Configuring the Multiprotocol over ATM Server

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.

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.

For MPOA to work properly, a LANE client must have an ELAN ID for all ELANs represented by the LANE clients.

Caution

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

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:

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

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

1.    Router(config)# mpoa server config namemps-name

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

3.    Router(config-if)# mpoa server namemps-name

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

5.    Router(config-subif)# lane client mpoa server namemps-name

1.    Router(mpoa-server-config)# mpoa server config namemps-name

2.    Router(mpoa-server-config)# atm-addressatm-address

3.    Router(mpoa-server-config)# holding-timetime

4.    Router(mpoa-server-config)# keepalive-lifetimetime

5.    Router(mpoa-server-config)# keepalive-timetime

6.    Router(mpoa-server-config)# network-idid

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

Router# show mpoa default-atm-addresses

Router# show mpoa server [name mps-name
]

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

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

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

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