What is QoS?
Quality of Service or QoS is a method of providing better service for selected traffic types over various types of packet-switched networks. The network medium used could be any one of several types of technology ranging from Ethernet to Wireless and Frame Relay networks. QoS provides a method for determining which traffic should be given priority on a network segment.
Core issue
The implemenation of Quality of Service (QoS) on a PIX/ASA Firewall is desired to specify the bandwidth that a certain type of traffic utilizes.
Resolution
Note: The QoS can be configured from code 7.0(x) and later. This feature was not available in earlier versions of code installed on the PIX. This code is supported only on PIX 515/515E, 525 and 535 series of PIXes.
In order to implement the QOS, complete these steps:
- Identify the traffic or define the traffic classes.
Refer to the Identifying Traffic for QoS section of Applying QoS Policies for more information.
- Associate actions with each traffic class in order to formulate policies with the use of Policy Map.
Refer to the Creating a Policy for Standard Priority Queueing and/or Policing section of Applying QoS Policies for more information about QoS policy maps.
- Issue the service-policy command in order to activate the policies.
Use the service-policy command in order to apply the policy map globally or to a specific interface.
Refer to this configuration example in order to specify bandwidth for port 25:
PIX(config)#access-list qos extended permit tcp any any eq 25
PIX(config)#class-map qos
PIX(config-cmap)#match access-list qos
PIX(config-cmap)#exit
PIX(config)#policy-map global_policy
PIX(config-pmap)#class qos
PIX(config-pmap-c)#police output 6144000
PIX(config-pmap-c)#exit
PIX(config-pmap)#exit
PIX(config)#
Refer to these documents for more information:
Acknowledgment:
QoS
