Hi Team,

we just upgraded from  jgroups-3.4.0.Alpha2 to 3_6_19. post the UDP cluster communication is not working.

after upgrade, we were hitting some warning as below and we solved those by changing property_string of UDP.

Warnings:

WARNING: JGRP000014: Discovery.timeout has been deprecated: GMS.join_timeout should be used instead
[2020-06-17 14:05:49.271] ALL 000000000000 GLOBAL_SCOPE Jun 17, 2020 2:05:49 PM org.jgroups.stack.Configurator resolveAndAssignField
WARNING: JGRP000014: Discovery.num_initial_members has been deprecated: will be ignored

[2020-06-17 14:05:49.396] ALL 000000000000 GLOBAL_SCOPE Jun 17, 2020 2:05:49 PM org.jgroups.protocols.pbcast.NAKACK init
WARNING: use_mcast_xmit should not be used because the transport (TCP) does not support IP multicasting; setting use_mcast_xmit to false

To solve above warnings, we went through tcp.xml which was shipped using in 3_6_19 jar:

and now our properties looks like:

property_string=UDP(bind_addr=hostIP;bind_port=39061;mcast_addr=239.255.166.17;mcast_port=39060;ip_ttl=32;mcast_send_buf_size=150000;mcast_recv_buf_size=80000):PING:MERGE2(min_interval=5000;max_interval=10000):FD_ALL(interval=5000;timeout=20000):VERIFY_SUSPECT(timeout=1500):pbcast.NAKACK(use_mcast_xmit=true;retransmit_timeout=300,600,1200,2400,4800;discard_delivered_msgs=true):UNICAST:pbcast.STABLE(desired_avg_gossip=20000):FRAG(frag_size=8096):pbcast.GMS(join_timeout=5000;print_local_addr=true)

distribution_property_string=TCP(bind_port=39060;thread_pool_rejection_policy=run):TCPPING(async_discovery=true;initial_hosts=hostIP[39060];port_range=0:MERGE2(min_interval=3000;max_interval=5000):FD_SOCK:FD(timeout=5000;max_tries=48):VERIFY_SUSPECT(timeout=1500):pbcast.NAKACK(use_mcast_xmit=false;discard_delivered_msgs=true:pbcast.STABLE(stability_delay=1000;desired_avg_gossip=20000;max_bytes=0):pbcast.GMS(join_timeout=5000;print_local_addr=true)

lock.protocolStack=UDP(bind_addr=hostIP;bind_port=39062;mcast_addr=239.255.166.17;mcast_port=39069;ip_ttl=32;mcast_send_buf_size=150000;mcast_recv_buf_size=80000):PING:MERGE2(min_interval=5000;max_interval=10000):FD_ALL(interval=5000;timeout=20000):VERIFY_SUSPECT(timeout=1500):pbcast.NAKACK(use_mcast_xmit=true;retransmit_timeout=300,600,1200,2400,4800):UNICAST:pbcast.STABLE(desired_avg_gossip=20000):FRAG(frag_size=8096):pbcast.GMS(join_timeout=5000;print_local_addr=true):CENTRAL_LOCK(num_backups=2)

With above properties, we are not seeing any warning or error. But still cluster communication is not working with UDP. 

Please help me in resolving the same 

Thank 

Janardhan