CTI Products EXB-IP Ethernet System Extender - Manual (Page 15)

CTI Products, Inc. EXB-IP User Guide
IP Configuration – EXB Config 15
IP A DDRESS M ODE
EXB-IP modules can communicate with other EXB-IP modules using either “Unicast/Replicated” or
“Multicast” mode.
Unicast/Replicated
Unicast/Replicated addressing mode allows point-to-point or point-to-multipoint connections in any IP network.
It is used in the following configurations:
• Point-to-Point connection should be used if only two modules will be communicating.
• Point-to-Multipoint connection can be used when Multicast is not supported on the IP network (non-
preferred)
In multipoint applications, Unicast/Replicated address mode uses more Ethernet channel bandwidth than
Multicast mode. For each MCN data packet received, an EXB-IP module in Unicast/Replicated mode will send
out an Ethernet packet to each remote EXB-IP module. For example, in a system with 5 EXB-IP modules, each
module would generate 4 Ethernet packets for each MCN packet received. (A good portion of this extra traffic
can be eliminated in systems that have multiple comparator sites feeding only 1 PC site. In this application,
each of the comparator site EXB-IP modules can be programmed to send data to only the Central Site EXB.)
Multicast
Multicast addressing mode allows efficient point-to-multipoint communications in a network. A single MCN
message packet entering any one of the EXB-IP modules results in a single multicast IP packet being sent out
the Ethernet port of that module to be received by all other EXB-IP module members configured to the same
Multicast IP address. Because only one IP packet is generated for every MCN message packet, multicast
addressing mode uses far less network bandwidth than Unicast/Replicated.
Before choosing multicast addressing mode, it is important to determine the following capabilities of the IP
network to which the EXB-IP modules will be connected:
• IP routers must be capable of handling IP multicast traffic.
• IP routers must have IP multicast enabled
• IP routers must forward the appropriate multicast traffic destined to the destination UDP Port number
in use by the EXB-IP modules in the channel.
• If the routers filter multicast traffic based on source UDP Ports, they must forward packets from a
source UDP Port of 1283.