Comparison between Intelligent Optical Network and Traditional Optical Network. Principle of Intelligent Optical Network, страница 4

2.  CSPF

After the topology information of the whole AREA service plane is collected through the OSPF protocol, the CSPF algorithm is used to search for the service path. The constrained conditions to consider include the maximum and available link bandwidth, shared link risk group, inevitable nodes (or avoidable nodes), SLA, optical path distance, and so on.

The paths calculated by CSPF algorithm include both the end-to-end service working path and the corresponding service protection path. To make the protection efficient, there should be no node or link intersection between the two end points of the protection path and working path. Once the working path is worked out, you can calculate the protection path in a simple way by cutting off all nodes and links (excluding the source and destination nodes) covered by the working path and then finding a path connecting the source and destination in the simplified network.

As there are many constrained conditions involved in the calculation, the efficiency of the algorithm is severely influenced. Therefore, to weight an algorithm, you should not only attach importance to the result, but also consider its calculation efficiency.

3.  GMPLS

The GMPLS protocol set (which is an extension of the MPLS)-based intelligent optical network control protocol include route protocol, signaling protocol and link management protocol (LMP).

Figure 4-3 GMPLS protocol of intelligent optical network

The route protocol includes:

n  OSPF protocol with traffic engineering extensions (OSPF-TE)

n  Intermediate system-intermediate system route protocol with traffic engineering extensions (IS-IS-TE)

n  CSPF protocol

The signaling protocol includes:

n  RSVP with traffic engineering extensions (RSVP-TE)

n  Constrained route-label distribution protocol (CR-LDP)

The LMP is running on the transmission plane between adjacent nodes to provide links and isolate faults. It also manages the bidirectional control channel between nodes. It has the following essential functions: control channel management, link connection verification and fault location/isolation.

4.3  Intelligent Features of OptiX OSN 9500

The OptiX OSN 9500 provides a set of stand-alone intelligent software system which is quite convenient and flexible in use in dynamic bandwidth allocation, intelligent route finding and configuration of services. The bandwidth availability using the OptiX OSN 9500 is improved.

The OptiX OSN 9500 allows the following functions:

n  Supporting SLA.

n  Supporting automatically configure the end-to-end service.

n  Providing traffic engineering control to guarantee the load-balance traffic networkwide and improve the bandwidth availability.

n  Providing distributed mesh network protections in real-time reroute and preconfigure schemes; support span protection and end-to-end service protection, improving the scalability of the network.

4.4  Intelligent Service Request

The optical network is evolving from an integrated network providing transmission paths only to a service operation network. The intelligent feature provides users with various high-quality bandwidth applications and services: lease and wholesale bandwidth, bandwidth business, traffic engineering, SLA.

4.4.1  SLA Service