Cisco WAN Switching Modules

Field Notice 980515: ALM/B With Firmware C.B.C or Earlier Cannot Pass Frame Lengths of 6 Bytes or Less

May 13, 1998

Bug Details

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Products Affected

IGX ATM Line Module B (ALM/B)

Problem Description

The IGX-ALM/B loaded with firmware C.B.C or earlier causes frames of 6 bytes or less to be discarded when traversing ALM/B trunks.

Problem Symptoms

The symptoms include frame discards (use the dspchstats <slot.port.dlci> and dspportstats <slot.port> commands to observe discards), failed links on SNA connections, data links that come up and then drop, and other types of data discontinuities.



The solution is to upgrade the firmware on the IGX-ALM/B to support short frame sizes. The correct firmware to load on the IGX-ALM/B is C.B.D or later.


The workaround is to route protocols using frames shorter than 6 bytes over network trunk modules (NTMs).


Obtain the ALM/B firmware from CCO by visiting URL: Use your CCO account User ID and password to log in, go to Software and Support, then to the Software Center. Download ALM/B firmware version C.B.D or later.

Related Field Notice

Field Notice 980514 UFM-U Firmware Y.A.A or UFM-C Firmware Z.A.E. or Earlier Do Not Pass Frame Lengths of 5 Bytes or Less.

For More Information

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