Cisco Systems OL-16066-01 appendix Service Classes, Abr, Cbr

Appendix K Router Platform User Interface Reference

PVC Policy Page

Table K-27 PVC Dialog Box—QoS Tab (Continued)

Traffic Shaping settings

Traffic Shaping	The type of service to define on the PVC:
	• [null]—The bit rate is not defined.
	• ABR—Available Bit Rate. A best-effort service suitable for applications
	that do not require guarantees against cell loss or delays.
	• CBR—Constant Bit Rate service. Delay-sensitive data, such as voice or
	video, is sent at a fixed rate, providing a service similar to a leased line.
	• UBR—Unspecified Bit Rate service. A best-effort service suitable for
	applications that are tolerant to delay and do not require realtime
	responses.
	• UBR+—Unspecified Bit Rate service. Unlike UBR, UBR+ attempts to
	maintain a guaranteed minimum rate.
	• VBR-NRT—Variable Bit Rate - Non-Real Time service. A service
	suitable for non-realtime applications that are bursty in nature. VBR is
	more efficient than CBR and more reliable than UBR.
	• VBR-RT—Variable Bit Rate - Real Time service. A service suitable for
	realtime applications that are bursty in nature.
	For more information about each service class, see Understanding ATM
	Service Classes, page 15-48.
ABR	The following fields are displayed when ABR is selected as the Bit Rate:
	• PCR—The peak cell rate in kilobits per second (kbps). It specifies the
	maximum value of the ABR.
	• MCR—The minimum cell rate in kilobits per second (kbps). It specifies
	the minimum value of the ABR.
	The ABR varies between the MCR and the PCR. It is dynamically controlled
	using congestion control mechanisms.
CBR	The following field is displayed when CBR is selected as the Bit Rate:
	• Rate—The constant bit rate (also known as the average cell rate) for the
	PVC in kilobits per second (kbps). An ATM VC configured for CBR can
	send cells at this rate for as long as required.

	User Guide for Cisco Security Manager 3.2
OL-16066-01		K-65