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Cisco IOS Software Releases 12.1 Mainline

Field Notice: *Expired* FN - 20673 - TCP Errors Cause DLSw/TCP Peer Failures


Revised April 15, 2008

September 2, 2002


NOTICE:

THIS FIELD NOTICE HAS BEEN EXPIRED AND IS NO LONGER MAINTAINED OR UPDATED BY CISCO.

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE, WARRANTY OR SUPPORT. USE OF THE INFORMATION ON THIS FIELD NOTICE OR MATERIALS LINKED FROM THIS 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

Cisco IOS® Software Releases 12.1(10.1) through, but not includung, 12.1(15)

All platforms running Cisco IOS software and configured for DLSw+

Cisco IOS Software Releases 12.2(5.5) through, but not including 12.2(10b)

All platforms running Cisco IOS software and configured for DLSw+

Cisco IOS Software Releases 12.1(10.5)E through, but not including 12.1(12.5)E

All platforms running Cisco IOS software and configured for DLSw+

  

Problem Description

When using DLSw TCP with Cisco IOS Software Releases from 12.1(10.1) to, but not including, 12.1(15), as well as from 12.2(5.5), to, but not including, 12.2(10b), and 12.1(10.5)E to, but not including 12.1(12.5)E, performance problems and DLSw peer disconnects may occur.

Background

DLSw peers fail because of TCP related timer problems.

Problem Symptoms

DDTS

Symptoms

CSCdu18397

TCP applications such as DLSw+ may experience performance problems due to continuous TCP retransmissions caused by round-trip timeout. The RTT value is not adjusted effectively when the transmission occurs.

CSCdw58350

When there are retransmissions that occur between the TCP endpoints, the KRTT value can become excessively large, causing the TCP connection to drop. This situation frequently affects DLSw by causing the DLSw peers to sporadically drop.

  

Workaround/Solution

Fixes for these issues are included Cisco IOS Software Release 12.1(15) and later for Release 12.1, for Release 12.2, Cisco IOS Software Release 12.2(10b) and Cisco IOS Software Release 12.2(10.5) and later, and, for Release 12.1E, Cisco IOS Software Release 12.1(12.5)E and later.

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

CSCdu18397 (registered customers only)

TCP round-trip time is not adjusted effectively.

CSCdw58350 (registered customers only)

TCP retransmit timeout value expands endlessly.

  

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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