Cisco BPX/IGX/IPX WAN Software

Field Notice: VNS Voice Calls Exhibit Poor Quality

September 17, 1999

Products Affected




This problem affects only voice connections established through Voice Network Switching (VNS).


This problem affects only voice connections established through VNS.

Problem Description

Poor voice quality is experienced on VNS connections.

Problem Symptoms

The first symptom noticed by network users is poor quality voice connections. Network maintenance staff will observe Software Error 332 after issuing the xlat_verify StrataCom log in command on nodes where the connections were not properly deleted.


Voice connections set up by VNS may experience poor quality with IGX switch software versions 9.1.00 through 9.1.15.

The poor quality is due to incomplete voice SVC tear down after a call is completed while the two endpoint nodes are in a comm break condition. This software problem will be corrected in a future release of software version 9.1.

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

View bug details for CSCdm8663 (registered customers only) .



Issue the updates 3 * command at each node periodically, but at least one time per day. This command is not intrusive or disruptive of user traffic and may only be issued by Service Level log in or higher.


A release of 9.1 switch software will correct this problem.

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: