Functions of the OSPF protocol intended for ASON

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The control plane of Huawei ASON applies the OSPF-TE, which is an extended protocol for OSPF, and implements the following functions.

Creates and maintains control links.

Establishes neighbor relationship.

Floods and collects the information about the control links on the control plane. Based on the information, the protocol then generates the information about the routes that are required for forwarding messages on the control plane.

Floods and collects the information about the TE links on the transport plane. The protocol then generates the information about the network service topologies for service trail computation.

Other related questions:
Method used to configure the OSPF protocol for ASON NEs?
In general, it is not allowed to disable the OSPF protocol for an ASON network. In some scenarios, however, disabling the OSPF protocol for ASON NEs can release resources and therefore enable resources to be properly utilized.

Whether the OSPF protocol is supported by WDM devices and functions of the OSPF protocol
The OSPF protocol is required in the IP over DCC solution used in the DCN communication between WDM devices. The OSPF protocol is a dynamic routing protocol based on link status. It divides an AS (Autonomous System) into several areas. Route nodes exchange routing information in an area. The route nodes at the edge of an area make summary and exchange information with the routers in other areas. Each area is identified by different IDs and the area IDs have the same format as the IP addresses. Currently, the OSPF protocol of a WDM device supports only intra-area routes but does not support inter-area routes. Therefore, the gateway NE and non-gateway NEs managed by the protocol must be in the same OSPF area. By default, the line port of a WDM device is enabled with the OSPF protocol but the Ethernet port is not enabled with the OSPF protocol. To form a network through the Ethernet port, you need to modify the OSPF setting of the NE. In addition to the dynamic routing protocol, the NE supports static routes, which are manually configured. Static routes have a higher priority than dynamic routes. When a route conflict occurs, the device selects static routes.

Whether the OSPF protocol needs to be configured for WDM devices and methods for configuring the OSPF protocol
The OSPF protocol is required in the IP over DCC solution used in the DCN communication between WDM devices. The OSPF protocol is a dynamic routing protocol based on link status. You can enable the OSPF protocol so that the routing information on the gateway NE can be automatically diffused to other NEs.

Reason why CSPF is used on ASON networks
Constraint Shortest Path First (CSPF) is a routing algorithm that calculates the optimal route for a service, ensuring that the service is quickly restored after rerouting.

Functions of the RES and GCC bytes in the ASON domain
The OSPF and RSVP protocols transmit messages through the GCC or RES bytes in OTN overhead. Control links and control channels for the ASON are created in OTN overhead (electrical-layer ASON uses RES_ODU or GCC bytes) and DCC channels (optical-layer ASON uses D4 to D12 bytes).

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