Example: Defining Interface Bandwidth Maximums

This example shows you how to configure the maximum bandwidth for a physical or logical interface.

• Requirements
• Overview
• Configuration
• Verification

Requirements

Before you begin:

• Configure the router interfaces. See the Network Interfaces Configuration Guide.
• Configure an interior gateway protocol. See the Routing Protocols Configuration Guide.
• Configure a multicast protocol. This feature works with the following multicast protocols:
  • DVMRP
  • PIM-DM
  • PIM-SM
  • PIM-SSM

Overview

The maximum bandwidth setting applies admission control either against the configured interface bandwidth or against the native speed of the underlying interface (when there is no configured bandwidth for the interface).

If you configure several logical interfaces (for example, to support VLANs or PVCs) on the same underlying physical interface, and no bandwidth is configured for the logical interfaces, it is assumed that the logical interfaces all have the same bandwidth as the underlying interface; this can cause oversubscription. To prevent oversubscription, configure bandwidth for the logical interfaces, or configure admission control at the physical interface level.

You need only define the maximum bandwidth for an interface on which you want to apply bandwidth management. An interface that does not have a defined maximum bandwidth transmits all multicast flows as determined by the multicast protocol that is running on the interface (for example, PIM).

If you specify maximum-bandwidth without including a bits-per-second value, admission control is enabled based on the bandwidth configured for the interface. In the following example, admission control is enabled for logical interface unit 200, and the maximum bandwidth is 20 Mbps. If the bandwidth is not configured on the interface, the maximum bandwidth is the link speed.

Configuration

CLI Quick Configuration

To quickly configure a flow map, copy the following commands and paste the commands into the CLI.

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Modification of the Junos OS Configuration in Junos OS CLI, Release 10.3.

To configure a flow map:

1. Configure the a logical interface bandwidth.

   [edit]user@host# edit interfaces[edit interfaces]user@host# set fe-0/2/0 unit 200 bandwidth 20m[edit interfaces]user@host# exit

2. Enable admission control on the logical interface.

   [edit]user@host# edit routing-options[edit routing-options]user@host# set multicast interface fe-0/2/0.200 maximum-bandwidth

3. On a physical interface, enable admission control and set the maximum bandwidth to 60 Mbps.

   [edit]user@host# edit routing-options[edit routing-options]user@host# set multicast interface fe-0/2/1 maximum-bandwidth 60m

4. For a logical interface on the same physical interface shown in 3, set a smaller maximum bandwidth.

   [edit]user@host# edit routing-options[edit routing-options]user@host# set multicast interface fe-0/2/1.200 maximum-bandwidth 10m

Results

Confirm your configuration by entering the show interfaces and show routing-options commands.

Verification

To verify the configuration, run the show multicast interface command.

Related Topics

• Example: Configuring a Multicast Flow Map
• Bandwidth Management Overview