Roei.Network

📘 IOSv 17.15 — Class-Level Shaping Enforced

Date: April 22, 2025

Model: IOSv (IOL)   |   Version: 17.15   |   Platform: CML

This lab demonstrates an undocumented behavior where class-level shaping within a CBWFQ class is fully functional on IOSv, despite Cisco's official guidelines.

🔖 Cisco states:
“Traffic shaping must be configured in the primary-level (parent) policy map.”
— Cisco QoS Configuration Guide

📄 Configuration Summary

policy-map test
 class test-queue
  bandwidth 400
  fair-queue
  shape average 51200

interface Ethernet0/1
 service-policy output test

📟 Command Outputs (Hover to Reveal)

• show interface e0/1

  Ethernet0/1 is up, line protocol is up
    MTU 1500 bytes, BW 512 Kbit/sec
    Queueing strategy: Class-based queueing
    Output queue: 0/1000/1608102 (size/max total/drops)
    Total output drops: 1608102

• show policy-map interface e0/1

  Class-map: test-queue
    1608212 packets
    shape (average) cir 51200
    (queue depth/total drops/flowdrops) 0/1608102/1608102
    (pkts output/bytes output) 110/82878

• show run | section policy-map

  policy-map test
   class test-queue
    bandwidth 400
    fair-queue
    shape average 51200
   class class-default
    bandwidth 100