Re: [mpls-tp] Alarm Reporting (aka AIS)

[<[e-mail]>]

re-send as plain text and snipped...(too big message received)


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	From: Harrison,N,Neil,DKQ7 R 
	Sent: 09 December 2010 10:26
	To: 'Alexander Vainshtein'; Maarten Vissers
	Cc: [e-mail]; Reid,ABD,Andy,DEE1 R
	Subject: RE: [mpls-tp] Alarm Reporting (aka AIS)
	
	
	The key points are:
	-    AIS is technically not necessary for any pkt-based technologies at all.....we need not consider anything further from this killer observation alone...but if we do, we then observe....
	-    it only has meaning in (i) regular-time slice co-cs mode networks and (ii) only when the client is permanently bound to its server, ie the client never moves...once the client 'clears' or 'moves' wrt to its routing *in the client layer network* (and the server MUST NOT even try and know this!) then the server has no idea who to send the redundant AIS signal to.
	 
	regards, Neil   


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		From: [e-mail] [mailto:[e-mail]] On Behalf Of Alexander Vainshtein
		Sent: 09 December 2010 10:05
		To: Maarten Vissers
		Cc: [e-mail]
		Subject: Re: [mpls-tp] Alarm Reporting (aka AIS)
		
		

		Maarten,

		One brief comment that you probably have heard quite a few times from me.

		 

		You have said in your response to Andy Reid:

		The adaptation sink functions in the transport network technologies not only "can know" this information, they actually "do know" this information.

		The problem with MPLS-TP is that, as long as its data plane is aligned with that of MPLS (and it is!) its analog of the "adaptation sink function", namely the ILM entry with the "Pop and Loop" action on a specific label do not have this information. I.e., when MPLS pops a label, it can handle both labeled and unlabeled packets that result from this action. When the resulting packet is labeled, handling of the next label does not depend on the previous one. 

		And of course handling unlabeled packets (IP as an immediate client of an MPLS-TP LSP) is just as possible and, IMHO, just as relevant...

		 

		After writing this, I think (and I apologize that I've only noticed it that late), that IP as an MPLS-TP client that does not have any AIS is a great counter-example to AIS into the clients...

		 

		Regards,

		     Sasha