IBM Support

IP Extension traffic is not passing traffic across a FCIP Tunnel after the FCIP Tunnel has a disruption.

Troubleshooting


Problem

There are two issues associated with the SAN42B-R (Brocade 7840) which can cause degraded performance of IP Extension traffic. If there is a disruption with the FCIP Tunnel then there could be degraded performance of IP Extension traffic. Depending on the FOS version currently running on the SAN42B-R, the use of IP SEC may be a contributing factor. For one of the issues, IP SEC would be in use and disabling IP SEC will not improve the degraded performance. The degree of the impact can vary from slightly degraded to no traffic being passed and it depends on IP Extension traffic levels at the time of the WAN interruption.

Symptom

For SAN42B-R extension switches configured in the hybrid mode of operation (Fibre Channel based FCIP and IP Extension traffic both allowed), the degraded performance only impacts IP Extension traffic. Fibre Channel based FCIP traffic is NOT impacted.

Cause

There are 2 different causes for these impacts and the version of firmware running on the SAN42B-R extension switch is a factor. The issues involve resource allocation (credits and buffers).

Resolving The Problem

The buffers issue is resolved permanently with an upgrade of the firmware version FOS 7.4.1d or higher 7.4.x version and FOS 8.0.1 or higher. The credits issue is resolved with FOS 8.0.1 or higher. A temporary work-around is to reboot the SAN42B-R extension switch which will impact all traffic flows through the SAN42B-R. To properly assess the situation and accurately troubleshoot either issue, please open a hardware PMR for IBM support to perform problem determination. Please refer to this Technote (S1010536) when contacting support since it has additional information for the IBM support team's reference. The Release Notes for firmware version 8.x can be found at:
http://www-01.ibm.com/support/docview.wss?uid=ssg1S1009577
and the firmware version 7.x Release Notes are located at
http://www-01.ibm.com/support/docview.wss?uid=ssg1S1003855

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Document Information

Modified date:
17 June 2018

UID

ssg1S1010536

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