Wavecom GX64 GSM 27.010 Multiplexer Feature Application Note - page 10
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GR/GS64 27.010 MUX Implementation
GR/GS64 27.010 implementation conforms to the Release 99 GSM specification 3GPP
27.010 version 3.4.0. 3GPP 27.010 defines three operating options: basic, advanced
without error recovery and advanced with error recovery. The GR/GS64 supports basic
option. 3GPP 27.010 defines four convergence layer types and GR/GS64 only
supports convergence layer type 1. All other MUX services that are defined in the
27.010 spec but not mentioned in this section are not supported by GR/GS64.
5.1 Basic Option
The GR/GS64 supports basic option and thus it only supports non-error-recovery
mode and uses UIH frame to carry user data. In addition, basic option also means the
following:
-
Length indicator used instead of the HDLC transparency mechanism.
-
Different flag octet (0xF9) from that used by HDLC.
-
Can not be used on links that use XON/XOFF flow control.
-
May have longer recovery procedure from loss of synchronization.
Basic option is intended for serial links with good quality.
5.2 Convergence Layer Type 1
GR/GS64 only supports convergence layer type 1. Convergence layer type 1 is used to
transfer over channels where there is no need to convey the control signals (such as
embedded V.24 signals) along with the information. The V.24 information instead will
be carried by the MSCs on the MUX control channel. Only UIH frames are used for data
frames.
5.3 Number of Channels
A Data Link Connection (DLC) is used to identify a virtual channel. A MUX control
channel (DLC 0) is used to exchange management information, such as parameter
negotiation, testing, flow control, close down, etc. In the context of this document,
channel and DLC will be used interchangeably.
GR/GS64 supports up to 8 channels in addition to a MUX control channel. MUX
control channel has high priority and all other channels have same priorities.
Gx64 APPLICATION NOTE
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27.010 MUX Feature
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