Acreo highlights GMPLS
tove.madsen@acreo.se
Generalized Multi-Protocol Label Switching (GMPLS) is a new technology that will add increased possibilities for dynamical multi-layer control to service providers and operators networks.
GMPLS will add functions like fast-reroute, protection switching and restoration, not only to the networking layers they traditionally belong to, but to any physical, link or network layer. Fast provisioning will be made possible by GMPLS and time can be heavily reduced compared to manually provisioning e.g. minutes instead of months when setting up new connections.
This will open up for a new set of customer services more or less on demand.
MPLS and GMPLS
The technology known as GMPLS originated from the MPLS technology. MPLS was created to meet several requirements in existing IP networks, e.g. traffic engineering using different types of already installed infrastructure technologies and service availability.
In MPLS the forwarding decision is taken based on a Label attached to the packet. To make this possible, signaling protocols were developed that based on the information created by the routing protocol established Label Switched Paths through the network. MPLS in itself is only specified for networks that forward IP packets or L2 frames.
It was soon found that this limitation is not necessary, the MPLS technology could be used to set up very different kinds of paths, e.g. TDM circuits or wavelengths. The ”only thing” needed was to specify technology specific labels and use the IP routing protocols and the MPLS signaling protocols to establish paths. It also becomes possible to create a common control plane for several networking layers.
It may be said that GMPLS is a subset of MPLS, but it is actually the same technology developed by two working groups (CCAMP and MPLS) in the IETF.
GMPLS as a common control plane
Extensive testing of GMPLS, the method for multi-layer control of the network, will be performed in the part of the Acreo National Test bed in Stockholm. The standardization of the GMPLS base functionality has been completed by the IETF, and the work in standard has started on specifying additional functions. One way of visualizing the GMPLS functionality is to look at four network layers: WDM, Ethernet, IP, and Application. In order to realize the real-time services in the network, which corresponds to the fourth layer “Application”, one also needs to deploy a dynamic control of all the lower layers.
The dynamic multi-layer control adds coordinated dynamic setup and tear down of connections as well as protection switching at all network layers. The method is to use MPLS at the third layer and the GMPLS extensions for the lower layer networks. The GMPLS extensions will thus be used to implement an optical control plane and the technology as such a multi-layer control plane.
ASON and GMPLS
The standards for automatically switched optical networks (ASON) are being developed by several different standards organizations, including IETF and ITU-T. ITU-T is developing requirements and architectures, while IETF develops the protocols needed. Some industrial forums are working on implementation agreements based on the standards specified by ITU-T and IETF. The protocols developed by IETF have been included as part of the ASON standards. However, the scope of the IETF and ITU-T solutions are different. The ITU-T solutions are ”limited” to request a service from one networking layer at the time over a UNI interface, while the IETF aims at creating a common control plane for all layers. (See right hand figure.)
In the Acreo National Broadband Test bed one of the primary goals in the control plane testing is to test the multi-layer control mechanisms as specified in the IETF. Later Acreo will do comparative test between the two approaches.
MPLS and GMPLS deployment
MPLS is a widely deployed technology. One of the major applications for service providers is to deliver L3 VPNs based on their MPLS enabled IP networks. Today all major service providers use MPLS.
GMPLS, as a control plane for the optical layer, is just on the verge to be deployed.
Advanced technology testing
The GMPLS interoperability testing at Acreo has so far included testing of equipment from Lumentis and Juniper, as well as connecting the GMPLS test beds at Acreo and KTH. The results from the Lumentis and Juniper test are available at www.lumentis.se/pdf/GMPLS-interop-test-whitepaper-A.pdf. The test was demonstrated at the ECOC 2004.
Acreo and TS-lab at KTH in cooperation are extending the GMPLS test bed network in order to test e.g. fast re-route, restoration and protection switching. In the first step equipment from Lumentis and Juniper will be used. Shortly equipment from other vendors will be added.
The Acreo National Broadband Test bed is a unique test bed with equipment from several vendors. These are tested in long term tests, with real end-users constantly giving feedback on the services and the service quality. One idea guiding the setup of the test bed is that services and functions included in the network shall continue to be offered by the test bed. It is anticipated that equipment added to the test bed will stay in the test bed as long as it is necessary to perform exhaustive testing.
EU-projects
The plan includes establishing connectivity to other European ASON and GMPLS test beds through the EU-project MUPBED. The main goal of MUPBED is to integrate and validate, in the context of user-driven large-scale test beds, state-of-the-art ASON/GMPLS technology and network solutions as enablers for future upgrades to European research infrastructures. As a specific example GRID implementations in an ASON/GMPLS enabled network will be tested using a PAN European test bed that consists of our Acreo test bed and test beds in Berlin, Northern Italy and Spain.
Another EU-project (NOBEL) works on requirements and architectures for the next generation ASON/GMPLS networks. Acreo is active in this project, and some of the testing of these architectures will be done in the Acreo multi-vendor network.
Standards
Acreo is active in the IETF and making critical contributions to the standards development. Currently Acreo employees hold positions as chairman for the MPLS working group and secretary in the CCAMP working group.
Seminars
Acreo has taken the initiative for a seminar series on GMPLS that has been running over the last two years. Several of the world leading experts on MPLS and GMPLS have made presentations at those seminars, including Kireeti Kompella and Adrian Farrel (co-chairs of the CCAMP working group at the IETF) and other international and Swedish experts.
GMPLS for the future
GMPLS promises to increase the possibilities for Operators and service providers to effectively deliver next generation services. GMPLS will make it possible for vendors to build new and effective solutions.
Acreo intends to continue expanding the test environment with equipment from new vendors, and create a world leading testing possibility for both vendors and operators.