Diameter routing

A brief look into the future of the Diameter Routing Agent

1 min. read


Diameter Signalling is effectively the language used by software and servers within the core of the Long Term Evolution (LTE) network. When LTE Networks and the introduction of Diameter Signalling went live in 2010, it became apparent there was a need for a Routing function to control it. Diameter Routing Agents are responsible from the beginning to forward and control the signalling packets in the mobile core network. With the evolution and introduction of new innovative services in LTE throughout the years, the role and functionality of the DRA has changed considerably. Early deployments of first-generation DRA were responsible for:

  • Static management of centralized routing
  • Overload protection, Ingress & Egress throttling
  • Basic AVP level mediation and manipulation
  • Enabling LTE roaming
  • Admission / Access control

The Next Generation Diameter Routing Agent

Today, many service providers have a first-generation DRA live in their network, capable and limited to handle above functionalities while running on dedicated expensive hardware. In many installations, certain vendors announced their customer DRA is End of Sales and will become End of Support in the future. This has consequences for mobile operators as there are :

  • Future capacity extension will not be possible due to End of Sales
  • No further developments for new features on existing DRAs
  • DRA swap and migration should be planned

Service Providers are rapidly discovering that these DRAs cannot meet the multi-source, multi-destination signalling challenge they face. Static routers perform effective signalling control only in a static environment where everything is known in advance.

The consequential risk is that as a result, new services may take longer to be supported, leaving operators trying to find workarounds that even if they succeed in the short term, ultimately put service availability at risk.

Features required for the next DRA

Next to Mobile/Fixed convergence, Security is a hot topic at the Service Providers setting complete new requirements to the Diameter Routing Agent. Subscribers should experience the same services, QoS and security in each connected domain. To achieve this, interworking between different signalling protocols like Radius & HTTP is a requirement.

This is the exact reason why a lot of the current active DRAs require an urgent upgrade or replacement. The Next Generation's Diameter Routing Agent should include advanced features such as :

  • Protocol Interworking with legacy and IT protocols such as SS7, Radius, HTTP, ENUM, etc.
  • Diameter Firewall compliant to GSMA FS.19 incl. Cat. 0-3 filtering mechanisms
  • Intelligent Routing based on several parameters in a dynamic environment
  • Subscriber Lookup Function (SLF), based on external data sources like LDAP, HTTP, ENUM, etc.
  • Advanced message mediation and manipulation to provide flexibility and vendor independency.

As the CAPEX and OPEX cost is under pressure at the Service Providers, hosting multiple functions like DRA, STP and interworking within the same network component could help to reduce this as much as possible. This will also imply an architecture simplification resulting in lower operational cost and an easier way of maintaining their network. Also a clear roadmap towards 5G should be available to host the Security Edge Protection Proxy (SEPP) within the DRA and with the same capabilities as the DRA.

Nomios has a next generation DRA in it’s portfolio that delivers the above functionalities and executed many first generation DRA swaps without any traffic interruption. Next to that it is a pure software solution that can run on COTS hardware or on any available virtualization platform as VMware, KVM, Xen, etc. Also it operates as a combined STP/DRA through a single software engine, and it is future 5G compliant as a SEPP through HTTP/2 support.

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