 036
> >>
> >>
> >>Neil,
> >>
> >>are you talking about packets exchange over the TCP
> >>connection between two LDP peers, or (labeled) packets in genral?
> >>
> >>/Loa
> >>
> >>neil.2.harrison@bt.com wrote:
> >>
> >>>Eric,
> >>><Snipped>
> >>> 
> >>>
> >>>
> >>>>Not if the downstream router sends a label withdraw as an
> >>
> >>appropriate
> >>
> >>>>recovery response to getting a packet with a label that 
> is invalid.
> >>>
> >>>
> >>>Is there not a possibility that packets might end up at the wrong
> >>>destination for other (defect) reasons?  And in such a case 
> >>
> >>sending a
> >>
> >>>label withdraw seems the wrong action...comments?
> >>>
> >>>regards, Neil
> >>>
> >>>
> >>>_______________________________________________
> >>>mpls mailing list
> >>>mpls@lists.ietf.org https://www1.ietf.org/mailman/listinfo/mpls
> >>>
> >>>
> >>
> >>--
> >>Loa Andersson
> >>
> >>Principal Networking Architect
> >>Acreo AB                           phone:  +46 8 632 77 14
> >>Isafjordsgatan 22                  mobile: +46 739 81 21 64
> >>Kista, Sweden                      email:  loa.andersson@acreo.se
> >>                                            loa@pi.se
> >>
> > 
> > 
> > 
> 
> -- 
> Loa Andersson
> 
> Principal Networking Architect
> Acreo AB                           phone:  +46 8 632 77 14
> Isafjordsgatan 22                  mobile: +46 739 81 21 64
> Kista, Sweden                      email:  loa.andersson@acreo.se
>                                             loa@pi.se
> 

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