Cisco Systems OL-7396-01 CTT Row, RM CAC Support

16-18
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter16 Configuring Tag Switching and MPLS
CTT Row
Table16-7 gives the eight t hresholds for threshold groups 6, 7, 8, and 9.
For more information about threshold groups and configuration parameters, see Cha pter 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 se t 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.
Table16-7 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