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Application Note
Building Fault-tolerant SS7
Systems Using the
®
Intel NetStructure™
SIU520 SS7 Signaling Gateway
Intel in
Communications
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note Table of Contents Abstract 1 Introduction 1 Overview of SIU Operation 2 Circuit-switched API Operation 2 Transaction-based API Operation 3 Management Interface 3 Potential Points of Failure 3 Failure of SS7 Links 4 Failure of Routes 5 Failure of Power Supply 6 Failure of Signaling Interface Unit 6 Routing Architectures of a Dual-resilient SIU System 7 Dual SIU architecture for Circui
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Table of Figures ® Figure 1 Structure of the Intel NetStructure™ SIU520 SS7 Signaling Gateway 2 Figure 2 Integrating the SIU520 3 Figure 3 SIU Connected to Adjacent Node with Two Links in Link Set 4 Figure 4 SIU520 Connected to Mated STP Pair Providing Route Resiliency 5 Figure 5 Dual SIU Architecture 6 Figure 6 Transmit Routing to a Single Destination 7 Figure 7 Dual-resilient SIUs
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note Because of the high expectation of service reliability by Abstract the users of public telephone networks, equipment In order to achieve five-nines (99.999%) reliability and a manufacturers and system integrators demand high high degree of fault tolerance in an SS7 environment levels of fault tolerance and availability, often citing the ® using Intel NetStructure™ SIU520 signaling ga
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Application Application #1 #0 #N Ethernet API Layer/Ethernet Driver MAP or INAP or IS41 ISUP TUP TCAP Configuration and Management SCCP MTP Levels 1-3 SIU 520 ® Figure 1. Structure of the Intel NetStructure™ SIU520 SS7 Signaling Gateway The SS7 signaling may be presented from the network Overview of SIU Operation multiplexed in a timeslot on an E-1 (2.048 MB/s) or T-1 Th
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note E-1 or T-1 Trunks, Voice Circuits Only CT Application Platform } SIU520 E-1 or T-1 Trunks with SS7 Channel SS7 and Voice Circuits Information } CT Application Platform Ethernet Figure 2. Integrating the SIU520 Transaction-based API Operation Potential Points of Failure TCAP-based applications can be distributed on multiple In this section, the most critical points of failure of an In
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway A) Load sharing between link 0 and link 1 under normal conditions Link id 0, slc 0 SIU520 SSP/SCP Link id 1, slc 1 Point Code Point Code 0x100 0x200 Link Set id 0 B) Traffic sent over link 1 under failure of link 0 SSP/SCP SIU520 Point Code Point Code 0x100 0x200 Figure 3. SIU Connected to Adjacent Node with Two Links in Link Set Failure of SS7 Links Link failure management is a sta
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Link id 1, slc 0 Link id 1, slc 0 ® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note A) Load sharing between link set 0 and link set 1 under normal Link Set id 0 STPA Point Code 0x200 SSP/SCP SIU520 Point Code Point Code STPB 0x100 0x400 Link Set id 1 Point Code 0x300 B) Traffic sent over link set 1 under failure of STP Link Set id 0 SSP/SCP SIU520 Point Code Point Code 0x100 STPB 0x400 Link Set id 1 Point Code 0x300 Figure 4. SIU520
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Ethernet Ethernet SIUA SIUB API Layer/Ethernet Driver API Layer/Ethernet Driver Distributed Layer 4 MAP or INAP MAP or INAP Management or IS41 or IS41 ISUP TUP TCAP ISUP TUP TCAP SCCP SCCP Distributed MTP3 Management MTP Levels 1-3 MTP Levels 1-3 Link Set Figure 5. Dual SIU Architecture Solution — A major feature of the SIU architecture is Failure of Power Supply that tw
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note A) Normal routing case Single Point Code Inter-SIU Link Set SIUA SSP/SCP F-Links Link Set id 0 SIUB Link Set id 1 B) Routing under network link failure Single Point Code Inter-SIU Link Set SIUA Link Set id 0 SSP/SCP SIUB Link Set id 1 Figure 6. Transmit Routing to a Single Destination partner SIU across the inter-SIU link set and sent out to from SIUA are sent to the destination SSP
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Single Point Code Link Set id 1 Inter-SIU STPA Link Set SIUA Link Set id 0 SSP/SCP A-Links SIUB STPB Link Set id 2 Figure 7. Dual-resilient SIUs Connected to a Mated STP Pair in a Straight Link Configuration Single Point Code Link Set id 1 Inter-SIU Link Set STPA SIUA Link Set id 0 SSP/SCP SIUB STPB Link Set id 2 Figure 8. Dual-resilient SIUs Connected to a Mated STP Pair in a Cross
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note A) Normal routing case (both network link sets available) Single Point Code Link Set id 1 Inter-SIU Link Set STPA SSP/SCP SIUA Link Set id 0 A-Links SIUB C-Links STPB Link Set id 2 B) Routing under failure of network link set between SIUA and adjacent STP Single Point Code Link Set id 1 Inter-SIU Link Set SSP/SCP SIUA A-Links Link Set id 0 SIUB C-Links STPB Link Set id 2 Transmit Tra
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SS7 ® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway MTP1-3 Circuit Group 0 [Active] Circuit Group 1 [Inactive] SIUA Adjacent Signaling Inter-SIU Application Point SS7 Link Set TCP/IP Ethernet Circuit Group 0 [Inactive] Circuit Group 1 [Active] MTP1-3 SIUB 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 signaling for eac
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note MTP1-3 Circuit Group 0 [Active] Circuit Group 1 [Inactive] SIUA Adjacent Signaling Inter-SIU Application Point SS7 Link Set TCP/IP Ethernet Circuit Group 0 [Inactive] Circuit Group 1 [Active] MTP1-3 SIUB Transmit traffic for circuits active on SIUA Received traffic for circuits active on SIUA Figure 11. Routing When All Local Links Have Failed, Group 0 Controlled by SIUA ■ If all the
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway SIUA Adjacent TCP/IP Ethernet Signaling Application Point Circuit Group 0 [Active] Circuit Group 1 [Active] MTP1-3 SIUB Figure 12. Routing Following Failure of SIUA The circuit group control will then appear as shown in two stages. The group should be deactivated from one Figure 12. unit (if communication with that unit is possible) before being activated on the partner SIU. To prot
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note A) Dual-resilient SIUs running SS7 protocol stack to TCAP B) Dual-resilient SIUs running SS7 protocol stack up to SCCP Host 0 Host N Host 0 Host N TC User TC User . . . TC User TC User . . . TCAP TCAP DTC DTC Ethernet SIUB SIUA Ethernet SIUA SIUB TCAP TCAP DTS DTS SCCP SCCP SCCP SCCP MTP MTP MTP MTP Figure 13. Two Different Architectures for a TCAP Processing SIU System Dual SIU Ar
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SS7 SS7 ® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway SIUA TCAP instance = 0 Ethernet SCCP MTP Adjacent Inter-chassis Application Signaling communication Point (RSI) MTP SCCP TCAP instance = 1 SIUB Transmit message for transaction handled by TCAP B Message received for transaction handled by TCAP B Figure 14. Message Flow on a Dual-resilient System Running the SS7 Stack up to TCAP In the second case, each unit controls half of
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Subnetwork 1 Subnetwork 2 ® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note Application Host SIU520 Application Host Figure 15. Dual LAN Operation on the SIU520 available to allow TCAP-based applications to failover to Failure of IP Subnetwork other hosts. Problem — Should one subnetwork go down due to a network component failure, the hosts connected to the Details — For TCAP-based applications, the SIU allows SIU over the other sub
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® Application Note Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Host 0 Host 1 Host 2 Host 3 Application Application Application Application Ethernet SIU520 TCAP SCCP MTP Figure 16. TCAP Dialogue Groups Example TCAP Resiliency Based on DTS/DTC Option each application host. Consequently, the total capacity of such a system depends on the number of application Alternatively, it is possible to distribute SCCP traffic to hosts, each host bringing an
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® Building Fault-tolerant SS7 Systems Using the Intel NetStructure™ SIU520 SS7 Signaling Gateway Application Note Signaling Card PCM Trunk #0 SS7 Network E-1 Trunk Containing SS7 Signaling Only PCM Trunk #1 SIUA PCM Trunk #2 PCM Trunk #3 Inter-SIU SS7 Link Set Signaling Card E-1 Trunk PCM Trunk #0 SS7 Network E-1 Trunk Containing SS7 Signaling Only PCM Trunk #1 SIUB PCM Trunk #2 PCM Trunk #3 Figure 17. Inter-SIU Link over Crossed E-1/T-1 Cable Hardware Requirements Configuring a Dual SIU Pair
