DIGITAL GIGAswitch/Router User Reference Manual
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Configuring Frame Relay Interfaces for the GSR
Virtual Circuits
You can think of a Virtual Circuit (VC) as a “virtual interface” (sometimes referred to as
“sub-interfaces”) over which Frame Relay traffic travels. Frame Relay interfaces on the
GSR use one or more VCs to establish bidirectional, end-to-end connections with remote
end points throughout the WAN. For example, you can connect a series of multi-protocol
routers in various locations using a Frame Relay network.
Permanent Virtual Circuits (PVCs)
WAN interfaces can take advantage of connections that assure a minimum level of
available bandwidth at all times. These standing connections, called Permanent Virtual
Circuits (PVCs), allow you to route critical packet transmissions from host to peer without
concern for network congestion significantly slowing, let alone interrupting, your
communications. PVCs are the most prevalent type of circuit used today and are similar to
dedicated private lines in that you can lease and set them up through a service provider.
In a corporate setting, network administrators can use PVCs in an internal network to set
aside bandwidth for critical connections, such as videoconferencing with other corporate
departments.
Configuring Frame Relay Interfaces for the GSR
This section provides an overview of configuring a host of WAN parameters and setting
up WAN interfaces. When working in the Frame Relay protocol environment, you must
first define the type and location of the WAN interface. Having established the type and
location of your WAN interfaces, you need to (optionally) define one or more service
profiles for your WAN interfaces, then apply a service profile to the desired interface(s).
An example of this process is covered in
“Frame Relay Port Configuration” on page 305
.
Defining the Type and Location of a Frame Relay and VC Interface
To configure a frame relay WAN port, you need to first define the type and location of one
or more frame relay WAN ports or virtual circuits (VCs) on your GSR. The following
command line displays a simplified example of a frame relay WAN port definition:
Note:
If the port is a HSSI port that will be connected to a HSSI port on another router,
you can also specify
clock
<clock-source>
in your definition.
Define the type and location of
a frame relay WAN port.
port set
<port>
wan-encapsulation frame-
relay speed
<number>