Subtending in a Direct Connect Configuration

Overview and Purpose

Guidelines for Subtending a Direct Connection Configuration

Subtending Direct Connect Subscribers

Subtending in a Direct Connect Configuration

This chapter describes how to set up subtended systems in a direct connect configuration.

This chapter includes the following sections:

Overview and Purpose

Subtending allows you to use one ATM backbone for multiple Cisco 6100/6130 chassis. In addition, once you have provisioned the primary network interface module, that configuration replicates in all subtended systems.

Subtending is a Cisco 6100 Series system feature that reduces the cost per subscriber by amortizing the expense of the network interface module and the edge switch port connection over a large number of subscribers. Subtending provides the following advantages to your system:

Services and aggregates the data from one or more remotely located Cisco 6100/6130 into a host Cisco 6100/6130. This configuration takes advantage of the data network interface on the host Cisco 6100/6130.

Reduces the number of ATM edge-switch ports that are required to terminate the Cisco 6100/6130 chassis.

Figure 5-1 illustrates the connections of a subtended Cisco 6100 Series system with six subtended systems.

Figure 5-1: Subtending Connections

Figure 5-2 shows valid address ranges for each Cisco 6100 Series system.

Figure 5-2: Valid ATM Connection Space

Guidelines for Subtending a Direct Connection Configuration

The following guidelines apply to subtending Cisco 6100 Series nodes:

You can subtend up to six Cisco 6100/6130s to one subtending host Cisco 6100/6130 that is connected to the ATM network backbone (refer to Figure 5-1).
Switch subtended VCCs to the ATM bearer service either through VCCs or VPCs. See the ATM Addressing Guidelines appendix in the ViewRunner for HP OpenView User Guide for more information.
Use standard Cisco 6100 Series system network interface modules on the subtended Cisco 6100 Series system for interconnection to the host node.
Subtend as many as seven chassis to support up to 2800 subscribers per network connection.
The Cisco 6100 Series system can support up to 9000 VCCs. The total number depends on the amount of system-controller and network-interface RAM that the resident application code consumes.
Cisco recommends a maximum of 1500 VCCs within the valid address space. Software limits might not be built in, because of the temporary nature of this ceiling.
Cisco recommends that you provision transit subscribers on the subtend ports of the host Cisco 6100 Series system for each of the subscribers that are provisioned on the subtended Cisco 6100 Series ports.
You must assign the transit subscribers on the subtending host Cisco 6100 Series system the same VPI/VCI addresses that you assigned to them on the subtended Cisco 6100 Series node.
- For example, if you assign subscriberA to VPI 5 and VCI 10 on the subtended Cisco 6100 Series system, you must assign transit subscriberA to VPI 5 and VCI 10 on the host Cisco 6100 Series system. Transit subscribers on the subtending host Cisco 6100 Series system are logical containers for traffic that passes from the subtended Cisco 6100 Series system; therefore, you can create multiple transit subscribers on one port.
- Each VPI/VCI must be unique on any one network interface, subtended or not, and must be the same on both ingress and egress.
You can define four VCCs per subscriber line that enters from the subtended Cisco 6100 Series system.
You can assign subscribers from the subtended node across VCCs on the subtending Cisco 6100 Series host. That is, you can assign all subscribers from a subtended node to VCC 1, or you can distribute them across all of the 32 VCCs.
You can group subscribers as you choose. For example, if you assign all subscribers from one subtended node to one VCC on the subtending host, you can lock all those subscribers at one time if you need to bring the node down for any reason.
You must conduct data path tests between your Cisco 6100 Series system and far-end equipment. See "Testing Configuration Connections for the Cisco 6100 Series System" for procedures for conducting data path tests.

Subtending Direct Connect Subscribers

If you are subtending Cisco 6100 Series systems, provision the local Direct Connect subscribers and their PVCs just like you do any Cisco 6100 Series system according to the preceding directions. However, you must also provision transit subscriber and transit PVCs on each of the subtending host Cisco 6100 Series systems in the path of each PVC for a subtended Cisco 6100 Series system.

Transit subscribers are simply placeholders for bundling transit PVCs. Unlike standard subscribers, they do not need to be locked to have transit PVCs assigned to or deleted from them. Typically, a single transit subscriber is assigned to each subtend port, or multiple subscribers could be assigned to aggregate traffic for a specific Cisco 6100 Series system that is subtended from a node. Up to 32 total transit subscribers can be defined per Cisco 6100 Series system.

Note Locking a transit subscriber takes all of the PVCs that are owned by that subscriber out of service.

The transit PVCs on the subtend port have the same VPI/VCI as the subtended PVC on the network interface of the subtended Cisco 6100 Series system. The VPI/VCI that the transit PVC is cross-connected to on the subtending Cisco 6100 Series system network interface must either be connected to another transit PVC on another Cisco 6100 Series system, or to the target VPI/VCI on an ATM edge switch. Figure 5-3 illustrates an end-to-end PVC across a subnetwork of subtended Cisco 6100 Series systems.

Note The subtended VPI/VCI is restricted on subtended cisco 6100 Series systems.

Figure 5-3: Subtend Provisioning

If there are existing subscribers, Figure 5-3 shows subscriber x on Cisco 61xx 4 has a PVC y that is connected to a LIM or ATU-C port on VPI=vpi₁/VCI=vci₁. Within Cisco 6100 Series system number 2, this PVC is cross-connected to the NI on VPI=vpi₂/VCI=vci₂. On Cisco 61xx 2, a Transit subscriber w is defined to which Transit PVC z is added. Transit PVC z has its ingress side connected to the same VPI/VCI as the egress side of the PVC from Cisco 61xx 4, VPI=vpi₂/VCI=vci₂. The cross-connection within Cisco 61xx 2 is then connected to VPI=vpi3/VCI=vci₃on the Cisco 61xx 2 network interface. Finally, Cisco 61xx 1 takes in the PVC on Transit subscriber m, Transit PVC n. Transit PVC n connects VPI=vpi₃/VCI=vci₃on the subtend port to VPI=vpi₄/VCI=vci₄on the network interface and into the ATM cloud.

To add a transit subscriber, use the following procedures:

Step 1 Go to the Map View.

Step 2 Click New Equipment.

Step 3 Right- or double-click on the intended system to subtend on the map.

Step 4 Click Edit and Copy.

Step 5 In the Subtend Group, click Edit and Paste.

Step 6 Go back to New Equipment to copy another system.

Step 7 Check for a subtend host module (STM).

Step 8 Hold down the Ctrl key, click Host.

Step 9 Click Configuration to make a subtend connection.

Step 10 Open the subtended system.

Step 11 Input the subscriber ID.

Step 12 The STM Port Configuration dialog box appears, as shown in Figure 5-4. Click Add to add a transit subscriber.

Figure 5-4: STM Port Properties Dialog Box

Step 13 A dialog box appears, as shown in Figure 5-5, where you specify the subscriber ID for the transit subscriber. Enter the ID and click OK.

Figure 5-5: Add Transit Subscriber Dialog Box

Step 14 The new subscriber appears in the list of subscribers. Highlight the new subscriber, and click Edit.

Step 15 The Transit Subscriber Properties dialog box opens, as shown in Figure 5-6, for you to provision the transit subscriber.

Figure 5-6: Transit Subscriber Properties

Notice that the Transit Subscriber dialog box is similar to the local service provisioning dialog boxes, but it labels the subscriber side VPI/VCI connection fields as "Transit Subscriber VPI/VCI.

Step 16 Click Subtend Network to access the Service Provisioning PVC Type.

Step 17 Click PVC and Add Now.

Step 18 Click OK.

Step 19 Open the head node.

Step 20 Click View All Subscribers.

Step 21 Click Subtend instead of Local PVC.

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