Compare and contrast the following terms: access rate, CIR, CBIR, and BE.

Compare and contrast the following terms: access rate, CIR, CBIR, and BE.

Access rate (or port speed)

• The capacity of the local loop.
• This line is charged based on the port speed between the DTE and the DCE (customer to service provider).

CIR: Committed Information Rate

• The capacity through the local loop guaranteed by the provider.
• Customers normally choose a CIR lower than the access rate to allow them to take advantage of bursts.

CBIR: Committed Burst Information Rate

• The maximum number of frames allowed in a burst.
• It cannot exceed the CIR for the link.

BE: Excess Burst

• The amount of data above the CBIR that the network tries to deliver, up to the maximum speed of the access link.
• Packets over CIR are marked discard eligible (DE), indicating that they may be dropped if the network does not have capacity.

Exam with this question: EWAN v4 Chapter 3 Check Your Understanding: Frame Relay