Beta Draft Confidential
Configuring SPVCs
Defining a Point-to-Point Offnet Circuit Connection
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000
1/19/05
18-19
Zero CIR
(Frame Relay
endpoint -
forward or
reverse
direction)
If you select the check box (enable Zero CIR), the offnet circuit has an
assigned CIR value of zero (0) and is a best-effort delivery service.
Customer data that is subscribed to Zero CIR service can burst to the
port speed if there is network bandwidth available to deliver frames.
However, no frame-delivery guarantees are made. All frames entering
the network on Zero CIR PVCs have discard eligible (DE) set to 1.
Note: If you enable Zero CIR, you cannot set the CIR, BC, and BE
values.
CIR (kbits/sec)
(Forward and
Reverse
direction)
Select the CIR in kilobits per second (Kbps) at which the network
transfers data under normal conditions. Normal conditions refer to a
properly designed network with ample bandwidth and switch capacity.
The rate is averaged over a minimum increment of the committed rate
measurement interval (Tc). The value on each PVC is asymmetric (you
can set a different CIR in each direction), which provides more
efficient use of bandwidth.
BC (kbits)
(Forward and
Reverse
direction)
Select the maximum amount of data, in kilobits (Kb), that the network
attempts to transfer under normal conditions during a specified time
interval, Tc. Tc is calculated as Bc/CIR. This value must be greater
than zero and is typically set to the same value as CIR.
BE (kbits)
(Forward and
Reverse
direction)
Select the maximum amount of uncommitted data, in Kbs, that the
network will attempt to deliver during a specified time interval, Tc. Tc
is calculated as Bc/CIR. The network treats this data as DE data.
Rate Enf.
Scheme
(Forward or
Reverse
direction)
Indicates the rate enforcement scheme. Choose one of the following
buttons:
Simple – (default) Provides better switch performance (but less
accurate rate enforcement) than the Jump scheme; Simple also disables
the “bad” PVC detection feature.
Jump – Provides more accurate rate enforcement (but slightly worse
switch performance) than the Simple scheme.
For more information on rate enforcement schemes for Frame
Relay-to-ATM interworking circuits, see the Frame Relay Services
Configuration Guide for CBX 3500, CBX 500, and B-STDX 9000.
Table 18-6.
Add Offnet Circuit: Traffic Type Tab Fields (Continued)
Field
Action/Description
Содержание CBX 3500
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