ITU-T V.150.1

15.1.3 V.42 I-/UI Frame preservation
Information is copied between V.42 I- / UI- frames and the appropriate MoIP Gateway PDU
without regard to any field structure of the V.42 I- / UI- frames. It is copied as a sequence of octets,
with the order of the octets preserved.
15.2 Gateway Capability and Call Set-up messages
This clause defines the functionality of the messages that are exchanged between Gateways during
the Call Set-up phase. These definitions are used by the following protocols: ITU-T H.323 Annex
P, H.248 (TBD), H.245 and SIP/SDP. The values shown in this set of messages represent what
should be functionally indicated by the signalling protocol. Actual values are outside the scope of
this Recommendation.
Note: in the following definitions default parameter values, if they exist, are shown underlined.
15.2.1 V.150.1 Version
This is the version of this Recommendation that the gateway implements. See Clause 3.2.
15.2.2 TCX definitions
The following definitions are included in the Call Set-up message. These are used as part of the
TCX procedures as defined in clause 22.2.
15.2.2.1 Supported Trans-compression Capability
(Mnemonic: tcxMode) This message indicates the TCX capability of the gateway. Only one mode
should be indicated.
TABLE 2/V.150.1
Supported TCX capability Values
Parameter
Supported TCX capability
Value
Non-TCX/
Single-TCX/
Double-TCX
15.2.2.2 Compression Modes Available
(Mnemonic: cpxSupport) This bit field indicates the compression capabilities the Gateway is able to
support.
TABLE 3/V.150.1
Optional Compression Modes Available
Optional Compression Mode
Value
V.44 Available/Not
Available
MNP5 mode (See Appendix VI) Available/Not
ITU-T Rec. V.150.1 (01/2003) – Prepublished version 26