![](http://datasheet.mmic.net.cn/330000/PM7323_datasheet_16444372/PM7323_183.png)
STANDARD PRODUCT
PM7323 RCMP-200
DATASHEET
PMC-960543
ISSUE 2
ROUTING CONTROL, MONITORING, & POLICING
200 MBPS
Proprietary and Confidential to PMC-Sierra, Inc.
and for its Customer’s Internal Use.
172
The connection removal process examples are not illustrated because the results
are exactly the reverse of the connection provisioning. (Swap the "BEFORE" and
"AFTER" labels.)
12.4.5 Multicast Connections
The search table may be constructed so a single received cell results in an
arbitrary number of output cells. This is achieved through a linked list of
Secondary Search Table entries, each with an associated VC Table Record which
defines the characteristics of a outgoing VC. Adding and removing multicast VCs
is done by manipulating the linked list.
All ones in the Select field of the Secondary Search Table entry identifies it as a
multicast linked list element, except for the last in the linked list. The Left_Branch
field contains the VC table address of the multicast VC. The Right_Branch field
points to the Search Table address of the next VC in the multicast. The linked list
is terminated by setting the Select field to an all zeroes value. An all zeroes
value in the Select field indicates that the Left_Branch field provides the final VC
Search Table Address of the multicast set.
Adding a Multicast Connection
A multicast VC is inserted at the head of the linked list. The following are the
microcontroller actions required to provision a multicast connection:
1. Determine the next available VC Table address. Initialize the contents of the
VC Table Record via the Microprocessor RAM Address and Data registers
(0x21 through 0x25).
2. Perform a binary search to determine the head of the linked list. If the binary
search terminates at a VC Table Record which does not match the candidate
search key (i.e. empty list), the insertion proceeds as for a non-multicast
connect as described above.
3. Find a free Secondary Search Table entry and initialize it. Set the
Left_Branch to point to the VC Table address of the new VC Table Record.
Set the Right_Branch to point to the Search Table address of the old head of
the linked list.
An extra step is required when a unicast VC is converted to a multicast with
two VCs. A second Secondary Search Table entry needs to be allocated