The Software Defined Operator

Network operators are reconsidering the architecture of their networks to better address the quickly evolving traffic and connectivity requirements. DT is one of them and in a recent presentation at the Bell Labs Open Days in Antwerp, Axel Clauberg gave his vision of the next generation ISP network. This is not the first presentation that DT employees give on their TerraStream vision for future networks. However, there are some points that are worth being noted.

A first objective is a radical simplification of the network with only a few remaining key technologies : IPv6, Tunnels, DHCP and 100 Gbps Ethernet. In the lower layers, ATM and SDH disappear, as well as solutions like OTN, GMPLS or MPLS-TP. The network layer is radically simplified as well. Only one data plane protocol, IPv6 is supported. IPv4 becomes a service that will be provided on top of the IPv6 network. Perhaps more surprisingly, MPLS and related protocols such as TE or FRR disappear as well. Traffic engineering seems to be less an issue with overprovisionning and apparently a full-mesh in the core. MPLS fast reroute is probably replaced by simpler techniques such as Loop-Free-Alternates.

A second objective is to more heavily rely on software to manage the network. DT is not the first operator to go in this direction, but it is interesting to note some evolution in their presentations. One year ago, Axel Clauberg gave another presentation on Revolutionizing Carrier Service Delivery using a Software Defined native IP Network. This presentation was partially questioning the utilisation of Openflow. Today, DT seems to have opted for IETF solutions such as YANG and NetCONF form tail-f systems.

A third objective is to leverage internal datacenters to provide advanced services, including access to IPv4 Internet, VPNs (based on L2TPv3 instead of MPLS), … Most of these services will be provided by software running on virtual machines. In this respect, DT seems to have opted for two open-source solutions as the building blocks for their Network Function Virtualisation (NFV) : KVM and openstack that they seem to be extending to better suit their requirements and usage of IPv6.

Although some tests have already been started, it will probably take several years before this vision of the Software Defined Operator will become a reality…