Cisco ASA 5505 - Manual (Page 1152)

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Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 54 Configuring QoS
Configuring QoS
Detailed Steps
Examples
The following example establishes a priority queue on interface “outside” (the GigabitEthernet0/1
interface), with the default queue-limit and tx-ring-limit:
hostname(config)# priority-queue outside
The following example establishes a priority queue on the interface “outside” (the GigabitEthernet0/1
interface), sets the queue-limit to 260 packets, and sets the tx-ring-limit to 3:
hostname(config)# priority-queue outside
hostname(config-priority-queue)# queue-limit 260
hostname(config-priority-queue)# tx-ring-limit 3
Command Purpose
Step 1 priority-queue interface_name
Example:
hostname(config)# priority-queue inside
Creatse the priority queue, where the interface_name argument
specifies the physical interface name on which you want to enable
the priority queue, or for the ASA 5505 or ASASM, the VLAN
interface name.
Step 2 queue-limit number_of_packets
Example:
hostname(config-priority-queue)#
queue-limit 260
Changes the size of the priority queues. The default queue limit is
1024 packets. Because queues are not of infinite size, they can fill
and overflow. When a queue is full, any additional packets cannot
get into the queue and are dropped (called tail drop). To avoid
having the queue fill up, you can use the queue-limit command to
increase the queue buffer size.
The upper limit of the range of values for the queue-limit
command is determined dynamically at run time. To view this
limit, enter queue-limit ? on the command line. The key
determinants are the memory needed to support the queues and
the memory available on the device.
The queue-limit that you specify affects both the higher priority
low-latency queue and the best effort queue.
Step 3 tx-ring-limit number_of_packets
Example:
hostname(config-priority-queue)#
tx-ring-limit 3
Specifies the depth of the priority queues. The default
tx-ring-limit is 128 packets. This command sets the maximum
number of low-latency or normal priority packets allowed into the
Ethernet transmit driver before the driver pushes back to the
queues on the interface to let them buffer packets until the
congestion clears. This setting guarantees that the hardware-based
transmit ring imposes a limited amount of extra latency for a
high-priority packet.
The upper limit of the range of values for the tx-ring-limit
command is determined dynamically at run time. To view this
limit, enter tx-ring-limit ? on the command line. The key
determinants are the memory needed to support the queues and
the memory available on the device.
The tx-ring-limit that you specify affects both the higher priority
low-latency queue and the best-effort queue.