3Com CoreBuilder 9000, User Manual

Page: 322 / 468

322 C
HAPTER
11: N
ETWORK
I
NTERFACE
M
ANAGEMENT
Network Interfaces
To enable individual ATM devices to function together in an ATM
network, standard software interfaces are provided between each device
and the devices to which it is connected.
Three types of interfaces are used:
User-Network Interface (UNI) — The interface between an ATM user
device and an ATM switch unit.
Network, Network Interface (NNI) — The interface between two ATM
switch units.
Gateway Interface (GWY) — An IISP interface for connecting the
CoreBuilder
®
9000 ATM Enterprise Switch to switches of other
vendors.
User Network
Interface
A User-Network Interface (UNI) operates between an ATM user and a
private ATM switch, or between a private ATM switch and the public
carrier ATM network. There is very little difference between a public and a
private UNI. Private UNIs support physical-layer interfaces for
short-distance links, and public UNIs support interfaces between a user
and a carrier that require longer distance performance and carrier
management.
Network Interface A Network-to-Network Interface (NNI) operates between two ATM
network devices (switches). Each switch may be a private ATM switch or
the public carrier ATM network.