SDH Networks

This module allows to create end-to-end virtual circuits and all other logical entities required by the SDH protocol¹. Let’s introduce some concepts first. See Figure 1 for sample connection that illustrate the following terms.

1. TransportLink A point-to-point logical connection that represents a single STMX. By default, the TransportLinks included in Kuwaiba are SMT1, STM4, STM16, STM64 and STM256.
2. ContainerLink It’s a logical connection that may or may not have multiple hops and connects ports within the boundaries of the transport network. A ContainerLink ends where at least one TransportLinks ends, but in its path, the ContainerLink may have used many TransportLinks. In simple terms, a ContainerLink is an SDH virtual circuit. By default there are 5 types of ContainerLinks defined: VC12, VC3, VC4, VC4-04 and VC4-16. The latter two provide support for concatenation.
3. TributaryLink Objects of this type are not circuits themselves, they rather use actual virtual circuits (ContainerLinks) and end in the ports where the SDH service is delivered to the customer (usually tributary ports).

Figure 1. Sample multi-hop SDH circuit and its relationships with services, customers and physical resources

In short, Transport and ContainerLinks provide the foundations for the hierarchy, while the TributaryLinks provide information about where the circuits are delivered (that is, what are the endpoints of the connections).

Creating an SDH view

To create an SDH topology, go to the menu option Figure 2.

Figure 2. SDH Module

This will open an empty canvas similar to the Topology Designer.

Figure 3. SDH canvas

The table below lists the tools and their description:

Tool	Description
	Open SDH view
	New SDH view
	Remove view
	Add devices
	Remove from database and view
	Remove from view
	Export as image
	Connect

Using the tool to add devices add the equipment you need Figure 4.

Figure 4. Add devices window

Let’s consider this 4 equipment topology Figure 5.

Figure 5. Some routers and multiplexers in an SDH topology

What we are going to do is to create a ring using STM-4 on one branch and SMT-1 on the other. We will create a VC12 between SDH-87 and Router 1. Each equipment has the same board/port layout: Two boards Figure 6, a tributary and an aggregate one, with two ports each Figure 7.

Figure 6. Board layout

Figure 7. Port layout

Creating TransportLinks

First, we have to create the most basic support, that is the TransportLinks (STMX). Use the connect tool and drag a line from one equipment to the other. That will start a wizard Figure 8.

Figure 8. Select connection type window

The first step of the wizard will request for the basic information: name and type Figure 9

Figure 9. Creating a TransporLink, step 1

The second will request the connection endpoints, which will always be aggregate ports.

Figure 10. Creating a TransporLink, step 2

After repeating the procedure three more times, the ring will be finished. In the Figure 11

Figure 11. SDH ring

Creating ContainerLinks

The next level in the hierarchy is the set of structured high-order circuits (VC4) that will contain the E1s that we will add later. We will create three VC4: A long one, from SDH-87 to Router 1, a short one, from SDH-87 to Router 2, and finally another short one between Router 2 and Router 1. This will provide two paths to route the E1s later on. To create the VC4 connections (a.k.a. ContainerLinks). To create the first ContainerLink using the Connection tool , let’s drag a line between the SDH-87 and the Router 1. That will start a wizard.

Figure 12. New ContainerLink, step 1

Again, the first step is about basic information: Container name and type. We will create a simple VC4. The next step is about routes. You will find two routes. In the center panel, the detail of the chosen route will be displayed.

Figure 13. New ContainerLink, step 2

The next step will ask you to define what timeslots you will use from each TransportLink in the route Figure 14. To select the timeslot from the list. This list will be populated with the available timeslots, but it will also inform you what timelots are already in use and who’s using them.

Figure 14. New ContainerLink, step 3

It’s not necessary to select any endpoint ports, since they’re taken from the underlying TransportLinks. Once created, you won’t see anything different in the view, since the only connections to be displayed are the TransportLinks.

Creating TributaryLinks

The last step is to create a TributaryLink, that is, the actual E1 to be delivered. For that, we have to press the connection tool . As usual, drag a line between the end equipment, in this case, SDH-87 and Router 1. This will open another wizard.

Figure 15. New TributaryLink, step 1

In the next step, you will be requested to pick a route. Note that the STM4-based route won’t be offered, as it doesn’t have ContainerLinks to transport the TributaryLink.

Figure 16. New TributaryLink, step 2

The third step consists of choosing the timeslot in the ContainerLink (VC4)

Figure 17. New TributaryLink, step 3

The next step is choosing the endpoints. For this example, we’re going to end the SDH connection in a tributary port of a PDHBoard. It could, of course, end in any port of any board, however this is the most common scenario.

Figure 18. Choosing the endpoints

Finally, as an option, you can associate the newly created TributaryLink to a service instance. Note that this list will be populated only with objects of subclasses of GenericSDHService previously created in the Service Manager, as seen in the Figure 19.

Figure 19. Optionally, relating the circuit to a service

Important

As an exercise for the reader, create Container and TributaryLinks using the alternate STM4-based route.

Module Actions

Delete Transport Link

Applies to object instances of GenericSDHTransportLink subclasses.

Figure 20. Delete Transport Link

Delete Container Link

Applies to object instances of GenericSDHContainerLink subclasses.

Figure 21. Delete Container Link

Delete Tributary Link

Applies to object instances of GenericSDHTributaryLink subclasses.

Figure 22. Delete Tributary Link