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To set up and use NetWare Link/Frame Relay, you must determine the following network service parameters at subscription time. These parameters are statically configured before link activation and are in effect on a per-virtual-circuit basis.
DLCIs ---The PVC numbers that you need for data transfer. (One DLCI denotes one end of a virtual circuit; it takes two DLCIs to form one end-to-end virtual circuit.) The DLCI is also known as the virtual circuit number.
Bc ---The Committed Burst size, or the maximum number of data bits that a network agrees to transfer under normal conditions over a measured time interval.
Be ---The Excess Burst size, or the maximum number of uncommitted data bits that the network attempts to deliver over a measured time interval.
CIR ---The Committed Information Rate, or the user information rate, in bits per second, at which the network agrees to transfer data on a particular virtual circuit under typical operating conditions.
AR ---The Physical Access Rate of the user channel in bits per second. The offered load to the frame relay network is bounded by this parameter.
T ---A measurement interval, or the time interval over which rates and burst sizes are measured.
When a client workstation needs access to a remote node, the NetWare Link/Frame Relay router sends the frame to the local frame relay network switch, which sends it through the network to the remote end node.
The CIR protocol is used to enforce minimum committed bandwidth access. If a user exceeds the specified CIR limit, there is a risk of dropped packets; however, users working within their set CIR are usually guaranteed delivery by the service provider.
The frame relay network switch monitors the access rate and size of data frames transferred through the mesh network. The data throughput CIR is guaranteed by the network, but allows for excess bursts (Be) of data not to exceed the access rate (AR) of the connection. The committed burst size (Bc) sets the maximum amount of data that the network agrees to transfer in a specified time period.
Bursting above the set CIR is allowed only if the connection is configured for it and the actual bandwidth is available on an end-to-end basis. This means that the entrance edge node into the frame relay network, the transit nodes within the network, and the exiting edge node of the network must be available.
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