Resolution:
Description:
============
In TIBCO BusinessEvents 3,x, When the Cache Server starts, it throws the error, "UnicastUdpSocket failed".
   Or
Cache server may not start or participate in cluster formation.
   Or
Issue with Multicasting while starting the Cache Server.


Environment:
==========
TIBCO BusinessEvents 3.x
Linux OS

Symptoms:
=========
Cache Server is not able to start and form a cluster.


Cause:
=====
The issue may be due to improper setting of the buffer in Linux Environment.


Resolution:
==========
Perform the following steps to set the buffer size on Linux -
    

1). Login as root to the Linux machine where the buffer needs to be set.


2). The following are the 4 UDP parameters related to setting the buffer with their descriptions -  

   a). net.core.rmem_max
      This sets the max OS receive buffer size for all types of connections.
    
   b). net.core.wmem_max  
      This sets the max OS send buffer size for all types of connections.    

   c). net.core.rmem_default  
      This sets the default OS receive buffer size for all types of connections.      

   d). net.core.wmem_default  
      This sets the default OS send buffer size for all types of connections.

      
3). Try /sbin/sysctl -A to see the values for these UDP parameters. For example:
    [root@]#/sbin/sysctl -A|grep net.core.rmem_max


4). You can then set new values to these parameters as /sbin/sysctl -w &ltparameter name>=new value


Perform tests after setting the appropriate values. It is always recommended to first  consult the Linux SysAdmin before doing any changes on the system as it may cause side effects.