Qos on g ant
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QoS on GÉANT. Premium IP and Less than Best Effort. Premium IP service. The Premium IP service aims at offering the equivalent of an end-to-end leased line service at the IP layer across multiple domains.

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Qos on g ant


Premium IP and Less than Best Effort

Premium ip service
Premium IP service

  • The Premium IP service aims at offering the equivalent of an end-to-end leased line service at the IP layer across multiple domains.

  • Model suggested by SEQUIN: end-to-end deployment of Quality of Service (QoS) operating across multiple management domains and exploiting a combination of various technologies (IP and ATM).

Qos metrics
QoS metrics

  • From users’ requirements and technical considerations :

    • One-way delay (OWD)

    • IP packet delay variation (IPDV)

    • Bandwidth

    • One-way packet loss (OWPL)

  • The parameters definitions were chosen accordingly to the IETF IPPM working group.

Packets differentiation
Packets differentiation

  • The Premium IP packets are tagged (marked) with the DIFFserv code point 46 (101110 in binary) by the source.

  • The LBE ones are tagged DSCP 8 (001000)


  • Implemented based on the diffserv EF PHB.

    • that each node on the path of a diffserv domain must be EF compliant.

      • EF PHB goal: forward the packet as soon as possible.

    • The mechanism used to forward the packets as soon as possible is a scheduling mechanism.

      • Their goal is to serve preferrentially the Premium queue than the other queues.

      • The scheduling mechanism on the Juniper is the Weighted Round Robin (WRR)

      • The Premium IP packets should be classified in a queue with a very high service rate.

  • Can find configuration information on

    • http://www.dante.net/staff/nicolas/PIP_config_backbone.html

    • http://www.dante.net/staff/nicolas/Cos/pip_lbe_backbone.html (not the lastest one)


Queue 0 (weight 5 - high priority) - loss-priority

low Best Effort No tag

high DWS tag DSCP 32

Queue 1 (weight 90 - high priority) - loss-priority

low Premium IP tag DSCP 46

high /

Queue 2(weitgth 1- low priority) – loss-priority

low LBE tag DSCP 8

high tag to BE unauthorised PIP and DWS

Queue 3 (weight 4- high priority) - network control

low Network control tag DSCP 48

high Network control tag DSCP 56

Premium ip and diffserv
Premium IP and DIFFserv

  • The Premium IP traffic bandwidth utilisation should be lower than 10% of the link capacity.

    • To reach 20% of the bandwidth in case of link failure.

  • [reminder] QoS techniques do not create bandwidth.

    • What you give to one class of service, you have to take it from another one.

Premium ip atm and over provisioning
Premium IP, ATM and over-provisioning

  • Premium IP and ATM

    • guarantees provided by ATM PVCs

  • Premium IP and over-provisioning

    • what is over-provisioning? (less than 30% of bandwidth utilisation)

    • very close monitoring needed

Premium ip specification
Premium IP specification

Classification and high priority scheduling (DSCP) on all nodes

Police by (AS source, destination)

Aggregate capacity on all border nodes

Do not police on egress

Do not shape anywhere

Policing can be avoided at ingress when receiving from a trusted backbone

Classify (IP pair prefixes)

Police - Strict, Capacity


Example one direction
Example (one direction)

Domain 2


Dedicated PVC

Domain 1

802.1p VLAN

Or dedicated wire

Classification (DSCP)


Classification (IP)

Policing (strict 2 MTU)

Marking - scheduling

Domain 3


Domain 4

Classification (DSCP)

Policing (AS aggregate)

Domain 5

802.1p VLAN

Or dedicated wire


  • According to the SEQUIN workshop, the Premium IP monitoring is one of the most important requirement of the end-users.

    • Verify the behavior of the network

    • SLA verification

    • the for parameters should be monitored

  • Taksometro monitor the Premium IP

    • bandwidth utilisation on the GÉANT circuits and on the access

    • bandwidth received on a NREN per destination NREN

    • losses due to the policers on a NREN access


  • Still to be implemented

    • One-way delay monitoring (require strong synchronisation between the machines)

      • edge to edge

      • per link

    • IPDV, related to one-way delay monitoring but does not request any synchronisation.

      • Edge to edge

      • per link

    • These monitoring tools should be able to monitor the Premium IP as well as any other services deployed on GÉANT.


  • In addition to the monitoring infrastructure, some tools are needed to help the debugging.

    • A CoS traceroute has been developed by SEQUIN. Its goal is to indicate where the tagging is changed.

Less than best effort
Less than Best Effort

  • The main idea of LBE is that this traffic class is able to make use of unutilised bandwidth in the network, but in a way such that in cases of competition for resources, the LBE traffic will be discarded before any Best Effort (BE) or higher-class traffic.

    • Equivalent to scavenger

    • applications: mirroring, support of new transport protocols non TCP compliants, networks backups, estimation of available bandwidth

  • see GÉANT deliverable D9.9 (mid-September)