Juniper JUNOSE SOFTWARE 11.2.X - LINK LAYER CONFIGURATION GUIDE 7-7-2010 Configuration Manual page 40

JunosE 11.2.x Link Layer Configuration Guide
8
Table 4: Traffic Parameters Used to Compute Bandwidth (continued)
Service Category Traffic Parameter Used to Calculate Required Bandwidth
VBR-RT SCR
VBR-NRT SCR
UBR UBR bandwidth configured on the ATM major interface
UBR with PCR UBR bandwidth configured on the ATM major interface
How CAC Works
With no connections, the available bandwidth is equal to the subscription port bandwidth.
While connections are requested, the required bandwidth, which is based on the service
category and traffic parameters of the connection, is compared against the available
port bandwidth. If sufficient bandwidth is available, the router accepts the connection
and updates the available port bandwidth accordingly.
Similarly, when a connection is deleted, the available port bandwidth is updated
accordingly.
Configuring CAC
You enable and configure CAC on an ATM major interface using "atm cac" on page 26 .
When you enable CAC on an ATM interface, you can optionally specify a subscription
bandwidth and a UBR weight:
The subscription bandwidth can be greater than the effective port bandwidth to allow
oversubscription. The default value of the subscription bandwidth is the effective
bandwidth of the ATM port.
The UBR weight enables you to limit the number of UBR connections by assigning a
bandwidth or weight to each UBR or VBR with a PCR connection
CAC and ATM Bulk Configuration
You cannot configure CAC on an ATM interface on which you have created a
bulk-configured virtual circuit (VC) range for use by a dynamic ATM 1483 subinterface.
Conversely, you cannot create a bulk-configured VC range on an ATM interface on which
you have configured CAC. The router rejects these configurations, which causes them to
fail.
If you are upgrading to the current JunosE Software release from a lower-numbered
release, configurations that use CAC and bulk configuration on the same ATM interface
continue to work. However, we recommend that you disable CAC on these ATM interfaces
to ensure continued compatibility with future JunosE releases.
For information about how to use the atm cac command to configure CAC, see "Setting
Optional Parameters" on page 23. For information about how to use the atm bulk-config
command to create a bulk-configured VC range, see "Bulk Configuration of VC Ranges"
on page 627 in "Configuring Dynamic Interfaces Using Bulk Configuration" on page 619.
Copyright © 2010, Juniper Networks, Inc.