2.2.1 Protocols used for communication

(1) Communication between an EADS client and an EADS server

Communication between EADS clients and EADS servers is performed using TCP (Transmission Control Protocol).

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(2) Communication between EADS servers

Communication between EADS servers is performed using TCP and UDP (User Datagram Protocol).

TCP is used for the following communication between EADS servers:

• Creating redundant copies of data

• Checking for live servers^#

• Restoration processing

• Scale-out processing (adding EADS servers)

UDP is used for the following communication between EADS servers:

• Heartbeat^#

#

Heartbeats are multicast within a cluster.

Heartbeats consist of packets distributed in a cluster to report that the EADS servers are running normally.

A check conducted by one EADS server to determine whether another EADS server that is not sending heartbeats has gone down is called a check for live servers.

For details, see 2.9 Monitoring a cluster.

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