z/OS® V2R1 Communications
Server relieves CSM storage constraints when processing ICMP Timestamp
requests.
Because the z/OS TCP/IP
stack replies to these requests, a flood of such requests can cause
problems under the right conditions. Such a flood causes the TCP/IP
stack to back up because it cannot get the responses out quickly enough,
which results in a constrained CSM condition.
If the constrained
CSM condition is not relieved, it might cause a stack outage. This
behavior might happen with:
- Other ICMP requests that always generate a response (for example,
echo requests)
- UDP requests to an application that behaves in a similar manner
QDIO outbound packets will be dropped when CSM storage is constrained
and the outbound queues are congested. This support alleviates these
problems.
Restriction: This support applies only to
data sent out over OSA-Express QDIO and HiperSockets™ interfaces.