Hello everyone!
Today, I'm going to share with you some information about the SDH trail. I hope you like it!
What is an SDH trail?
A type of managed object that is displayed on the NMS GUI based on the SDH technology. It can directly reflect the routing status of SDH signals on the transmission network. Through SDH trails, the NMS can conveniently and flexibly manage SDH services on the transport network in an end-to-end manner.
SDH trails on NCE
Graphical mode:
List mode:
By type, service trails and server trails can be classified into service trails and server trails.
What is the SDH service trail?
The service trail refers to the trail that is directly used to carry customer services.
SDH service trails include VC12/VC3/VC4/VC4-xC. On a network consisting of traditional SDH equipment, the SDH service trail is located between tributary boards.
What is the SDH server trail?
The server trail refers to a bearer layer trail that serves as the SDH trail. Generally, VC4 service trails and MS trails are included.
VC4 server trail
VC4 server trail exists between line boards of SDH equipment. It is used to carry lower-order service trails such as VC12 and VC3.
MS trail
Multiplex section (MS) trails exist between line boards of adjacent NEs on an SDH network. On the NMS, MS trails are automatically generated along with the fiber connections between line boards. An MS trail is used to carry VC4-xC trails, VC4 trails, and VC4 server trails.
SDH trails are displayed in the same diagram in a centralized manner:
Dependencies between SDH trails at different layers
From the preceding screenshots, we can see that:
1. VC12 and VC3 trails depend on the VC4 server trail. End-to-end VC-12 and VC-3 trails cannot be created before the VC-4 server trail is created. Of course, if you use the single-site configuration method, you can circumvent this limitation.
2. The VC4-xC trail, VC4 trail, and VC4 server trail are independent of each other, but they all depend on the establishment of the MS trail. Before the MS trail is created, you cannot create the MS trail on the NMS. The single-site configuration method can circumvent this limitation.
3. MS trails depend on the establishment of logical fibers. If logical fiber connections between NEs are not created on the NMS, MS trails are not automatically generated.
On the WDM/OTN network, MS trails depend on the establishment of ODUk trails. All the SDH trails are client trails on WDM/OTN networks.
The following uses an OSN 7500 board as an example:
PQ1: 63xE1 service processing board
EGS4: 4xGE switching and processing board
DX1: DDN service accessing and converging board
SXCSA: super cross-connect and synchronous timing board
SL64: 1xSTM-64 optical interface board
That's all. If you want to learn more about the basics of optical transport networks, please subscribe to Basics of Optical Transmission Network.
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