
Configuring ATM Services
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The MPC monitors traffic flows between a local source and remote
destinations. When traffic volume between a source and a destination exceed a
pre-configured threshold level (for example x packets to the same network
layer address in y seconds), the MPC attempts to set up an SVC between
source and destination workstations.
In attempting to set up an SVC, the MPC first looks in a local cache of
network layer to ATM address mappings. If MPC finds the destination address
in its local cache, it immediately begins to establish the SVC. If it fails to
locate the destination address in the local cache, it generates an MPOA
address resolution request to an adjacent MPOA server.
• MPOA router
The MPOA router is a collection of logical functions that map network layer
addresses to ATM addresses. The MPOA router maintains tables of adjacent
network layer (IP), MAC layer, and ATM addresses, in addition to standard
routing tables derived from a routing protocol (generally OSPF or RIP).
MPOA routers communicate via NHRP to map network layer addresses to
ATM addresses. BayRS provides MPOA router functionality to map IP
addresses to their ATM counterparts.
• MPOA server
The MPOA server (MPS) is a logical function that mediates between local
MPCs and the MPOA router. It receives MPOA address resolution requests
from MPCs and passes them to the MPOA routing function. The MPOA
router, using NHRP, resolves the address and passes the requested ATM
address back to MPS. MPS, in turn, forwards the resolved address to the
requesting MPC. BayRS provides MPOA server functionality.
MPOA Basic Elements
MPOA services are dependent on three basic elements.
• LANE
LANE (LAN emulation) provides transparent support for legacy LANs in an
ATM topology. LANE enables intrasubnet communication, and MPOA
provides intersubnet communication.
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