23-4
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter23 Configuring the ATM Traffic-Shaping CarrierModule
Configuring the ATM TSCAM
Each TSCAM requires 2MB of contiguous main memory availability in the system.
The maximum rate at which a VC can be shaped on an OC-12 interface is 595,085 Kbps.
The minimum rate at which a VC can be shaped to is as below :
36 Kbps for DS3, E3, T1, and E1 interfaces
37 Kbps for OC-3 Interfaces
145 Kbps for OC-12 Interfaces.

About Interface Congestion Thresholds

A total of 256K cell buffers are available on the TSCAM. On an interface enabled for shaping, the
number of available cell buffers is the same as the maximum threshold for that interface. Table 2 3-1 lists
the maximum threshold values. These values are the defaults and depend on the number of interfaces
configured for traffic shaping. The maximum congestion thresholds for interfaces are not configurable.
Configuring the ATM TSCAM
To configure traffic shaping on your ATM TSCAM, perform the following steps, beginning in global
configuration mode:
Table23-1 Default Interface Maximum Thresholds
Number of
Shaped Interfaces
Maximum Cell Threshold
for Unshaped Interfaces
Maximum Cell Threshold
for Shaped Interfaces

0 65536 0

1 2816 253952

2 4096 126976

3 4096 86016

4 0 65536

Command Purpose
Step1 Switch(config)# interface atm
card/subcard/port
Switch(config-if)#
Selects the physical interface to be configured.
Step2 Switch(config-if)# atm traffic shaping enable
{vbr [pcr-only] | best-effort}
Switch(config-if)# exit
Enables traffic shaping.
Step3 Switch# copy system:running-config
nvram:startup-config
Copies the running configuration in system
memory to the startup configuration stored in
NVRAM.