IPv6 and Quality of Service

Transcription

1 Irish IPv6 Task Force IPv6 and Quality of Service

2 Irish IPv6 Task Force IPv6 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)

3 Presentation Structure 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.

4 IPv6 and QoS Introduction

5 Introduction Quality of Service (QoS). Sometimes said Kwos. Many things to many people. Basically: making network good enough for apps.

6 What is QoS?

7 QoS: What is the 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,

8 How is it used?

9 QoS: Typical Uses 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.

10 How is it implemented?

11 QoS: How to 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?

12 QoS Architecture 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.

13 IntServ 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.

14 DiffServ 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.

15 Manual/ad hoc Manual configuration always an option. May partially fit into some bigger scheme. Examples: 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.

16 What is its current state in the Internet?

17 QoS Today 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.

18 How does IPv6 fit into the QoS picture?

19 IP(v6) and QoS 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.

20 IPv6 Flow Label 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.

21 IPv6 Side Effects 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.

22 Summary 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.

23 Acknowledgements This presentation includes some material from these other sources: Name of person/people??? (organisation??)

24 Contact Mícheál Ó Foghlú Research Director Telecommunications Software & Systems Group Waterford Institute of Technology Cork Road Waterford Ireland (w) (Personal Blog)

25 Further Information Web Sites: National Irish IPv6 Centre Irish IPv6 Task Force IPv6 eprints Server (Public Documents) IPv6 Dissemination (Public Training) Individual Documents/Presentations: (Iljitsch van Beijnum, 7th March 2007) (Geoff Huston APNIC, 2006) Vision_2010_v 6.pdf (IPv6 Forum Roadmap & Vision, 2006) 06_Advancing_Information_Sharing_And_Data_Architecture/IPV6/NIST%20ipv6-doc-eaiv4% ppt (Doug Montgomery NIST, 2005)

26 Thank you! This presentation has been shared under the Creative Commons Attribution 2.0 UK: England & Wales Licence ( by the Irish IPv6 Task Force ( Please acknowledge this source if you use it for free or for profit