This section explains how to create a configuration file for an application server that provides major applications to customers. The procedure uses as its example the BigAPPS server from Figure 33–4.
The following configuration file defines IPQoS activities for the BigAPPS server. This server hosts FTP, electronic mail (SMTP), and network news (NNTP) for customers.
fmt_version 1.0 action { module ipgpc name ipgpc.classify params { global_stats TRUE } class { name smtp enable_stats FALSE next_action markAF13 } class { name news next_action markAF21 } class { name ftp next_action meterftp } filter { name smtpout sport smtp class smtp } filter { name newsout sport nntp class news } filter { name ftpout sport ftp class ftp } filter { name ftpdata sport ftp-data class ftp } } action { module dscpmk name markAF13 params { global_stats FALSE dscp_map{0-63:14} next_action continue } } action { module dscpmk name markAF21 params { global_stats FALSE dscp_map{0-63:18} next_action continue } } action { module tokenmt name meterftp params { committed_rate 50000000 committed_burst 50000000 red_action_name AF31 green_action_name markAF22 global_stats TRUE } } action { module dscpmk name markAF31 params { global_stats TRUE dscp_map{0-63:26} next_action continue } } action { module dscpmk name markAF22 params { global_stats TRUE dscp_map{0-63:20} next_action continue } }
Log in to the IPQoS-enabled application server, and create a new IPQoS configuration file with a .qos extension.
For example, you would create the /var/ipqos/BigAPPS.qos file for the application server. Begin with the following required phrases to start the action statement that invokes the ipgpc classifier:
fmt_version 1.0 action { module ipgpc name ipgpc.classify params { global_stats TRUE } |
For an explanation of the opening action statement, refer to How to Create the IPQoS Configuration File and Define Traffic Classes.
Create classes to select traffic from three applications on the BigAPPS server.
Add the class definitions after the opening action statement.
class { name smtp enable_stats FALSE next_action markAF13 } class { name news next_action markAF21 } class { name ftp enable_stats TRUE next_action meterftp } |
Creates a class that is called smtp, which includes email traffic flows to be handled by the SMTP application
Enables statistics collection for the smtp class. However, because the value of enable_stats is FALSE, statistics for this class are not taken.
Instructs the ipgpc module to pass packets of the smtp class to the markAF13 action statement after ipgpc completes processing.
Creates a class that is called news, which includes network news traffic flows to be handled by the NNTP application.
Instructs the ipgpc module to pass packets of the news class to the markAF21 action statement after ipgpc completes processing.
Creates a class that is called ftp, which handles outgoing traffic that is handled by the FTP application.
Enables statistics collection for the ftp class.
Instructs the ipgpc module to pass packets of the ftp class to the meterftp action statement after ipgpc completes processing.
For more information about defining classes, refer to How to Create the IPQoS Configuration File and Define Traffic Classes.
Define filter clauses to select traffic of the classes defined in Step 2.
filter { name smtpout sport smtp class smtp } filter { name newsout sport nntp class news } filter { name ftpout sport ftp class ftp } filter { name ftpdata sport ftp-data class ftp } } |
Gives the name smtpout to the filter.
Selects traffic with a source port of 25, the well-known port for the sendmail (SMTP) application.
Identifies the class to which the filter belongs, in this instance, class smtp.
Gives the name newsout to the filter.
Selects traffic with a source port name of nntp, the well-known port name for the network news (NNTP) application.
Identifies the class to which the filter belongs, in this instance, class news.
Gives the name ftpout to the filter.
Selects control data with a source port of 21, the well-known port number for FTP traffic.
Gives the name ftpdata to the filter.
Selects traffic with a source port of 20, the well-known port number for FTP data traffic.
Identifies the class to which the ftpout and ftpdata filters belong, in this instance ftp.
To define filters, refer to How to Define Filters in the IPQoS Configuration File.
To define forwarding behaviors for application traffic, refer to How to Configure Forwarding for Application Traffic in the IPQoS Configuration File.
To configure flow control by using the metering modules, refer to How to Configure Flow Control in the IPQoS Configuration File.
To configure flow accounting, refer to How to Enable Accounting for a Class in the IPQoS Configuration File.
The next procedure shows how to configure forwarding for application traffic. In the procedure, you define per-hop behaviors for application traffic classes that might have lower precedence than other traffic on a network. The steps continue building the /var/ipqos/BigAPPS.qos file in Example 34–3.
The procedure assumes that you have an existing IPQoS configuration file with already-defined classes and already-defined filters for the applications to be marked.
Open the IPQoS configuration file that you have created for the application server, and locate the end of the last filter clause.
In the /var/ipqos/BigAPPS.qos file, the last filter is the following:
filter { name ftpdata sport ftp-data class ftp } } |
action { module dscpmk name markAF13 |
Invokes the marker module dscpmk.
Gives the name markAF13 to the action statement.
Define the per-hop behavior to be marked on electronic mail traffic flows.
params { global_stats FALSE dscp_map{0-63:14} next_action continue } } |
Enables statistics collection for the markAF13 marker action statement. However, because the value of enable_stats is FALSE, statistics are not collected.
Assigns a DSCP of 14 to the packet headers of the traffic class smtp, which is currently being processed by the marker.
Indicates that no further processing is required on packets of the traffic class smtp. These packets can then return to the network stream.
The DSCP of 14 tells the marker to set all entries in the dscp map to the decimal value 14 (binary 001110). The DSCP of 14 sets the AF13 per-hop behavior. The marker marks packets of the smtp traffic class with the DSCP of 14 in the DS field.
AF13 assigns all packets with a DSCP of 14 to a high-drop precedence. However, because AF13 also assures a Class 1 priority, the router still guarantees outgoing email traffic a high priority in its queue. For a table of possible AF codepoints, refer to Table 37–2.
Add a marker action statement to define a per-hop behavior for network news traffic:
action { module dscpmk name markAF21 params { global_stats FALSE dscp_map{0-63:18} next_action continue } } |
Gives the name markAF21 to the action statement.
Assigns a DSCP of 18 to the packet headers of the traffic class nntp, which is currently being processed by the marker.
The DSCP of 18 tells the marker to set all entries in the dscp map to the decimal value 18 (binary 010010). The DSCP of 18 sets the AF21 per-hop behavior. The marker marks packets of the news traffic class with the DSCP of 18 in the DS field.
AF21 assures that all packets with a DSCP of 18 receive a low-drop precedence, but with only Class 2 priority. Thus, the possibility of network news traffic being dropped is low.
To add configuration information for web servers, refer to How to Create the IPQoS Configuration File and Define Traffic Classes.
To configure flow control by using the metering modules, refer to How to Configure Flow Control in the IPQoS Configuration File.
To configure flow accounting, refer to How to Enable Accounting for a Class in the IPQoS Configuration File.
To configure forwarding behaviors on a router, refer to How to Configure a Router on an IPQoS-Enabled Network.
To activate the IPQoS configuration file, refer to How to Apply a New Configuration to the IPQoS Kernel Modules.
To control the rate at which a particular traffic flow is released onto the network, you must define parameters for the meter. You can use either of the two meter modules, tokenmt or tswtclmt, in the IPQoS configuration file.
The next procedure continues to build the IPQoS configuration file for the application server in Example 34–3. In the procedure, you configure not only the meter but also two marker actions that are called within the meter action statement.
The steps assume that you have already defined a class and a filter for the application to be flow-controlled.
Open the IPQoS configuration file that you have created for the applications server.
In the /var/ipqos/BigAPPS.qos file, you begin after the following marker action:
action { module dscpmk name markAF21 params { global_stats FALSE dscp_map{0-63:18} next_action continue } } |
Create a meter action statement to flow-control traffic of the ftp class.
action { module tokenmt name meterftp |
Invokes thetokenmt meter.
Gives the name meterftp to the action statement.
Add parameters to configure the meter's rate.
params { committed_rate 50000000 committed_burst 50000000 |
Assigns a transmission rate of 50,000,000 bps to traffic of the ftp class.
Commits a burst size of 50,000,000 bits to traffic of the ftp class.
For an explanation of tokenmt parameters, refer to Configuring tokenmt as a Two-Rate Meter.
Add parameters to configure traffic conformance precedences:
red_action markAF31 green_action_name markAF22 global_stats TRUE } } |
Indicates that when the traffic flow of the ftp class exceeds the committed rate, packets are sent to the markAF31 marker action statement.
Indicates that when traffic flows of class ftp conform to the committed rate, packets are sent to the markAF22 action statement.
Enables metering statistics for the ftp class.
For more information about traffic conformance, see Meter Module.
Add a marker action statement to assign a per-hop behavior to nonconformant traffic flows of class ftp.
action { module dscpmk name markAF31 params { global_stats TRUE dscp_map{0-63:26} next_action continue } } |
Invokes the marker module dscpmk.
Gives the name markAF31 to the action statement.
Enables statistics for the ftp class.
Assigns a DSCP of 26 to the packet headers of the traffic class ftp whenever this traffic exceeds the committed rate.
Indicates that no further processing is required on packets of the traffic class ftp. Then these packets can return to the network stream.
The DSCP of 26 instructs the marker to set all entries in the dscp map to the decimal value 26 (binary 011010). The DSCP of 26 sets the AF31 per-hop behavior. The marker marks packets of the ftp traffic class with the DSCP of 26 in the DS field.
AF31 assures that all packets with a DSCP of 26 receive a low-drop precedence, but with only Class 3 priority. Therefore, the possibility of nonconformant FTP traffic being dropped is low. For a table of possible AF codepoints, refer to Table 37–2.
Add a marker action statement to assign a per-hop behavior to ftp traffic flows that conform to the committed rate.
action { module dscpmk name markAF22 params { global_stats TRUE dscp_map{0-63:20} next_action continue } } |
Gives the name markAF22 to the marker action.
Assigns a DSCP of 20 to the packet headers of the traffic class ftp whenever ftp traffic conforms to its configured rate.
The DSCP of 20 tells the marker to set all entries in the dscp map to the decimal value 20 (binary 010100). The DSCP of 20 sets the AF22 per-hop behavior. The marker marks packets of the ftp traffic class with the DSCP of 20 in the DS field.
AF22 assures that all packets with a DSCP of 20 receive a medium-drop precedence with Class 2 priority. Therefore, conformant FTP traffic is assured a medium-drop precedence among flows that are simultaneously released by the IPQoS system. However, the router gives a higher forwarding priority to traffic classes with a Class 1 medium-drop precedence mark or higher. For a table of possible AF codepoints, refer to Table 37–2.
Add the DSCPs that you have created for the application server to the appropriate files on the Diffserv router.
To activate the IPQoS configuration file, refer to How to Apply a New Configuration to the IPQoS Kernel Modules.
To add configuration information for web servers, refer to How to Create the IPQoS Configuration File and Define Traffic Classes.
To configure flow accounting, refer to How to Enable Accounting for a Class in the IPQoS Configuration File.
To configure forwarding behaviors on a router, refer to How to Configure a Router on an IPQoS-Enabled Network.