After you have
defined global controllers, you can add subscriber BWCs to packages and map
these subscriber BWCs to different global controllers.
A Subscriber BWC
controls subscriber bandwidth consumption for upstream or downstream flows. It
controls and measures the bandwidth of an aggregation of traffic flows of a
service or group of services.
Each package has its
own set of BWCs that determine the bandwidth available per package subscriber
for each available service.
The two Primary BWCs,
one for upstream traffic and one for downstream traffic, allocate bandwidth to
specific subscribers. Bandwidth is allocated based on the Committed Information
Rate (CIR), the Peak Information Rate (PIR), and the Subscriber relative
priority settings. You can configure these parameters, but the Primary BWCs
cannot be deleted.
There are two default
BWCs, one for upstream traffic and one for downstream traffic. By default, all
services are mapped to one of these two BWCs. The BWC mechanism controls rate
subpartitioning within the default BWC rate control, based on the CIR, PIR, and
AL. You can configure these parameters, but the default BWCs cannot be deleted.
You can add up to 32
user-defined BWCs per package:
- Subscriber BWCs operate at
the service-per-subscriber level. They allocate bandwidth for services for each
subscriber, based upon the CIR, PIR, global controller, and Assurance Level
(AL) set for the BWC. Each rule defines a link between the flow of the service
and one of the BWCs (unless the flows are to be blocked). See
Defining Per-Flow Actions for a Rule section.
- Extra BWCs also operate at
the subscriber level. Extra BWCs (based on the CIR, PIR, global controller, and
AL) can be allocated for services that are not included in the Primary BWC.
These are services that are not often used but have strict bandwidth
requirements, for example, video conference calls. The Extra BWCs are BWCs that
control a single service (or service group). BWCs cannot borrow bandwidth from
Extra BWCs and vice versa.
Each user-defined BWC
controls either downstream or upstream traffic.
If you enable or
disable Virtual Links mode, all user-defined global controllers are deleted
from the service configuration. A BWC that pointed to a user-defined global
controller now points to the default global controller. Other parameters of
these BWCs remain unchanged.
The Cisco SCE
supports a maximum of 2000 BWCs. You cannot apply a PQB file to a Cisco SCE if
the file contains more than 2000 BWCs. But, the Subscriber BWCs with same
values for GC Index, AL Level, PIR, and CIR are considered as a single BWC;
even if the BWCs are mapped to different flows. So, in effect, Cisco SCA BB may
support more than 2000 BWCs.