Alternate link failure

An alternate link problem occurs when a CTC link fails while global resource serialization is using the link to send the ring acceleration signal. An alternate link failure does not always disrupt ring processing.

If global resource serialization detects an alternate link failure, it issues messages ISG046E and ISG047I to describe the error.

If global resource serialization was using the alternate link to send the ring acceleration shoulder-tap signal, it tries to locate another alternate link to use for ring acceleration. If one is available, global resource serialization uses it to send the signal. If one is not available, global resource serialization stops sending the signal between the two systems and issues the following message:

    
  ISG083E GRS CANNOT SEND ACK-TAP SIGNALS TO SYSTEM sysname

Ring processing continues normally, but throughput might slow down on one of the systems because all requests for global resources must wait for ring processing. If an alternate link becomes available, global resource serialization begins using it to send the ring acceleration signal and deletes message ISG083E.