Intel SIU520 SS7 manual Dual SIU Architecture for Circuit-Switched Applications

Application Note Building Fault-tolerant SS7 Systems Using the Intel® NetStructure™ SIU520 SS7 Signaling Gateway

Application

TCP/IP Ethernet

MTP1-3

Circuit Group 0

[Active]

Circuit Group 1

[Inactive]

SIUA

Inter-SIU

SS7 Link Set

SS7

Adjacent

Signaling

Point

	SS	7
	Circuit Group 0
	[Inactive]
	Circuit Group 1
	[Active]
SIUB	MTP1-3

Transmit traffic for circuits active on SIUA

Received traffic for circuits active on SIUA

Figure 10. Normal Routing for Circuit Group 0 When Controlled by SIUA

Dual SIU Architecture for Circuit-Switched Applications

Within the SIU environment, circuits are configured in groups, each group equating to all the circuits multiplexed onto a single E-1 or T-1 PCM trunk. The SIU provides the SS7 circuit control and the application platform (or host) terminates the physical channels, typically with a voice processor.

For normal operation, half the circuit groups are controlled by SIUA and half by SIUB. As each application platform starts up and connects to both SIUA and SIUB, the application must nominate which SIU is to control the

signaling for each of the circuit groups it terminates. A circuit group activation command must be sent to the selected SIU for each circuit group. Any outgoing messages for circuits in this group must be sent to this SIU, as shown in Figure 10.

The adjacent signaling point views the links connected to SIUA and SIUB as the same link set and, as such, is free to send messages for the circuits controlled by SIUA to either unit. In the case where SIUB receives a message for a circuit controlled by SIUA, the message is automatically routed to the correct controlling circuit group using the LAN Ethernet connection (shown by the shaded arrows in Figure 10).

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