Telco NFV is not about virtualizing the different telecom applications and simply deploying them on a couple of servers in any Data Center. There are many aspects to consider and an important key success factor for Telco NFV is to seamlessly provide connectivity between the telecom operator’s IP/MPLS network and their Cloud environment.
Over the last 15 years, telecom operators around the world have introduced IP/MPLS Network Infrastructure in order to cost efficiently address the growth of traffic and deploy new services. This transition, which started with the deployment of triple-play services, has since evolved to address enterprises services and support mobile broadband’s rapid growth with the introduction of LTE. The different IP/MPLS networks have evolved to cope with the traffic and service demand, and the most common service used is BGP-based L3 VPN.
Currently the biggest evolution for telco network infrastructure is the introduction of virtualization and SDN-NFV transformation. In order to benefit from the promise of NFV in terms of agility, there are two aspects related to connectivity that the Cloud environment supporting the Virtual Network Functions (VNF) needs to provide:
- Seamless interconnection with the existing IP/MPLS Network Infrastructure
- Integration with the Cloud environment to enable automation
For the first part, the most scalable approach is to extend the IP/MPLS encapsulation up to the virtual machines that are running the different VNFs. This can be achieved by using MPLS over GRE between the DC Gateways and the vSwitch connecting the different VMs. Connectivity between the vSwitch and the DC Gateway is then controlled by an SDN Controller using existing and well proven protocol such as BGP. An MP-BGP session is established between the SDN Controller and the DC Gateway in order to exchange L3 VPN and label information.
The figure above illustrates Dynamic and Seamless IP/MPLS Connectivity in the Cloud Environmentthe correspondence between the type of services offered by the telecom operator to their customer (mobile, fixed, enterprises…) and their network infrastructure.
In order to enable this seamless connectivity, a set of control protocols needs to be deployed between different elements. Such as the overall Orchestrator, the OpenStack Cloud Management Platform, the SDN Controller, the vSwitch and the DC Gateway. One element to be developed is the REST API between OpenStack Neutron and the SDN Controller.
At the recent OpenStack Summit in Vancouver, AT&T and Ericsson jointly presented an SDN-based L3VPN solution that uses this OpenStack Neutron and OpenDaylight integration. This work brings together OpenStack and OpenDaylight capabilities in to order enable telecom operator to deliver L3VPN connectivity up to any virtual machine.
The complete presentation can be seen on the OpenStack Summit website here.
Ericsson and AT&T are collaborating together with other parties in OpenDaylight, OpenStack as well as OPNFV to define the proper models, APIs and mechanisms that enable telecom operators to seamlessly provide connectivity between their existing IP/MPLS networks and their NFV Infrastructure. This can be seen as the foundation for the future telecom operator network Infrastructure.