IC90924: APPLICATION OPTIMIZATION (AO) SELF BALANCING INCREASED LATENCY AND SENDING ICMP FRAGMENTATION REQUIRED
Fixes are available
Fix packs for DataPower Low Latency Appliance version 5.0
Fix packs for DataPower B2B appliances version 5.0
Fix packs for DataPower Integration appliances version 5.0
Fix packs for DataPower XML Security Gateway appliances version 5.0
Fix packs for DataPower Service Gateway appliances version 5.0
Fix packs for DataPower Service Gateway XG45 Virtual Edition version 5.0
Fix packs for DataPower Integration Appliance XI52 Virtual Edition version 5.0
Closed as program error.
When using AO Self Balancing, the active group member may send "ICMP fragmentation required" back to the client when trying to forward large packets to a different group member. If the "Don't Fragment" flag was set in the incoming tcp packet, the connection will also experience additional latency because the client will have to retransmit the packet. This may result in performance degradations.
If the network allows, the MTU of the DataPower interfaces may be increased to allow forwarding of packets larger than the configured MTU. This local fix 'may' help in some situations.
Affected are all users of AO Self Balancing on a 10G or 1G network interface card. There was a clash between an Active Distributor group member (merging small request packets into bigger ones to forward to another self-balanced group member) and the client packets having set the "Don't Fragment" flag. This condition prevents the targeted member from receiving the merged packet when its network interface is configured with smaller MTU than the receiving packet. This fix permanently turns off the packet merging (Large Receive Offload), thus lifting the need for a (client restricted) fragmentation of the large packets.
The fix is available in 18.104.22.168. For a list of the latest fix packs available, please see: http://www-01.ibm.com/support/docview.wss?uid=swg21237631
If the network allows, the MTU of the DataPower interfaces may be increased to allow forwarding of packets larger than the configured MTU.
Reported component name
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APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
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Applicable component levels
More support for:
WebSphere DataPower Integration Appliance XI52
Software version: 5.0.0
Reference #: IC90924
Modified date: 27 August 2013