Table of Contents

Configuration, BXM VSIs

Configuration, BXM VSIs

This chapter provides a brief description of the BXM Virtual Switch Interfaces (VSIs) and some of the new features with Release 9.2. Refer to Cisco WAN Switch Command Reference for further details. Refer to Release Notes for supported features.

The chapter contains the following:

• Virtual Switch Interfaces
  
  
• VSI Master and Slaves
  
  
• Class of Service (COS) Templates
  
  

Virtual Switch Interfaces

Virtual Switch Interfaces (VSIs) allow a node to be controlled by multiple controllers such as MPLS, PNNI, and so on. These control planes can be external or internal to the switch.

When a virtual switch interface (VSI) is activated on a port, trunk, or virtual trunk for use by a master controller, such as a PNNI controller, or a MPLS controller, the resources of the virtual interface associated with the port, trunk or virtual trunk are made available to the VSI.

VSI Controller

A VSI controller, such as an MPLS controller, is added to a BPX switch using the addshelf command with the VSI option. In the MPLS case, the routing protocol such as OSPF, uses the Label Distribution Protocol (LDP) to set up MPLS virtual connections (VCs) on the switch.

Virtual Interfaces

The BXM has 31 virtual interfaces that provide a number of resources including qbin buffering capability. One virtual interface is assigned to each logical trunk (physical or virtual) when the trunk is enabled. (See Figure 16-1.)

Each virtual interface has 16 qbins assigned to it. Qbins 0-9 are used for Autoroute and 10-15 are available for use by a VSI enabled on the virtual interface. (In Release 9.1, only qbin 10 was used.) The qbins 10-15 support class of service (CoS) templates on the BPX.

A virtual switch interface may be enabled on a port, trunk, or virtual trunk. The virtual switch interface is assigned the resources of the associated virtual interface.

With virtual trunking, a physical trunk can comprise a number of logical trunks called virtual trunks, and each of these virtual trunks is assigned the resources of one of the 31 virtual interfaces on a BXM (see Figure 16-1).

VSI Master and Slaves

A controller application uses a VSI master to control one or more VSI slaves. For the BPX, the controller application and Master VSI reside in an external 7200 or 7500 series router and the VSI slaves are resident in BXM cards on the BPX node (see Figure 16-2).

The controller sets up the following types of connections:

• Control virtual connections (VCs)
  
  
  • Master to Slave
    
    
  • Slave to Slave
    
    
• User Connection
  
  
  • User connection (that is, cross-connect)
    
    

The controller establishes a link between the VSI master and every VSI slave on the associated switch. The slaves in turn establish links between each other (see Figure 16-3).

With a number of switches connected together, there are links between switches with cross connects established within the switch as shown in Figure 16-4.

Partitioning

Partitioning. The VSIs need to partition the resources between competing controllers, Autoroute, Tag, and PNNI for example. Partitioning is done with the cnfr command.

For Release. 9.1 and Release 9.2, just one controller (of a particular type) is supported. However, you can have different types of controllers splitting up a partition's assets. For example, Autoroute and tag, or Autoroute and PNNI (svcs), but not both PNNI and MPLS for Release 9.1 and Release 9.2.

The resources that need to be configured for a partition are shown in Table 16-1 for a partition designated ifci, which stands for interface controller 1 in this instance. The three parameters that need to be distributed are number of logical connections (lcns), bandwidth (bw), and virtual path ids (vpi).

The controller is supplied with a logical lcn connection number, that is slot, port, and so on., information that is converted to a logical connection number (lcn).

Some ranges of values available for a partition are listed in Table 16-2:

When a trunk is added, the entire bandwidth is allocated to Autoroute. To change the allocation in order to provide resources for a vsi, the cnfr command is used on the BPX switch. A view of the resource partitioning available is shown in Figure 16-5.

Class of Service Templates

Class of Service Templates (COS Templates) provide a means of mapping a set of standard connection protocol parameters to "extended" platform specific parameters. Full QoS implies that each VC is served through one of a number of Class of Service buffers (Qbins) which are differentiated by their QoS characteristics.

When you activate an interface with an uptrk or upport command, a default service template is automatically assigned to that interface. The corresponding qbin templates are simultaneously set up in the BXM's data structure.

Functional Description

The service class template provide a means of mapping a set of extended parameters, which are generally platform specific, based on the set of standard ATM parameters passed to the VSI slave during connection setup.

A set of service templates is stored in each switch (e.g., BPX) and downloaded to the service modules (e.g., BXMs) as needed.

The service templates contains two classes of data. One class consists of parameters necessary to establish a connection (that is, per VC) and includes entries such as UPC actions, various bandwidth related items, per VC thresholds, and so on. The second class of data items includes those necessary to configure the associated class of service buffers (qbins) that provide QoS support.

The general types of parameters passed from a VSI Master to a Slave include:

• A service type identifier
  
  
• QOS parameters (CLR, CTD, CDV)
  
  
• Bandwidth parameters (e.g. PCR, MCR)
  
  
• Other ATM Forum Traffic Management 4.0 parameters
  
  

Each VC added by a VSI master is assigned to a specific service class by means of a 32-bit service type identifier. Current identifiers are for:

• ATM Forum service types
  
  
• Autoroute
  
  
• MPLS Switching
  
  

When a connection setup request is received from the VSI master in the Label Switch Controller, the VSI slave (in the BXM, for example) uses the service type identifier to index into a Service Class Template database containing extended parameter settings for connections matching that index. The slave uses these values to complete the connection setup and program the hardware.

One of the parameters specified for each service type is the particular BXM class of service buffer (qbin) to use. The qbin buffers provide separation of service type to match the QoS requirements.

Service templates on the BPX are maintained by the BCC and are downloaded to the BXM cards as part of the card configuration process as a result of card activation, rebuild, or switchover. In Release 9.2 the templates are non-configurable.

There are 3 types of templates:

• VSI Special Types
  
  
• ATMF Types
  
  
• MPLS Types
  
  

You can assign any one of the nine templates to a virtual switch interface. (See Figure 16-6.)

Structure

When the upport or uptrk command is used to activate an interface on the BXM card, the default service template, which is MPLS1, is assigned to the interface. This service template has an indentifier of "1". The service template assigned to an interface can be changed with the cnfvsiif command. This can be done only when there are no active VSI connections on the BXM. The templates can be displayed with the dspvsiif command.

Each template table row includes an entry that defines the qbin to be used for that class of service (see Figure 16-7).

This mapping defines a relationship between the template and the interface qbin's configuration.

A qbin template defines a default configuration for the set of qbins for the logical interface. When a template assignment is made to an interface, the corresponding default qbin configuration becomes the interface's qbin configuration. Some of the parameters of the interface's qbin configuration can be changed on a per interface basis. Such changes affect only that interface's qbin configuration and no others, and do not affect the qbin templates.

Qbin templates only are used with qbins that are available to VSI partitions, namely qbins 10 through 15. Qbins 10 through 15 are used by the VSI on interfaces configured as trunks or ports. The rest of the qbins (0-9) are reserved for and configured by Autoroute.

Downloading Service Templates

Service templates are downloaded to a card (BXM) under the following conditions:

• add y-red card
  
  
• on a BCC (control card) switchover
  
  
• when a card has active interfaces and is reset (Hardware reset)
  
  
• on a BCC (control card) rebuild
  
  

Assignment of a Service Template to an interface

A default service template is assigned to a logical interface (VI) when the interface is upped via upport/uptrk.

For example:

• uptrk 1.1
  
  
• uptrk 1.1.1 (virtual trunk)
  
  
• upport 1.1
  
  

This default template has the identifier of 1. Users can change the service template from service template 1 to another service template using the cnfvsiif command.

The cnfvsiif command is used to assign a selected service template to an interface (VI) by specifying the template number. It has the following syntax:

cnfvsiif <slot.port.vtrk> <tmplt_id>

For example:

• cnfvsiif 1.1 2
  
  
• cnfvsiif 1.1.1 2
  
  

The dspvsiif command is used to display the type of service template assigned to an interface (VI). It has the following syntax:

dspvsiif <slot.port.vtrk>

• dspvsiif 1.1
  
  
• dspvsiif 1.1.1
  
  

Card Qbin Configuration

When an interface (VI) is activated by uptrk or upport, the default service template is assigned to the interface (VI). The corresponding qbin template is then copied into the card's (BXM) data structure of that interface. A user can change some of the qbin parameters using the cnfqbin command. The qbin is now "user configured" as opposed to "template configured". This information may be viewed on the dspqbin screen.

Qbin dependencies

The available qbin parameters are shown in Table 16-3. Notice that the qbins available for VSI are restricted to qbins 10-15 for that interface. All 31 possible virtual interfaces are each provided with 16 qbins.

Additonal service template commands are:

dspsct: This command is used to display the template number assigned to an interface. The command has three levels of operation:

dspsct {with no arguments lists all the service templates resident in the node.

dspsct <tmplt_id> {lists all the Service Classes in the template.

dspsct <tmplt_id> SC lists all the parameters of that Service Class.

dspqbintmt: displays the qbin templates.

cnfqbin {configures the qbin, The user can answer yes when prompted and the command will used the card qbin values from the qbin templates.

dspqbin {displays qbin parameters currently configured for the virtual interface.

dspvsipartinfo {displays some VSI resources for a trunk and partition.

dspcd {display the card configuration.

Extended Services Types Support

The service-type parameter for a connection is specified in the connection bandwidth information parameter group. The service-type and service-category parameters determine the service class to be used from the service template.

Connection Admission Control

For Release 9.2, when a connection request is received by the VSI Slave, it is first subjected to a Connection Admission Control (CAC) process before being forwarded to the FW layer responsible for actually programming the connection. The granting of the connection is based on the following criteria:

LCNs available in the VSI partition

• Qbin
  
  
• Service Class
  
  

QoS guarantees

• max CLR
  
  
• max CTD
  
  
• max CDV
  
  

When the VSI slave accepts (that is, after CAC) a connection setup command from the VSI master in the MPLS Controller, it receives information about the connection including service type, bandwidth parameters, and QoS parameters. This information is used to determine an index into the VI's selected Service Template's VC Descriptor table thereby establishing access to the associated extended parameter set stored in the table.

Supported Service Types

The service type identifier is a 32-bit number. In Release 9.2.30, there are three service types: VSI Special Type, ATMF Types, and MPLS types. A list of supported service types is shown in Table 16-4.

VC Descriptors

A summary of the parameters associated with each of the service templates is provided in Table 16-5 through Table 16-8. Table 16-9 provides a description of these parameters and also the range of values that may be configured if the template does not assign an arbitrary value.

Table 16-5 lists the parameters associated with Default (0x0001) and Signaling (0x0002) service template categories.

Table 16-6 and Table 16-7 lists the parameters associated with the PNNI service templates.

* indicates not applicable

Table 16-8 lists the connection parameters and their default values for tag switching service templates.

VC Descriptor Parameters

Table 16-9 describes the connection parameters that are listed in the preceding tables and also lists the range of values that may be configured, if not pre-configured.

Every service class does not include all parameters. For example, a CBR service type have fewer parameters than an ABR service type.