GMPLS Working principle

At present, telecom enterprises are seeking to integrate IP and optical network technology, in order to develop efficient advanced business. The first thing to overcome is the high complexity of IP services that are designed to support voice and fixed-circuit multi-tier architectures, resulting in the need for a control plane that extends from Layer 3 IP to layer 1.

The goal of the GMPLS (Universal Multiprotocol Label Switching) technology is to cater to this need, and to extend the intelligence of the network, from the edge devices of the network to the core devices, and back to the edges, under a unified control plane.

As an IETF standard in the proposal, GMPLS is still in development, and it is estimated that it is unlikely to be heavily applied within a year or two. In fact, this technology is not a new technology, because it is built on the development and standardization of the many results of MPLS, MPLS through the replacement of ATM and Frame Relay devices to monitor network transmission of the project to simplify the network structure.

GMPLS Working principle

MPLS can improve the size and QoS of IP by generating virtual LSP (tag switching path) on a LSR (tag switched router) network. One of the enhancements relative to Mpls,gmpls is the ability to connect at the layer 1 level.

GMPLS has two application models: overlay model and matching model. In the overlay model, also known as uni, routers are a client of the fiber domain, only directly with neighboring fiber nodes, and the actual physical optical path is determined by the optical network rather than the router.

In the matching model, the IP/MPLS layer acts as an exact match for an optical transport layer, especially if the IP router can determine the entire path of the connection, including through a fibre optic device.

Regardless of the matching model or the overlay model, the goal of GMPLS is to extend the MPLS range from the router to the fiber domain, and its transport decision is based on the time slot, wavelength, or physical port (referred to as the "hint tag" in the GMPLS technology) rather than the line of information packets. GMPLS enables such a connected domain to be matched by supporting new kinds of LSR (including dense wavelength split multiplexer, plus/minus multiplexer, and fiber crossover).

GMPLS uses the IGP (internal Gateway Protocol) extension to support multiple connection types, including regular, non-packet and contiguous connections into the connection state database. If the nodes at either end of the connection are able to send and receive packets, GMPLS treats them as a regular connection, whereas they are connected as a non-packet. If a LSR generates and maintains a token exchange path, it can advertise the LSP into the IGP as a forward adjacency.

The key to this approach is that GMPLS defines the level of LSP, which enables the nesting of LSP to support the establishment of a communication trunk. This feature is similar to the MPLS support for tag stacks, and many small lsp can be aggregated into a large LSP. Gmpls and LSP work in much the same way, they are all a virtual expression of the physical path.

At the level established by GMPLS, LSP, which starts and terminates the packet switching node, is at the lowest level, and then gradually increments to the LSP that connects the TDM Exchange node, the Lamba switching node, and the Fiber Exchange node.

GMPLS is expected to help business providers dynamically deliver bandwidth and capacity, improve network resilience, and reduce operating costs. Businesses with new profit growth points such as fibre optic VPN may also be generated by GMPLS. Another predictable benefit is the GMPLS's support for open standards, which allows telecommunications providers to use the best standards-compliant equipment when building networks.

With the growth of IP communications and business, the demand for GMPLS will increase. But challenges also exist, and manufacturers need to build successful business cases that introduce GMPLS. And if companies want maximum efficiency, they also have to overcome the barriers that separate their own organization from fibre-optic transmission and IP management domains.