This chapter describes techniques for modeling Cisco WAN network types and products. It contains the following sections:
The information in this chapter is most helpful if you already know how to use the NMT, have created a configuration, and want to make changes to address specific needs.
Each section in this chapter consists of a description of a topic, followed by configuration notes. The configuration notes provide information about the tables and fields that need to be modified.
Tiered networks are a special network configuration of Cisco WAN switches. A tiered network consists of a BPX node linked to a maximum of 16 IPX nodes or AXIS shelves designated as feeder nodes. A feeder node expands the port capacity of the BPX switch. A feeder node has no routing capabilities, so it does not count against the maximum number of switches allowed in the network. It must be used when the BPX does not support a required line interface, such as T1/E1/V35/X21, or does not provide required network services, such as Frame Relay or circuit emulation. In a tiered network, each feeder has only one link to the BPX.
If an IPX feeder is not in the Sites table but is generated by NMT, it is called an implicit feeder. In NMT, tiered network generation is driven by the type and the line interface of the connection for creating IPX feeders and AXIS shelves.
Figure 4-1 shows an example of a tiered network.
Refer to Table 4-1 for information on modeling a tiered network with the NMT.
Figure 4-1: Example of a Tiered Network
Table 4-1: Tiered Network Configurations
| Topic
| Required Settings
| Comments
|
|---|
| IPX Feeders
| Sites table
Type field: Enter BPX
IGX field: Enter N
BC field: Enter T3 or E3
FC field: Enter AIT
RLC field: Enter Y for trunk card redundancy
Bursty Traffic table
Type field: Enter FR, ATF, or FTA. (Frame Relay supported only on IPX feeders.)
BC field: Enter T1, E1, V, X, or PC (for Port Concentrator).
Fdr BC field: Leave blank or enter line interface for IPX access feeder such as Port Concentrator, Cisco 3800, or FastPAD.
| IPX tiered network feeders can have no voice or data connections.
Specify IPX type of feeder for BPX type of site in the Sites table; specify the type of the link between BPX hub and IPX device (feeder, trunk card, and redundant trunk card).
The redundancy of feeder links is determined by the RLC field in the Sites table.
The link type for IPX feeders is controlled by the site BC and FC fields.
Hub IDs and feeder IDs are not defined for implicit IPX feeders. To specify the physical location of IPX feeders, you must make the IPX feeder explicit by having it appear in the Sites table.
In the Bursty Traffic table, verify that the connection originates or terminates on the IPX feeder as a Frame Relay connection.
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| AXIS Feeders: General Instructions
| Bursty Traffic table
Site field: Enter the site name. Must be BPX site.
Type field: any from the list of choices.
BC (Back Card) field: Enter the back card that connects the BPX to the BNM card on the AXIS shelf.
Fdr BC (Feeder Back Card) field: Enter the customer interface on the AXIS service module.
| AXIS shelves are provisioned from the BC and Fdr BC fields in the Bursty Traffic table. If the back card specified can support ANIX, and the feeder back card can support the traffic type with an AXIS service module, NMT will provision an AXIS shelf.
The Fdr BC field determines the connection interface to the AXIS feeder. The NMT determines the front card (FRSM, AUSM or CESM), based on the feeder back card selected. If T3 is selected as the feeder back card, the NMT assigns as SRM-3T3 service module.
If connection type implies AUSM card, the PCR value determines the port speed and whether more than one T1/E1 is required.
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- AXIS Feeders: Port to Multiport
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Bursty Traffic table
Fdr I/D fields (Feeder identification fields): ID values must be assigned.
ID values can be
- Slot.Port for AUSM and CESM cards (e.g., 5.3); this format can be used also for FRSM cards to specify physical port (line) without specifying logical port.
- Slot.Line.Port for FRSM card (e.g., 5.2.6).
- Zero, indicating no unique port constraint.
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By assigning IDs to the ports of the AXIS service module cards, you can put the connection on a particular port.
Feeder IDs can also control port-to-multiport connections.
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- AXIS Feeders: Multiple Feeders at a Site
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Bursty Traffic table
Hub ID field
- All connections associated with a specific AXIS should have the same hub ID throughout the Bursty Traffic table.
- It is not necessary to use the HUB ID field for the site at the other end of the connection.
- Hub ID values can be
- Slot.Port (e.g., 12.2)
- Zero, indicating no unique port constraint
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You need to configure a site with multiple AXIS feeders only if you require connections between the feeders or if you need to associate specific connections with specific feeders (e.g., if the feeders are at different locations).
Assign hub IDs to identify the port of the BNI/BXM card on the BPX that connects to the specific AXIS shelf.
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- Limit Speed of Access Port
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Access Ports table
Hub ID field: Enter the hub ID for the access port on IPX feeder or trunk port on BNI/BXM card for the AXIS shelf.
Feeder field: Enter feeder ID for the access port on the AXIS shelf or leave blank for the IPX access port.
Speed field: Enter port speed value. (Press the Help key for a list of choices.)
| The speed field implicitly determines the signalling type on the E1 line for the AUSM and CESM cards. It also determines the number of T1/E1 lines on IMA ports for AUSM-8 card.
For FRSM card, the speed field implicitly determines DS0 time slot speed--56 or 64 kbps.
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A star network is found only within NMT; it is initiated when the link and connection requirements can be supported only by more than one switch or by a switch different from the one specified in the Sites table.
A star network is created when an IPX or IGX node exceeds its configuration capacity, or when a BPX node cannot provide the line interfaces (T1/E1/V35/X21/HSSI) or network services (voice, data) that the connections require. Switches that NMT creates implicitly in a star network can be routers or feeders for tiered networks. The NMT can add to the hub node up to 16 local IGX/IPX star-feeder nodes to serve the connections. Star-feeder nodes count against routing resources in NMT, even if they are tiered network feeders.
A star network is generated when a site requires more than one switch to serve the connection. Star network behavior with an IPX/IGX as the hub is different than it is with a BPX at the hub:
- An IPX or an IGX node stars only when link and connection demands exceed its configuration capacity. An IPX site stars only to other IPX switches; IGX sites star to either IGX or IPX switches, depending on the setting in the IGX field in the Sites table. The star-feeders are routers, and the user cannot control the connection distribution between hub and star-feeders.
- A BPX site stars only because the connection type or feeder interface could not be supported on the BPX. The star uses a BPX hub node and an IGX or IPX feeder node. In this case, star-feeders that are IPX and that carry only Frame Relay are tiered network feeders. All others are routers.
Refer to Table 4-2 for information on modeling a star network with the NMT.
Table 4-2: Star Network Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Specifying types of switches and links for a star network
| Sites table
IGX field: Y, if feeders should be IGX; N, if feeders should be IPX.
BC (back card) field: Specify a back card for the link between hub and feeder.
FC (front card) field: Specify a front card for the link between hub and feeder.
RLC (redundant link card) field: Y, if you want to have a redundant trunk card.
| To find out if a network has starred, select Sites from the Display menu, which displays the number of switches at a site. If the number is greater than 1, the site has starred.
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IPX and IGX switches can include devices that concentrate small connections into large ones or convert normal voice or legacy data connections into Frame Relay connections. NMT supports three access feeders that concentrate or convert data: the Cisco 3800 product line, the Port Concentrator, and the FastPAD. One IGX or IPX node can support up to 64 of these devices.
Using NMT to model connections that terminate on these access feeders is similar to the modeling of AXIS feeders for a tiered network.
The NMT supports the Cisco 3800 product line configured with an IGX switch. A Cisco 3800 can concentrate voice and data connections into Frame Relay connections. The NMT configures as many Cisco 3800s as are required to support the traffic, using the chassis size (1, 3, or 8 slots) that is most cost effective. NMT generally sets the composite link speed to the minimum speed that can carry the traffic.
NMT designs Cisco 3800s only if Cisco 3800 connections are added to the Voice Traffic, Data Traffic, or Bursty Traffic table and if the model is based on switch software release versions 8.2.5 to 8.3.9, or 899 (which is used to model networks that contain Release 8.2.x and 8.4.x).
Refer to Table 4-3 for information on modeling a network that uses the Cisco 3800 product line.
Note For many of the fields, you can press the Help key for a list of choices and choose a value that is followed by 3800 (Cisco 3800 type connection).
Table 4-3: Cisco 3800 Product Line Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Setting Cisco 3800 Release
| Model Settings table. Change the value in switch software release to a valid value. (825 to 839, or 899)
| If a value is not set, NMT will try to design FastPADs.
|
| Adding Cisco 3800 data connections
| Data Traffic table:
Type field: Enter the data traffic speed.
BC (Back Card) field: For each end of the connection, enter the back card of the FTC/ FTM card that links the hub IPX/IGX to the Cisco 3800 (T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: Enter the connection interface on the line side of the Cisco 3800.
| Each Cisco 3800 data connection must originate and terminate on a Cisco 3800. If the switch software release does not support the Cisco 3800, NMT designs FastPADs.
The maximum speed for synch data is 115.2 kbps. For legacy data like HDLC, use the Bursty Traffic table.
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| Adding Cisco 3800 dedicated voice connections
| Voice Traffic table
Type field: Enter C32, C24, A32, A24, L8, L8V, L16, or L16V. The numbers refer to kbps.
BC (Back Card) field: For the Cisco 3800 end of the connection, enter the back card of the FTC/FTM card that links the hub IPX/IGX to the FastPAD (T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: For each end of the connection having a Cisco 3800, enter V for analog voice, or T1 or E1 for digital voice.
| Cisco 3800 dedicated voice connections can have one end at a Cisco 3800 and the other at a CDR, CVM, or UVM card at an IPX or IGX.
For each feeder back card entry, the NMT establishes a dedicated virtual circuit that connects one voice port on a Cisco 3800 to one voice port on another Cisco 3800 or on an IPX/IGX.
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| Adding Cisco 3800 bursty data connections
| Bursty Traffic table
Type field: Enter FR.
BC (Back Card) field: On the connection side that uses a Cisco 3800, enter the back card of the FTC card that links the hub IPX/IGX to the FastPAD (T1, E1, V, or X). On the other side of the connection, enter the back card of the FRP/FRM (also T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: For the connection side with a Cisco 3800, enter the connection interface on the line side of the FastPAD.
MIR field: Specify the bandwidth requirements on the composite link and the network backbone.
PIR field: Specify the port and bus bandwidth requirements
| A Cisco 3800 data connection can have one end at a Cisco 3800 and the other at an IPX/IGX FRP/FRM card.
At least one end of the connection must have an entry in the Fdr BC field in order for a Cisco 3800 to be designed. If the switch software release does not support the Cisco 3800, NMT designs FastPADs.
Remember to set the connection bandwidth by adjusting the MIR and PIR fields.
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| Setting up switched voice connections
| Voice Traffic table
- Quantity field: Set the number of connections between a pair of Cisco 3800s to the estimated peak number of simultaneous cell transmissions.
- Type field: Enter Session.
- BC (Back Card) field: Select valid FTC back card (V, X, T1, E1).
- Fdr BC (Feeder Back Card) field: Leave blank.
Create dummy Cisco 3800 connections:
- Site 1, Site 2. Connect each site entered above to itself, e.g., Boston, Boston.
- Hub ID fields: Optional. Hub 1 ID and Hub 2 ID can be used to specify the slot port of each end of the connection. Connect a site entered above to itself, e.g., 8.1.8.1. This connection is intrasite, intracard, and interport.
- Quantity field: The number of dummy connections should equal one half the peak number of simultaneous calls expected between the FastPAD and all other switched voice destinations.
- Type field: Enter the voice traffic speed type.
- Fdr BC (Feeder Back Card) field: Enter V for the VFC-03 card.
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To add Cisco 3800 switched voice connections, i.e., voice connections between at least one voice port on a Cisco 3800 connected to at least one voice port on many Cisco 3800s, you must perform a two-step process: connect the Cisco 3800s and add dummy Cisco 3800 connections.
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| Setting up multiple Cisco 3800s at the same site
| Data Traffic table, Voice Traffic table, Bursty Traffic table
- Hub ID field: The ID is given to the port of the FTC/FTM card on the IPX/IGX that connects to the specific Cisco 3800. ID values can be
- Port only: 0
- Slot and port: mm.nn
- where mm = 1 to 32 and nn = 1 to 31
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For connections between multiple Cisco 3800s at a site or to associate specific connections with specific Cisco 3800s, use the Hub ID field for all Cisco 3800 connections that originate or terminate at that site.
All connections associated with one specific Cisco 3800 should have the same Hub ID throughout the three traffic tables.
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| Changing Default Parameters
| Feeders table
- Hub ID field: Enter Slot Port (e.g., 6.4).
- Type field: Enter 38-1, 38-3, or 38-8 for a 1-slot, 3-slot, or 8-slot Cisco 3800. Enter 3800 for any Cisco 3800.
- Speed field: Enter the speed you want.
Data Traffic table, Voice Traffic table, Bursty Traffic table
- Hub 1 ID field: Enter the Hub ID value entered in the Feeders table (e.g., 6.4).
- Hub 2 ID field: Enter the appropriate Hub ID value.
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You can specify a 1-, 3-, or 8-slot Cisco 3800 unit and can specify the maximum speed of the composite link, that is, 64 kbps, 128 kbps, or 256 kbps.
If you specify Cisco 3800 (a generic Cisco 3800), NMT chooses the best one. If you specify a speed of 0, NMT chooses the best one.
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The Port Concentrator provides a method for concentrating voice and data connection types as a Frame Relay connection extending to an FTC or FRM card. The NMT models and provisions Port Concentrators so that they support Frame Relay connections. The card is modeled as a 44-port FRP card, with the PC interface being optional but defaulting to V35.
Refer to Table 4-4 for information on modeling a network that uses port concentrators.
Table 4-4: Port Concentrator Configuration Notes
| Topic
| Required Settings
| Comments
|
|---|
| Instructing the NMT to Design Port Concentrators
| Bursty table
Type field: Select FR, ATF, or FTA.
BC (back card) field: To specify a PC termination, enter PC in the BC field of the site that has the PC. The NMT rejects PC if the connection type is incorrect.
Fdr BC (feeder back card) field: Each PC termination can also specify which PC interface is required. Enter V (for V.35), V1 (for V.11) or V2 (for V.28) in the corresponding Fdr I/F field. If you leave the field blank, the interface defaults to V.35.
Hub ID (for Site 1 and Site 2) fields
- The port ID is the slot.port ID for an FRP-PC card and is a virtual port. The virtual port range is from 1 to 44, where ports 1 to 11 are on physical port 1, 12 to 22 are on physical port 2, 23 to 33 are on port 3, and 34 to 44 are on port 4.
- Hub IDs can be used to model over-subscription, port-to-multiport connections, and multiple PCs.
- A hub ID of 0 allows NMT to do design.
FdrID (Feeder ID) field: Not used
Access Ports table
Hub ID field: Slot is the PC slot and port is the virtual port (1 to 44). Do not use feeder slot or feeder port column.
Speed field: Enter the port speed. If not supported, it will be rounded up to the nearest supported speed. Speeds 9, 14, 19, and 38 will be respectively interpreted as 9.6, 14.4, 19.2, and 38.4. If you have an Access Port table entry for a PC port, the port speed is determined by the connections assigned to it.
| NMT designs port concentrators if, and only if, you enter connections that have port concentrator terminations.
Geis bundling format is not supported for FRP-PC.
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A FastPAD connection is a connection where at least one end terminates on a FastPAD. FastPADs always connect to the network on a Frame Relay composite link to an FTM or FTC card. FastPAD enables you to concentrate voice and data connection types as a Frame Relay connection joined to an FTC or FRM card.
NMT designs FastPADs only if FastPAD connections are added to the Bursty Traffic, Data Traffic, or Voice Traffic table.
The FastPAD comes in two sizes, one with eight slots and one with four slots, called the FastPAD micro. By default NMT
- Configures as many FastPADs as required to support the traffic
- Chooses an 8-slot FastPAD unless no more than four slots and one low-speed data port are needed, in which case the NMT chooses the FastPAD micro
- Acts on the assumption that the speed of the composite link is limited by the maximum speed supported by the FTC card (512 kbps)
Refer to Table 4-5 for information on modeling a tiered network with the NMT.
Note For many of the fields, you can press the Help key for a list of choices and select a value that is followed by FP (FastPAD Type Connection).
Table 4-5: FastPAD Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Adding FastPAD Data Connections
| Data Traffic table
Type field: Enter the data traffic speed.
BC (Back Card) field: For each end of the connection, enter the back card of the FTC/FTM card that links the hub IPX/IGX to the FastPAD (T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: Enter the connection interface on the line side of the FastPAD (S, R, V, V1, or V6).
| FastPAD data connections must originate and terminate on a FastPAD. If the switch software release supports the Cisco 3800, NMT will design Cisco 3800s, not FastPADs, unless the hub ID fields and the Feeder table are used.
For each feeder back card entry, the NMT establishes a dedicated virtual circuit that connects one data port on one FastPAD to one data port on another FastPAD.
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| Adding FastPAD Dedicated Voice Connections
| Voice Traffic table
Type field: Enter ATC8, ATC12, ATC16, CELP8, or CELP48. The numbers refer to kbps.
BC (Back Card) field: For each end of the connection, enter the back card of the FTC/FTM card that links the hub IPX/IGX to the FastPAD (T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: For each end of the connection, enter V for the VFC-03 card.
| FastPAD dedicated voice connections must originate and terminate on a FastPAD.
For each back card field entry, the NMT establishes a dedicated virtual circuit that connects one voice card on one FastPAD to one voice card on another FastPAD.
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| Adding FastPAD Bursty Data Connections
| Bursty Traffic table
Type field: Enter FR.
BC (Back Card) field: If the end has a FastPAD, enter the back card of the FTC that links the hub IPX/IGX to the FastPAD (T1, E1, V, or X). If the end is not a Cisco 3800, enter the back card of the FRP/FRM at that end (also T1, E1, V, or X).
Fdr BC (Feeder Back Card) field: If the end has a FastPAD, enter the connection interface on the line side of the FastPAD (S, R, V, V1, or V6). If the end does not have a FastPAD, leave this field blank.
| A FastPAD bursty data connection may have one end at a FastPAD and the other at an IPX/IGX FRP/FRM card. At least one end of the connection must have an entry in the Fdr BC.
|
| Setting Up Switched Voice Connections
| Voice Traffic table
Connect the FastPADs:
- Quantity field: Set the number of connections between a pair of FastPADs to the estimated peak number of simultaneous cell transmissions.
- Type field: Enter Session.
- BC (Back Card) field: Select valid FTC back card (V, X, T1, or E1).
- Fdr BC (Feeder Back Card) field: Leave blank.
Create dummy FastPAD connections:
- Site 1, Site 2 fields. Connect a site entered above to itself, e.g., Boston, Boston
- Hub ID fields. Optional. Hub 1 ID and Hub 2 ID can be used to specify the slot port of each end of the connection. Connect a site entered above to itself, e.g., 8.1, 8.1. This connection is intrasite, intracard, and interport.
- Quantity field: The number of dummy connections should equal one half the peak number of simultaneous calls expected between the FastPAD and all other switched voice destinations.
- Type field: Enter the voice traffic speed type.
- Fdr BC (Feeder Back Card) field: Enter V for the VFC-03 card.
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To add FastPAD switched voice connections, i.e., voice connections between at least one voice card on a FastPAD connected to at least one voice card on many FastPADs, you must perform a two-step process: connect the FastPADs and add dummy FastPAD connections.
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| Setting Up Multiple FastPADs at the Same Site
| Data Traffic table, Voice Traffic table, Bursty Traffic table
- Hub ID field: The ID is given to the port of the FTC/FTM card on the IPX/IGX that connects to the specific FastPAD. ID values can be
- Port only: 0
- Slot and port: mm.nn
- Where mm = 1 to 32 and nn = 1 to 31
|
For connections between multiple FastPADs at a site or to associate specific connections with specific FastPADs, use the Hub ID field for all FastPAD connections that originate or terminate at that site.
All connections associated with one specific FastPAD should have the same Hub ID throughout the three traffic tables.
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| Changing Default Parameters
| Feeders table
- Hub ID field: Enter Slot.Port (e.g., 6.4).
- Type field: Enter FP-4 for a FastPAD Micro, FP-8 for a regular FastPAD, or FP to have the NMT determine which one to use.
- Speed field: Enter the speed you want.
Data Traffic table, Voice Traffic table, Bursty Traffic table
- Hub1 ID field: Enter the Hub ID value entered in the Feeders table (e.g., 6.4).
- Hub 2 ID field: Enter the Hub ID for the appropriate site.
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You can specify a FastPAD or FastPAD micro unit and can specify the maximum speed of the composite link, i.e., 64 kbps, 128, kbps, or 256 kbps. If you specify FP (a generic FastPAD), NMT chooses the best one. If you specify 0 as the speed, NMT picks the best one.
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NMT allows you to model ATM to Frame Relay interworking connections. Refer to Table 4-6 for information on modeling ATM to Frame Relay interworking connections.
Table 4-6: ATF and FTA Connection Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Modeling ATM to Frame Relay
| Bursty Traffic table
Type field: Enter ATF or FTA.
| Use ATF when the ATM interface at Site1 interworks to a Frame Relay interface at Site2. Use FTA when a Frame Relay interface at Site1 to interworks to an ATM interface at Site2.
The ATM end must support the specified traffic type (i.e., must be a BPX or an IGX with 8.2.5 functionality).
All traffic values (MIR, PIR, QIR, CIR) are given in kbps for ATM traffic.
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An IMATM trunk is an ATM link of one to eight DS1 lines. Each IMATM trunk card uses a slot of an AXIS shelf and is connected to the BPX switch by means of a T3/E3 port on a BNI card. The trunk can be configured so that it fails only if more than n DS1 lines fail.
The NMT does not model IMATM trunk resiliency during failure analysis. To exclude IMATM trunks from failure analysis, see the section "Fail Analysis" in the chapter "Using the NMT."
Refer to Table 4-7 for information on configuring an IMATM trunk in the NMT.
Table 4-7: IMATM Trunk Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Specifying an IMATM Trunk
| Links table
Trunk (type) field: Specify a trunk of T1 or E1. Prepend the number of DS1s for the trunk, for example 5T1 or 8E1.
Trunk (capacity) field: For E1 links, specify number of DS0 in the line: 30 for CCS signalling or 32 for Clear Channel signalling.
Trunk card field: Specify IMA for both trunk front cards.
IMA_RD field: enter the resiliency degree.
| Both sites must be BPX.
The IMA_RD field is on the second screen of the Links table.
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The virtual trunking feature introduces the concept of defining multiple trunks within a single trunk port interface. It was developed to provide connectivity for a hybrid network consisting of Cisco ATM switches through a public ATM cloud.
NMT models virtual trunks on BNI, BXM, BTM, and AIT ports. To exclude virtual trunks from failure analysis, see the section "Fail Analysis" in the chapter "Using the NMT."
Refer to Table 4-8 for information on virtual trunk configurations.
Table 4-8: Virtual Trunk Configuration
| Topic
| Required Settings
| Comments
|
|---|
| Specifying a Virtual Trunk
| Links table
M (Media) field: Enter VT
Trnk_Cd field: Both ends must be specified. The ends can be different.
VTRate field: Specify the VT rate in cells per second.
...&Type field: Define the ATM type of link (ABR, CBR, UBR, VBR, or leave blank if the links support all types of traffic).
| If the back cards are different, the maximum size of VT is the minimum of the two protocols.
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