Example: Limit the Number of ATM Virtual Circuits
This commit script example limits the number of Asynchronous Transfer Mode (ATM) virtual circuits (VCs) configured on an ATM interface.
Requirements
This example uses a device running Junos OS with an ATM interface.
Overview and Commit Script
For each ATM interface, the set of corresponding VCs is selected.
The number of those VCs, as determined by the built-in Extensible
Stylesheet Language Transformations (XSLT) count() function, cannot exceed the
limit set by the global variable limit.
If there are more ATM VCs than limit, a
commit error is generated, and the commit operation fails.
The example script is shown in both XSLT and SLAX syntax:
XSLT Syntax
<?xml version="1.0" standalone="yes"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:junos="http://xml.juniper.net/junos/*/junos" xmlns:xnm="http://xml.juniper.net/xnm/1.1/xnm" xmlns:jcs="http://xml.juniper.net/junos/commit-scripts/1.0"> <xsl:import href="../import/junos.xsl"/> <xsl:param name="limit" select="10"/> <xsl:template match="configuration"> <xsl:for-each select="interfaces/interface[starts-with(name, 'at-')]"> <xsl:variable name="count" select="count(unit)"/> <xsl:if test="$count > $limit"> <xnm:error> <edit-path>[edit interfaces]</edit-path> <statement><xsl:value-of select="name"/></statement> <message> <xsl:text>ATM VC limit exceeded; </xsl:text> <xsl:value-of select="$count"/> <xsl:text> are configured but only </xsl:text> <xsl:value-of select="$limit"/> <xsl:text> are allowed.</xsl:text> </message> </xnm:error> </xsl:if> </xsl:for-each> </xsl:template> </xsl:stylesheet>
SLAX Syntax
version 1.0;
ns junos = "http://xml.juniper.net/junos/*/junos";
ns xnm = "http://xml.juniper.net/xnm/1.1/xnm";
ns jcs = "http://xml.juniper.net/junos/commit-scripts/1.0";
import "../import/junos.xsl";
param $limit = 10;
match configuration {
for-each (interfaces/interface[starts-with(name, 'at-')]) {
var $count = count(unit);
if ($count > $limit) {
<xnm:error> {
<edit-path> "[edit interfaces]";
<statement> name;
<message> {
expr "ATM VC limit exceeded; ";
expr $count;
expr " are configured but only ";
expr $limit;
expr " are allowed.";
}
}
}
}
}Configuration
Procedure
Step-by-Step Procedure
To download, enable, and test the script:
Copy the script into a text file, name the file atm-vc-limit.xsl or atm-vc-limit.slax as appropriate, and copy it to the /var/db/scripts/commit/ directory on the device.
Select the following test configuration stanzas, and press Ctrl+c to copy them to the clipboard.
If you are using the SLAX version of the script, change the filename at the
[edit system scripts commit file]hierarchy level to atm-vc-limit.slax.system { scripts { commit { file atm-vc-limit.xsl; } } } interfaces { at-1/2/3 { unit 15 { family inet { address 10.12.13.15/20; } } unit 16 { family inet { address 10.12.13.16/20; } } unit 17 { family inet { address 10.12.13.17/20; } } unit 18 { family inet { address 10.12.13.18/20; } } unit 19 { family inet { address 10.12.13.19/20; } } unit 20 { family inet { address 10.12.13.20/20; } } unit 21 { family inet { address 10.12.13.21/20; } } unit 22 { family inet { address 10.12.13.22/20; } } unit 23 { family inet { address 10.12.13.23/20; } } unit 24 { family inet { address 10.12.13.24/20; } } unit 25 { family inet { address 10.12.13.25/20; } } unit 26 { family inet { address 10.12.13.26/20; } } } }In configuration mode, issue the
load merge terminalcommand to merge the stanzas into your device configuration.[edit] user@host# load merge terminal [Type ^D at a new line to end input] ... Paste the contents of the clipboard here ...
At the prompt, paste the contents of the clipboard by using the mouse and the paste icon.
Press Enter.
Press Ctrl+d.
Commit the configuration.
user@host# commit
Verification
Verifying the Commit Script Output
Purpose
Verify that the script behaves as expected.
Action
Review the output of the commit command. The
sample configuration stanzas configure 12 virtual circuits on the
ATM interface atm-1/2/3. Because the commit script only allows 10
ATM VCs to be configured on any ATM interface, the script generates
an error, and the commit operation fails. The following output appears
after issuing a commit command:
[edit] user@host# commit [edit interfaces] 'at-1/2/3' ATM VC limit exceeded; 12 are configured but only 10 are allowed. error: 1 error reported by commit scripts error: commit script failure