05.03.2015 Views

A Seamless Migration from WiMAX to LTE Using ... - Sonus Networks

A Seamless Migration from WiMAX to LTE Using ... - Sonus Networks

A Seamless Migration from WiMAX to LTE Using ... - Sonus Networks

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

A <strong>Seamless</strong> <strong>Migration</strong> <strong>from</strong> <strong>WiMAX</strong> <strong>to</strong><br />

<strong>LTE</strong> <strong>Using</strong> the <strong>Sonus</strong> SIP Core Network<br />

www.sonus.net


Table of Contents<br />

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1<br />

The <strong>Sonus</strong> SIP Core ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 1<br />

<strong>Using</strong> the <strong>Sonus</strong> SIP Core <strong>to</strong> Manage Services <strong>to</strong> <strong>WiMAX</strong> Subscribers... .. .. .. .. 1<br />

Migrating the <strong>WiMAX</strong> network <strong>to</strong> an <strong>LTE</strong> network . . . . . . . . . . . . . . . . 2<br />

Securing the Border Between the SIP Core and the <strong>LTE</strong> Network. . . . . . . 2<br />

But I Thought You Needed an IMS Core <strong>to</strong> Deploy <strong>LTE</strong>?... .. .. .. .. .. .. .. .. .. .. .. . 3<br />

Adding Mobility <strong>to</strong> the <strong>LTE</strong> Network via an IMS Core Network. . . . . . . . . 3<br />

Tying It All Together: <strong>Sonus</strong> Global Services. . . . . . . . . . . . . . . . . . . 5<br />

Conclusion ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 5<br />

Disclaimer and Restrictions<br />

This document is for informational purposes only and is subject <strong>to</strong> change without notice. <strong>Sonus</strong> has no obligation <strong>to</strong> provide any<br />

future releases or upgrades or any of the features, enhancements or functions set forth in this document. Unless specifically<br />

required in a written agreement with <strong>Sonus</strong>, no product purchased <strong>from</strong> <strong>Sonus</strong> is conditioned upon <strong>Sonus</strong>' development or delivery<br />

of any future release or upgrade or of any feature, enhancement or function. All releases, upgrades, features, enhancements and<br />

functions <strong>to</strong> be delivered by <strong>Sonus</strong> are provided on a "when-and-if-available" basis.


Introduction<br />

The widespread adoption of smartphones and tablet devices is changing the way that subscribers see their service providers.<br />

Unlimited voice services no longer command premium pricing, but are viewed as “table stakes” in a broader service offering<br />

that must now include multimedia (voice, data, video) communications with a mobility component. As a result of this shift,<br />

many service providers are adopting a SIP-based, Long Term Evolution (<strong>LTE</strong>) network strategy <strong>to</strong> deliver this multimedia<br />

experience <strong>to</strong> their subscribers. While <strong>LTE</strong> is <strong>to</strong>day seen as the most viable of the mobile multimedia network architectures, it<br />

has never been the only architecture. As recently as 2008, <strong>WiMAX</strong> was viewed as a logical, long-term architecture <strong>to</strong> deliver<br />

IP voice, data and video over wireless networks.<br />

Today, as the industry shifts its attention <strong>to</strong> <strong>LTE</strong> and Voice over <strong>LTE</strong> (Vo<strong>LTE</strong>) networks, early <strong>WiMAX</strong> adopters are looking<br />

<strong>to</strong> migrate their network strategy away <strong>from</strong> the <strong>WiMAX</strong> model <strong>to</strong> the more broadly adopted <strong>LTE</strong> model. Although both<br />

<strong>WiMAX</strong> and <strong>LTE</strong> leverage IP/SIP-based core networks, an IP Multimedia Subsystem (IMS) core is often implicit in an <strong>LTE</strong><br />

strategy because of its suitability for providing Service Consistency and Continuity (SCC) within the Vo<strong>LTE</strong> sub-model . Yet<br />

the adoption of <strong>LTE</strong> does not require a similar adoption of Vo<strong>LTE</strong> and, in cases where a service provider plans <strong>to</strong> continue<br />

offering fixed-only voice services through their existing Voice over Broadband (VoBB) model, there is no requirement <strong>to</strong><br />

migrate <strong>from</strong> the existing VoBB core <strong>to</strong> an IMS core.<br />

This whitepaper seeks <strong>to</strong> explain how a service provider can migrate <strong>from</strong> a <strong>WiMAX</strong> network <strong>to</strong> an <strong>LTE</strong> network in a seamless,<br />

secure and cost-efficient manner. Specifically, this paper reveals how a SIP core network <strong>from</strong> <strong>Sonus</strong> <strong>Networks</strong> can enable<br />

such a migration by allowing service providers <strong>to</strong> leverage the same core network elements whether deploying a <strong>WiMAX</strong>, <strong>LTE</strong><br />

or Vo<strong>LTE</strong> network.<br />

The <strong>Sonus</strong> SIP Core<br />

For more than a decade, <strong>Sonus</strong> <strong>Networks</strong> has built and deployed SIP core networks for many of the world’s leading service<br />

providers. The key network elements of the <strong>Sonus</strong> SIP core solution are proven in some of the most demanding voice networks<br />

and include the GSX9000 High-Density Media Gateway, SBC 9000 Session Border Controller, PSX Centralized Routing<br />

and Policy Server, SGX Signaling Gateway and ASX Feature Server. For the purposes of our case study, we’ll assume that<br />

Company A has a SIP core configuration that includes the following <strong>Sonus</strong> and <strong>Sonus</strong> Partner elements:<br />

> > <strong>Sonus</strong> SBC 9000 Session Border Controller (SBC) for connectivity <strong>to</strong> the PSTN and secure connectivity <strong>to</strong> the IP cloud<br />

> > <strong>Sonus</strong> PSX Server for centralized session routing and policy management<br />

> > <strong>Sonus</strong> SGX2000 signaling gateway for SS7 connectivity with the PSTN<br />

> > <strong>Sonus</strong> ASX server (including the ADS subscriber database server) for the management and delivery of essential Class 5<br />

features including call waiting, call forwarding, etc.<br />

> > <strong>Sonus</strong> Element Management System and DataStream Integra<strong>to</strong>r for centralized network management and billing<br />

mediation, respectively<br />

> > <strong>Sonus</strong> Insight Cus<strong>to</strong>mer Portal (ICP) for web-based subscriber provisioning of call features/services<br />

> > Foundry switching equipment for the interconnection of VoIP core elements<br />

> > Iperia Voicemail VX servers<br />

> > Radisys Convedia media server for various services (IP-PBX, IVR, contact center, etc.)<br />

<strong>Using</strong> the <strong>Sonus</strong> SIP Core <strong>to</strong> Manage Services <strong>to</strong> <strong>WiMAX</strong> Subscribers<br />

In our example, Company A has already deployed a remote <strong>WiMAX</strong> network for the purpose of delivering wireless broadband<br />

access that includes VoBB service <strong>to</strong> fixed (but not mobile) phones. Subscribers within the <strong>WiMAX</strong> network receive their voice<br />

services through a non-IMS SIP client based on the RFC 3261 SIP specification. Mobile phone services are made available <strong>to</strong><br />

these subscribers on a separate GSM network that partners with Company A. For their part, Company A does not provide any<br />

mobile voices services through its own network and has no immediate plans <strong>to</strong> do so, instead adopting the model of a Mobile<br />

Virtual Network Opera<strong>to</strong>r (MVNO).


The <strong>WiMAX</strong> network is connected <strong>to</strong> the <strong>Sonus</strong> SIP core network via a third-party Access Service Network (ASN) Gateway as<br />

depicted in the following illustration:<br />

SIP<br />

SIP<br />

<strong>WiMAX</strong><br />

BTS<br />

ASN Gateway<br />

SIP<br />

DSI-1<br />

ASX-1<br />

ADS-1<br />

PSX<br />

Slave<br />

D+<br />

SIP<br />

PSX<br />

PSX<br />

Slave<br />

D+<br />

Hybrid<br />

Trunking<br />

SIP<br />

IP Cloud<br />

ADS-2<br />

D+<br />

<strong>Sonus</strong><br />

VoIP Core<br />

Figure 1 – <strong>Sonus</strong> SIP core<br />

network connected <strong>to</strong> a<br />

remote <strong>WiMAX</strong> network<br />

DSI-2<br />

ASX-2<br />

SIP<br />

ICP<br />

Media Server<br />

EMS<br />

SGX2K<br />

PSTN<br />

TDM Cloud<br />

The <strong>WiMAX</strong> network currently provides wireless broadband data access and both residential and business voice services <strong>to</strong><br />

fixed, SIP-based phones. A key criterion of the <strong>Sonus</strong> SIP core is the ability <strong>to</strong> maintain service consistency between the two<br />

networks. That is, subscribers on the <strong>WiMAX</strong> network must share the same voice service experience as the VoIP and PSTN<br />

subscribers who access the SIP core directly for services. This is achieved in the above example by hosting all subscribers<br />

and services on two geographically distinct (but centrally managed) <strong>Sonus</strong> ASX/ADS servers.<br />

Migrating.the.<strong>WiMAX</strong>.network.<strong>to</strong>.an.<strong>LTE</strong>.network<br />

In its migration <strong>from</strong> <strong>WiMAX</strong> <strong>to</strong> <strong>LTE</strong>, Company A will need <strong>to</strong> preserve the same VoBB services for both sets of subscribers.<br />

During this migration, Company A has the option of connecting ASX/ADS-1 <strong>to</strong> their existing <strong>WiMAX</strong> network and ASX/ADS-2<br />

<strong>to</strong> the <strong>LTE</strong> network they’re building (see figure 2). Such a scenario gives Company A two alternative migration paths:<br />

1. Build an <strong>LTE</strong> network in the background and, when it’s ready for deployment, turn off the <strong>WiMAX</strong> network and turn on the<br />

new <strong>LTE</strong> network<br />

2. Deploy the <strong>LTE</strong> network and gradually migrate <strong>WiMAX</strong> subscribers <strong>to</strong> the <strong>LTE</strong> environment, keeping both networks<br />

operational in parallel for a period of time.<br />

SIP<br />

SIP<br />

<strong>WiMAX</strong><br />

BTS<br />

ASN Gateway<br />

SIP<br />

DSI-1<br />

ASX-1<br />

ADS-1<br />

PSX<br />

Slave<br />

D+<br />

SIP<br />

PSX<br />

PSX<br />

Slave<br />

D+<br />

Hybrid<br />

Trunking<br />

SIP<br />

IP Cloud<br />

WiMax <strong>to</strong><br />

<strong>LTE</strong> <strong>Migration</strong><br />

ADS-2<br />

D+<br />

<strong>Sonus</strong><br />

VoIP Core<br />

MME<br />

HSS<br />

DSI-2<br />

ASX-2<br />

SIP<br />

ICP<br />

Media Server<br />

EMS<br />

SGX2K<br />

PSTN<br />

TDM Cloud<br />

SIP<br />

E-UTRAN<br />

SG GW<br />

EPC<br />

SIP<br />

PDN GW<br />

Figure 2 – <strong>WiMAX</strong> <strong>to</strong> <strong>LTE</strong> <strong>Migration</strong> with Service Consistency via <strong>Sonus</strong> ASX


Securing.the.Border.Between.the.SIP.Core.and.the.<strong>LTE</strong>.Network<br />

Although the ASX Feature Server is a highly scalable and robust platform designed <strong>to</strong> support millions of subscribers, it is<br />

not designed <strong>to</strong> function as a border security or session management device. In order <strong>to</strong> provide load balancing and protect<br />

the SIP core network <strong>from</strong> Denial of Service (DoS) attacks and other security threats, <strong>Sonus</strong> recommends using the <strong>Sonus</strong><br />

SBC 5200 as an Access SBC between the SIP core and the <strong>LTE</strong> network (see figure 3). The <strong>Sonus</strong> SBC 5200 provides a<br />

proven, scalable solution for secure IP-<strong>to</strong>-IP interconnect between core and access networks, including:<br />

> Protection against DoS and Distributed DoS attacks<br />

> Media and signaling encryption<br />

> Load balancing and overload controls<br />

> SIP, H.323 and IPv4/IPv6 interworking<br />

> Media transcoding for HD and non-HD media codecs<br />

SIP<br />

SIP<br />

<strong>WiMAX</strong><br />

BTS<br />

ASN Gateway<br />

SIP<br />

DSI-1<br />

ASX-1<br />

ADS-1<br />

PSX<br />

Slave<br />

D+<br />

SIP<br />

PSX<br />

PSX<br />

Slave<br />

D+<br />

Hybrid<br />

Trunking<br />

SIP<br />

IP Cloud<br />

WiMax <strong>to</strong><br />

<strong>LTE</strong> <strong>Migration</strong><br />

ADS-2<br />

D+<br />

<strong>Sonus</strong><br />

VoIP Core<br />

MME<br />

HSS<br />

DSI-2<br />

ASX-2<br />

SIP<br />

For Throtting and<br />

DOS attack<br />

ICP<br />

Media Server<br />

EMS<br />

SGX2K<br />

PSTN<br />

TDM Cloud<br />

SIP<br />

E-UTRAN<br />

SG GW<br />

EPC<br />

PDN GW<br />

SIP<br />

Figure 3 – <strong>WiMAX</strong> <strong>to</strong> <strong>LTE</strong> <strong>Migration</strong> with Service Consistency<br />

via ASX and Security via Access SBC<br />

But.I.Thought.You.Needed.an.IMS.Core.<strong>to</strong>.Deploy.<strong>LTE</strong>?<br />

In our example, Company A has elected not <strong>to</strong> deliver mobile voice services through the <strong>LTE</strong> network but will instead<br />

continue <strong>to</strong> deliver the same fixed-line VoBB services that are already offered through the <strong>WiMAX</strong> network. Where mobility is<br />

not a requirement, Vo<strong>LTE</strong> and VoBB are identical in functionality, and thus can utilize the same SIP core network (see figure<br />

4). Company A has elected instead <strong>to</strong> enter in<strong>to</strong> an MVNO relationship with a third-party GSM network opera<strong>to</strong>r, and no IMS<br />

core is required because Company A is not concerned with managing the mobile handoff between the GSM and <strong>LTE</strong> networks.<br />

SIP<br />

E-UTRAN<br />

MME<br />

EPC<br />

HSS<br />

NOTE: In cases where mobility is a requirement, Vo<strong>LTE</strong> should be deployed with a 3GPPdefined<br />

IMS core network in conjunction with a legacy GSM network. This configuration<br />

provides not only the service consistency between the IMS core and GSM access<br />

networks, but also provides the requisite service continuity as mobile subscribers roam<br />

between <strong>LTE</strong> and non-<strong>LTE</strong> coverage areas.<br />

For Throtting and<br />

DOS attack<br />

SG GW<br />

SIP<br />

PDN GW<br />

DSI-1<br />

ASX-1<br />

ADS-1<br />

PSX<br />

Slave<br />

D+<br />

SIP<br />

PSX<br />

PSX<br />

Slave<br />

D+<br />

Hybrid<br />

Trunking<br />

SIP<br />

IP Cloud<br />

ADS-2<br />

D+<br />

<strong>Sonus</strong><br />

VoIP Core<br />

Figure 4 – <strong>Sonus</strong> SIP Core with Access<br />

SBC Deployed with <strong>LTE</strong> network<br />

DSI-2<br />

ASX-2<br />

SIP<br />

ICP<br />

Media Server<br />

EMS<br />

SGX2K<br />

PSTN<br />

TDM Cloud


Adding.Mobility.<strong>to</strong>.the.<strong>LTE</strong>.Network.via.an.IMS.Core.Network<br />

Since we’ve introduced the notion that Company A will partner with a third-party GSM opera<strong>to</strong>r <strong>to</strong> deliver mobile services,<br />

let’s take it <strong>to</strong> the next logical step and imagine that Company A would like <strong>to</strong> bundle those services in<strong>to</strong> a continuous<br />

subscriber experience. This is a more common Vo<strong>LTE</strong> scenario and will require an IMS core architecture <strong>to</strong> provide a Service<br />

Consistency and Continuity (SCC) framework <strong>to</strong> manage sessions as they move between the core network, <strong>LTE</strong> network and<br />

the third-party GSM network.<br />

Fortunately for Company A, <strong>Sonus</strong> SIP core elements are designed <strong>to</strong> transition seamlessly in<strong>to</strong> an IMS architecture (see<br />

figure 5), fulfilling key functions within the IMS core as follows:<br />

> The <strong>Sonus</strong> SBC 5200 which, as an Access SBC, provides SIP interoperability between the IMS and <strong>LTE</strong> networks and can<br />

serve multiple, additional roles within the IMS architecture including:<br />

• Proxy Call Session Control Function (P-CSCF)<br />

• Access/Core Border Gateway Function (A/C-BGF)<br />

• Access Transfer Control Function (ATCF) and IMS Access Gateway (IMS-AGW) for voice call continuity<br />

• Emergency CSCF (E-CSCF) for E911 and other emergency services<br />

> The <strong>Sonus</strong> ASX Feature Server, which can be converted in<strong>to</strong> a Telephony Application Server with a simple software<br />

upgrade <strong>to</strong> support:<br />

• The IMS Service Control (ISC) interface <strong>to</strong> the Serving CSCF (S-CSCF)<br />

• Integration with the IMS core<br />

• The Sh interface <strong>to</strong> the <strong>Sonus</strong> ADS database or, if desired, for migration <strong>to</strong> a Home Subscriber Server (HSS) database<br />

> The <strong>Sonus</strong> SBC 9000, which can be upgraded via software <strong>to</strong> serve the roles of:<br />

• Media Gateway (MGW) and Media Gateway Controller (MGCF)<br />

• Interconnect Border Control Function (I-BCF) and Interconnect Border Gateway Function (I-BGF)<br />

> The <strong>Sonus</strong> PSX Centralized Routing and Policy Server, which can be upgraded <strong>to</strong> serve the Border Gateway Control<br />

Function (BGCF) between the IMS core and the circuit-switched GSM network<br />

> The <strong>Sonus</strong> SGX Signaling Gateway, which would continue <strong>to</strong> act as an interconnect device <strong>to</strong> the SS7 network with no<br />

upgrade required<br />

In addition, <strong>Sonus</strong> works with partners <strong>to</strong> bring in the necessary IMS pieces for a best-of breed solution including:<br />

> Radisys Convedia Media Server<br />

> Service Consistency and Continuity Application Server<br />

(SCC AS)<br />

HLR<br />

SMSC<br />

> Interrogating CSCF (I-CSCF)<br />

> Serving CSCF (S-CSCF)<br />

IMS-SIP<br />

GSM<br />

BSC/BTS<br />

MSC<br />

3rd Party<br />

Mobile CS<br />

Core<br />

ISUP or BICC<br />

or SPI-I<br />

IMS SIP<br />

ATC/AGW,<br />

P-CSCF, C/A-BGF<br />

IMS SIP<br />

TAS AS<br />

SCC AS<br />

BGCF<br />

S-CSCF<br />

<strong>Sonus</strong> IMS Core<br />

MGCF/MGW and<br />

I-BCF/I-BGF<br />

SIP<br />

IP Cloud<br />

<strong>LTE</strong> <strong>to</strong> 2G/3G<br />

Network<br />

I-CSCF<br />

SGX2K<br />

PSTN<br />

TDM Cloud<br />

MME<br />

HSS<br />

PCRF<br />

For Throtting and<br />

DOS attack<br />

HSS<br />

Media Server<br />

IMS-SIP<br />

Non-IMS<br />

SIP<br />

E-UTRAN<br />

SG GW<br />

EPC<br />

PDN GW<br />

Figure 5 – <strong>Sonus</strong> IMS Core with Vo<strong>LTE</strong> via <strong>LTE</strong> network (fixed) and Third-Party<br />

GSM Network (mobile)


Tying It All Together: <strong>Sonus</strong> Global Services<br />

Over the years, <strong>Sonus</strong> Global Services has developed best practices for the effective migration of communications networks<br />

that take in<strong>to</strong> account network planning and architecture, subscriber data migration , SBC migration and other key technical<br />

considerations. <strong>Sonus</strong> Network <strong>Migration</strong> Services are designed <strong>to</strong> help service providers seamlessly move legacy systems<br />

on<strong>to</strong> new platforms and quickly reach ROI-driven miles<strong>to</strong>nes. Each migration engagement is led by a senior <strong>Sonus</strong> engineer<br />

and backed by a world-class team of network engineers with specialized skills in network design, subscriber and trunk<br />

migration, PSTN signaling interconnection and network security.<br />

<strong>Sonus</strong> Network <strong>Migration</strong> Services include:<br />

> > Subscriber data migration, integration and configuration<br />

> > Risk management rollback procedures<br />

> > Signaling, gateway ad call routing design modifications<br />

> > Legacy equipment provisioning modifications<br />

> > SS7/C7 signaling link installation and migration<br />

> > Class 3/4/5 trunk installations and migration<br />

Conclusion<br />

<strong>Sonus</strong> <strong>Networks</strong> provides a cost-efficient and seamless migration path <strong>from</strong> <strong>WiMAX</strong> <strong>to</strong> <strong>LTE</strong> networks through its unique SIP<br />

core architecture. By leveraging existing <strong>Sonus</strong> SIP core network elements, service providers can protect their investments in<br />

hardware, architecture and internal skill sets. In addition, the <strong>Sonus</strong> solution allows service providers <strong>to</strong> have more flexibility<br />

with their <strong>LTE</strong> deployment including:<br />

> > The ability <strong>to</strong> run <strong>WiMAX</strong> and <strong>LTE</strong> networks in tandem using the service consistency features of the <strong>Sonus</strong> ASX server<br />

> > A secure border between the <strong>LTE</strong> and SIP core networks via the <strong>Sonus</strong> SBC 5200<br />

> > A simple, seamless migration <strong>from</strong> SIP core <strong>to</strong> IMS core that supports Service Consistency and Continuity.


<strong>Sonus</strong> <strong>Networks</strong> –<br />

North American Headquarters<br />

4 Technology Park Drive<br />

Westford, MA 01886<br />

U.S.A.<br />

Tel: +1-855-GO-SONUS<br />

<strong>Sonus</strong> <strong>Networks</strong> – EMEA Headquarters<br />

56 Kings<strong>to</strong>n Road<br />

Staines, TW18 4NL<br />

United Kingdom<br />

Tel: +44 207 643 2219<br />

<strong>Sonus</strong> <strong>Networks</strong> – APAC Headquarters<br />

1 Fuller<strong>to</strong>n Road #02-01<br />

One Fuller<strong>to</strong>n<br />

Singapore 049213<br />

Singapore<br />

tel: +65 6832 5589<br />

<strong>Sonus</strong> <strong>Networks</strong> – CALA Headquarters<br />

Mexico City, Campos Eliseos Polanco<br />

Andrés Bello 10, Pisos 6 y 7, Torre Forum<br />

Col. Chapultepec Morales, Ciudad de México<br />

Mexico City, 11560 Mexico<br />

Tel: +52 55 36010600<br />

The content in this document is for informational purposes only and is subject <strong>to</strong> change by <strong>Sonus</strong> <strong>Networks</strong> without notice. While reasonable efforts have been made in the preparation of this publication<br />

<strong>to</strong> assure its accuracy, <strong>Sonus</strong> <strong>Networks</strong> assumes no liability resulting <strong>from</strong> technical or edi<strong>to</strong>rial errors or omissions, or for any damages resulting <strong>from</strong> the use of this information. Unless specifically<br />

included in a written agreement with <strong>Sonus</strong> <strong>Networks</strong>, <strong>Sonus</strong> <strong>Networks</strong> has no obligation <strong>to</strong> develop or deliver any future release or upgrade or any feature, enhancement or function.<br />

Copyright © 2012 <strong>Sonus</strong> <strong>Networks</strong>, Inc. All rights reserved. <strong>Sonus</strong> is a registered trademark, GSX9000, SBC 5200, SBC 9000, PSX, SGX2000 and ASX are trademarks of <strong>Sonus</strong> <strong>Networks</strong>, Inc.. All other<br />

trademarks, service marks, registered trademarks or registered service marks may be the property of their respective owners.<br />

Printed in the USA 05/12<br />

WP-1163 Rev. B

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!