Re: [ippm] draft-baillargeon-ippm-twamp-value-added-octets

Sorry, there is a typo in my previous mail,

My proposal should be:

+--------------------------------+
+------------------------------+
|           Node A               |                       |           Node B
|
|  +---------------------------+ |                       |
+--------------------------+ |
|  | Forward-Control-Client    |<--Forward-OWAMP-Control-->| Forward-Server
| |
|  | Forward-Fetch-Client      |                           |
| |
|  | Forward-Session-Sender    |---Forward-OWAMP-Test----->|
Forward-Session-Receiver | |
|  +---------------------------+ |                       |
+--------------------------+ |
|                                |                       |
| 
|  +---------------------------+ |                       |
+--------------------------+ |
|  | Reverse-Control-Client    |<--Reverse-OWAMP-Control-->| Reverse-Server
| |
|  | Reverse-Fetch-Client      |                           |
| |
|  | Reverse-Session-Receiver  |<--Reverse-OWAMP-Test------|
Reverse-Session-Sender   | |
|  +---------------------------+ |                       |
+--------------------------+ |
|                                |                       |
|  
+--------------------------------+
+------------------------------+ 

Regards,
Xiangsong

> -----Original Message-----
> From: Andreas Johnsson A [mailto:andreas.a.johnsson@ericsson.com]
> Sent: Friday, May 06, 2011 10:54 PM
> To: 'Xiangsong Cui'; Christofer Flinta; 'Henk Uijterwaal'; ippm@ietf.org
> Subject: RE: [ippm] draft-baillargeon-ippm-twamp-value-added-octets
> 
> Hi Xiangsong,
> We are drifting away from the topic here. What we want to do is to include
> functionality in the TWAMP spec for measuring available capacity in both
the
> forward and reverse direction. This interest was also raised by for
example Al
> and Yaakov (maybe throughput was the main idea here?). The problems with
> loss measurements are outside the scope of this discussion, but do belong
to
> draft-ietf-ippm-rt-loss-00 by Al.
> 
> There seem to be a little bit of confusion when it comes to TWAMP. As you
> know, TWAMP time stamps packets when a packet is sent at the session
> sender, when it is received at the reflector, when it is sent by the
reflector and
> when it is again received by the session sender. From this it is very easy
to
> deduct forward and reverse delay, and with our proposal also forward and
> reverse available capacity. Sure, OWAMP can be used to do these
> measurements, but the intention with TWAMP is to perform both
> measurements in both directions (and round trip) with only one trigger. I
think
> this is a strong argument for trying to put new functionality into TWAMP
and
> not only focus on OWAMP.
> 
> I hope this resolves any issues you have with the intention with our
draft,
> although maybe the draft needs to be enhanced or split into several.
> Suggestions are welcome.
> 
> Best regards
> Andreas Johnsson
> 
> -----Original Message-----
> From: ippm-bounces@ietf.org [mailto:ippm-bounces@ietf.org] On Behalf Of
> Xiangsong Cui
> Sent: Wednesday, May 04, 2011 4:09 AM
> To: Christofer Flinta; 'Henk Uijterwaal'; ippm@ietf.org
> Subject: Re: [ippm] draft-baillargeon-ippm-twamp-value-added-octets
> 
> 
> > This draft is trying to provide a means for measuring the capacity in
> > both
> the
> > forward and reverse directions as two separate measurements. This is
> similar
> > to the current capabilities of TWAMP, where e.g. delay and packet loss
> > can
> be
> > measured separately in both directions.
> 
> If you are referring to one-way metric, e.g. one-way packet loss, how can
you
> get the one-way metric by the two-way test?
> That said, how can the session-sender get to know whether the packet is
lost
> before or after the session-reflector?
> 
> Regards,
> Xiangsong
> 
> 
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