Cisco Certification Exam Review:

Frame Relay Traffic Shaping Terms And Definitions

By Chris Bryant, CCIE #12933

Frame Relay Traffic Shaping Terms:

CIR - Committed Information Rate - the rate of data transfer guaranteed by the frame provider.

CRMI - Committed Rate Measurement Interval - unit of time used by the provider to measure the CIR. Indicated by the letters Tc, generally referred to as "time interval". By default, this is 1/8th of a second (.125).

Bc - Committed Burst - amount of data that will be transferred during the CRMI. For instance, a three-second CRMI and a CIR of 512 KBPS will result in a Bc of 1536.

EIR - Extended Information Rate - amount of data transfer above and beyond the CIR.

Be - Excess Burst - amount of data transferred above and beyond the CIR per CRMI.

FRTS is applied to an interface through a map class.

The "peak" value configured in the frame-relay traffic-rate command is the CIR + EIR.

Additional FRTS Information:

FECNs indicate that congestion was encountered in the direction in which the frame was traveling; BECNs indicate that congestion was encountered in the opposite direction in which the frame was traveling. To configure an interface to dynamically throttle back on its transmission rate when BECNs start being received, use the frame-relay adaptive-shaping becn command.

It's possible for both a physical interface and subinterface to have IP addresses. Not always advisable, but it's certainly possible.

If an interface is configured with Cisco encapsulation, frame map statements can still be configured with IETF individually if need be.

To view BECN and FECN statistics, run show frame pvc.

Frames marked DE are Discard Eligible, and will be discarded first when congestion occurs. The DE bit makes these particular frames less important than other frames that do not have this bit set.

To your success,

Chris Bryant

CCIE #12933

chris@thebryantadvantage.com