Cisco IOS Switching Services Configuration�Guide, Release�12.2
Configuring the MPOA Server
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Configuring the Multiprotocol over ATM Server

Table Of Contents

Configuring the Multiprotocol over ATM Server

How MPS Works

MPS-NHRP-Routing Interaction

Shortcut Domains

MPS Configuration Task List

Configuring the ELAN ID

Configuring the MPS

Configuring the MPS Variables

Monitoring and Maintaining the MPS

MPS Configuration Example


Configuring the Multiprotocol over ATM Server


This chapter describes the required and optional tasks for configuring the Multiprotocol over ATM (MPOA) server (MPS).

For a complete description of the commands in this chapter, refer to the the Cisco IOS Switching Services Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release. For more information, see the section "Identifying Supported Platforms" in the chapter "Using Cisco IOS Software."

The MPS supplies the forwarding information used by the MPOA clients (MPCs). The MPS responds with the information after receiving a query from a client. To support the query and response functions, MPOA has adopted the Next Hop Resolution Protocol (NHRP). The MPS on the router can also terminate shortcuts.

How MPS Works

The MPS software module implements the functionality of the MPS in compliance with the ATM Forum MPOA specification. The following sections describe the functions of MPS:

MPS-NHRP-Routing Interaction

Shortcut Domains

MPS-NHRP-Routing Interaction

MPS must interact with the NHRP module in the router to smoothly propagate MPOA/NHRP packets end to end. MPOA frames are identical to NHRP frames except for some specific op-codes and extensions for MPOA.

The following process explains the interaction of MPS and NHRP:

1. MPS converts MPOA resolution requests to NHRP requests and sends it either to the next hop MPS or to the Next Hop Server (NHS), depending on the configuration. MPS searches for the next hop routing information to determine the interface and sends the packet with correct encapsulation to an MPS or an NHS.

2. NHS sends resolution requests to MPS when the next hop is on a LAN Emulation (LANE) cloud or when NHS is unsure of the packet destination. MPS may do further processing, such as prompt NHS to terminate the request or throw away the packet.

3. NHS sends resolution replies to MPS when the next hop interface is LANE or when the replies terminate in the router. Then MPS sends an MPOA resolution reply to the MPC.

Shortcut Domains

Within a router, it is possible to permit shortcuts between one group of LAN Emulation Clients (LECs) and deny it between some other groups of LECs. Cisco introduces a notion of network ID associated with an MPS. By default, all the MPSs in a router get a network ID of 1.

If the administrator wants to segregate traffic, then MPSs can be given different network IDs, in effect preventing shortcuts between LECs served by different MPSs. This can be configured in the definition of an MPS database.

If a router has both MPS and NHRP configured, then the same network ID is required to facilitate requests, replies, and shortcuts across the MPS and NHRP. The interface-specific NHRP command (ip nhrp network-id) must be the same for an MPS; otherwise, there will be a disjointed network.

MPS Configuration Task List

To configure an MPS on your network, perform the following tasks:

Configuring the ELAN ID (Required)

Configuring the MPS (Required)

Configuring the MPS Variables (Optional)

Monitoring and Maintaining the MPS (Optional)

Configuring the ELAN ID

For MPOA to work properly, a LANE client must have an ELAN ID for all ELANs represented by the LANE clients. To configure an ELAN ID, use either of the following commands in lane database configuration mode or in interface configuration mode when starting up the LAN Emulation Client Server (LECS) for that ELAN:

Command
Purpose

Router(lane-config-dat)# name elan-name elan-id id

Configures the ELAN ID in the LECS database to participate in MPOA.

Router(lane-config-dat)# lane server-bus {ethernet | tokenring} elan-name [elan-id id]

Configures the LAN Emulation Server (LES) with the ELAN ID to participate in MPOA.



Caution If an ELAN ID is supplied by both commands, make sure that the ELAN ID matches in both.

Configuring the MPS

To configure an MPS, use the following commands beginning in global configuration mode. The MPS starts functioning only after it is attached to a specific hardware interface:

 
Command
Purpose

Step 1 

Router(config)# mpoa server config name mps-name

In global configuration mode, defines an MPS with the specified name.

Step 2 

Router(config)# interface atm {slot/port | number}

Specifies the ATM interface to attach the MPS.

Step 3 

Router(config-if)# mpoa server name mps-name

In interface configuration mode, attaches the MPS to the ATM interface.

Step 4 

Router(config-if)# interface atm {slot/port.subinterface-number | number.subinterface-number}

Specifies the ATM interface to bind the MPS to a LEC.

Step 5 

Router(config-subif)# lane client mpoa server name mps-name

In subinterface configuration mode, binds a LANE client to the specified MPS.

Configuring the MPS Variables

An MPS must be defined with a specified name before you can change the MPS variables specific to that MPS.

To change MPS variables specific only to a particular MPS, use the following commands beginning in MPS configuration mode:

 
Command
Purpose

Step 1 

Router(mpoa-server-config)# mpoa server config name mps-name

Defines an MPS with the specified name.

Step 2 

Router(mpoa-server-config)# atm-address atm-address

(Optional) Specifies the control ATM address that the MPS should use (when it is associated with a hardware interface).

Step 3 

Router(mpoa-server-config)# holding-time time

(Optional) Specifies the holding time value for the MPS-p7 variable of the MPS.

Step 4 

Router(mpoa-server-config)# keepalive-lifetime time

(Optional) Specifies the keepalive lifetime value for the MPS-p2 variable of the MPS.

Step 5 

Router(mpoa-server-config)# keepalive-time time

(Optional) Specifies the keepalive time value for the MPS-p1 variable of the MPS.

Step 6 

Router(mpoa-server-config)# network-id id

(Optional) Specifies the network ID of the MPS.

Monitoring and Maintaining the MPS

To monitor and maintain the configuration of an MPS, use the following commands in EXEC mode, as needed:

Command
Purpose

Router# show mpoa default-atm-addresses

Displays default ATM addresses for an MPS.

Router# show mpoa server [name mps-name]

Displays information about a specified server or all servers depending on the specified name of the required server.

Router# show mpoa server [name mps-name] cache
[ingress | egress] [ip-address ip-address]

Displays ingress and egress cache entries associated with a server.

Router# show mpoa server [name mps-name] statistics

Displays all the statistics collected by a server including the ingress and egress cache entry creations, deletions, and failures.

Router# clear mpoa server [name mps-name] cache [ingress | egress] [ip-addr ip-addr]

Clears cache entries.

Router# mpoa server name mps-name trigger ip-address ip-address [mpc-address mpc-address]

Originates an MPOA trigger for the specified IP address to the specified client. If a client is not specified, the MPOA is triggered to all the clients.


MPS Configuration Example

This section contains an example of the commands needed to configure an MPS. The lines beginning with exclamation points (!) are comments explaining the command shown on the following line. Figure 100 shows an example of how you can configure your system to utilize MPOA.

Figure 100 Example of an MPOA Configuration

The following example configures the MPS and attaches the MPS to a hardware interface:

! Define the MPS "MYMPS"
 mpoa server config name MYMPS
! Leave everything as default
 exit
! Enter into interface config mode
 interface ATM 1/0
! Attach MPS MYMPS to the HW interface
 mpoa server name MYMPS
! Go back up to global config mode
 exit

The following example shows a typical MPS configuration file:

version 11.3
hostname MPS
! Define the MPS "mps"
mpoa server config name mps
! Specify the ATM interface to which the MPS is attached
interface ATM4/0
no ip address
atm pvc 1 0 5 qsaal
atm pvc 2 0 16 ilmi
lane config auto-config-atm-address 
mpoa server name mps
! Specify the ATM interface that contains the LEC to which you will bind the MPS
interface ATM4/0.1 multipoint
ip address 1.1.1.2 255.255.255.0
lane client mpoa server name mps
lane client ethernet elan1
interface ATM4/0.2 multipoint
ip address 1.1.2.1 255.255.255.0
lane client mpoa server name mps
lane client ethernet elan2
end