Nortel Networks 8000 - Manual (Page 293)

Nortel Secure Router 8000 Series
Configuration -WAN Access 8 Frame relay configuration
8.1 Introduction
This section covers the following topics that you need to know before you configure FR:
FR protocol and related concepts
PVC standby of frame relay switching
Frame relay compression
multilink
References
8.1.1 FR protocol and related concepts
FR protocol FR interface type
A Frame Relay (FR) network provides data communication between user devices (such as
routers and hosts).
According to different functions, frame relay devices and interfaces can be divided into the
following three types:
• The user device is called Data Terminal Equipment (DTE). The interfaces on the DTE
are called DTE interfaces.
• The device that provides access for DTE is called Data Circuit-terminating Equipment
(DCE), belonging to the network device. The interfaces on the DCE devices are called
DCE interfaces or Network-to-Network Interfaces (NNIs) interfaces.
The interfaces that connect the DTE and the DCE are User-to-Network Interfaces (UNIs).
• The interface between the frame relay switches is NNIs.
In actual networking, the DTE interface can be connected only to the DCE interface and the
NNI interface can be connected only to the NNI interface.
Figure 8-1 FR interface type
UNI NNI UNI
_f
DTE
ServerA
DC ^^U^ NNI
RouterA
NNI
RouterB RouterC
DTE
Lf
ServerB
For the equipment used for FR switching, its frame relay interface type should be NNI or
DCE.
A FR network can be a public network, a private network, or a network formed by direct
connection between data devices.
Issue 5.3 (30 March 2009) Nortel Networks Inc. 8-3