ASON Links

Control Channels

The LMP creates and maintains the control channel between NEs. The control channel then provides a physical channel for the LMP packets. The control channels are classified into in-fiber and out-fiber control channels. The in-fiber control channels auto discover and use OTN overhead or the D4-D12 bytes of DCC. The out-fiber control channel uses the Ethernet links, which should be manually configured.

The verification of TE links can be performed if the control channels are available between two adjacent nodes.

Control Links

Control links are the communication links created for the communication between the protocol entities of NEs.

The OSPF control links are created and maintained by the OSPF protocol between two nodes. The information of the OSPF control links is flooded to the entire network. In this way, each NE can attain the information and then can form the control topology. The OSPF protocol of each NE computes the shortest control routes to each NE according to the control topology. The routes are then recorded in the forward table. The signaling RSVP then uses the routes to transmit message packets.

By default, control links are created in fibers. Control links can also be created outside fibers on the condition that the OSPF protocol of the Ethernet ports is enabled.

NOTE:

Although the control links and control channels are created in the OTN overheads or DCC channels (D4-D12), they differ in terms of functions and are independent of each other. The OSPF protocol floods the information about the control links to the entire network. Each ASON NE stores the information about the network-wide control links. The ASON NEs do not flood the information about the control channels to the entire network. Each NE manages and stores the information only about its own control channels.

TE Links

See Figure 1. After the wavelength trail is created between the NS4 boards at two ASON NEs, the OTU4 TE link and ODU4 TE link are generated automatically. The signal type of the OTU4 TE link is OTU4 and the payload type is ODU4. The signal type of the ODU4 TE link is ODU4 and the payload type is ODU3.

Figure 1 OTU4 TE link and ODU4 TE link

See Figure 2. After the wavelength trail is created between the FIU boards at two ASON NEs, the OMS/OTS TE link is generated automatically.

See Figure 2. After the wavelength trail is created between the NS3 boards at two ASON NEs, the OTU3 TE link and ODU3 TE link are generated automatically. The signal type of the OTU3 TE link is OTU3 and the payload type is ODU3. The signal type of the ODU3 TE link is ODU3 and the payload type is ODU2.

Figure 2 OTU3 TE link and ODU3 TE link

See Figure 3. After the wavelength trail is created between the NS2 boards at two ASON NEs, the OTU2 TE link and ODU2 TE link are generated automatically. The signal type of the OTU2 TE link is OTU2 and the payload type is ODU2. The signal type of the ODU2 TE link is ODU2 and the payload type is ODU1. See Figure 3.

Figure 3 OTU2 TE link and ODU2 TE link

See Figure 4. After the wavelength trail is created between the LQMS boards at two ASON NEs, the OTU1 TE link and ODU1 TE link are generated automatically. The signal type of the OTU1 TE link is OTU1 and the payload type is ODU1. The signal type of the ODU1 TE link is ODU1 and the payload type is GE/Any.

Figure 4 OTU1 TE link and ODU1 TE link

See Figure 5, The ODU1 TE link will be automatically created only after the ODU2 TE link generates, and the cross-connection between the TQSTOM and NS2 boards is created. When the accessed signal is STM-16/OC-48, the ODU1 TE link will be automatically created, the signal type of which is ODU1 and the payload type is Any.

Figure 5 ODU1 TE link

See Figure 6. After the wavelength trail is created between the L4G boards at two ASON NEs, the OTU5G TE link and ODU5G TE link are generated automatically. The signal type of the OTU5G TE link is OTU5G and the payload type is ODU5G. The signal type of the ODU5G TE link is ODU5G and the payload type is GE.

Figure 6 OTU5 TE link and ODU5 TE link