Why RV Retransmission and Dataloss error messages on low message volume using multicast addressing on OpenVMS server V7.3-2?
Article ID: KB0091995
Updated On:
| Products | Versions |
|---|---|
| TIBCO Rendezvous | - |
| Not Applicable | - |
Description
Resolution:
This might be due to an OS defect. HP released a patch to fix it. This problem is described under call id 'QXCM1000419821' by HP. Here is problem abstract and the solution, as given by HP:
Problem Abstract: Multicast traffic may be lost when aggressive IGMP snooping is enabled on a switch. This is the result of OpenVMS delaying IGMP REPORTS when the IGMP QUERY contains a "Max RespTime" less than 10 seconds.
For smaller values of "Max RespTime", then it is more likely OpenVMS will repeatedly delay sending an IGMP REPORT.
Solution: Simply by honoring the "Max Response Time" in the query, the condition: if (inm->inm_timer > timer) will only have a probability of being true for the very first IGMP QUERY or if a subsequent IGMP QUERY reduces the "Max Response Time". In these cases, we must promptly reduce our 'inm_timer' value to a random number between 1 and "Max Response Time". To this end, the IGMP_RANDOM_DELAY() macro has been modified with a second parameter, which limits the maximum value it can return.
This might be due to an OS defect. HP released a patch to fix it. This problem is described under call id 'QXCM1000419821' by HP. Here is problem abstract and the solution, as given by HP:
Problem Abstract: Multicast traffic may be lost when aggressive IGMP snooping is enabled on a switch. This is the result of OpenVMS delaying IGMP REPORTS when the IGMP QUERY contains a "Max RespTime" less than 10 seconds.
For smaller values of "Max RespTime", then it is more likely OpenVMS will repeatedly delay sending an IGMP REPORT.
Solution: Simply by honoring the "Max Response Time" in the query, the condition: if (inm->inm_timer > timer) will only have a probability of being true for the very first IGMP QUERY or if a subsequent IGMP QUERY reduces the "Max Response Time". In these cases, we must promptly reduce our 'inm_timer' value to a random number between 1 and "Max Response Time". To this end, the IGMP_RANDOM_DELAY() macro has been modified with a second parameter, which limits the maximum value it can return.
Issue/Introduction
Why RV Retransmission and Dataloss error messages on low message volume using multicast addressing on OpenVMS server V7.3-2?
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