max-queues

Syntax

Hierarchy Level

Description

Configure the maximum number of queues allowed per line card in an MX240, MX480, MX960, MX2008, MX2010, MX2020, MX10001, MX10002 router or fixed MIC with XFP in an MX5, MX10, MX40, MX80, MX104, MX304 modular chassis router.

Reducing the number of queues allowed in a hierarchical scheduling environment in turn reduces the degree of jitter in the queues.

CAUTION:

Committing a change to the maximum number of queues on a line card causes a reset of the line card.

Options

queues-per-line-card

Maximum number of queues allowed for the line card. Only the following keywords are valid: 8k, 16k, 32k, 48k, 64k, 96k, 128k, 192k, 256k, 384k, 512k, 768k, 1M, 1536k, or 2M.

Built-in 10-Gigabit Ethernet MICs and MPC1 Q line cards support up to 128 K queues. You can use this statement to configure the single Packet Forwarding Engine to support a lower maximum number of queues.
MPC2 Q and MPC2 EQ line cards support up to 256 K queues. You can use this statement to configure the two Packet Forwarding Engines to support a lower maximum number of queues.

If you configure a keyword for a value that exceeds the number of queues supported by the line card hardware, the system uses the maximum number of queues supported by the line card.

If the max-queues statement is not configured on MPC7E, MPC8E, and MPC9E, which is the default mode, the MPC starts with a message similar to the following:

FPC 0 supports only port based queuing. A license is required for per-VLAN and hierarchical features.

If the max-queues statement is configured on MPC7E, MPC8E, and MPC9E and the value is less than or equal to 32,000, the MPC starts with a message similar to the following:

FPC 0 supports port based queuing and is configured in 16384 queue mode. A limited per-VLAN queuing license is required for per VLAN and hierarchical queuing features.

If the max-queues statement is configured on MPC7E, MPC8E, and MPC9E and the value is greater than 32,000, the MPC starts with a message similar to the following:

FPC 0 supports port based queuing and is configured in 524288 queue mode. A full scale per-VLAN queuing license is required for per VLAN and hierarchical queuing features.

Required Privilege Level

interface—To view this statement in the configuration.

interface-control—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 13.2.

Support for MPC7E, MPC8E, and MPC9E from Junos OS Release 15.1F4.

Starting with Junos OS Release 24.4R2, the configured max-queues value is divided by the maximum number of PFEs supported on the FPC. For example on an MX304, which can have a maximum of six PFEs, if you set chassis fpc 0 max-queues 256k, each PFE is allocated 256k / 6 = 42k queues. This ensures that sufficient queue resources are reserved for PFEs that may come online later due to dynamic MIC insertions.

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