Recommended configuration change for clustered multicast environment using Cisco Ethernet Switch cabable of IGMP snooping

Document ID : KB000053815
Last Modified Date : 14/02/2018
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Description:

If running the CA PPM application on any currently released version in a clustered multicast environment and using a Cisco catalyst switch capable of IGMP snooping, you will need to make a configuration change during implementation in order to avoid multicasting traffic issues. So far, the Cisco switches we have observed this behavior in have been enterprise class switches (model 3950) and larger.

Symptoms of Issues which the default Cisco Switch configuration will create:

  1. Out of memory errors resulting from heap overflow.
  2. No errors present to explain these heap issues in CA PPM System Administration (CSA) application or Beacon logs.
  3. In multicast environment, only one Beacon will be visible in CSA where there are more present which should be visible.

If experiencing this type of behavior, check to see if you are using a Cisco Ethernet Switch enterprise class model 3950 or larger capable of IGMP snooping. Other models of Cisco Ethernet switches may experience this too but this is the model range we have found to be the culprit when customers have encountered this issue in the past.

IGMP snooping is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined. It provides switches with a mechanism to prune multicast traffic from links that do not contain a multicast listener (IGMP client). A switch that does not IGMP snoop will, by default, 'flood' multicast traffic to all the ports in a broadcast domain (or the VLAN equivalent). ulticast can cause unnecessary or even crippling load on host devices by requiring them to process packets they have not solicited.

Solution:

Here is the recommended configuration change:

  1. Stop the CA PPM Application services, CSA services, then the Beacon services in the environment  
  2. Make the Cisco Ethernet Switch configuration change to enable IGMP snooping for the VLAN these two servers belong to: ip igmp snooping
  3. Start the Beacon services, then the CSA services, then the application servers  
  4. Only one CSA instance should be started, the one on the primary server  
  5. Log into the CSA and in the overview page click on the "refresh" button  
  6. Both servers should be listed by their IP address. There may be an additional listing of "localhost" but this can be ignored