Traffic Shaping

Managing Traffic

AKA Packet Shaping or Traffic Shaping. This is a way of prioritizing certain packets over others. There are many ways to implement this. Two standards are described below:

Class of Service (CoS)

This is performed in the Ethernet Frame Header in the 802.1Q trunk. It is only performed in switch devices.

Differentiated Services

Performed in the IP Frame Header. This is usually performed inside of routers or firewalls. Adds two fields to the IP Header:

Differentiated Services Code Point (DSCP)

• 6 bits

Explicit Congestion Notification (ECN)

• 2 bits
• Takes Values:
  • 00 - Not QoS Aware
  • 01 - QoS Aware, no congestion
  • 10 - QoS Aware, no congestion
  • 11 - QoS Aware, congestion present