QOS
- Class class-default need “fair-queue” if “bandwidth” was not specified.
- When using “ip rsvp bandwidth” on a sub-interfaces, it is also required to be configured on the main interface.
- When using multiple sub-interfaces with “ip rsvp bandwidth”, the main interface should be configured to be the sum all sub-interfaces.
- RSVP requires fair-queue to be enabled. With FRTS, WFQ is disabled by default, re-enable with “frame-relay fair-queue” in the map-class.
- When doing MQC configurations using the bandwidth percent command, do not forget to change the “max-reserve-bandwidth %”.
- Custom queueing defaults – Byte-count = 1500 bytes & Queue-limit = 20.
- Know the NBAR mime categories: “image/*” or “audio/*” or “application/*” or “text/*”
- Voice EF class = 46 decimal and 101110 in dscp-binary.
- FRTS formulas:
Bc = CIR * Tc
Be = (CAR – CIR) * Tc
- WRED formula:
= (1/MPD)
- CAR (Police) formula:
Bc = CIR / 8 * Tc (Default Tc = 1.5 seconds)
Be = 2 * Bc
Routing-Bits 