Specifications

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Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases
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Chapter 9 Cisco IGX 8400 Series Frame Relay Service
Frame Relay—Functional Overview
Using Frame Relay Classes
For each FR connection you add, you must specify an FR class. An FR class is a set of parameters that
specify the bandwidth and congestion-prevention characteristics for a connection. Cisco provides ten
predefined classes, but you can modify any of the ten FR classes with the cnfcls command. To see the
parameters in all connection classes, run the dspcls command. An FR class is relevant only at the time
you add a connection with the addcon command. Once the connection exists, the system uses the
parameters but does not keep track of the class number.
Apart from using the cnffrcls command, you can change one or more FR parameters with the addcon
command. When you add an FR connection with addcon, a prompt appears requesting an FR class. At
this prompt you can do one of the following:
• Enter the number of a predefined class. The range is 1–10.
• Enter the number of a class modified with the cnffrcls command. The range is 1–10.
• Override one or more parameters in a connection class by typing the class number—without
pressing the Return key—then continue the line by typing either a new value or an asterisk (*) for
each parameter. Separate each item with a space and no comma.
If you are overriding class parameters, but want to keep the existing value of the parameter, use the
asterisk to cause the connection to use the existing value of the parameter in that class. Most parameters
are bidirectional and have the format parameter/parameter. If you want to keep a value for both
directions, enter a single *. If you want to change a value for only one direction, enter the parameter in
the form */new_parameter or new_parameter/*. When you type individual parameters, you need to enter
characters only up to the last changed item. Before the last item, you must enter new values or * as a
placeholder.
The parameters in the list that follows make up an FR class. Collectively, the name of these parameters
is frp_bw. For most parameters, you can specify the value for each direction of the connection, so most
parameter names appear in the format parameter/parameter. ForeSight (FST) is the exception because
ForeSight automatically applies to both directions.
• MIR/MIR is defined as fr_MIR_Tx /fr_MIR_Rx, where fr_MIR is the minimum information rate
for the connection. The range for MIR is 2.4 kbps–2048 kbps.
• CIR/CIR is defined as fr_CIR_Tx and fr_CIR_Rx, where fr_CIR is defined as the committed
information rate guaranteed to the user.
The full range of values for FR cards is 0–2048 kbps. Note that a CIR of 0 is not a standard setting.
The standard range is 2.4 kbps–2048 kbps. CIR = 0 is a valid parameter only if the connection
terminates at both ends on either a UFM or FRM. Before you can specify CIR = 0 with either addcon
or cnffrcls, you must enable IDE-to-DE mapping with the cnffrport command. If you do not first
enable IDE-to-DE mapping, the range for CIR is 2.4 Kbps–2048 kbps. Additionally, the CIR = 0
specification is necessary at only one end of the connection.
• VC_Q/VC_Q is defined as fr_vc_q_Tx/fr_vc_q_Rx, where fr_vc_q Tx is the transmit VC
maximum queue depth. Specify the VC_Q in bytes within the range 1–65535.
Bc/Bc is defined as fr_Bc_Tx /fr_Bc_Rx. If you have selected FR Forum standard parameters
(through the cnfsysparm command), the Committed Burst (Bc) parameter is used instead of vc_q.
Bc is defined as the amount of data the network can accept over a variable time interval Tc for
committed delivery on a specific PVC. Specify Bc in bytes in the range 1–65535. Bc has meaning
for only FST connections. The relationship between Bc and VC_Q is Bc = VC_Q / ((1 – (CIR/port
speed)).
• PIR/PIR is defined as fr_PIR_Tx /fr_PIR_Rx, where fr_PIR_Tx is the peak transmit rate for the
PVC. The PIR range is 2.4–2048 kbps. You can also specify the value 0 to cause PIR to default to
the port speed. Thus, you can modify PIR, leave it the same, or set it to the port speed.