Tag Switching 9-13
Tag Switching Resource Configuration Parameters
Table 9-2 Port Connection Allocations
(where x is the port number, and subscript “
1
” is the partition number)
AutoRoute is guaranteed to have its assigned connection spaces (LCNs) available. Tag switching,
uses one connection space (LCN) per Tag VC (TVC). This is usually one connection space (LCN)
per source-destination pair using the port where the sources and destinations are tag edge routers.
Beyond the guaranteed minimum number of connection spaces (LCNs) configured for a port VSI
partition, a tag switching partition uses unallocated LCNs on a FIFO basis from the common pool
shared by all ports in the port group. These unallocated LCNs are accessed only after a port partition
has reached its guaranteed minimum limit, “minvsilcns”, as configured by the cnfrsrc command.
Useful Default Allocations
Reasonable default values for all ports on all cards are listed in Table 9-3. If these values are not
applicable, then other values may be configured using the cnfrsrc command.
Here, a(x) = 256, n
1
(x) = 512, and m
1
(x) = 16384.
The next section describes more rigorous allocations which may be configured in place of using
these default allocations.
Connection Type
cnfrsrc
cmd
parameter Variable Description
AutoRoute LCNs maxpvclcns a(x) Represents the number of AutoRoute (PVC) LCNs
configured for a port.
Minimum VSI LCNs
for partition 1
minvsilcns n
1
(x) Represents the guaranteed minimum number of LCNs
configured for the port VSI partition. This value is not
necessarily always available. Reaching it is dependent
on FIFO access to the unallocated LCNs in the port
group common pool.
Maximum VSI LCNs
for partition 1
maxvsilcns m
1
(x) Represents the maximum number of LCNs configured
for the port VSI partition. This value is not necessarily
reached. It is dependent on FIFO access to the
unallocated LCNs in the port group common pool.
Table 9-3 Port Connection Allocations, Useful Default Values
Connection Type Variable
Useful
Default
Value cnfrsrc cmd parameter
AutoRoute LCNs a(x) 256 maxpvclcns
Minimum VSI LCNs for partition 1 n
1
(x) 512 minvsilcns
Maximum VSI LCNs for partition 1 m
1
(x) 16384 maxvsilcns
Different types of BXM cards
support different maximums. If
you enter a value greater than
the allowed maximum, a
message is displayed with the
allowable maximum.
