Congestion Point Expressions

You can enter a congestion point expression by using the syntax listed in this topic. You can also embed Python scripting expressions within the congestion point expression.

If you embed Python expressions within a congestion point expression, use the escape sequence <- then -> to enclose the Python expression. See Methods for Use with Scripting Expressions and Match Criteria for Congestion Point Classification .

The syntax for a congestion point expression is:

<NetworkDevice>/<NetworkInterface>[/<CongestionPoint>]

  • <NetworkDevice>—Network device listed in the directory.
  • <NetworkInterface>—Network interface listed in the directory.

    For information about interfaces, see Overview of Classification Scripts .

  • <CongestionPoint>—(Optional) Name of an instance of a congestion point that is automatically created.

If one of the elements with the path contains a slash (/), use a backslash (\) as an escape character for the slash. For example, \/.

Expressions in Templates for Congestion Point Profiles

You can create a congestion point profile to be used as a template for other profiles. Templates simplify management of congestion points. Rather than configuring each congestion point individually, you can create templates to define common parameters for a class of individual congestion points.

For example, in an environment in which VLAN interfaces GigabitEthernet1/0.1 through GigabitEthernet1/0.1000 have the same available bandwidth, you can specify the characteristics of the VLAN interface once and have SRC-ACP create the congestion points based on the template configuration.

When a congestion point expression has the third element (<CongestionPoint>), SRC-ACP uses the <NetworkDevice>/<NetworkInterface> part of the expression to load the congestion point from the directory, and uses it as a template to create a congestion point in memory for subscriber. The <CongestionPoint> part of the expression distinguishes each congestion point (available bandwidth) created from this template.

Methods for Use with Scripting Expressions

SRC-ACP provides the following methods to use in scripting expressions:

  • slot(nasPortId)—Collects the slot number from the nasPortId or interfaceName

    Example—slot(“ atm 4/5:0.32” ) == “ 4”

  • port(nasPortId)—Collects the port number from the nasPortId or interfaceName

    Example—port(“ atm 4/5:0.32” ) == “ 5”

  • l2id(nasPortId)—Collects the layer 2 ID from the nasPortId (VLAN id or ATM vpi.vci)

    Example—l2id(“ atm 4/5:0.32” ) == “ 0.32”

  • escape(string)—Replaces any slash with the escape sequence \/

    Example—escape("atm 4/5") == "atm 4\/5"

Match Criteria for Congestion Point Classification

You can use the match criteria in Python scripting expressions for a congestion point expression. For more information about the match criteria, see Congestion Point Classification Criteria.