CSTCP_IPMAXRT6_tcpipstackname

Description:

Checks to see whether the total number of IPv6 indirect static and dynamic routes in the TCP/IP stack's routing table has exceeded the maximum threshold (default 2000). The tcpipstackname suffix is the job name of the TCP/IP stack to which this check applies. Use CSTCP_IPMAXRT6_* to reference this check for all stacks.

Reason for check:

A high number of routes added by OMPROUTE and the TCP/IP stack can potentially result in high CPU consumption from routing changes. A large routing table is considered to be inefficient in network design and operation. By default, this check is performed once at 30 minutes after stack initialization, at once whenever the total number of routes exceeds the threshold, and then will be repeated once at the specified intervals (default 168 hours for weekly).

z/OS® releases the check applies to:

z/OS V1R12 and later.

User override of IBM values:

The following sample shows the defaults for customizable values for this check. Use this sample to make permanent check customizations in an HZSPRMxx parmlib member used at IBM Health Checker for z/OS startup. If you just want a one-time only update to the check defaults, omit the first line (ADDREPLACE POLICY) and use the UPDATE statement on a MODIFY hzsproc command. Note that using non-POLICY UPDATEs in HZSPRMxx can lead to unexpected results and is therefore not recommended. End of change

ADDREPLACE POLICY[(policyname)] [STATEMENT(name)]
UPDATE
CHECK(IBMCS,CSTCP_IPMAXRT6_tcpipstackname)
DATE('date_of_the_change')
REASON('Your reason for making the update.')
PARM('IPMAXRT6(2000)')
ACTIVE
SEVERITY(LOW)
INTERVAL(168:00)

The following examples show how you can make runtime updates of CSTCP_IPMAXRT6_tcpipstackname default values:

F hzsproc,update,check=(ibmcs,cstcp_ipmaxrt6_*),parm='ipmaxrt6(1000)'   
F hzsproc,update,check=(ibmcs,cstcp_ipmaxrt6_*),interval=02:00         
F hzsproc,update,check=(ibmcs,cstcp_ipmaxrt6_*),interval=01:00,parm='ipmaxrt6(1500)'

Debug support:

Verbose support:

Parameters accepted:

Yes - IPMAXRT6 is an integer value indicating the maximum threshold value for the number of IPv6 indirect static and dynamic routes that the TCP/IP stack can add to its routing table before issuing a warning message to indicate a potential high CPU consumption. Value must be in the range 1 to 65536. Default: IPMAXRT6(2000)

Reference:

See Minimizing the routing responsibility of z/OS Communications Server in z/OS Communications Server: IP Configuration Guide.

Messages:

This check issues the following exception messages:

EZBH013E

See z/OS Communications Server: IP Messages Volume 2 (EZB, EZD).

SECLABEL recommended for multilevel security users:

SYSLOW - see z/OS Planning for Multilevel Security and the Common Criteria for information on using SECLABELs.