Function Structure of the ASON

An ASON network consists of ASON NEs, TE links, domains and SPC (soft permanent connections).

Figure 1 Function structure of the ASON

ASON NE

An ASON NE is one of the topology components in the ASON. An ASON NE has the following functions in relation to a traditional NE. See Figure 2.

Figure 2 ASON NE

Node ID is the unique identification of the ASON NE in the control plane. The format of the node ID is the same as that of the IP address. But the node ID and the IP address of the NE must be at different network sections.

As a unique identification for NEs on the transport plane, the node ID has the same meaning regarding an ASON NE and a traditional NE.

The node ID, the NE ID, and the NE IP address are independent of one another.

TE Link

TE link is a traffic engineering link. The ASON NE sends its bandwidth information to other ASON NEs through the TE link to provide data for route computation. One inter-station fiber can be configured with one TE link.

The resources of a TE link can be classified into three types: non-protection resources, working resources, and protection resources.

If the MSP is configured on some channels of a fiber, there are three types of resources. For example, if a 10 Gbit/s (64 VC4s) optical interface is configured with a 2.5 Gbit/s MSP, the TE links are allocated as follows.

1-8 VC4s are the working resources of the TE link.
33-40 VC4s are the protection resources of the TE link.
The rest VC4s are non-protection resources of the TE link.

If the MSP is configured completely in a fiber, there are only working and protection resources in this fiber.

If the MSP is not configured in a fiber, there are only non-protection resources in this fiber.

Component Link

Component link is a bandwidth unit smaller than a TE link. One TE link consists of only one component link in the actual ASON software.

NOTE:

Each ASON NE floods its own TE links to the whole network through OSPF-TE. Each NE obtains the network-wide TE links. ASON NEs do not flood their own component links to the whole network. They only manage and store their own component links.

ASON Domain

An ASON domain is a subset of a network, which is classified by function for the purpose of route selection and management. An ASON domain consists of several ASON NEs and TE links. One ASON NE belongs to one ASON domain.

SPC

In the case of soft permanent connection (SPC), the connection between the user and the transmission network is configured directly by the NM. The connection within the transmission network, however, is requested by the NM and then created by the NE's control plane through signaling. When ASON service is mentioned, it usually refers to SPC.

Permanent connection (PC) is a service connection calculated beforehand and then created through the NM by issuing a command to NE. A traditional SDH service is a PC.

Switched connection (SC) is a service connection requested by a terminal user (for example, a router) and is then created in the ASON control plane through signaling.

NOTICE:

Web LCT only supports SPC and PC. SC is not supported at present.