Subject: [Megaco] Question concerning COT using H.248 Basic Continuity Package

From: "Kamitses, Jerry" <[email-masked]>
Date: Tue, 26 Nov 2002 12:07:52 -0500

The H.248 Basic Continuity Package (PackageID ct) defines 
one event (cmp) and two signals (ct and rsp) for controlling 
the continuity test on a circuit. 

The signal/event pair ct and cmp would be used to initiate 
the COT, while the rsp signal is used to perform a COT response.

There are three distinct types of COT which can be performed 
per ITU and Bellcore standards and usually this determined by 
whether the circuit termination at the gateway is either of 
type 4-wire or 2-wire (though there are instances where this 
can be overridden and the particular test selection determined 
by other means).  

In the similar MGCP event package the MG Controller selects 
the COT type by virtue of the fact that the MGCP package 
specifies the pair of distinct tones needed to perform the 
different types of COT distinct signals and requested events.

Based on the procedure defined by H.248 for performing an 
initiating or responding type COT, it appears that the 
type of COT is determined independently by the Gateway. 

Is there anyone on this list that either agrees or 
disagrees with this conclusion? 

Note that I have raised this question only since the early 
proposal that MGCP also operate in a similar manner, and 
rely on the Gateway to independently choose the COT type
(during "formative" days of MGCP), generated a fair amount 
of controversy and eventually led to defining events that 
gave the MG Controller total control of the COT type. 

For H.248, if the gateway is required to know via provisioning 
which type of COT it needs to perform, then is such provisioning 
provided in the Megaco MIB ? 
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