Cisco IGX 8400 Series Switches

Field Notice 981211: Y-Redundanct SDPs Stop Passing Traffic After 8.4.30 to 9.1.04 Upgrade

December 28, 1998

Products Affected




This problem has been observed on Y-redundant Synchronous Data PAD Cards (SDPs).

Problem Description

Upgrading from software release 8.4.30 to 9.1.04 causes Y-redundant-paired SDP card databases to experience an anomaly which results in the cessation of traffic through the active Y-redundant SDP.

This problem has not been observed on non-Y-redundant SDPs or on the similar IGX-HDM, either in Y-redundant or non-Y-redundant mode.


Y-redundancy is a feature of the IPX, IGX-8400, and BPX-8600 series switches. As implied, the redundancy is achieved by placing two similar cards in adjacent slots and connecting the inputs of the two cards together via a simple "Y" cable. Similarly, the outputs of both the adjacent cards are connected via a "Y" cable. The input and output impedances are adjusted so that the dual termination does not degrade the signal transmitted or received levels significantly.

The Y-Redundant feature is available on most port and trunk cards in the IPX, IGX-8400, and BPX-8600 series switches. Y-Redundnacy is supported on E1, T1, E3, T3, SMF, V.35, RS-232 (V.11), X.21, HSSI, and RS-449 interfaces. This feature increases availability significantly and is recommended for applications that are mission-critical.

Problem Symptoms

The main symptom is that traffic passing through the affected SDP stops. You will not be able to log in to remote resources and operating logins may time out immediately after the upgrade is executed.

Using the command line interface (CLI), issue the dspbob slot.port command to check the affected permanent virtual connection. If this command results in a software error "532", you are affected by this problem. To observe the software error, issue the dspswlog command. The following entry may be observed:

curly          VT    StrataCom       IPX 16    9.1.04    Nov. 19 1998 14:18 PST

Active Control Card's Software Log

No.  Type    Number      Data(Hex)  PC(Hex)    PROC   SwRev   Date     Time
12.  Error   532         00000005   304B1592   VT_1   9.1.04  11/19/98 13:47:58

Note that the date and time stamp of the software error should coincide with the date and time when the dspbob slot.port command was issued.


WorkAround: Delete Y-redundancy before the software upgrade. Use the delyred primary_slot_number command. After the upgrade is complete, re-add Y-redundancy to the appropriate card set using the addyred primary_slot_number secondary_slot_number command.

Solution: There is no solution for this problem. Follow the workaround instructions prior to upgrading switch software.


This defect has been assigned bug number CSCdk67621 - SDP stops passing traffic after 8.4.30 to 9.1.04 upgrade.

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 CSCdk67621 (registered customers only)

Related Bugs

Software defect CSCdk71951 is related to this issue - Two CVMs (Y-red cards) went to mismatched state during upgrades.

View CSCdk71951 (registered customers only)

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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