RAD Data comm IPmux-11 Timeslot Assignment in a Bundle , Testing , Timing Modes

Chapter 1 Introduction Installation and Operation Manual
1-6 Functional Description IPmux-11 Ver. 2.00
Unframed
In the unframed 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 timeslots (according to framing). Each predefined group of timeslots 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.
Fractional with CAS
In the fractional-with-CAS mode, the structure block (as described under
Fractional Operation Modes, above) also includes Channel Associated Signaling
(CAS) from timeslot 16 (E1) or robbed bit (T1). The relevant portion of the signaling
channel is packetized and sent to the destination.
Timeslot Assignment in a Bundle
A bundle is a group of timeslots associated with a specific E1 or T1 channel.
IPmux-11 places individual or multiple TDM timeslots (up to 31 timeslots for E1 or
up to 24 for T1) into bundles with a single IP address destination.
Testing
Diagnostic capabilities include E1/T1 local and remote loopback tests for rapid
localization of faults. The E1/T1 traffic can be looped locally, toward the line, or
toward the remote end (see Chapter 6 for more information).
Timing Modes
The E1/T1 Tx clock can operate in several timing modes to provide maximum
flexibility for connecting the IPmux-11 E1 or T1 channels.
Each of the clocks must be configured correctly on both the receive and transmit
ends to ensure proper operation and prevent slips (see Figure 1-3, Figure 1-4 and
Figure 1-5).
The E1/T1 available Tx modes are:
• Loopback timing – the E1/T1 Tx clock is derived from the E1/T1 receive (Rx)
clock.
• Adaptive timing – in this mode, the E1 or T1 Tx clock is regenerated using the
adaptive method. In this method, the fill level of the buffer receiving packets is
monitored. If the buffer begins to overfill, the regenerated Tx clock frequency
increases to avoid overflow. If the buffer begins to empty, the Tx clock
frequency (toward the TDM device) decreases to avoid underflow.