Specifications

Installation and Operation Manual Chapter 1 Introduction
MPW-1 MP-4100 Ver. 2.0 Functional Description 1-13
 The packet processor recovers the payload carried by the packets and
restores the original data stream of the pseudowire, in accordance with
the selected framing mode.
When the pseudowire carries only selected timeslots, the payload is
reinserted in the appropriate timeslots. Therefore, when several
pseudowires carry payloads destined to the same internal DS1 port, all
the useful payload is reinserted in the original timeslots, and only the
remaining empty timeslots in the internal port frame are filled with a
user-selectable idle code.
In a similar way, the signaling information related to the voice timeslots
transported by each pseudowire is reinserted in the positions
corresponding to the pseudowire timeslots.
Since the TDMoPSN packet structure for framed ports does not depend
on the port frame structure, a pseudowire carrying traffic from an E1 port
can be directed to a T1 port at the far end, as long as the total number
of timeslots does not exceed 24, and the payload type is data (signaling
cannot be transferred between E1 and T1 ports).
HDLCoPSN Processing
HDLCoPSN packet processing is similar to the processing of TDMoPSN packets
described above, except that the HDLCoPSN protocol is intended to provide
port-to-port transport of HDLC-encapsulated traffic, in accordance with RFC4618,
for example, Frame Relay or CCS protocols.
For framed ports, the HDLC traffic is carried in specific timeslots (these timeslots
are specified during the configuration of a HDLCoPSN pseudowire and are always
considered data timeslots).
For HDLCoPSN, it is not necessary to configure the same number of timeslots at
the pseudowire end points. The pseudowire bandwidth will be determined by the
endpoint with the smaller number of assigned timeslots.
The HDLCoPSN protocol can also handle whole (unframed) E1 streams.
When assembling packets for a HDLC pseudowire, HDLC idle flags are removed,
and only the contents of HDLC packets with useful payload are inserted in
packets. This results in better bandwidth utilization efficiency. At the receive end,
HDLC packet structure is restored and inserted in the restored port data stream.
Therefore, HDLC pseudowires can connect only ports with the same framing
mode.
SAToPSN Processing
SAToPSN is different from the TDMoPSN and HDLCoPSN protocols, in that it is
used to transfer transparently a bit stream at the nominal port rate
(2.048 Mbps). Therefore, SAToPSN can be used only when the port uses the
unframed mode, and thus only one pseudowire can be configured per port.
SAToPSN packet payload consists of a user-specified number of raw TDM bytes (4
to 1440 bytes), and is treated as data payload.
Note