Subject: [Sipping] New I-Ds: draft draft-dawes-sipping-debug-event-00 and draft-dawes-sipping-debug-id-00

From: "Dawes, Peter, VF-Group" <[email-masked]>
Date: Tue, 20 May 2008 17:14:32 +0200

Hello All, 
 
I have written two drafts
(http://www.ietf.org/internet-drafts/draft-dawes-sipping-debug-event-00.
txt
<blocked::http://www.ietf.org/internet-drafts/draft-dawes-sipping-debug-
event-00.txt> ,
http://www.ietf.org/internet-drafts/draft-dawes-sipping-debug-id-00.txt
<blocked::http://www.ietf.org/internet-drafts/draft-dawes-sipping-debug-
id-00.txt> ) intended to provide debugging and regression testing of SIP
networks. A new event package supplies debugging configuration to SIP
entities, and a new private header carries an identifier that can be
used to trigger logging of signalling and can also be used in post
processing to correlate logs from various entities. 
 
I hope that the SIPPING working group will consider such debugging and
testing to be useful functionality, and any comments and questions are
most welcome.
 
Best Regards,
Peter Dawes 
 
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Use [email-masked] for questions on current sip
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---

From: [email-masked]
Date: Wed, 21 May 2008 14:06:41 -0400

From: "Dawes, Peter, VF-Group" <[email-masked]>

You've described all the details of the mechanism (I think) but given
no one-page overview of what your mechanism is and what it makes
possible.  The only way I could tell if it is at all useful in my
environment is to digest all the details of the proposals first.  I
would help a great deal if you gave a simple summary.

Dale

---

From: "Dawes, Peter, VF-Group" <[email-masked]>
Date: Thu, 22 May 2008 12:55:17 +0200

Hello Dale,
Thanks for taking a look at the drafts and for your comments. Below is a
first attempt at a one-page summary to illustrate the mechanism and its
purpose. I could add something like this to a future version 01 of
draft-dawes-sipping-debug-id.

Best Regards,
Peter

Summary
-------
Alice has a SIP client on her laptop, which she has been using for some
time to make video calls to work colleagues inside her company. Today,
she tried to set up a call to Bob, who recently installed an audio-only
SIP phone at home, but the call failed and Alice does not know why. She
contacts those who manage the SIP network within her company to ask them
to fix the problem. 

The network administrators configure Alice's UA and the SIP proxy that
Alice uses to log SIP signalling the next time she sends an INVITE
request. Alice retries calling Bob and signalling is logged until the
dialog with Bob ends. Later examination of these logs shows that
although requests and responses are correctly exchanged with Bob,
Alice's SIP client is not accepting audio-only sessions and is sending
BYE immediately. This problem had not come to light previously as all
calls within Alice's company are video calls. 

The debugging configuration (supplied by subscription to the debug-event
package) used to investigate the problem is shown below. Alice's UA
inserts the configured identifier (P-Debug-ID:A076D1) to trigger logging
of signalling at the proxy, and the same identifier is used to correlate
signalling logged at Alice's UA and at the Proxy after logging has
finished. 

        Alice                  Proxy                    Bob
        [email-masked]      p1.example.com           [email-masked]
         
        P-Debug-ID:A076D1      From:[email-masked]
                               P-Debug-ID:A076D1

The outline call flow below illustrates how debugging works. Signalling
logged at Alice's UA and the Proxy shows that requests and responses are
successfully exchanged, but Alice's UA will not set up an audio-only
session and sends BYE immediately.                               

        Alice                  Proxy                    Bob
          |(1) INVITE            |                       |
          | m = audio            |                       |
          | m = video            |                       |
          | From:[email-masked]                       |
          | P-Debug-ID:A076D1    |                       |
          | Alice's UA starts logging                    |
          |--------------------->|                       |
          |                      | (2) INVITE            |
          |                      | P-Debug-ID: and From: |
          |                      | match debugging config|
          |                      | so proxy starts       |
          |                      | logging               |
          |                      |---------------------->|
          |                      |                       |
          |                      | (3) 200 OK            |
          |                      | m = audio             |
          |                      |<----------------------|
          |(4) 200 OK            |                       |
          |<---------------------|                       |
          |                      |                       |
          |(5) ACK               |                       |
          |--------------------->|                       |
          |                      | (6) ACK               |
          |                      |---------------------->|
          |                      |                       |
          |(7) BYE               |                       |
          |--------------------->|                       |
          |                      | (8) BYE               |
          |                      |---------------------->|
          |                      |                       |
          |                      | (9) 200 OK            |
          |                      |<----------------------|
          |                      | Dialog has ended so   |
          |                      | Proxy stops logging   |
          | (10) 200 OK          |                       |
          |<---------------------|                       |
          | Dialog has ended, so |                       |
          | Alice's UA stops     |                       |
          | logging              |                       |

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of [email-masked]
Sent: 21 May 2008 19:07
To: [email-masked]
Subject: Re: [Sipping] New I-Ds: draft
draft-dawes-sipping-debug-event-00and draft-dawes-sipping-debug-id-00

 

 
   id-00.txt> ) intended to provide debugging and regression testing of
SIP
    
   I hope that the SIPPING working group will consider such debugging
and
   testing to be useful functionality, and any comments and questions
are
   most welcome.

You've described all the details of the mechanism (I think) but given no
one-page overview of what your mechanism is and what it makes possible.
The only way I could tell if it is at all useful in my environment is to
digest all the details of the proposals first.  I would help a great
deal if you gave a simple summary.

Dale
_______________________________________________
Sipping mailing list  https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP Use
[email-masked] for questions on current sip Use
[email-masked] for new developments of core SIP
_______________________________________________
Sipping mailing list  https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: [email-masked]
Date: Fri, 23 May 2008 18:19:51 -0400

Interesting...  A few comments:

- Why is this a P- header?  Since the event package needs to be
  standardized, there seems to be no reason not to standardize the
  Debug-Id header as well.

- Your example does not show how the event package is used to retrieve
  the logging information.  (I assume that is its purpose.)

- You write "The network administrators configure Alice's UA and the
  SIP proxy that Alice uses to log SIP signalling the next time she
  sends an INVITE request."  Looking at the following paragraph, I
  wonder if you mean, "By subscribing to the debug-event package at
  Alice's UA and the SIP proxy, the network administrators ..."?

  Also, it seems that the logging does not apply to "the next time she
  sends an INVITE request" but "any dialog carrying debug ID A076D1".

- Actually, there really are *two* kinds of debugging configuration,
  one instructing a UA to apply a particular debug ID to any dialog it
  produces (and also to log information), and the other instructing a
  proxy or similar agent to log information about a particular debug
  ID.  Seeing has how a single device can act as a UA in some cases
  and a proxy in others, distinguishing these might be important.

- How does this work in environments where the dialog passes through
  several proxies in several different administrative domains?

- Are there any recommendations for using this technique in
  environments containing SBCs or B2BUAs?

Dale

---

From: "DRAGE, Keith \(Keith\)" <[email-masked]>
Date: Wed, 28 May 2008 11:56:14 +0200

>   standardized, there seems to be no reason not to standardize the

If you look at RFC 3427 you will see that like headers, there are two
classes of event package documentation. One is placed in an
informational RFC and one in a standards track RFC.

So we need to evaluate RFC 3427 requirements for both the proposed
header and event package, and come to a decision on whether the proposal
has specific applicability (and therefore documented in information
RFCs), or whether it is generally applicable to the SIP world (and
therefore needs to be standards track documents).

Regards

Keith

> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of [email-masked]
> Sent: Friday, May 23, 2008 11:20 PM
> To: [email-masked]
> Subject: Re: [Sipping] New I-Ds: 
> draftdraft-dawes-sipping-debug-event-00and 
> draft-dawes-sipping-debug-id-00
> 
> Use [email-masked] for questions on current 
> sip Use [email-masked] for new developments of core SIP
>