CIRCUITO
CARIOCA TI · DOCUMENTATION
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Configuration generator

Cisco Bandwidth Policy Generator

Generate Cisco IOS/IOS XE bandwidth policing with MQC / Policy-Map or legacy Committed Access Rate (CAR), including CIR and burst calculations.

Cisco IOSQoSMQCPolicy-MapPolicingrate-limit

Cisco IOS bandwidth control

Choose modern MQC / Policy-Map or legacy rate-limit compatibility.

MQC / Policy-Map

Creates a modular policy with policy-map, police and service-policy. This is the preferred baseline for platforms and releases that support the generated syntax.

Legacy rate-limit

Generates the older interface rate-limit syntax for compatibility with legacy Cisco IOS environments. Support depends on platform and IOS release.

Examples: 50, 100, 250.5. Decimal comma is also accepted.
Used to calculate Bc = CIR × time ÷ 8. Validate the resulting burst against the target platform limits.
Default 1500 ms follows Cisco's documented CAR burst-sizing reference; maximum burst is generated as 2 × normal burst.
UNDERSTAND THE METHODS

MQC and legacy rate-limit are not the same configuration model

MQC organizes QoS through policies that can be attached to interfaces with service-policy. The generated baseline applies a single-rate policer to class-default: traffic within the CIR is transmitted and traffic above it is dropped.

The legacy rate-limit option generates the older interface-level Committed Access Rate style. It is kept here for operational compatibility with older environments, not as a replacement for MQC.

CIR / BURST

How the burst value is obtained

The generator converts Mbps to bps and uses the selected time interval to obtain a byte quantity: burst = CIR (bps) × interval (seconds) ÷ 8. A 100 ms interval therefore represents one tenth of a second of traffic at the configured CIR.

Burst sizing affects how the policer reacts to short traffic bursts. Do not treat the generated value as a universal recommendation: hardware architecture, interface speed, traffic behavior and IOS/IOS XE release can impose different limits or syntax.

POLICING VS. SHAPING

This generator creates policing, not shaping

Policing enforces a rate by taking an action when traffic exceeds the configured profile; in this generator, exceeding traffic is dropped. Shaping is a different mechanism that normally buffers and schedules excess traffic. Choose the mechanism according to the objective and platform.

LEGACY CAR

Legacy CAR has its own documented numeric constraints

For the classic IOS rate-limit command, Cisco documents the average rate in 8 kbps increments and a range from 8,000 to 2,000,000,000 bps. This generator validates those constraints in legacy mode instead of silently producing a value that falls outside the documented command range.

PLATFORM LIMITS

A syntactically valid policy can still be unsupported by the hardware

Cisco QoS capabilities vary by platform, interface type and IOS/IOS XE release. Minimum and maximum police rates, burst granularity, supported directions and hardware resource consumption can differ substantially. Always validate the generated policy against the target model and release before deployment.

FAQ

Frequently asked questions

Is MQC always supported?+

No. QoS capabilities, command syntax, direction support and hardware limits vary by Cisco platform and software release. Validate the generated configuration against the target device documentation.

Why keep the legacy rate-limit option?+

Some older Cisco IOS environments used interface-level rate-limit configuration. The option is provided for compatibility and operational reference, while MQC remains the preferred baseline when supported.

Does this tool perform shaping?+

No. Both generated modes are policing examples. Traffic that exceeds the configured profile is dropped by the generated configuration.