User`s guide

Configuring Frame Relay
Using the MultiVoice Gateway as a Frame Relay concentrator
MultiVoice Gateway for the MAX— User’s Guide Preliminary November 23, 1998 7-3
User to Network Interface—Data Communications Equipment (UNI-DCE)
Figure 7-4. User to Network Interface-Data Communications Equipment (UNI-DCE)
UNI is the interface between an end-user and a network end point (a router or a switch) on the
Frame Relay network. In a UNI-DCE connection, the MultiVoice Gateway operates as a Frame
Relay router communicating with a DTE device. To the DTE devices, it appears as a Frame
Relay network end point. (For more information, see “Configuring a UNI-DCE interface” on
page 7-7.)
User to Network Interface—Data Terminal Equipment (UNI-DTE)
In a UNI-DTE connection, configure the MultiVoice Gateway as a UNI-DTE communicating
with a Frame Relay switch. It acts as a Frame Relay feeder and performs the DTE functions
specified for link management. (For more information, see “Configuring a UNI-DTE
interface” on page 7-7.)
Figure 7-5. User to Network Interface - Data Terminal Equipment (UNI-DTE)
Types of Frame Relay connections
For Frame Relay connections, the MultiVoice Gateway supports gateway connections and
Frame Relay circuits:
Gateway connections
The MultiVoice Gateway receives an incoming PPP call, examines the destination IP address,
and brings up the appropriate Connection profile to that destination, as usual. If the Connection
profile specifies Frame Relay encapsulation, the Frame Relay profile, and a DLCI, the
MultiVoice Gateway encapsulates the packets in Frame Relay (RFC 1490) and forwards the
data stream out to the Frame Relay switch using the specified DLCI. The Frame Relay switch
uses the DLCI to route the frames. This is known as gateway mode.
Frame Relay circuits
A Frame Relay circuit is a permanent virtual circuit (PVC) segment that consists of two DLCI
end points and possibly two Frame Relay profiles. It requires two and only two DLCI numbers.
If the circuit has only one DLCI, the MultiVoice Gateway drops the data. If you configure
more than two DLCIs, Frame Relay only uses two DLCI numbers. You define a circuit in two
CPE
UNI-DTE
UNI-DCE
MultiVoice
FR switch
UNI-DTE UNI-DCE
MultiVoice