irish ipv6 task force

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Irish IPv6 Task Force

IPv6 and Quality of

Service


Irish IPv6 Task ForceIrish IPv6 Task ForceIPv6 Training Slide-setsIPv6 Training Slide-sets

1. The Bigger Picture: Why is IPv6 so Important?

2. Introduction to IPv6 Fundamentals (technical)

3. IPv6 Deployment & Strategy (technical)

4. The Business Case for IPv6

5. Mobile IPv6 (technical)

6. IPv6 Quality of Service (technical) <- This slide set is sixth in a series

7. IPv6 Security (technical)


• Introduction

• What is QoS?

• How is it used?

• How is it implemented?

• What is its current state in the Internet?

• How does IPv6 fit into the QoS picture.

Presentation Presentation StructureStructure


IPv6 and QoS –Introduction


• Quality of Service (QoS).

• Sometimes said “Kwos”.

• Many things to many people.

• Basically: making network good enough for

apps.

IntroductioIntroductionn


What is QoS ?


QoS: What is the QoS: What is the aim?aim?

• Network needs to be good enough.

• How do we measure good?−Enough bandwidth?−Enough buffering?−Short enough delay?−Consistent enough delay?−Enough packets arrive intact?

• Often summarised as delay, loss, jitter, bw,

…


How is it used ?


QoS: Typical QoS: Typical UsesUses

• Video/Voice traffic more sensitive than bulk data.

• Safety critical traffic may be protected.

• ISPs may prioritise premium customers.

• Netadmins may protect control traffic (BGP, ssh, …)

• Gamers don’t want to get fragged!

• Preventing virtual links from interacting.

• Interactive applications usually have some QoS needs.− Dialup and the World Wide Wait.


How is it implemented ?


QoS: How to QoS: How to achieve?achieve?

• If network is big and empty, QoS is easy.−Known as overprovisioning.

• Otherwise identify traffic’s needs.

• Treat traffic differently based on needs.

• (Im)Possible to meet some/all needs?


QoS QoS ArchitectureArchitecture

• We need to -−identify the traffic.−check that it is in spec.−decide how to queue it.−decide how to serve the queues.−manage, account and configure all this.


IntServIntServ

• One of two standardised frameworks for IP QoS.

• Hosts ask routers to treat particular flow

specially.

• They use the Reservation Protocol (RSVP).

• It describes how to match packets and required

QoS.

• Each router has to track each flow.

• Signalling and tracking makes scaling harder.


DiffServDiffServ

• Offer applications a short menu of QoS types.

• Type required is written into small field in packet.

• Menu items are called Per-Hop-Behaviours (PHB).

• The field is called the Differentiated Services Code Point (DSCP) value.

• Routers look at packets and decide how to queue.

• Limited menu may not suit all apps.

• No active negotiation, so need to police settings.

• All traffic with same DSCP is treated in same way.


Manual/ad Manual/ad hochoc

• Manual configuration always an option.

• May partially fit into some bigger scheme.

• Examples:− 802.11 gives some control packets high priority.

− A 3G operator might make Skype packets low priority.

− A router might move BGP packets to head of queue.


What is its current state in the Internet ?


QoS QoS TodayToday

• Not widely deployed in public Internet.

• Inter-network issues too great relative to demand?− Inter ISP policing, monitoring, charging, …

• DiffServ and manual more widely deployed in ISPs and enterprise networks.

• Most common solution is lots of bandwidth.

• Becoming more common in home appliances with VoIP and video streaming.

• Wireless an interesting case - overprovisioning much harder.


How does IPv6 fit into the QoS picture ?


IP(v6) and IP(v6) and QoSQoS

• Any packet matching system must be able to deal with IPv4/IPv6 packets.

• Often involves fields in TCP/IP headers, such as addresses, protocols and ports.

• Need to extend to be able to deal with IPv6 addresses.

• The DSCP value lives in the Type of Service (ToS) field in IPv4.

• The DSCP value lives in the Traffic Class (TC) field in IPv6.


IPv6 Flow IPv6 Flow LabelLabel

• IPv6 has new flow label header.

• 20 bits to identify flows.

• Determined by end hosts.

• Intended to facilitate QoS.

• Could be used by IntServ to pick out flows.

• Might help identify encrypted flows for QoS.

• No final answer yet, but additional flexibility.


IPv6 Side IPv6 Side EffectsEffects

•Less NAT means flows easier to identify

•Better mobility -> better network path -> better QoS.•IPv6 extension headers may be applied to QoS in future.•IPv6 transition mechanisms can lead to poor performance if carelessly deployed!•E.g. Many tunnels in 6bone lead to scenic routing.

•6bone now retired and production routing is being refined.

•QoS and IPv6 support are often considered advanced features, vendors sometimes unclear about their interactions.


• QoS allows traffic with special requirements to be treated specially.

• DiffServ and manually configured QoS have some deployment.

• As long as IPv6 packets can be classified, QoS in the IPv4 and IPv6 looks similar.

• The IPv6 Flow Label is intended to facilitate QoS flow identification.

SummarSummaryy


AcknowledgemAcknowledgementsents

This presentation includes some material from these other sources:

• Name of person/people ??? (organisation??)


ContactContact

Mícheál Ó Foghlú

Research Director

Telecommunications Software & Systems Group

Waterford Institute of Technology

Cork Road

Waterford

Ireland

+353 51 302963 (w)

[email protected]

http://www.tssg.org

http://www.ofoghlu.net/log (Personal Blog)

mailto:[email protected]

http://www.tssg.org/

http://www.ofoghlu.net/log


Further Further InformationInformation

Web Sites:

• National Irish IPv6 Centre http://www.ipv6-ireland.org

• Irish IPv6 Task Force http://www.ipv6.ie

• IPv6 ePrints Server (Public Documents) http://www.6journal.org/

• IPv6 Dissemination (Public Training) http://www.6diss.org/tutorials/

Individual Documents/Presentations:

• http://arstechnica.com/articles/paedia/IPv6.ars/1 (Iljitsch van Beijnum, 7th March 2007)

• http://bgp.potaroo.net/ipv4/ (Geoff Huston APNIC, 2006)

• http://www.6journal.org/archive/00000261/02/

WWC_IPv6_Forum_Roadmap__Vision_2010_v6.pdf (IPv6 Forum Roadmap & Vision,

2006)

• http://colab.cim3.net/file/work/Expedition_Workshop/2005-12-

06_Advancing_Information_Sharing_And_Data_Architecture/IPV6/NIST%20ipv6-doc-eai-

v4%2012062005.ppt (Doug Montgomery NIST, 2005)

http://www.ipv6-ireland.org/


Thank you!Thank you!

This presentation has been shared under the Creative Commons Attribution 2.0 UK:

England & Wales Licence (http://creativecommons.org/licenses/by/2.0/u

k)by the Irish IPv6 Task Force

(http://www.ipv6.ie)

Please acknowledge this source if you use it for free or for profit

irish ipv6 task force - irish ipv6 task force ipv6 and quality of service

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