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• Case Study

-----------------NGN Dual-

Homing Solution

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Dual-Homing Solution OverviewDual-Homing Solution Overview

The Solution For PTCL NGN C4The Solution For PTCL NGN C4

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Dual Homing is Necessary in NGN

NGN system is based on IP network, so the system can be

deployed to a wider area than PSTN, and cover more

subscribers. If the SoftSwitch is crashed in a disaster, the

impact will be very severe.

Dual Homing is the solution for recovering the services

shortly during a disaster.

That is, two SoftSwitches will be running in the NGN system. In case a

SoftSwitch fails, its service will be taken over by its dual homing SoftSwitch

instantly so that services will be recovered immediately.

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Dynamic Dual Homing

SoftX1SoftX1 SoftX2SoftX2

IP CoreIP Core

UMGUMG

Heart BeatHeart Beat

AMGAMGUMGUMG UMGUMG AMGAMG

iManageriManagerN2000N2000

SecondaryPrimary

•SoftX1 and SoftX2 are running

in the NGN network simultaneously.

•IP address of SoftX1 and SoftX2

are different.

•All the access equipments are

registered to the SoftX1 in the

normal condition.

•The network management

system (iManager N2000) configure

data to both SoftX1 and SoftX2.

•Access equipments are master in

SoftX1, are slave in SoftX2.AMGAMG

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Dynamic Dual Homing (Switchover)

SoftX1SoftX1

IP CoreIP Core

Heart BeatHeart Beat

1. UMG registered in SOFTX1

2. SoftX1 is crashed

4. UMG is unregistered due to

timeout

3. Heartbeat is broken, SoftX2 connect the registration of UMG

UMGUMG5. Register to SoftX2

6. Registration is success, service is recovered

iManageriManagerN2000N2000

Alarm

SoftX2SoftX2

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Dynamic Dual Homing (Switchback)

SoftX1SoftX1

IP CoreIP Core

Heart BeatHeart Beat

1. UMG registered in SOFTX2

5. SoftX1 accept the registration.

4. Register to SoftX1

UMGUMG

3. SoftX2 release the UMG

SoftX2SoftX2

2. Heartbeat is recovered

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Key Points of Dynamic Dual Homing

•Switchover will be initialized by UMG registration timeout.

•The synchronization of configuration is supported by the

network management system.

•The switchover will happen only when heartbeat between

two Softswitch are is broken AND the registration of UMG

is timeout.

•Dynamic dual homing support switchover manually also.

Switchover command will be sent by NMS.

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Dynamic Dual Homing (Analysis)

Advantage:

• Softswitch can detect the failure, and switchover automatically,

service can be recovered in short time.

• There is no need for data backup as two softswitches are

managed by the NMS in a unified manner.

Disadvantage:

• Access equipment should support register to second Softswitch if

first one is failed.

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Some Concepts of Dynamic Dual Homing

Heartbeat signal

A kind of handshaking signal used by two dual homing softswitches for

detecting the state of the softswitch at the other end.

It’s a private protocol encrypted using MD5 algorithm.

Sent directly by the softswitch.

The number of heartbeat timeout is configurable.

Master/Slave state

The state of a softswitch configured on the gateway.

In a dual homing system, each gateway is configured with information of

two softswitches. One softswitch is set to master and another one set to

slave.

Similarly, gateway also need to be configured as master in one softswitch

and slave in another softswitch.

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Why No Billing Data is Stored for Calls Held during a Switchover?

Call during switchover is implemented on the GW. Every call passing the gateway will be continued ( intra-office call, an outgoing call, or an incoming one ). However, when the gateway registers with the standby softswitch, no information on call statuses are transferred, so the held calls will be released and no charging information is generated or stored on the standby softswitch.

Suggestion: If CDR generation fails in long time call case or disaster case, suggest to use segmented CDR function.

Technical clarification

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Dual-Homing Solution OverviewDual-Homing Solution Overview

The Solution For PTCL NGN C4The Solution For PTCL NGN C4

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Current PTCL NGN C4 Networking

SoftX3000SoftX3000IslamabadIslamabad

SoftX3000SoftX3000KarachiKarachi

IP CoreIP Core

UMGUMG UMGUMG UMGUMG UMGUMG

INT. IP Carrier 1 INT. IP Carrier N

H.248/M2UA

SIP/H.323

2 Softswitch exist, one in Islamabad which is charge of all 20 UMGs and another in Karachi which is not no working now.

Only International incoming service is handled by NGN system, INT.IP Carrier interworking with SoftX3000 by SIP or H.323 protocol.

202.125.146.1202.125.146.1

iManager iManager N2000N2000

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Requirement for Network Stability

1 The karachi Softswitch need to act as a standby softswitch

2 Int. IP carriers connected with PTCL on SIP & H.323 wants to make their configurations on single IP. They can not establish two different links for both active/standby softswitch

3 When there is swapping between active/standby softswitch then the ongoing calls should not drop

4 The charging of ongoing calls during swapping should not loss

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HUAWEI SBC SE2300 Introduction

−SE can be deployed between IP networks of different carriers

−or between different IP networks of one carrier.

IP CoreIP CoreNGN Core ANGN Core ANGN Core BNGN Core B

Softswitch

SBC BSBC BSBC ASBC A

Softswitch BB

Media trafficMedia traffic

Signaling trafficSignaling traffic

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HUAWEI SBC SE2300 Introduction

IP-IP Gateway

Support SIP/SIP-T and H.323 trunk;

Prefix based call routing;

IP based call routing;

Security

Topology hiding and pinhole firewall;

Defend IP DoS and DDoS attacks;

CAC (Call Admission Control);

QoS

Support session based QoS police;

Support VLAN ,Signaling traffic and Media traffic can be marked different

VLAN ID;

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PTCL NGN C4 disaster protection Solution

SoftX3000SoftX3000IslamabadIslamabad

SoftX3000SoftX3000KarachiKarachi

IP CoreIP Core

UMGUMG UMGUMG UMGUMG

INT. IP Carrier 1 INT. IP Carrier N

H.248/M2UA

SIP/H.323

SBC2300SBC2300202.125.146.1202.125.146.1

UMGUMG

SIP/H.323

Heart BeatHeart Beat

iManager iManager N2000N2000

1. Deploy SBC2300 in the network with current MGC IP Address

2. Deploy the 2nd SoftSwich in the network, two Softswitch have new different IP Adress and heart beat

3.SBC2300 registered to Active Softswitch and send handshake message

4 Active Softswitch is crashed, heart beat and handshake is broken

5.SBC2300 registered to Standby Softswitch and transfer the signaling and media

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International VOIP Carrier

Signal Stream

Terminal Terminal

Backup Channel

SE Dual System

IP CoreIP Core

Master Homing

Slave Homing

Switch Dual System

Heartbeat

Detect Softswitch statue

PTCL NGN Network

Networking of Peer to Peer Network Disaster Solution

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Technical clarification

1 This “Dual-homing” solution with SBC is a new solution suited in peer to peer network disaster protection-- “opposite VoIP network to Softswitch”.Currently, the part of “MG to Softswitch Dual-Homing” is available, but the part of “opposite VoIP network to Softswitch” need more software R&D 2 Int. IP carriers do not need to establish two different links for both active/standby Softswitch ， they will connect to SBC without anyupgrade and configuration.

3 The bill issues is same with previous dual-homing solution.