PI73727: INACCURATE TIMEOUT OF ARP ENTRIES AND FAILURE TO SEND HEARTBEATS WITH NO REPLICATION RECORD

Fixes are available

APAR status

Closed as program error.

Error description

Inaccurate timeout of arp entries, and failure to send
heartbeats with no replication record in a single heartbeat
pair environment.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  IBM WebSphere Application Server Edge       *
*                  Component Load Balancer for ipv4 and ipv6   *
*                  users                                       *
****************************************************************
* PROBLEM DESCRIPTION: Excessive ARP requests will be seen     *
*                      from the load balancer machine and      *
*                      very brief delays may randomly be       *
*                      experienced.                            *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The load balancer must obtain the ethernet address (MAC) for
all hosts on the local subnet within the load balancer
configuration file. This address mapping (shown as the
neighbor state on the server object) should remain valid once
learned but the load balancer is expiring the mapping every 10
to 15 seconds and relearning the mapping. If a network trace
is examined from the load balancer machine, excessive ARP
requests and responses will be observed. Resolution typically
only take a few microseconds but during this time, the load
balancer will be unable to forward requests to the host.

Problem conclusion

Code has been corrected to eliminate expiration of valid ARP
entries. Address resolution is only requested when at executor
start time and retried for failed resolutions.

ARP resolution (referred to as neighbor state discovery for
ipv6) occurs for (when defined) any backend servers on the
local subnet, the clientgateway, the clientgatewayipv6, reach
targets, remote heartbeats and router addresses used for NAT
servers.

Fix levels :
   8.0.0.13
   8.5.5.12
   9.0.0.3
Content based routing, Site Selector and the Load Balancer for
ipv4 do not experience this problem.

Temporary fix

Comments

APAR Information

APAR number
PI73727
Reported component name
WS EDGE LB IPV4
Reported component ID
5724H8812
Reported release
850
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-12-14
Closed date
2016-12-14
Last modified date
2016-12-14

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name
WS EDGE LB IPV4
Fixed component ID
5724H8812

Applicable component levels

R850 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.5","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
04 May 2022

Tips

PI73727: INACCURATE TIMEOUT OF ARP ENTRIES AND FAILURE TO SEND HEARTBEATS WITH NO REPLICATION RECORD

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R850 PSY

Document Information

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