When natural disasters like tropical storm Sandy hit, IP networks bring about a different challenge than traditional networks. Where network operators traditionally could block or throttle traffic after a storm to ensure congestion would not bring down networks, the status quo now is to have many elements of the network under the control of a 3rd party, which means operators cannot directly control all parts of their networks in a crisis.

Because IP invites many new methods for communicating, it also has to invite many new methods for managing the network. And as we see it, the network must be controlled at two different points: the packet network where the data flows, and the control plane where the signaling controls the sessions.

We also see two distinct forms of signaling, with signaling in the RAN and signaling at the core with Diameter. These forms of signaling serve different purposes. The signaling at the RAN typically establishes data session (or voice session if applicable), and signaling in the core uses Diameter to authorize and authenticate subscribers. Though the latter is not invoked as frequently as RAN signaling, it is just as critical to the operations of the network.

As proven during Sandy and other natural disasters, congestion of the core signaling network is a key concern operators have to address when friends and families flood lines in search of loved ones. When the core fails, nothing works, therefore making the core becomes a critical component in the network. This was also true within the SS7 domain, where operators also blocked traffic at the core level.

But, in using a point-to-point architecture, where the Diameter end-points are actually embedded within a network element, blocking of traffic could become difficult, if not impossible. That is attributable to the fact that congestion control can be applied only at the point at which the function resides. It’s well accepted, therefore, that a centralized approach to end-to-end core network congestion control is most effective.

The Importance of a Diameter Signaling Router in Crisis Situations

Geographic redundancy and traffic control is paramount to a robust signaling network that can survive any crisis. There exist countless examples of how the SS7 network survived calamities such as floods, earthquakes, fires, and even terrorist attacks. It was usually geographic redundancy and optimal routing managed through the core rather than the end points that made this possible.

In a Diameter world, the Diameter protocol itself does not inherently support automatic re-routing and disaster recover functions like SS7 did, but the same can be accomplished through a centralized routing function in the network core. That’s why a Diameter routing agent like our Diameter Signaling Router (DSR) is becoming so important to preventing core signaling outages during a crisis. The DSR ensures messages reach their destination through alternative routes known to the DSR. That means the messages so important to subscriber databases like the Home Subscriber Server (HSS) , policy servers (PCRF), charging systems and gateways will get through in times of disaster.

And most importantly, it means operators can continue to generate revenue from services requiring Diameter signaling, even in times of disaster.

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With the Olympic Games just around the corner, network engineers everywhere are asking the same question: ‘How big an impact will the Olympics have on wireless networks?’ The Olympics can serve as a microcosm of analogies to a bigger issue – the impact of data surges on Diameter signaling, especially where LTE coverage is available.

The Olympics pose an opportunity for service providers to monitor Diameter signaling traffic and analyze the trends for future engineering. In doing so, they have many points to consider:

For one, it will be interesting to see how the cellular networks perform in London. Though the packet network will be upgraded to support higher data rates, the signaling core will remain SS7, as LTE will not be implemented in time for the Games.

Two, the devices and the savviness around their use have only improved since the last Olympics in Beijing, so social media and mobile devices will be the primary media over which events will be viewed and information shared. Video usage will be off the charts in comparison to what was possible in China, where the first “digital” Olympics took place (albeit on far fewer channels than are available today). There’s no question the London Games will generate unprecedented amounts of video content via official and not-so-official channels, such as Olympic Committee YouTube channels and related Facebook, Twitter and other social media channels. All will see significant increases in their traffic as viewers in different countries elect to watch through their iPads and Smartphones.

NBC alone is expected to deliver 5,535 hours of programming, with HD programming available through broadcast channels. Additionally, NBC (and other broadcasters like the BBC) will provide live streams through various web sites and social media. While this may not have a direct impact on London mobile networks, there may be residual impacts on home networks where LTE is available, as social media connections will inevitably increase Diameter signaling –especially where connections are left on all day, and if policy is implemented to assure certain quality levels or to control congestion.

Another interesting point to ponder is the level of personalization that will emerge in these Olympics. For example, NBC will allow viewers to select what view of an event they want (i.e., what apparatus in a gymnastics event they want to see). That ability may generate a significant amount of video streams and hence a lot more signaling (albeit Diameter signaling as opposed to SS7 signaling).

In addition to watching the impact of actual video consumption, operators should watch closely the impact of WiFi, as roamers will have about 100,000 hotspots throughout London with which to alleviate roaming fees they’d otherwise incur on the mobile network.

In all, London will strive to provide 4 times the capacity than was possible in Beijing. With so many visitors and professionals covering the events (21,000 reporters converging on the city to cover the Games), every Gigabyte of capacity will count.

Not only should mobile operators consider the impact on London’s networks, but also the impact on their own networks, as fans not able to travel to London will watch their favorite athletes through the numerous online channels being made available to them.

With millions of Smartphones and tablets sold in the last several years (especially iPads and iPhones), expect a huge increase not only in data traffic but in signaling traffic as well.

As stated earlier, Diameter will be affected anywhere 3G or LTE is deployed. It’s just not clear yet how significantly. We suspect there are enough subscribers on LTE networks today to have an impact on any service provider’s network.

With so many variables to Diameter traffic engineering, it is impossible to put a number on the amount of Diameter traffic we will see just by evaluating data. Suffice it to say, however, there will be significant impacts on signaling as a whole, and where policy is implemented in 3G and LTE networks, that impact will be much greater.

By Matt McCann, Principal Architect

The Diameter protocol is widely used in 3G, IMS and LTE architectures to transport policy, charging, authentication and mobility management messages – traffic that will rapidly rise as mobile data usage increases.

To best manage the growth of Diameter traffic, operators are examining how to create a separate Diameter signaling infrastructure at the network core. The goal is to facilitate signaling between network elements, eliminating a mesh-like architecture of direct connections between endpoints such as mobility management entities (MMEs) and home subscriber servers (HSSs). This would relieve endpoints of handling all session-related tasks such as routing, load balancing, congestion control and failover management.

Initially, implementing an IMS or LTE network without a signaling core may be sufficient, but as traffic levels grow, the lack of a capable signaling infrastructure poses a number of challenges, including:

• Scalability: Each endpoint must maintain a separate SCTP association with each of its Diameter peers as well as the status of each, placing a heavy burden on the endpoints as the number of nodes grows.
• Congestion control: Diameter lacks the well-defined congestion control mechanisms found in other protocols such as SS7.
• Protocol mediation: Vendors are likely to use their own variants of the Diameter protocol based on how they believe a specific interface should be implemented. This implementation can vary slightly from those of another vendor, creating potential interworking issues when multi-vendor equipment is combined in one network, a common approach for operators that take a best-of-breed approach.
• Network interconnect: A fully meshed network is completely unworkable when dealing with connections to other networks because there is no central interconnect point. This also exposes the operator’s network topology to other operators and can lead to security breaches.
• Interoperability testing (IOT): Protocol interworking becomes unmanageable as the number of devices supplied by multiple vendors increases. With no separate signaling or session framework, IOTs must be performed at every existing node when a new node or software load is placed in service.
• Support for both SCTP- and transmission control protocol (TCP)-based implementations: SCTP-based elements cannot communicate with TCP-based elements unless they are upgraded or all of the elements support both protocol stacks.
• Subscriber to HSS mapping: When there are multiple HSSs in the network, subscribers may be homed on different HSSs. Therefore, there must be some function in the network that maps subscriber identities to HSSs.
• Policy and charging rules function (PCRF) binding: When networks require multiple PCRFs, operators must have a way to ensure that all messages and sessions associated with a particular user are processed by the same PCRF.

Centralizing Diameter routing creates a signaling architecture that reduces the cost and complexity of the core network and enables core networks to grow incrementally to support increasing service and traffic demands. It also facilitates network monitoring by providing a centralized vantage point in the signaling network. A centralized Diameter router is also the ideal place to add other advanced network functionalities like address resolution, Diameter interworking and traffic (roaming) steering.

The rapid uptake in smartphones and data-hungry applications such as mobile video and social networking has set the stage for the mobile data explosion. Operators are being forced to evolve their networks to higher bandwidth IP networks such as long term evolution (LTE) to handle the surge in mobile application bandwidth demands.

Attend this free Tekelec webinar  on March 17 to learn more about the path to LTE and how operators can create an intelligent network core and create new revenue opportunities. Topics of discussion include:

• Factors driving the mobile data explosion
• Scaling the control plane in packet core networks
• Managing and monetizing mobile data services

Register today.

By Amir Majlesi, Technical Sales Manager

Top 5 operators Deutsche Telekom, Orange, Telecom Italia, Telefonica and Vodafone announced their decision at MWC11 in Barcelona to commercially launch Rich Communication Suite (RCS) across several European markets from late 2011. Other MNOs are expected to join this initiative. The launch will be based on a new adapted version of RCS Release 2.0, which is called RCS-e, and will be based on the use across networks of IP Multimedia Subsystem (IMS) technology, an architectural framework for delivering IP multimedia services. The idea is that mobile customers can use instant messaging (IM), live video sharing and file transfer simultaneously during calls across any device on any network operator in a simple and more intuitive way. This renewed focus is based on results from RCS trials to date and a better understanding of where operators can further enhance their offering to deliver more value to customers and complement established 3rd party services.

This is a pragmatic approach by MNOs to reduce time-to-market and stimulate roll-out of rich communication services in order to combat competitive pressures from over-the-top players. So far deployment of RCS faced two hurdles: unavailability of RCS-ready handsets and complexity of RCS interoperability between MNOs. The RCS-e initiative addresses both obstacles. RCS-e specification reduces terminal conformance requirements to core functionalities in order to ensure availability on low end devices and, therefore, boosts the market penetration curve. Strong endorsement of G5 MNOs pushes now the handset vendors to expedite introduction of RCS-ready phones or to open up their platforms to allow seamless integration of 3^rd party RCS clients into the phone’s native address book. Even Apple cannot continue to be silent about RCS anymore. On the other hand, RCS-e specification focuses on easy interoperability by making “social profile information via presence“ an optional feature. The fundamental mechanism that enables RCS-e is service or capability discovery using SIP OPTIONS. This discovery mechanism is important in that it allows users to determine what services are available before calling and allows operators to roll-out new agreed services to their own schedule. RCS-e provides an adaptive framework for deployment of additional services such as presence, social networking and location base services (LBS).

Moreover, this initiative fosters development of RCS based apps and a growing RCS ecosystem. We expect to see more innovative apps using enriched services that RCS makes possible. Think about for example how social networks, premium content providers, advertising firms, gaming or e-commerce businesses can benefit from rich services such as IM, video sharing and file transfer interoperable between all devices and networks.

Tekelec welcomes RCS-e and looks forward to working with operators on this initiative.

The Tekelec Blog will provide insights on the mobile data explosion and beyond. Increasing bandwidth demand and changing consumer behaviors are causing service providers to migrate to more flexible and cost-effective all IP network architectures including LTE and IMS. This transition requires them to manage hybrid network operating environments – with disparate  network technologies, handsets, and consumer expectations – for years to come.

The blog relies on the deep experience and expertise of a team of technologists and thought leaders within Tekelec. Check back periodically for updates.