Configuring Trunks and Adding Interface Shelves

After you have configured the nodes, you must activate the trunks. Trunks are intranode communication links in a network. A trunk can connect any combination of IGX or BPX nodes.

Configuring Trunks

Physical line type:	T1 (including fractional) and IMA E1 (including fractional) and IMA Subrate, E3, T3, or OC-3 (STM1) and OC-12 with BXM
Communication technology:	Asynchronous Transfer Mode (ATM) or FastPackets.

The communication technology for each node type, card combination, and line type are listed in Table 18-1.

Table 18-1 Supported Card Types
Node Type	Front Card	Back Card	Line Types	Technology
IGX	NTM	BC-T1	T1, Fractional T1	FastPacket
IGX	NTM	BC-E1	E1, Fractional E1	FastPacket
IGX	NTM	BC-SR	Subrate	FastPacket
IGX	NTM	BC-Y1	Y1, Fractional Y1	FastPacket
IGX	UXM	BC-UAI-2-155-SMF, BC-UAI-4-155-SMF BC-UAI-2SMFXLR, BC-UAI-4SMFXLR BC-UAI-4-155-MMF BC-UAI-4-STM1E, BC-UAI-4T1-DB15 BC-UAI-4E1-DB15 BC-UAI-4-E1-BNC BC-UAI-8T1-DB15, BC-UAI-8E1-DB15, BC-UAI-8E1-BNC BC-UAI-3-T3 BC-UAI-6-T3 BC-UAI-3-E3 BC-UAI-6-E3	OC-3 OC-3 OC-3 OC-3 OC-3 STM1 Electrical T1 E1 E1 T1 E1 E1 T3 T3 E3 E3	ATM
BPX	BNI	LM-3T3, LM-3E3	T3, E3	ATM
BPX	BNI-155, BNI-155E	2OC3-SMF or 2OC3-MMF	OC-3 (STS)	ATM
BPX	BXM-155-8	MMF-155-8 SMF-155-8 SMFLR-155-8	OC-3 (STS)	ATM
BPX	BXM-155-4	MMF-155-4 SMF-155-4 SMFLR-155-4	OC-3 (STS)	ATM
BPX	BXM-622-2	SMF-622-2 SMFLR-622-2 SMFXLR-622-2	OC-12 (STM4)	ATM

Setting Up a Trunk

Before executing the commands in this section, you must have finished setting up the nodes (see Chapter 17, "Initial BPX 8600 Node Configuration.") Also, the front and back cards that support the proposed line type and communication technology must reside in the slot intended for the trunk.

You can configure port, routing trunk, and feeder trunk interfaces simultaneously on a slot containing a BXM card. For example, you can up port 1 on a BXM slot as a trunk interface while also upping port 2 as a line interface. For BXM cards, you do not need to upgrade the firmware.

You cannot use a virtual trunk as an interface shelf (feeder) trunk; similarly, you cannot configure an interface shelf trunk to act as a virtual trunk. Similarly, you cannot terminate interface shelf (feeder) connections on a virtual trunk.

The interface types that are supported on the same card are listed in Table 18-2.

Table 18-2 Interface Types Supported on the Same Card
Interface Type	BXM	UXM
Physical trunks	supported	supported
Virtual trunk	supported	supported
Interface shelf (feeder) trunks	supported	not supported
Ports (UNI/NNI)	supported	supported

Use the uptrk command to activate the trunk so that it can start to generate framing. It also determines whether the trunk is a physical-only trunk or a virtual trunk. The third digit you specify in the uptrk command (represented by slot.port.vtrk) indicates that the trunk is virtual. For details on virtual trunking, see Chapter 24, "Configuring BXM Virtual Trunks."

Use the uptrk command at each end of the trunk. When the trunk is upped at only one end, the node detects the trunk as being in an alarm state. For more information, refer to the dsptrks command of the Cisco WAN Switching Command Reference, Reference 9.3.30. If you up the trunk at both ends, the alarm is cleared.

Step 2

Use the cnftrk command to override the trunk default values. You must use the cnftrk command for virtual trunks, but it is an optional command for physical trunks. For virtual trunks, you must change the VPI to a nonzero value before executing the addtrk command.

If you use the cnftrk command, you must make the same changes at both ends of the trunk. To display existing trunk parameters, use the dsptrkcnf command. The configurable parameters are listed for each card type in Table 18-1. (The possible parameters are PKT for FastPackets, ATM cells, BNI if the trunk is a BNI card, or All.) Not all of these parameters apply to the BPX node.

After you configure the trunk and add the trunk (addtrk), you can specify certain parameters again. For example, a period of trunk use can give you enough information to indicate that you should change parameters to optimize how the trunk is used.

Step 3

Use the addtrk command to add the trunk. Adding the trunk makes the trunk a usable resource, so you can add connections (addcon) to carry traffic. You need to add only one end of the trunk.

Reconfiguring a Trunk

This section describes how to change trunk parameters after you have added the trunk.

After you have added a trunk, you can reconfigure some parameters without first deleting the trunk by using the deltrk command. This means that you can reconfigure the following list of trunk parameters when the trunk is in use. The cnftrk display highlights all configurable parameters, and dims parameters that are not configurable.

The following are the parameters that you can change without first deleting the trunk:

•

Trunk Receive Rate—On IGX platforms, configurable after a trunk has been added.

•

Trunk Transmit Rate—On BPX platforms, configurable after a trunk has been added.

•

F4 AIS Detection—This parameter modifies the value on one end of the trunk but does not automatically modify the value on the other end of the trunk.

For the cnftrk parameter definitions, refer to the Cisco WAN Switching Command Reference, Release 9.3.30.

To change the applicable parameters without deleting the trunk, use the following procedure.

Step 1

Execute the cnftrk command at both ends of the trunk to reconfigure parameters.

Step 2

Execute the addtrk command at only one end of the trunk to add the trunk.

Switch software triggers a reroute of connections only if a change to a parameter results in too few resources to support the current load of connections.

If you attempt to change one of the trunk parameters, the other endpoint is updated by switch software. It is not necessary to change both endpoints' parameters.

The following are the parameters that cannot be changed after adding a trunk by using the addtrk command:

To display the current trunk parameters, use the dsptrkcnf command. If you can make all the needed parameter changes without deleting the trunk, execute the cnftrk command. Use the cnftrk command at both ends of the trunk.

To change the applicable parameters that cannot be modified after adding a trunk, use the following procedure.

Step 1

Delete the trunk by executing the deltrk command at one end of the trunk.

Step 2

Execute the cnftrk command at both ends of the trunk to reconfigure parameters.

Step 3

Execute the addtrk command at only one end of the trunk to add the trunk.

Switch software triggers a reroute of connections only if a change to a parameter results in too few resources to support the current load of connections.

If you attempt to change one of the trunk parameters, the other endpoint is updated by switch software. It is not necessary to change both endpoints' parameters.

Note MPLS partitions are not affected by trunk and line reconfiguration, because label switching partitions cannot be increased beyond the available number of resources.

For a trunk between a node running the current release and a node running an earlier release (such as 9.2 or 8.5), you are prompted that you can change a parameter only if both ends allow such a change.

Removing a Trunk

Step 1

Use the deltrk command to delete the trunk. If both nodes are reachable, perform this command at one end of the trunk only. Otherwise, you must perform this command at both ends. If the deltrk command results in splitting up the network, connections whose endpoints are no longer in the same network are automatically deleted.

Step 2

Use the dntrk command to down the trunk. Execute the dntrk command at both ends of the trunk.

Displaying or Printing Trunk Configurations

You can display the network trunk configuration on the screen or print it on the printer in a one-step process by using any one of the following commands listed in Table 18-3.

Table 18-3 Trunk Configuration Commands
Name	Description
dsptrks	Displays the current trunk configuration and alarm status at a node.
prttrks	Prints the current trunk configuration and alarm status at a node.
dspnw	Displays all trunks for each node.
prtnw	Prints all trunks for each node.

Adding an Interface Shelf

An interface shelf is a nonrouting device that drives ATM cells to and from a BPX or IGX routing hub in a tiered network. (An interface shelf is also sometimes referred to as a feeder shelf.) An interface shelf can be:

For instructions on installing a Service Expansion Shelf in a BPX 8620 rack and initially powering up, refer to the Cisco Service Expansion Shelf (SES) Hardware Installation Guide. To configure an SES PNNI for a BPX 8620, refer to the Cisco SES PNNI Controller Software Configuration Guide.

Because tiered network capability is a purchased option, personnel in the Technical Assistance Center (TAC) must first configure a node to serve as an interface shelf. Then you must use the cnftrk command to configure an interface shelf to use STI cell headers and BPX Addressing Mode (BAM).

Before you can add an MGX 8220 shelf to a tiered network, the shelf must be an available resource in the network. (For instructions on how to bring up an MGX 8220 shelf, see the MGX 8220 documentation.)

To add an interface shelf, use addshelf. For an illustration of the command sequence for to set up an interface shelf, see Figure 17-5.

The designations for various devices that can be used as interface shelves are listed in Table 18-4. To display these designations, use the display commands dspnw and dspnode. The dspnode command identifies the hub and feeder nodes and shows the alarm status.

Device Serving as Shelf	Designation
MGX 8220	AXIS
MGX 8230 and MGX 8250	AAL5
SES (Service Expansion Shelf)	AAL5
IGX	IGX/AF

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