16-18
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter 16
Configuring Tag Switching and MPLS
CTT Row
Table 16-7
gives the eight thresholds for threshold groups 6, 7, 8, and 9.
For more information about threshold groups and configuration parameters, see
Chapter 9, “Configuring
Resource Management,”
and the
Guide to ATM Technology
.
CTT Row
A row in the connection traffic table (CTT) is created for each unique combination of traffic parameters.
When a TVC is set up in response to a request by tag switching, a CTT row is obtained from the resource
manager by passing the traffic parameters that include the service category (TBR_
x
[WRR_
x
], where
x
is 1, 2, 3, or 4). If a match is found for the same set of traffic parameters, the row index is returned;
otherwise a new table is created and the row index of that CTT row is returned. Since all data TVCs use
the same traffic parameters, the same CTT row can be used for all TVCs of a particular service category
once it is created.
Note
There are no user configurable parameters for the CTT with TVCs.
RM CAC Support
Connection admission control (CAC) is not supported for tag virtual channels (TVCs). All TVCs are best
effort connections; therefore, no bandwidth is guaranteed by the RS. Only the WRR scheduler is used.
So, all of the traffic parameters (PCR, MCR, MBS, CDVT, and SCR) are unspecified. There is no best
effort limit like there is with ATM Forum UBR and ABR connections. CAC is bypassed for TVCs.
Table 16-7 Region Thresholds for Threshold Groups
Region
Lower
Limit
Upper
Limit
Queue
Limit
Marking
Threshold
Discard
Threshold
0
0
8191
511
127
447
1
8128
16,383
255
63
223
2
16,320
24,575
127
31
111
3
24,512
32,767
63
15
63
4
32,704
40,959
31
15
31
5
40,896
49,151
31
15
31
6
49,088
57,343
31
15
31
7
57,280
65,535
31
15
31
