Control and Management Project

Today’s networks are heterogeneous by nature. They may not only be multi vendor, but may also utilise many transmission and control plane technologies. In a network you may encounter different equipment using IP, Ethernet, SDH or DWDM transmission technologies. You may also find many management domains. Providing a channel across one or more networks of this kind is not trivial and can take significant time and effort.

Generalised Multi Protocol Label Switching (GMPLS) includes a range of control plane protocols created to extend the concepts of MPLS in order to address the aforementioned issues.

There are three control plane models available. Each model determines how much visibility a client node, such as a router, has into the optical core or transport network. The first model is a user-to-network interface (UNI), which is often referred to as the overlay model and was created by the Optical Internetworking Forum (OIF). The second is known as the peer model and was created by the Internet Engineering Task Force (IETF). The third option is called augmented; it's a hybrid alternative and is usually a proprietary technology.

The use of a control plane has the potential to underpin the development of services that provide faster configuration of network paths with associated capacity along with other traffic engineering features. To support this and other related development work a control plane has been established successfully, consisting of routers supporting both the overlay and peer models. The next step is to enrich the network with equipment utilising other transmission technologies; different options are currently being considered. This will enable and automate the provision of new services by JANET in the future.

The operation of control plane architectures relies on an overlay network that uses the Link management protocol (LMP) to communicate information between different network devices. Other protocols involved are the Resource Reservation Protocol - with Traffic Engineering extensions (RSVP-TE) and Open Shortest Path First with Traffic Engineering extensions (OSPF-TE). Figure 1 shows an abstract example of a control plane established path across SDH cross connects(XC's) and reconfigurable optical add-drop multiplexers (ROADM's).

 

Figure 1. An example of end to end provisioning between 2 routers using a control plane. Dashed lines indicate the control channels, whereas the provisioned path is shown using blue lines.
(Click on the image to see an enlargement)