Multi-Tech Systems MTASR1-100 - Manual (Page 16)

MTASR1-100 Owner’s Manual
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1.4.2Typical Frame Relay Application
A typical application of a frame relay network with a RouteFinder 100 at the Mounds View site with two virtual
circuits communicating through a public or private frame relay network to two remote sites (one at River Falls
and the second at Minneapolis). One of the virtual circuits through the frame relay network ties the Mounds
View LAN to LAN 2 at the River Falls site. A second virtual circuit connects the Mounds View LAN to LAN 3 in
Minneapolis.
In a frame relay network, a single physical connection can support multiple logical connections. Three primary
elements apply in a frame relay network that need to be defined at the time the network is subscribed for; the
access line, port connection, and the Permanent Virtual Circuits (PVCs) assigned. The access line is the
physical line connection from the local site to the frame relay network. This access line is terminated at the
user's site by a DCE which in this example is a fractional T1 DSU at the Mounds View site and 64K DSUs at
the remote sites. The port connection is the access point into the frame relay network via the local phone
company's frame relay switch. The logical connections are defined by PVCs which are logical connections
between two nodes (or port connections) on the frame relay network. Mulitple PVCs for the Mounds View site
allow multiple logical connections to be carried over one physical line.
Figure 1-7. Frame Relay Example
To setup a RouteFinder 100 for frame relay services, the Ethernet port of the LAN has to be configured for the
router, virtual WAN setup for each frame relay network, frame relay services subscribed for (requested from
your service provider), the access device (DSU) connected to the RouteFinder
100 and the port of the frame
relay network.
1.4.3 Subscription
Subscription of frame relay services involve communicating with your local network service provider to have
the physical line connected, the port connection defined, and assigning the Data Link Connection Identifiers
(DLCIs) which are numbers between 16 and 1007 that identify the virtual connection (PVC) at the local
interface between the RouteFinder
100 and the phone company's switch. When each DLCI is assigned, your
local service provider will define the permanent virtual circuit (PVC) that is the virtual path to the destination.
Each PVC is assigned an average guaranteed throughput rate called committed information rate (CIR) and
may have an excess burst rate (Be). The sum of the CIR and Be for all PVCs can not exceed the port
connection capacity (bandwidth). Finally during subscription, the management type is defined by the local
frame relay service provider. The management type is a mechanism for communicating the status of all the
PVCs on the port connection. Three types of management are supported by the RouteFinder
100 : local
management interface (LMI), Annex D, and Annex A.