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White Paper Traffix Systems October 2011

Focus on the Control Plane for Optimal 4G Performance

The Emerging Centrality of Signaling as a Business Enabler

By Ben Volkow CEO Traffix Systems

CONTACT: info@traffixsystems.com

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Introduction

Deploying 4G networks is not simple and the delivery of 4G advanced services and better mobile

broadband is fraught with obstacles. Success however will come to those visionaries who begin with the

premise that this is a new world order, or at least as far the network is concerned. If in 3G the control

plane was left in the hands of network architects and planners, in 4G the control plane has gained

supreme importance and must be given greater priority in setting network and business strategies. If once

control plane signaling was triggered with the onset of a phone call, in 4G signaling is triggered up to 50

times more and creates hundreds of different use cases for service providers.

If once there were less than a dozen signaling usage scenarios focused on one centric service, now in 4G

there are dozens of new use cases, hundreds of services, and an unprecedented number of signaling usage

patterns for policy control and enforcement, end-to-end Qi’s over roaming, legacy to 4G interworking

functions, and many more. Furthermore, the introduction of Diameter control and signaling protocol in

4G, an IP-based protocol, has completely revolutionized the control plane and introduced innovative ways

to control and manage signaling messages.

In short, the control plane has been elevated to be the enabler for launching strategies for reliable, top

performing data service to unlimited masses of subscribers. This is the inflection point in which service

providers must rise to meet the challenges in signaling management by understanding the centrality that

the control plane plays in the network in 4G to achieve both operational and business goals. Despite the

promises of sophisticated services, huge bandwidth, tiered pricing, tuned policy and charging schemes, 4G

technologies cannot be operational until service providers change their perception on signaling

management and make it the number one priority. This paper will delve into the reasons why the time is

now for this juggling of priorities, and also what solutions are required to relate to signaling as the driver

of a network’s health.

The wide adoption of always on, always connected, mobile Internet devices creates a massive surge in

signaling as mobile broadband use escalates dramatically. To reach this understanding, we need to outline

4G pain points and their causes. One pain point relates to the way smartphones create signaling.

Smartphones are built to be user-friendly, however it’s battery-saving mechanism that activates signaling

surge upon touch is not necessarily network friendly, and the many and rapid opening and closing of

network connections, results in high volumes of signaling.

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Another pain point is the growing fragmentation of network architecture that leads to a spaghetti

configuration of elements and connections. There is a growing number of network functionalities defined

in 4G specifications. When coupled with the increasing number of network data centers due to the

growing number of smartphone subscribers, the combination escalates fragmentation and complexity of

the network and the control plane. In addition, many new applications such as mobile games, presence

services, and some networking applications leave the mobile device constantly on, generating constant

signaling, which is hard to manage due to the mobility side of the usage patterns. These pain points, in

addition to others, cause major signaling problems; so major that they can lead to network outages.

In this white paper we will address how service providers can take advantage of 4G Diameter signaling

solutions to avoid these problems. Once under control, service providers will be free to concentrate on

leverages the benefits of 4G technology and advanced services to increase revenues and profitability.

Service Providers’ Challenges on the Path to 4G

Diameter signaling in 4G networks is expected to grow by 50 times more in comparison to the volume of

signaling in existing legacy networks. There are a number of reasons behind this growth, starting from the

nature of Diameter protocol which is based on IP/TCP (or SCTP).

Another reason is the skyrocketing usage of mobile data with its myriad of applications, each one with its

own unique set of signaling needs. No longer is the network “voice-centric”- and voice hardly creates

signaling. In contrast, mobile applications are signaling hungry, creating far more signaling messages,

sometimes hundreds per session, and each application has specific signaling behaviors.

The gradual move to VOIP and Vo4G which is expected to arrive later in the decade will increase signaling

even more due to the need and complexity of maintaining Qi’s (quality-of-service) over packet switched

calls. All this massive signaling growth creates major network management and scalability issues and need

to be handled properly.

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Use Cases to Handle the Massive Growth in Signaling

1. Legacy/4G Cross Connectivity

The move to 4G is gradual as it involves the addition rather than the replacement of elements. During the

transition period, many service providers are using some of their existing working network legacy

functionalities as part of their 4G evolution. This gradual move enables faster service launch and better

cost control. However, retaining existing legacy functionalities leads to connectivity issues. Pre-4G

elements are using legacy protocols such as RADIUS, LDAP, HTTP, SS7, SOAP, while the new 4G network

functionalities are using Diameter interfaces. Diameter and the legacy protocols cannot work together

without the inclusion of gateways.

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2. Multi-vendor Connectivity

To say that 4G core architecture is highly fragmented is an understatement. Simply put, never before in

the history of telecom has network fragmentation reached such heights with multitudes of differently

defined functionalities deployed together to build the 4G network.

Most service providers choose the best-of-breed approach in building their 4G networks and fill in the

wide range of various functionalities as needed. This approach is a double-edge sword: the extreme

flexibility offered by Diameter protocol enables every vendor to create his own specific flavors, yet it

creates serious interconnectivity issues between the wide range of vendors and network functionalities.

3. Scalability

The spiraling increase in bandwidth demand points to the growing importance of network and signaling

scalability as part of a service provider’s strategy. The scalability issues in the Diameter control plane are

derived both from the increase in data traffic as well as from the increase of signaling from new services,

applications, QoS and policy and new charging models. Also the increased fragmentation of the control

plane into a growing number of data centers and different network functionalities adds to the complexity

which can slow down network operations.

As a result, service providers must be careful to scale up their network in a way that will accommodate the

wide set of new requirements in the most cost-effective approach possible. To enable cost-effective

network scalability, fast service introduction and effective data traffic management, service providers

must view the Diameter control plane as the focal part in its architecture strategy. By concentrating on the

control plane, service providers can achieve linear, non-disruptive scalability, high availability and service

assurance by efficient use of the relevant network elements in 4G networks.

Scalability needs to be looked at as a business decision, not just at the technological level in supporting

failover, redundancy, SLAs, policy enforcement and subscriber stickiness. Scalability in 4G needs to be

virtually unlimited to enable the network to grow as needed and only in a manner that protects and

promotes profitability.

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4. Network Architecture

4G architecture is continuing the trend started earlier by the 3GPP when they introduced IMS technology

with wider horizontal and functional fragmentation meaning many different logical functionalities, each

one defined to handle a very specific purpose. The control plane and signaling have never been more

strictly defined and fragmented than before. This causes increased network complexity due to the

constant growth of the number of network components in addition to the complex and high number of

interfaces and interactions between them. This phenomenon is not limited to the 4G core network. It is

also found in inter-network connectivity between different service providers, across GRX and IPX domains

where the volume of Diameter signaling, interfaces and network functionalities involved in the different

tasks is also growing to support 4G requirements.

Another issue affecting network architecture is the growing number of data centers that have been

established by large carriers to save costs and improve performance by maintaining data centers close to

the subscribers. However, having an increased number of data centers leads to new use cases and

increasingly complex connectivity between the different data centers.

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5. The Telco-grade Holy Grail (i.e. Network Assurance, Redundancy, Reliability & Failover)

The fragmented network architecture introduced by 4G fueled by huge increases in signaling sessions

creates extremely difficult technical challenges for service providers. Furthermore, given that the 3GPP

(3rd Generation Partnership Project, a collaboration of telecommunications associations) has not

addressed signaling connectivity needs in their 4G specifications, and has proposed point-to-point

connectivity between all the network functionalities (except for an optional DRA between PCRFs and

PCEFs), efforts to achieve the “telco-grade” stamp of certification have been obstructed. This means that

service providers are hard pressed to achieve network assurance, redundancy, reliability and failover

protection that without them, they cannot launch their 4G networks and services.

6. New Trends in Data Usage

Just look out on the street and you can see that the way users consume data with advanced devices and

smartphones is different than in former times. The difference is not only in the scale and magnitude of

data usage but also in the usage patterns. If in the past users were opening a connection and closing it,

with today’s smartphones and advanced devices, multiple sessions are being opened and left open,

particularly in apps such as games and social community sites. When added to other 4G advancements

such as end-to-end policy and enforcement, tiered charging plans, and other pricing schemes

unprecedented use cases are created, changing the game rules for service providers.

Help for Service Providers to Confront the Challenges on the Path to 4G

To overcome the many challenges potentially sabotaging a smooth path to 4G, service providers need to

have different signaling solutions deployed in their network architecture. Traffix has helped service

providers world over migrate to 4G with its Signaling Delivery Controller (SDC), the market’s only full 4G

signaling solution. Traffix SDC is a single product that consolidates Traffix robust, carrier-grade Diameter

Load Balancer, Diameter Router and Diameter Gateway solutions for maximum cost-effective scalability,

instant connectivity and comprehensive control of Diameter-based signaling networks.

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When service providers deploy the SDC, they benefit from the following functionality:

4G Signaling Gateway – Traffix SDC offers a full 4G signaling gateway with the ability to translate

between legacy protocols to Diameter. This enables the support of existing non-4G components or new

4G functionalities that do not fully conform to the latest 3GPP specifications by integrating them into the

architecture. Common usage scenarios are translations from/to RADIUS, LDAP, HTTP, MAP, CAMEL, GTP’

to/from Diameter. The Signaling Gateway can also translate Diameter connectivity between various

vendors, thereby bypassing and solving any interoperability issues between the different Diameter

implementations.

Diameter Router that includes a Diameter Routing Agent (DRA) – Traffix SDC offers full DRA

support. DRA is a central routing functionality that enables centralized network signaling management.

The DRA was standardized by the 3GPP as part of the 4G architecture. The DRA enables architecture

fundamentals such as redundancy, reliability, stickiness, scalability, performance and security. The Traffix

Diameter Router integrates an advanced contextual routing engine which enables full layer 4-7 signaling

routing and management based on combination of up to 12 different AVPs. Going far behind the standard

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requirements, the Traffix Router enables full dynamic control of the network inside the different data

centers and also in between and across them.

Diameter Edge Agent (DEA) – Traffix SDC offers enhanced DEA support. DEA is a central edge

network routing functionality standardized by the GSMA that enables cross network signaling

management for signaling interactions between different service providers domains, with full access

control, authentication and routing capabilities between the different domains.

Another important requirement of the DEA is to normalize incoming Diameter messages coming into the

network from external networks. When the DEA is located on the edge of the network it works to protect

and normalize the flow of messages. For example, if a problem arises between two networks' PCRFs –

both networks are protected from overflow or failover situations. Another example exists in roaming:

Signaling from roamers must be processed in a secure and safe manner inside the network. Of course, the

DEA needs to maintain the state for each one of those transactions so that the reply to the originating

source will be returned to its original format. It is truly a critical function in maintaining top network

performance.

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Network Visibility –With the increasing complexity of networks, the growing number of different

data centers and the best of breed approach, service providers introducing 4G networks are having a hard

time managing and understanding how their networks are operating and making sure the operation is

fully optimized. Traffix offers real time, statistical views into the network with the Traffix WideLens™

patented technology that enables transparency into the number of open sessions for each of the network

functionalities, timeouts, retransmissions and outages, real time alerting, and statistical view of network

behavior over time. By using WideLens™ service providers can gather different network signaling

transactions and group them together according to various criteria such as subscriber, rating group,

location or service to derive a better understanding of the operations, management and service of the

network.

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The Interworking Function (IWF) – The IWF was standardized by the 3GPP to support MAP to

Diameter translation to enable and support subscriber mobility management between legacy and 4G

networks. Traffix SDC fully supports 3GPP standards, and enables unlimited, cross generation roaming

between legacy and 4G networks.

Global Signaling Routing – Managing the signaling in a data center is not enough to meet service

providers’ 4G architecture requirements. Service providers need to have the ability to have a cross global

network, cross data centers management, redundancy and failover. Today’s networks usually employ a

hierarchical network design, consisting of a centralized network and multiple regional distributed sites

feeding into the centralized network. The centralized network is also typically split across multiple sites to

facilitate load distribution and latency requirements. The challenge service providers face as they deploy

Diameter signaling throughout the network is to support an architecture that can accommodate such

distributed architectures, while meeting carrier-grade high-availability standards.

By configuring a grid management “mesh” of the entire network consisting of a cloud-like network of

signaling routers across different data centers and sites, service providers benefit from centrally managed,

holistic, global network management where any data center can stand-in and replace the other

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automatically when needed. Traffix offers this comprehensive solution through its Global SDC for optimal

routing of signaling traffic without concern for network resource availability. This cloud-like configuration

for signaling meets large carrier's requirements for 4G network performance.

Summary

Networks with advanced Diameter solutions for routing, load balancing and connectivity have better

resilience and scalability of Diameter signaling. As a result, networks benefit from significantly better

signaling reliability and service continuity alongside the ability to support advanced services, policy and

charging schemes. Furthermore, service providers ultimately profit from simplified, virtually effortless

operations and maintenance support with reduced cost of operations.

That’s certainly great news for service providers, but it doesn’t stop there. Subscribers and roamers enjoy

improved quality of the user experience with a slew of advanced services and convenient price plans,

which lead to high customer satisfaction.

Despite the potential of many pain points on the path to 4G, there are advanced solutions to overcome

the challenges faced. Now is the time for service providers to meet the challenges in signaling

management by understanding the centrality that the control plane plays in the network in 4G to achieve

both operational and business goals.

In conclusion, for the sake of both network subscribers and service providers’ profitability, robust

Diameter solutions with innovative deployment scenarios are well worth the investment.

About Traffix

Traffix is the Diameter control plane expert since 2005 leading the market with a range of Diameter

products deployed at over 100 operators worldwide. Traffix supports telecommunications service

providers to build high capacity, high performance data networks for a cost-efficient path to 4G. For more

information, visit www.traffixsystems.com

Contact us: info@traffixsystems.com