NetWare Link/Frame Relay Parameters

NetWare Link/Frame Relay network service parameters, which are determined at subscription time, are in effect on a per-virtual-circuit basis. To set up and use NetWare Link/Frame Relay, the following parameters must be configured before frame relay link activation:

• DLCIs are the PVC numbers that you need for data transfer (one DLCI denotes one end of a virtual circuit). Two DLCIs, one at each end of the connection, are required to form one end-to-end virtual circuit. The DLCI is also known as the virtual circuit number.
• Committed burst size (Bc) is the maximum number of data bits that a network agrees to transfer under normal conditions over a measured time interval.
• Excess burst size (Be) is the maximum number of uncommitted data bits that the network attempts to deliver over a measured time interval.
• Committed information rate (CIR) is 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.
• The physical access rateaccess rate (AR) of the user channel is the throughput rate, in bits per second, that limits the load offered to the frame relay network.
• The measurement interval (T) is the time 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 then sends the frame through the network to the remote end node.

Minimum committed bandwidth access is enforced using the CIR protocol feature. 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, however, 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 from the network must be available before excess bursting can occur.