Cisco 6100 Series IP DSL Switches

Field Notice: Cisco 6100 DSLAM Running Software Release 2.3.1 Can Experience NI-1 Connection Table Corruption

November 16, 1999

Products Affected



Cisco 6100 (=)

Cisco 6100 with NI-1 running software release 2.3.1

Problem Description

In software release 2.3.1 of the Cisco 6100 digital subscriber line access multiplexer (DSLAM), downstream data paths may be destroyed. This problem occurs for transit subscribers and subscribers on the first 12 modem card slots by activating the last eight modem slot connections when more than 300 transit permanent virtual circuits (PVCs) are provisioned on the DSLAM. These downstream connections are destroyed and all data bound for those ports is rerouted to a single port within the first 12 modem slots. This will also corrupt that data stream. This problem occurs when tables associated with cell header translation for the affected slots are corrupted.

Note:?A transit subscriber is a user connection that has its traffic carried from a subtended system through the parent system.


See the Problem Description above.

Problem Symptoms

It may not be possible to make a PPP connection through a Cisco 6100 DSLAM due to a corrupt connection table on the NI-1.

The DSLAM connection table becomes corrupt when a large number of transit subscriber connections exist (800 connections consistently causes the problem), and a new digital subscriber line (DSL) connection is activated. The problem becomes progressively worse over time and is aggravated by frequent retraining of user sessions.


Upgrade the node software to release 2.3.3 (or later).


To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.



CSCdm76638 (registered customers only)

Connection entries on NI damaged

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods: