Frame Relay Networks
Frame Relay Networks became very popular in the 1990s due to the
efficiency and the economy of network facilities, as compared to point-to-point data
lines. While data lines are physical point-to point connections between specific
locations, frame relay networks consist of virtual connection between locations.
Locations in a frame relay network are physically connected to the
carrier’s network via a 56K or T-1 local loop provided by the local telephone company
(LEC). CNS can order this local loop from either the LEC directly or from the
carrier.
Each location in a frame relay network is assigned a port size, which is
how much bandwidth the carrier allows the end user as a maximum. A 56K line always
has a 56K port size. A T-1 line can have port sizes of 128K (2 channels on a T-1),
256K (4 channels), 384K, 512K, 768K, 1.023M or a full T-1 (1.536M). Each
location is programmed as to which other locations in the network it needs to transmit
data to and from. This virtual connection is called a PVC (Permanent Virtual
Connection). Each PVC is assigned a CIR (Committed Information Rate). The CIR
is the minimum guaranteed rate the carrier will allow on a particular PVC. As long as the
frame relay network is not at full capacity, the network will allow data to flow through
the network at rates higher than CIR. Transmitting data at speeds greater than CIR is
called “bursting”. As long as there is capacity in the network, the
frame relay network will allow data to be transmitted as fast as the port sizes of the two
locations.
Frame relay networks are designed with different port sizes, PVCs and
CIRs based on the needs of the particular customer and their application. Once the local
loops are installed into the various locations, port sizes (on a T-1) PVCs and CIRs can be
revised through software changes in the network. The only new installation at a
customer’s site would be if the port size (the local loop) had to be upgraded from a
56K line to a faster port size (T-1).
Each location on a frame relay network is assigned a DLCI (Destination
Link Connection Identifier), which essentially is the address of the location.
PVCs are designed as to which DLCI is allowed to transmit data to which location(s).
The cost of a frame relay connection is not usage or mileage sensitive.
Frame relay networks have (3) billing components, local loop, port size and PVC/CIRs.
The local loop will either be a 56K line or T-1. A T-1 loop
is typically 3-5 times more expensive than a 56K line. The local loop cost is mileage
sensitive and varies from local telephone company to local telephone company. CNS prices
out the local loop costs on a location-by-location basis. CNS requires the
area code and exchange of a location to get the cost of the local loops. In addition
to the local loop cost, the larger the port size and the larger the number and speed of
the PVC/CIRs are, the higher the cost.
A frame relay network will typically cost less than a private line
network when there are several locations and/or there is a great distance between
locations. Private line services are distance sensitive and tend to be less
expensive for shorter distances and few locations. CNS will price out both a frame
relay network and point-to point data lines to compare the cost for our customers.
CNS offers frame relay connections throughout the world, including
Canada, England, Spain, France, Italy, Australia, Hong Kong, Netherlands, Germany,
Belgium, Sweden, Switzerland, Puerto Rico, China, Japan, Singapore, Korea and Taiwan. |
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