[SIPForum-discussion] Post Dialing Delay (PDD)

Fri Apr 18 18:18:56 UTC 2008

Hadriel,

what I understand from PDD is http://www.voip-news.com/dictionary/pdd// and when we think about a NGN network as you know we will need separate elements that will have conversations.

Basically I thought Mario was asking a PDD "time" what I suggested him is a basic measurement via tools. (and how to do it)

If it is not related with subject sorry about that.
Selamlar,
Halit Sakca

From: HKaplan at acmepacket.com
To: sakcahalit at hotmail.com; mario.baron at ericsson.com; discussion at sipforum.org
Date: Fri, 18 Apr 2008 14:02:25 -0400
Subject: RE: [SIPForum-discussion] Post Dialing Delay (PDD)

I’m not sure I understand what you
mean?  Which part of the “network” do you mean, and what type of “health”?

PDD isn’t really useful for network health checks in my opinion,
although some people use it for determining peer provider “quality”,
just as they use ASR.  It’s a very coarse way of determining this, because
obviously the PDD or ASR is unique per called destination and even time of day,
not per next-domain, so it has to be carefully “averaged” over long
periods of time with a large data set to make smart decisions about the
relative quality among multiple peers.  Many SIP systems have that ability.

If you mean measuring the PDD for a
specific UA endpoint from the provider, there are ways of doing that too –
for example using PRACKs for the provisional response.

If you mean accurate measurement of
end-end network layer health for
media, RTP and RTCP quality measurements are often employed, and obviously SBC’s
have been measuring that for ages.

But anyway, if you feel something else is
needed for SIP layer measurements that isn’t specified in draft-ietf-pmol-sip-perf-metrics-00.txt,
then I encourage you join the PMOL WG mailing list and email your comments
there so that they can be discussed and included in the draft. (to join go to https://www1.ietf.org/mailman/listinfo/pmol)

-hadriel

From: Halit Sakca
[mailto:sakcahalit at hotmail.com] 

Sent: Friday, April 18, 2008 1:36
PM

To: Hadriel Kaplan;
mario.baron at ericsson.com; discussion at sipforum.org

Subject: RE: [SIPForum-discussion]
Post Dialing Delay (PDD)

you are right for far end perspective we don't need
a mirrored port. BUT what about network health check I mean this measurement
should be done from whole elements that will use 180 Ringing anyway.

Selamlar,

Halit Sakca

From: HKaplan at acmepacket.com

To: sakcahalit at hotmail.com; mario.baron at ericsson.com; discussion at sipforum.org

Date: Fri, 18 Apr 2008 12:35:53 -0400

Subject: RE: [SIPForum-discussion] Post Dialing Delay (PDD)

From:
discussion-bounces at sipforum.org [mailto:discussion-bounces at sipforum.org] On Behalf Of Halit Sakca

Sent: Friday, April 18, 2008 11:43
AM

> Can Anyone help me how we can measure and verify that the PDD is under

> a certain value?

> 

> Is there any ITU-T value for the PDD to take as a reference?

> 

> Our NGN provides the IP connetivity to IP carriers through Acmepacket
SBCs.

For doing that mentioned above you will need a mirror port on switch anyway.

If you can not set the time of all components same via NTP and trace
separately.

No, you don’t need to do that
with mirroring – most SBC’s measure that time already and report
it, as do other SIP device types.  PDD can typically be fully measured at
one spot, although it may not represent the user’s perceived PDD if
it’s not measured at the originating provider.

Also, you don’t really need NTP,
because the number is a differential value measured by the same entity that
sends the INVITE request.  Thus the local view of global time does not
really matter. (it does matter for reporting/determining when calls are made,
but not for their delays or durations)

-hadriel

Pahalı telefon faturaları? Windows Live Messenger'dan
ücretsiz ve sınırsız bilgisayardan bilgisayara aramalar - buradan ÜCRETSİZ
yükleyin! Buraya
tıkla!

_________________________________________________________________
Windows Live Hotmail size ücretsiz 5GB'lık ÜCRETSİZ depolama olanağını sunuyor! Ücretsiz Windows Live Hotmail hesabınızı buradan edinin!
http://get.live.com/mail/overview
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20080418/9f68b069/attachment-0002.html>