Guest

Cisco MGX 8800 Series Switches

Field Notice: FN - 23418 - CSCea24042 Results in Failed Connections and Loss of Redundancy on AXSM


Revised October 31, 2005

August 26, 2003


NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected

Product

Comments

AXSM

Loaded with 3.0.20

AXSM/B

Loaded with 3.0.20

Problem Description

A reset of the standby AXSM in a redundancy pair may result in a failure on the active card which interrupts user traffic. The affected active AXSM may go into degraded mode. Connections terminated on the affected card will not be impacted. Connections trunked through the affected AXSM will be rerouted if another route is available.

Background

The following conditions must be met.

  1. AXSM or AXSM/B must be in redundancy. Redundancy may be via Y-Redundant cable or via Automatic Protection Switch (APS) scheme.

  2. The Standby AXSM or AXSM/B must be reset. The reset reason may be due to a software glitch or user intervention.

  3. AXSM must have variable bit rate (VBR) connections.

  4. Certain combinations of Peak Cell Rate(PCR), Sustainable Cell Rate (SCR) , Maximum Burst Size (MBS) and Cell Delay Variation Tolerance (CDVT). This is observed when SCR and PCR are nearly equal. One documented instance of this anomaly occurred when PCR was set to 4835 and SCR was set to 4834.

Problem Symptoms

After resetting the standby card, the active card went to active-F state and the standby card went into failed state. The dspcds command, executed on the active PXM45, will show the affected active AXSM or AXSM/B cards in the active-F state.

Workaround/Solution

Workaround: In such cases where SCR is almost equal to PCR, set PCR equal to SCR to workaround this problem.

Solution: Upgrade to MGX Software Release 3.0.23 or later or 4.0.10 or later.

Registered users may download MGX software from Software Center (registered customers only) .

DDTS

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

DDTS

Description

CSCea24042 (registered customers only)

tVsiSync task suspend in active AXSM

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:

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