Subject: [Speermint] Should SIP Interconnect Guidelines recommend Transmission Loss?

From: David Hancock <[email-masked]>
Date: Wed, 24 Feb 2010 10:55:09 -0700

The current version of SPEERMINT draft-hancock-sip-interconnect-guidelines-02 places transmission loss out-of-scope. I'd like to propose that we move this to in-scope. I think this is important because the transmission loss inserted by both peering networks contributes to the end-to-end loss of the media connection. Improper end-to-end loss settings can affect voice quality (too loud/soft, annoying echo), and the ability of the connection to convey voice-band data such as DTMF digits.

Does everyone agree this should be placed in-scope? 

If yes, what is the requirement? My thought is that we recommend support of TIA-912B at a minimum (and possibly ETSI ES 202 020 for international networks). There are other standards that affect the Overall Loudness Rating (OLR) of the media connection (e.g., TIA-470 specifies the SLR/RLR for analog handsets). Should we include these additional standards as well, or assume they get pulled in by TIA-912B (since 912B does informatively reference these other documents)?  

Thanks
David

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From: "PFAUTZ, PENN L (ATTCORP)" <[email-masked]>
Date: Wed, 24 Feb 2010 13:07:35 -0500

David:
I do not believe in IP interconnection we should be involved in
manipulating loss. I see that as more a CPE or gateway function where
conversion to analog is taking place. I see this has separate from the
(IP) NNI. 

Penn Pfautz
AT&T Access Management
+1-732-420-4962

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of David Hancock
Sent: Wednesday, February 24, 2010 12:55 PM
To: [email-masked]
Subject: [Speermint] Should SIP Interconnect Guidelines
recommendTransmission Loss?

The current version of SPEERMINT
draft-hancock-sip-interconnect-guidelines-02 places transmission loss
out-of-scope. I'd like to propose that we move this to in-scope. I think
this is important because the transmission loss inserted by both peering
networks contributes to the end-to-end loss of the media connection.
Improper end-to-end loss settings can affect voice quality (too
loud/soft, annoying echo), and the ability of the connection to convey
voice-band data such as DTMF digits.

If yes, what is the requirement? My thought is that we recommend support
of TIA-912B at a minimum (and possibly ETSI ES 202 020 for international
networks). There are other standards that affect the Overall Loudness
Rating (OLR) of the media connection (e.g., TIA-470 specifies the
SLR/RLR for analog handsets). Should we include these additional
standards as well, or assume they get pulled in by TIA-912B (since 912B
does informatively reference these other documents)?  

Thanks
David
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Speermint mailing list
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https://www.ietf.org/mailman/listinfo/speermint

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From: "Elwell, John" <[email-masked]>
Date: Thu, 25 Feb 2010 10:15:11 +0100

David,

I too am concerned about this. Implementations of the NNI (SIP proxies, B2BUAs, SBCs, etc.) will not in general be the media endpoints, so if we specify anything of this nature it will need to be made explicitly clear that it applies to the media endpoints (e.g., user devices, gateways, media servers) and not to the signalling entities. In general a SIP service provider (carrier or enterprise) is not in control of the media endpoints that use its services and has no way of enforcing those media endpoints to comply with any NNI specification (and indeed has no way of telling those media endpoints whether a given medium for a given session is routed via an NNI). Therefore whatever we specify for media endpoints, there is no way of guaranteeing that only compliant media endpoints will find themselves involved in a session that crosses an NNI.

John

> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of PFAUTZ, PENN 
> L (ATTCORP)
> Sent: 24 February 2010 18:08
> To: David Hancock; [email-masked]
> Subject: Re: [Speermint] Should SIP Interconnect Guidelines