Re: [manet-dlep-rg] Peer termination

My view on DLEP is that it is loosely coupled with forwarding state. DLEP session termination doesn’t mean destinations are unreachable. If the modem sends Destination Down, it is likely the Destination is indeed unreachable. No guarantees here.

If the Modem knows Destinations are unreachable, it should send such.

Bit of a problem is Destination state the Router knows about, but no state was received in current DLEP session. State was set up by a previous DLEP session which was closed without Destination Down, or by the router hello protocol. I would say DLEP session state takes preference. Router is free to do otherwise.

Teco

PS. Radio Silence - Receive only is one of the operation modes I’m dealing with.

Op 12 nov. 2013, om 13:57 heeft Taylor, Rick <Rick.Taylor@cassidian.com> het volgende geschreven:

> +1
> 
> Keep the Peer Terminate message.  Include a status value to differentiate between a normal and abnormal termination.
> 
> Status 0 = Ok - Normal shutdown, e.g. user turned off device
> 1 = Missing heartbeats
> 2 = Incompatible configuration
> 
> I'm guessing at status codes here, but it's an idea.
> 
> Obviously a terminate can come from either modem or router, and MUST be the last message.
> 
> I am not sure it is clear that the termination of a DLEP session implies that all destinations are no longer reachable.  No more DLEP metrics about those destinations, sure, but unreachable?
> 
> Rick Taylor
> 
>> -----Original Message-----
>> From: manet-dlep-rg-bounces@ietf.org [mailto:manet-dlep-rg-
>> bounces@ietf.org] On Behalf Of Teco Boot
>> Sent: 11 November 2013 18:14
>> To: Stan Ratliff
>> Cc: DLEP Research Group (manet-dlep-rg@ietf.org)
>> Subject: Re: [manet-dlep-rg] Peer termination
>> 
>> 
>> Op 11 nov. 2013, om 18:34 heeft Stan Ratliff (sratliff)
>> <sratliff@cisco.com> het volgende geschreven:
>> 
>>> 
>>> On Nov 11, 2013, at 11:19 AM, Teco Boot <teco@inf-net.nl>
>>> wrote:
>>> 
>>>> 
>>>> Op 11 nov. 2013, om 01:55 heeft Stan Ratliff (sratliff)
>> <sratliff@cisco.com> het volgende geschreven:
>>>> 
>>>>> Oh, and on termination:  I'm not removing the "Peer Terminate". Yes, a
>> session can be brought down via TCP FIN. But, you can also announce it
>> with a Peer Terminate. Gives a more orderly way to clean everything up,
>> IMO.
>>>> 
>>>> It doesn't add anything, other than more messages, more state, more
>> code and more bugs.
>>>> What am I missing?
>>> 
>>> The ability for one side of the DLEP connection to tell the other *why*
>> things are going down.
>> 
>> I think a "Peer Down" message makes sense. This is very different than
>> terminating a DLEP session, in that the latter would not indicate peers
>> are no longer accessible. A "Peer Down" has an implicit meaning that all
>> Destinations are down. Closure of DLEP TCP connection would not indicate
>> such.
>> 
>> Maybe use a generic Peer Error message, as notification. Could be send
>> before TCP connection teardown.
>> 
>> Teco
>> 
>> 
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