PM7341 datasheet(119/413 Pages) PMC

119 / 413 page

PRELIMINARY

INVERSE MULTIPLEXING OVER ATM

PM7341 S/UNI-IMA-84

DATASHEET

PMC-2000223

ISSUE 4

INVERSE MULTIPLEXING OVER ATM

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

121

be independently configured to be provisioned (contain valid data) or

unprovisioned. The RCAS performs a table lookup to assign the provisioned

time-slots to a virtual link. After the selected timeslots are grouped into a virtual

link, virtual links are referred to as links. This look-up should be used to remove

byte 16 of the E1 frame, since byte 16 contains signaling data not ATM data and

is also used to implement a fractional T1 or E1. The first bit of time-slot 1 of a

channelized link is identified by noting the absence of the clock and its re-

activation.

Links may also be unchannelized. In this mode, all data is assumed to be valid

ATM data. The link clock is only active during bit times containing data to be

processed and inactive during bits that are to be ignored by the RCAS, such as

framing and overhead bits.

The RCAS provides diagnostic line-side loopback that is selectable on a per-

channel basis. When a channel is in diagnostic loopback, data on the received

links originally destined for that channel is ignored. Transmit data of that channel

is substituted in its place.

10.6 Microprocessor Interface

The Microprocessor Interface Block provides the interrupt logic and an interface

to normal-mode registers contained within the design blocks. The normal mode

registers are required for normal operation.

10.6.1 Mapping and link identification

Within the clock/data interface, the external links are mapped to a contiguous

space identified as Virtual Links. To support multiple fractional TC flows on a

single external signal, a mapping is used to split a single channelized external

signal into multiple Virtual Links. At the per-link FIFOs, the clock/data Virtual Link

naming convention is replaced 1:1 with the Physical Link naming convention.

The S/UNI-IMA-84 processes 84 Physical Links, numbered 0 to 83. Each line

interface uses a different Link naming convention, based on the nature of the

interface: the SBI Interface uses three SPEs, each carrying 28 Tributaries, and

the Clock and Data Interface uses 32 External Signal pins, which are mapped to

84 Virtual Links. In both cases, the 84 streams to/from the line interfaces are

referred to a Physical Links elsewhere inside the device.

PM7341 Datasheet(PDF) 119 Page - PMC-Sierra, Inc