Configure the Number of Active Ports on 16x10GE 3D MPC

Configuring active ports enhances system's ability to manage bandwidth allocation and ensure redundancy. This feature allows you to disable specific ports on the Packet Forwarding Engines (PFEs) to prevent oversubscription and maintain optimal performance. This topic covers how to disable a sub-set of the physical ports available on the Packet Forwarding Engines of the 16x10GE 3D MPC, and for PICs installed in MPC3, MPC4, MPC5, and MPC6.

Two common reasons for disabling ports are as follows:

• Ensure guaranteed bandwidth by preventing oversubscription—The 16x10GE 3D MPC supports one 10-Gigabit Ethernet tunnel interface for each Packet Forwarding Engine. The effective line-rate bandwidth of the MPC is 12 ports because of an oversubscription ratio of 4:3. Therefore, configuring a tunnel interface might further oversubscribe the Packet Forwarding Engines. To prevent such oversubscription and to ensure a guaranteed bandwidth, include the number-of-ports configuration statement to disable one or two ports per Packet Forwarding Engine.

• Enable Switch Control Board (SCB) redundancy—For maximum bandwidth capabilities (12-port line-rate bandwidth), the 16x10GE 3D MPC uses all the active SCBs in the chassis.

  If you require SCB redundancy, disable ports on the line card by setting the number of usable ports per line card to 8. In such a case, the system disables the third and fourth ports (ports 0/2-3, 1/2-3, 2/2-3, 3/2-3) on every Packet Forwarding Engine.

To configure the number of active ports on the 16x10GE 3D MPC, include the number-of-ports active-ports configuration statement at the [edit chassis fpc slot-number] hierarchy level:

To configure the number of active ports on a PIC in MPC3, MPC4, MPC5, or MPC6, include the number-of-ports active-ports configuration statement at the [edit chassis fpc slot-number pic pic-number] hierarchy level:

Specify either 8 or 12 ports using the statement above. When you configure eight active ports, the system disables two ports per Packet Forwarding Engine and lights the MPC LEDs in yellow. When you specify 12 active ports, the system disables one port per Packet Forwarding Engine and lights the corresponding LED in yellow. When you do not include this statement in the configuration, all 16 default ports on the MPC are active.

Note:

• Committing the configuration after including the number-of-ports active-ports configuration statement brings down the Ethernet interfaces for all the ports on the MPC before the ports configuration becomes active.

• A minimum of one high-capacity fan tray is necessary for meeting the cooling requirements of the MPC. The Junos OS generates a chassis yellow alarm recommending fan tray upgrade for optimal performance, if the chassis contains an old fan tray.

For more information about the 16x10GE 3D MPC, see the MX Series Interface Module Reference.