Re: [conex] WGLC for draft-ietf-conex-abstract-mech-06.txt

Bob Briscoe <> Mon, 10 December 2012 21:53 UTC

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Date: Mon, 10 Dec 2012 21:52:12 +0000
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Subject: Re: [conex] WGLC for draft-ietf-conex-abstract-mech-06.txt
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You're right. Good point. Certainly true for downstream cases out of 
the cellular network, where long-running flows are not uncommon.

When I wrote that, I wasn't thinking of mobility, I was thinking of 
much less frequent re-routing after failures, so I wasn't trying to 
make it seamless.

For explicit hand-overs as in the case you describe, there's explicit 
hand-over of operational state, so it wouldn't be impossible to 
hand-over credit too. Am I right, at least in an arm-wavy sense?

We should make it clear that the only state that re-creates itself is 
the flow-ID state, not the credit associated with it. I wrote that 
sentence (not Matt), and my motivation was to explain that a switch 
to a different audit wouldn't be catastrophic for the flow. I wasn't 
trying to claim that it would hand-over without a glitch. The audit 
would drop some packets, so the flow would send some Re-Echo-Loss, 
which would establish some credit and the flow could continue.


Sorry for delay replying.

At 13:27 21/11/2012, Ingemar Johansson S wrote:
>First time I had time to read carefully through this document
>The document is comprehensible and I don't find any serious issues with it.
>One comment though on page 5, 3rd para.
>" the flow-state required for audit creates itself as it detects new 
>flows.  Therefore a flow will not fail if it is re-
>    routed away from the audit box currently holding its flow-state. "
>If I map ConEx to a 3GPP LTE use case, the audit functions are best 
>placed in the eNodeB. When a new (long lived) flow is created it is 
>preferably preloaded with credit marks which are stored in the 
>auditor in the eNodeB which the terminal is "connected" to. When the 
>terminal hands over to another eNodeB the credit marks will be 
>lost.  This means that the ConEx markings will in this case be at 
>least one RTT behind with a higher risk of false positives in the 
>auditor in the new eNodeB
>To avoid this the credit marks would need to be forwarded to the new 
>eNodeB via e.g the X2 interface.
>So my question is, is it needed to add a statement that mentions this ?
>-----Original Message-----
>From: [] On 
>Behalf Of marcelo bagnulo braun
>Sent: 23 October 2012 06:54
>To: 'ConEx IETF list'
>Subject: [conex] WGLC for draft-ietf-conex-abstract-mech-06.txt
>This note issues the WGLC for
>Please reivew the document and provide comments. The WGLC will close 
>on the 20th of november.
>For you convenience, the draft can be found at:
>Regards, marcelo
>conex mailing list
>conex mailing list

Bob Briscoe,                                BT Innovate & Design