Re: [ANCP] ANCP behaviour for rate change

Hi Woj,

All explanations sound reasonable, but we are talking about an AN implementation and not an ANCP protocol issue.

ANCP has to report the port status. That’s the basic task of ANCP per definition.

Let me distinguish between two scenarios:

Scenario 1 Regular operation:

If line is up but line rate changes happen then option a) “Send a new Port-up with Rate Y” is preferable.

Scenario 2 Fault condition:

If a port is toggling the AN has to integrate a certain period of time the port status and to decide then if the port is up or down.

So the port has to send a port down message following the periodically change between port up/down status. The period is determined by timer value to be set by configuration.

So this happens in option b) “Send a Port-down followed by a Port-Up with rate Y”.

Result:

Sending a port down message followed by a port up message is necessary during resynchronisation in case of fault condition. IMO this is an implementation issue of an AN. ANCP has to be prepared to support both scenarios!

Regards

Thomas

Von: Philippe Champagne (pchamp) [mailto:pchamp at cisco.com]
Gesendet: Dienstag, 5. Februar 2008 16:58
An: Wojciech Dec (wdec); ancp at ietf.org
Betreff: Re: [ANCP] ANCP behaviour for rate change

Hi Woj

I agree with (a) otherwise it implies twice as many messages

There is that part in section 5.4.2:

    The message SHOULD be generated when a line first comes UP, or any of the
     attributes of the line change e.g. the line re-trains to a different
     rate or one or more of the configured line attributes are
     administratively modified.

So, it sounds like it is covering that. Is that what you were referring to but to be worded more specifically? Or perhaps you missed this text or I'm the one off track?

Regards

Phil

From: ancp-bounces at ietf.org [mailto:ancp-bounces at ietf.org] On Behalf Of Wojciech Dec (wdec)
Sent: Monday, February 04, 2008 11:46 AM
To: ancp at ietf.org
Subject: [ANCP] ANCP behaviour for rate change

Hi All,

I have a question about the expected behaviour of ANCP following line-rate changes. At the same time I would request that this behaviour be detailed in the appropriate drafts (Section 5.4.2 of protocol draft would appear to be a reasonable place for this).

Let's say that a line rate initially comes up at rate X. This is communicated in a Port-Up message.
Then, the line rate re-trains to rate Y. Is ANCP's expected behaviour to:
a) Send a new Port-up with Rate Y
b) Send a Port-down followed by a Port-Up with rate Y.

Behaviour a) would IMO be highly preferable and described in the text.

Comments?

Regards,
Woj.