Cisco Cisco IOS Software Release 12.0(23)S

This feature module describes the ATM Cell Loss Priority (CLP) setting feature. The ATM CLP setting 
feature allows users to control the ATM CLP bit setting on the 8-Port OC-3 STM-1 ATM line card for 
Cisco 12000 Series Internet Routers.

This document includes the following sections:

Before development of the ATM CLP Setting feature, the CLP bit in the ATM header of a cell provided 
a method of controlling the discarding of cells in a congested ATM environment. A CLP bit contains two 
settings: 0 or 1. Cells with a CLP bit setting of 1 are discarded before cells with a CLP bit setting of 0. 
Before the introduction of the ATM CLP Setting feature, the CLP bit was automatically set to 0 when 
Cisco routers converted packets into ATM cells for ATM networks.

The ATM CLP Setting feature allows users to control the CLP bit setting on Cisco 12000 Series Internet 
Routers equipped with the 8-Port OC-3 STM-1 ATM line card. The CLP bit is set on each packet 
individually, and the default CLP bit setting is 0. The application of the ATM CLP Setting feature 
changes the CLP bit setting to 1. Therefore, users have the option to leave each packet with the default 
CLP bit setting of 0 or to establish a new CLP bit setting of 1.

12.0(23)S

This feature was made available on the 8-Port OC-3 STM-1 ATM line card 
for Cisco 12000 Series Internet Routers.