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.