F.4. About RELAY2

The RELAY protocol bridges two remote clusters by creating a connection between one node in each site. This allows multicast messages sent out in one site to be relayed to the other and vice versa.
JGroups includes the RELAY2 protocol, which is used for communication between sites in Red Hat JBoss Data Grid's Cross-Site Replication.
The RELAY2 protocol works similarly to RELAY but with slight differences. Unlike RELAY, the RELAY2 protocol:
  • connects more than two sites.
  • connects sites that operate autonomously and are unaware of each other.
  • offers both unicasts and multicast routing between sites.