Category: QoS

Quality of Service II ( Deployment, Design )

Quality of Service Deployment

Choosing the correct WAN Type.

  • WAN Providers, you get what you pay for.
    • Tried and True providers
  • Don’t design a sinking ship, bandwidth.
  • Determine bursting capabilities.
  • QoS classes / Policies support.
  • Multicast support.

Modular QoS CLI ( MQC )

  • Class-map
R1(config)#class-map ccdp
Class-map configuration commands:
  description  Class-Map description
  exit         Exit from class-map configuration mode
  match        classification criteria
  no           Negate or set default values of a command

R1(config-cmap)#match ?
  access-group         Access group
  any                  Any packets
  atm                  Match on ATM info
  class-map            Class map
  cos                  IEEE 802.1Q/ISL class of service/user priority values
  destination-address  Destination address
  discard-class        Discard behavior identifier
  dscp                 Match DSCP in IPv4 and IPv6 packets
  fr-de                Match on Frame-relay DE bit
  fr-dlci              Match on fr-dlci
  group-object         Match object-group
  input-interface      Select an input interface to match
  ip                   IP specific values
  mpls                 Multi Protocol Label Switching specific values
  not                  Negate this match result
  packet               Layer 3 Packet length
  precedence           Match Precedence in IPv4 and IPv6 packets
  protocol             Protocol
  qos-group            Qos-group
  source-address       Source address
  vlan                 VLANs to match


Quality of Service I ( QoS, Models, Methods )

What is QoS?

  • Quality of life insurance
  • The ability to dictate traffic treatment

    • Prioritization.
      • Only happens with congestion.
    • Shaping / Policing.
      • Shaping: Mold the traffic down to a specific speed.
      • Policing: ‘evil’ traffic types ( p2p / video ).
    • Advanced Strategies ( WRED – Weighted random early detection)
      • Drop selective TCP streams so it won’t hit max.
  • Strategies to fight the enemy
    • Delay ( how long it takes for a Packet A to get to the other side).
    • Jitter ( Delay variation, Times between Packets A,Packet B,and Packet C taking to get to the other side)
    • Packetloss
Audio Requirements Video Requirements
Jitter< 30ms< 30ms
Delay< 150ms< 150ms
Loss < 1%< 1%