Specifications

Chapter 1 Introduction IPmux-1/1E Installation and Operation Manual
1-10 Functional Description
Operation Modes
Static Mode
When the timeslot allocation is static and no activity is detected, the payload can
be efficiently encoded using a constant bit rate.
The TDMoIP® payload consists of between one and thirty 48-octet subframes.
The number of subframes is pre-configured and typically chosen according to
latency and bandwidth constraints.
Dynamic CAS Mode
When timeslots are dynamically allocated, and CAS can be detected for
bandwidth conservation, the payload can be efficiently encoded using a variable
bit rate.
CESoIP Mode
In general, when the timeslot allocation is static and no activity is detected, the
payload can be efficiently encoded using a constant bit rate.
The CESoIP payload size is based on the packetization delay (in msec); the
minimum size is 1 msec, and increases in steps of 1 msec.
E1/T1
This section describes the IPmux-1 E1/T1 operation modes, which are:
• Unframed – valid for static and CESoIP/E1
• Fractional – valid only for static and CESoIP
• Fractional with CAS –valid only for static and dynamic CAS .
Unframed (Transparent)
In the transparent mode, the incoming bit stream from each channel (regardless of
framing) is converted into IP over Ethernet frames. This option provides clear
channel end-to-end service (unframed).
Fractional
In the fractional mode, the incoming bit stream is regarded as a sequence of
N × 64 kbps channel groups (according to framing). Each predefined group of
channels is converted into a structure block. The structure block is packetized into
IP frames and transmitted.
This mode allows transmission of several selected timeslots without the whole E1
or T1 frame, as in transparent mode.
Use Fractional mode when grooming ISDN BRI channels from a remote IPmux-1E
unit.
Note