ATM Configuration and Troubleshooting Guide

Configuring LAN Emulation Interfaces
Summary of LAN Emulation
Chapter 446
that the ATM Forum specifies that an MPC canbe used by more than
one LEC. However, in HP’s implementation of MPOA, an MPC can be
used by only one LEC.
• Next Hop Server (NHS)—A server part of the NHRP protocol; it
resides on an MPOA router, and the MPS on the same router works
with the NHS to resolve address resolution requests from MPCs.
• Next Hop Client (NHC)—A client part of the NHRP protocol; it can
reside on a router.
MPOA has these physical components:
• MPOA router—An ATM router that contains MPOA logical
components: one or more LECs, one or more MPSs, and one or more
NHSs. An MPOA router can also contain zero or more NHCs and
zero or more MPCs. An MPOA router uses NHRP to communicate
with other MPOA routers to resolve destination addresses. So, they
help MPCs to establish shortcut routes.
• MPOA host—An ATM host that contains one or more LECs and one
or more MPCs. This allows the host to send packets across subnet
boundaries, bypassing routers.
• MPOA edge device—An ATM edge device that contains one or
more MPCs. This allows the edge device to forward packets to an
MPOA host across subnet boundaries, bypassing routers.
How MPOA Works
The following sections describe some more MPOA terms, an overview of
describe some more MPOA terms, an overview of routing, and a
more-detailed description of how a packet gets routed.
More MPOA Terminology To understand how MPOA works, you first
must understand some more of the terminology. The part of the ATM
network that is MPOA capable is called the MPOA system. The point
where an inbound data flow enters the MPOA system is called the
Ingress, and the point where an outbound data flow exits the MPOA
system is called the Egress. An MPC that is at the Ingress is called an
Ingress MPC, and an MPC at the Egress is called an Egress MPC.
Likewise, an MPS that is serving an Ingress MPC for a specific data flow
is called the Ingress MPS, and an MPS serving an Egress MPC for a
specific data flow is called an Egress MPS.