PM9313 datasheet(74/343 Pages) PMC

74 / 343 page

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

PM9311/2/3/5 ETT1™ CHIP SET

PMC-2000164

ISSUE 3

ENHANCED TT1™ SWITCH FABRIC

Released

Data Sheet

PMC-Sierra, Inc.

linecard and the switch core CPU, and (3) Single Phase Control Packets which are used as a special form

of LCS Control packets for timing sensitive information.

1.6.3.1

LCS Control Packets

LCS CPs are specified by setting the Label_1/Label_2 Field to 14’h0000 (CP-category for LCS Control

Packets) and associated Type Field to 4’h0 (Type for Control Packets). Table 11 describes the contents of

the first 10-bytes of the LCS segment payload for an LCS CP format.

Because there is no flow control mechanism for LCS CPs sent to the switch fabric, and a CP request/grant

does not distinguish the CP_Type, care must be taken so as not to overflow the receiving CP queues. At

most, only one request for each CP_Type should be outstanding.

In what follows, the three CP_Types of currently defined LCS CPs are described.

NOTE: The actual LCS headers for Switch-to-Linecard Control Packets are not built in to the EPP.

Instead, the EPP expects to find the headers, preconfigured at specific queue locations

within the Dataslices. Thus, part of the initialization sequence of a new ETT1 port card is

to write the values of the Control Packets into the Dataslice queues. Section 3.3 “Output

Dataslice Queue Memory Allocation with EPP” on page 162, provides details of these

locations.

Table 11.

LCS Control Packet Format

Field

Size

(bits)

Definition

CP_Type

Indicates the type of LCS Control Packet (e.g. TDM)

CP_Type Extension

Indicates the information carried with this type of control packet. Unused bits

must be set to zero.

CRC-16

16-bit CRC calculated over 10-byte control packet payload.a

a. See Section 1.6.4.1 “Use of CRC-16 Field” on page 73 for details of CRC calculation.

PM9313 Datasheet(PDF) 74 Page - PMC-Sierra, Inc