IP Services: Use the new maximum segment size adjustments if required
Description
New function is introduced in z/OS V2R2 to automatically adjust the Maximum Segment Size (MSS) that is used on a TCP connection to avoid fragmentation. This function is turned on by default. If you need to continue using your existing setting for the MSS, see Steps to take.
Table 1 provides more details about this migration action. Use this information to plan your changes to the system.
| Element or feature: | z/OS Communications Server. |
|---|---|
| When change was introduced: | z/OS V2R2. |
| Applies to migration from: | z/OS V2R1 and z/OS V1R13. |
| Timing: | Before the first IPL of z/OS V2R2. |
| Is the migration action required? | Yes, if you do not want the automatic reduction of MSS. |
| Target system hardware requirements: | None. |
| Target system software requirements: | None. |
| Other system (coexistence or fallback) requirements: | None. |
| Restrictions: | None. |
| System impacts: | A performance degradation can result if the MSS is not configured to avoid fragmentation. |
| Related IBM® Health Checker for z/OS® check: | None. |
Steps to take
To disable the auto-adjusting function and continue using your existing setting for the MSS from the prior release, specify the subparameter ADJUSTDVIPAMSS NONE on the parameter GLOBALCONFIG.
Reference information
For more information, see z/OS Communications Server: IP Configuration Reference.