The CAC is enforced when an admin bandwidth is configured on a SAP (this may be when initially configuring the admin bandwidth or when modifying an existing admin bandwidth value).
The CAC enforcement is achieved by comparing the newly requested SAP admin bandwidth (the incremental admin bandwidth being configured above any currently assigned admin bandwidth) with the available admin bandwidth on its port or LAG.
The operation is as follows:
If a SAP's admin bandwidth is increased and the incremental requested admin bandwidth is:
larger than the port or LAG available bandwidth then the command to increase the SAP admin bandwidth fails.
smaller or equal to the available port or LAG bandwidth then the incremental bandwidth is subtracted from the available port or LAG bandwidth.
If a SAP's admin bandwidth is reduced then the available port or LAG bandwidth is increased accordingly.
If the port or LAG admin bandwidth is increased, the available port or LAG bandwidth is increased accordingly.
If the port or LAG admin bandwidth is decreased, the available port or LAG bandwidth is decreased accordingly. However, if the resulting available bandwidth would be less than the sum of the currently allocated SAP admin bandwidth on that port or LAG, then the command to decrease the admin bandwidth fails.
If the port or LAG booking factor is decreased, the available port or LAG bandwidth is decreased accordingly. However, if the resulting available bandwidth would be less than the sum of the currently allocated SAP admin bandwidth on that port or LAG, then the command to decrease the booking factor fails.
If the SAP admin bandwidth is removed, it is excluded from the SAP bandwidth CAC function. Its admin bandwidth is added to the related port or LAG available bandwidth.
The port or LAG admin bandwidth can only be removed if all of its SAPs are excluded from the CAC function.
An example is shown below. A port is configured with an admin bandwidth of 500 Mb/s, and a SAP on that port with a bandwidth of 10 Mb/s. The show output gives these configured values together with the port's available and booked admin bandwidth. An increase of the SAP admin bandwidth to 600 Mb/s is attempted, which fails as there is insufficient available admin bandwidth on the port.
The port's booking factor is increased to 200% and the increase of the SAP admin bandwidth to 600 Mb/s is then successful as the port's available admin bandwidth becomes 1 Gb/s. The port's booked admin bandwidth is 600 Mb/s and so its available admin bandwidth becomes 400 Mb/s.
*A:PE# configure port 1/1/1 ethernet access bandwidth 500000
*A:PE# configure service vpls 1 sap 1/1/1:1 bandwidth 10000
*A:PE# show service id 1 sap 1/1/1:1 detail | match Bandwidth
Bandwidth : 10000
*A:PE# show port 1/1/1 detail | match expression "Bandwidth | BW"
Access Bandwidth : 500000 Booking Factor : 100
Access Available BW: 490000
Access Booked BW : 10000
*A:PE# configure service vpls 1 sap 1/1/1:1 bandwidth 600000
MINOR: SVCMGR #2664 Insufficient bandwidth available
*A:PE# show service id 1 sap 1/1/1:1 detail | match Bandwidth
Bandwidth : 10000
*A:PE# *A:PE# configure port 1/1/1 ethernet access booking-factor 200
*A:PE# configure service vpls 1 sap 1/1/1:1 bandwidth 600000
*A:PE# show service id 1 sap 1/1/1:1 detail | match Bandwidth
Bandwidth : 600000
*A:PE# show port 1/1/1 detail | match expression "Bandwidth | BW"
Access Bandwidth : 500000 Booking Factor : 200
Access Available BW: 400000
Access Booked BW : 600000
*A:PE#