Cisco SCMS SM SCE-Sniffer DHCP LEG Reference Guide

A software component that performs subscriber login and logout operations on the SM and is used to handle dynamic subscriber integration.

A client/server data protocol that enables the SCE devices to export reports about network transactions to external collectors. This is a Cisco proprietary protocol.

A data modem that provides Internet access over Cable and Satellite networks. The modem usually corresponds to a single subscriber of the Internet Service Provider (ISP).

Any equipment that an end-user can connect to the network through a modem. The end-user usually owns multiple CPE devices that are used to connect to the Internet through a single modem.

The final packet that is transmitted from the DHCP server in each DHCP transaction (except the release transaction). After the transmission of the DHCP ACK packet, the results of the transaction are final.

A DHCP transaction for an initial logon of a network entity to the network. The purpose of the transaction is to assign an IP address to the newly connected entity. Because the modem MAC address is used as the subscriber name, the modem MAC address will be added by the DHCP relay agent during the initial logon query using option 82 (Remote-ID sub-option of the DHCP Relay Agent Information Option).

A DHCP transaction for renewal of the entity lease time. When the lease time has been reached, the network entity is removed from the network. The LEG uses this query to logon the subscriber using the new lease time.

A DHCP transaction for releasing IP addresses. This transaction is used to logout network entities from the network. The DHCP release transaction is rarely used. Logout is usually performed when the lease time expires, and not directly with a release transaction. The LEG uses the release query to logout a subscriber from the SM.

The software logic inside the SCE device that analyzes DHCP traffic and sends the information to the SCE-Sniffer DHCP LEG using the RDR protocol.

The SCE platform requires mappings between the network IDs (IP addresses) of the flows it encounters and the subscriber IDs. The SM database contains the network IDs that map to the subscriber IDs. The SCE network-ID-to-subscriber mappings are constantly updated from the SM database.

The main function of the SCE-Sniffer DHCP LEG is to provide the SM with network-ID-to-subscriber mappings in real time.

The SM provides the option of partitioning SCE platforms and subscribers into subscriber domains. A subscriber domain is a group of SCE platforms that share a group of subscribers. Subscriber domains can be configured using the SM configuration file and can be viewed using the SM Command-Line Utility (CLU).

For additional information about domains and domain aliases, see Appendix A of the Cisco SCMS Subscriber Manager User Guide.

The policy enforced by Cisco solutions on a certain subscriber is usually defined by a policy subscriber package. The SCE-Sniffer DHCP LEG can handle the package ID in any of the following ways:

For additional information, see Configuring the Package Association and the Cisco Service Control Application for Broadband User Guide.

The following is an example of a configuration file:

Dynamic assignment of package information is supported if the package information is submitted in the DHCP packets. The LEG concatenates the desired options and creates a package-name. It is possible to map using the configuration between package-names and the application package-IDs.

To extract the package information data from the DHCP packet, the configuration file dhcp_pkg.cfg should define the option types that contain the package information and the conversion map of package-names to the package IDs of the Service Control Application for Broadband (SCA BB).

The LEG is able to add additional data to the login operation based on the LEG configuration. This data is added as a key-value pair. Other modules in the login chain can use this data, such as the SOAP LEG (see the Cisco SCMS SM SOAP LEG Reference Guide). This data can be created by concatenating the data of several DHCP options and can be given a user-defined label.

The [Package Association] section contains the following parameters:

The [Package Names] section contains the information to convert from the package information as it appears in the DHCP packet to the package ID number to be used by the SCA BB application.

The [Additional Data] section of the configuration file contains the following parameters:

[Package Names]
gold_domain1=11
gold_domain2=12
silver_domain1=13
silver_domain2=14
This configuration means that if the DHCP packet contains the value 'gold' inside option 43 with subtype 102, and the value 'domain1' inside option 43 with subtype 101, then the package ID that will be associated to the subscriber in the SM will have the value 11.
The following configuration describes how to add the data of the Relay-Agent Circuit-Id option as additional data to the login operation:
[Additional Data]
label_options=82:1
label_keys=PORT_ID
label_option_type=binary
The following is an example of the entire configuration file:
[Package Association]
options_order_for_package_name=43:102,43:101
options_type=string,string
name_seperator_value=_
use_default=true
default_package=1
package_property_name=packageId

[Package Names]
gold_domain1=11
gold_domain2=12
silver_domain1=13
silver_domain2=14

[Additional Data]
label_options=82:1
label_keys=PORT_ID
label_option_type=binary

If the installation does not require dynamic assignment of package information, the configuration file dhcp_pkg.cfg should define the default package ID to be assigned to all subscribers, as shown in the following example:

All other configuration parameters should not be set.

The following is an example using the p3dhcpsniff command-line utility with the show operation:

> p3dhcpsniff --show

The following is an example of using the p3dhcpsniff command line utility with the showstatistics operation:

> p3dhcpsniff --show-statistics

The following is an example of using the p3dhcpsniff command line utility with the show-version operation:

> p3dhcpsniff --show-version