Intel SIU520 SS7 manual Failure of Power Supply, Failure of Signaling Interface Unit

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

Ethernet

SIUA

API Layer/Ethernet Driver

Application

Ethernet

SIUB

API Layer/Ethernet Driver

MAP or INAP

or IS41

	ISUP	TUP
TCAP

SCCP

Distributed Layer 4

Management

Distributed MTP3

Management

MAP or INAP

or IS41

TCAP

SCCP

ISUP

TUP

MTP Levels 1-3

SS7

MTP Levels 1-3

SS7

Link Set

Figure 5. Dual SIU Architecture

Failure of Power Supply

Problem — Ensuring that the unit survives the loss of one power supply and making it possible to replace a failed power supply without affecting the availability of the system.

Solution — The Intel NetStructure SIU520 SS7 signaling gateway can be optionally configured with a redundant and hot swappable power supply.

Details — Please refer to Intel NetStructure SIU520/Intel NetStructure SG430 Hardware User Manual, Issue 3 to obtain part numbers for redundant power supplies for the SIU520.

Failure of Signaling Interface Unit

Problem — Since the SIU520 provides an SS7 interface to a distributed application, it is usually deployed for high-density service platforms. Should the SIU of a single SIU-based system fail, many resources (telephony cir- cuits to TCAP dialogues) would become unavailable and would cause major service disruption.

Solution — A major feature of the SIU architecture is that two units can be configured to operate as a single entity, sharing the same local SS7 point code. In normal operation, signaling can be shared between two units. In the event of a failure, signaling is maintained by the remaining unit.

Details — In a dual configuration, one unit is assigned as SIUA, the other as SIUB. Under normal operation, the application uses both the resources of SIUA and SIUB (see Figure 5).

The distributed layer 4 management is achieved using a LAN connection and allows SS7 messages for any trans- action or call to be received by either unit, regardless of the unit that is actually processing the call or transaction.

The distributed MTP3 functionality is achieved using a specially configured inter-SIU link set, containing one or more signaling links. Transmit messages from each SIU are load shared between links that connect to the local SIU, if these are available. If all local network-facing SS7 links have failed, transmit messages are relayed to the

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