Contents. 1. Introduction to IPv6 2. Basic concepts of IPv6 3. The Need for IPv6 4. Where we are with IPv6 5. Summary & Discussion. Asela Galappattige

Transcription

1 Asela Galappattige Contents 1. Introduction to IPv6 2. Basic concepts of IPv6 3. The Need for IPv6 4. Where we are with IPv6 5. Summary & Discussion 1

2 What is IPv6? IPv6 is the successor of IPv4 It is the 6 th Version of Internet Protocol IPv6 is a network layer protocol used for data communication over a packet switched network. IPv6 or Internet Protocol Version 6 is the next generation protocol for the Internet Designed by the IETF (Internet Engineering Task Force) IPv6 has a very large address space (128 bits) compared as IPv4 (32bits) Uses same basic concepts as IPv4 Some modifications and additions to that of IPv4 How Big is IPv6? IPv6 usable address space: 128 bits 340,282,366,920 billion billion billion or trillion trillion trillion IPv4 usable address space: 32 bits 3.7 billion addresses 2

3 How Big is IPv6? Analogy: If all the IPv4 space would fit in an ipod, then all the IPv6 space is the size of the entire Earth. IPv4 IPv6 5 10^28 addresses per human on Earth. Understanding IPv6 Addresses The first thing you notice about IPv6 is that the addresses look quite different from IPv4 addresses. IPv6 addresses are 128 bits wide, and is commonly represented in a Hexadecimal format. IPv4 address 32 bits Example: Binary Dotted Decimal IPv6 address 128 bits (4 times wider) Example: Binary Dotted Decimal Binary Hexadecimal 2001:0db8:0000:0000:0000:0000:0000: :0db8::1 in shortened form 3

4 HEX notation Binary Decimal Hexadecimal A B C D E F IPv6 Address Representation Example: B Written as 805B: 2D9D : DC28 : : FC57 : D4C8 : 1FFF Notice the colon ( : ) used to separate 16 bit boundaries 4

5 IPv6 Address Representation 16 bit fields in case insensitive colon hexadecimal representation 2031:0000:130F:0000:0000:09C0:876A:130B Leading zeros in a field are optional: 2031:0:130F:0:0:9C0:876A:130B Successive fields of 0 represented as ::, but only once in an address: 2031:0:130F::9C0:876A:130B is ok 2031::130F::9C0:876A:130B is NOT ok Special cases: 0:0:0:0:0:0:0:1 ::1 (loopback address) 0:0:0:0:0:0:0:0 :: (unspecified address) IPv6 Address Types Address Block Description Binary IPv4 Equivalent ::/128 Unspecified (128 bits) ::1/128 Loopback (128 bits) ::FFFF/96 IPv4 mapped (96 bits) N/A FF00::/8 Multicast /4 FE80::/10 Link Local Unicast /16 FC00::/7 2001:db8::/32 Unique Local Unicast (ULA) Documentation Private, or RFC 1918 address space: /8, /12, / /24, /24, / ::/3 Global Unicast No equivalent single block 5

6 IPv6 Multicast Addresses IP multicast address has a prefix FF00::/8 The second octet defines the lifetime and scope of the multicast address. IPv6 Packet Header 32 bits 6

7 IPv6 Packet Header Fixed Size (40 bytes) Simple (8 fields) Flexibility with Extension Headers Low processing overhead at intermediate nodes Streamlined and contains only those pieces of information that are necessary on every IPv6 packet. Simplified IPv6 header Optional IP information Lower bandwidth and processing costs Intermediate routers only process 40 byte header Encoded in Extension Headers (EH) More efficient than the IPv4 header, Greater flexibility for future extensions and Options EH are only processed when necessary IPv6 Packet Header The following components make up the IPv6 header, Version: Traffic Class: 4-bit IP version number, set to 6 for IPv6 packets. The traffic class field is 8 bits long and is used to mark packets for differentiated service similar to the IPv4 Type of Service and Precedence bits. This practice is commonly called Class of Service (CoS) or Quality of Service (QoS) depending on the implementation. Flow Label: This 20-bit field is still experimental but its intent is to label sequences of packets (flows) that require special handling. RFC 2460 IPv6 Specification suggests non-default quality of service and real-time service as example uses for the flow label. 7

8 IPv6 Packet Header Payload Length: Unlike IPv4, which lists the total packet length in its header, the IPv6 header specifies payload length in other words, the length of everything that follows this header in the packet including any extension headers as well as the data being carried. This field is 16 bits long. Next Header: An 8-bit selector which uses the same values as the IPv4 protocol field to identify the type of header that immediately follows the IPv6 header. Hop Limit: Like Time To Live (TTL) in the IPv4 header, this 8-bit integer is decremented by 1 each time the packet is forwarded. If the Hop Limit reaches 0, the packet is discarded. Source Address: Dest. Address: The 128-bit IPv6 address of the node sending this packet. The 128-bit IPv6 address of the node intended to receive this packet. In addition to the required IPv6 header, IPv6 packets may have one or more of the optional extension headers. IPv6 Packet Header IPv6 header is simpler than IPv4 IPv4: 14 fields, variable length (20 bytes +) IPv6: 8 fields, fixed length (40 bytes) Header fields eliminated in IPv6 Header Length Identification Flag Fragmentation Offset Checksum Header fields enhanced in IPv6 Traffic Class Flow Label 8

9 Extension Headers Number & size of Options not limited Allows flexibility and innovation Routers process IP header (40byte) only Simplifies routing IPv6 header NH=TCP TCP header + data IPv6 header NH=Routing Routing header NH=TCP TCP header + data IPv6 header NH=Routing Routing header NH=Fragment Fragment header NH=TCP TCP header + data IPv6 Address Allocation Host Intf-1: 2001:db8:1:1::1 1 2 Subnet1: 2001:db8:1:1:/64 9

10 IPv6 Interface ID Lowest order 64-bit field of Unicast address may be assigned in several different ways: 1. Auto-configured from a 64-bit EUI Expanded from a 48-bit MAC address (e.g., Ethernet address) 3. Auto-generated pseudo-random number (to address privacy concerns) 4. Assigned via DHCP 5. Manually configured IPv6 Interface Auto Configuration MAC to EUI64 Format 10

11 ICMPv6 A new ICMP version is defined for IPv6 Apart from Error Messages & Diagnostics, it provides a framework for; Auto configuration Neighbor Discovery (ND) /Address Resolution Path MTU Discovery (PMTUD) Multicast Group Management (MLD-Multicast Listener Discovery) Duplicate Address Detection (DAD) IPv6 Mobility Neighbor Discovery Replaces ARP, ICMP (redirects, router discovery) Used to get Reachability information of Neighbors Hosts use it to discover routers, auto configuration of addresses Uses ICMPv6 messages, originated from node on link local with hop limit of 255. Five neighbor discovery messages 1. Router Solicitation (ICMPv6 type 133) RS 2. Router Advertisement (ICMPv6 type 134) RA 3. Neighbor Solicitation (ICMPv6 type 135) NS 4. Neighbor Advertisement (ICMPv6 type 136) NA 5. Redirect (ICMPV6 type 137) Nodes: Address Resolution Determine Link layer address changes Determine neighbor reachability Hosts: Discover neighbor routers Autoconfigure Routers: Advertise presence, config paramaters, prefixes Inform better Next Hops (Ridirect) 11

12 Neighbor Discovery Neighbor Solicitation: Send to discover link layer address of an IPv6 node For Layer 2 it is set to multicast for address resolution, unicast for node reachability IPv6 header, source address is set to unicast address of sending node (A), or :: for DAD Destination address is set to the unicast address for reachability and solicited node multicast for DAD Neighbor Advertisement: Response to neighbor solicitation message Also send to inform change of link layer address Stateless Auto Configuration RS RA 1. Node initialization 2. Node creates link-local address (FE80::/10) 3. Node runs duplicate address detection (DAD) process If process fails, autoconfiguration fails. Manual configuration required. 4. Host (not routers) sends an all-routers multicast (FF02::2) router solicitation (RS) to find a router on the link 5. A router responds to the RS with router advertisement (RA) 6. Host uses information contained in RA to: Create site-local address Build an on-link prefix-list Know the link MTU 12

13 Redirection Redirect is used by a router to signal the reroute of a packet to a better router Fragmentation Minimum link MTU for IPv6 is 1280 octets (versus 68 octets for IPv4) on links with MTU < 1280, link-specific fragmentation and reassembly must be used Implementations are expected to perform PMTUD to send packets bigger than 1280 A Hop-by-Hop Option supports transmission of jumbograms with up to 2^32 octets of payload Only Source can fragment Router do not fragment PMTUD: Path MTU Discovery is used to discover MTU (Max. Transmission Unit) for each destination 13

14 Extension Headers IPv4 options drawbacks IPv4 options required special treatment in routers Options had negative impact on forwarding performance. Therefore rarely used. Benefits of IPv6 extension headers Extension headers are external to IPv6 header Routers do not look at these options except for Hop-by-hop options No negative impact on router s forwarding performance Easy to extend with new headers and options Header Previous header s NH-value Hop-by-hop options 0 Destination options 60 Routing 43 Fragment 44 Authentication 51 Encapsulating Security Payload (ESP) 50 Destination options 60 OSPF for IPv6 89 Security The authentication header (AH) and encapsulated security payload (ESP) are the security mechanisms of the Internet protocol security architecture. The IPSEC mechanisms AH and ESP provide authentication, integrity and confidentiality security services. The AH and ESP are defined for both IPv6 and IPv4. The implementation of the security mechanisms is mandatory for IPv6 and optional for IPv4. The IP security architecture is defined as an integral part of IPv6. Thus, every vendor, who claims to offer IPv6 compliant implementation, must support authentication header and encapsulated security payload. Support for the AH and ESP does not mean that these services must be used, but they must be available if needed. "If security is provided at the Internet level, it becomes a standard service that all applications can use. The application can request the operating system to set up a security association before starting a TCP connection or a UDP exchange. Although the use of authentication, integrity and encryption adds to IP processing costs and increases communication latency, the availability of security services for end-use and infrastructure protection is worth the penalty. 14

15 Mobility Mobility is achieved by Mobile IP Same concept as in MIPv4, Except there are no foreign agents in MIPv6 In a foreign subnet, the mobile host acquires a Foreign Address Use Stateless Auto Conf Register with Home Agent (HA) Packets to Mobile s Home Address is intercepted by HA and sent to Foreign Address using encapsulation. Consequent packets use Mobile s Foreign Address directly MIPv4 Optimal Routing Better Security support No private addressing No Access control issues at Foreign Network MIPv6 DNS 15

16 DNS OS usually prefers AAAA record 1st DNS Resolver picks AAAA record 1st 16

17 Global Trend in Communications Global Trend in Communications New Emerging Economies New Networks New Users China, India, Africa, Latin America, Mobile phones, PDAs, media players, browser pads, cameras, sensors, wearable electronics, Alarms, CCTV, metering, remote monitoring, Multiple IP enabled devices per user Tracking, Maintenance, Navigation, Communication, Personal devices Sensors / Automation Vehicles Home electronics TV, Set top box, oven, fridge, curtains, Gates, Exponential growth in IP address requirement IPv6 provides sufficient addresses for the growth to continue 17

18 Global Trend in Communications From PC to ipod to ipot All use IP as its default networking protocol IPv4 Address Usage Following table shows the current usage of /8s in the internet As /8 (slash 8, Example: 203.xxx.xxx.xxx) contains 2^24 (16.7million IP Addresses) 18

19 Address Allocation Regional Internet Registries (RIRs) Your ISP IP Address Allocation Procedure IPv4 Address Exhaustion 19

20 IPv4 Address Exhaustion IANA IPv4 Pool Date-2: 1 st RIR Exhausts RIR allocation /8 Date-1: Last IANA /8 allocation IPv4 Address Exhaustion PREDICTION Ref: Geoff Huston, Chief Scientist, APNIC 03-May-2010 Prediction as at 03-May-2010: (Date-1) IANA allocated address pool will exhaust on 18-Sep-2011 (Date-2) First RIR exhausts its IANA allocation on 29-Apr

21 Statistics as at 24-June-2010 Ref: IPv6 Address Assigning Minimum ISP assignment is /32 32 bits Default assignment /48 for all End Sites Providing /16 bits of space for subnets Each end site can have 65,536 (2^16) subnets Single Subnet assignments: /64 *** Single subnet devices / LAN should receive /64 only 32 bits 16 bits 64 bits 64 bits Smaller assignments: /128 Devices with no subnets should receive /128 only Ex: remote sensor Single IP That s about 17 billion times more IPv6 than IPv4 when measured this way 21

22 Why IPv6? Why do we need IPv6? Mainly since we are Running Out of IPv4 addresses IPv4 usable address space: 32 bits 3.7 billion addresses IPv6 usable address space: 128 bits 340,282,366,920 billion billion billion or trillion trillion trillion Globally Unique IP for all devices How did IPv4 meet the IP demand up to now? NAT DHCP CIDR Tight RIR control and Reclaiming unused IP blocks IPv4 trading Market (future) Lessons Learnt from IPv4 are used by IPv6 to provide New Features & Functionality Auto Configuration Neighbour Discovery Extension Headers No fragmentation (PMTUD) In built L3 security (IPSec) Efficient Mobility Multicast enabled QoS enabled Only visible solution for address depletion IPv4 has also provided many of the features as add-ons IPv6 Market Opportunities There are a number of key IT-centric market verticals that will benefit from IPv6 New Features & Functionality Product Tethering Telematics Location-based services Internet Applications Unified communications Ubiquitous Networking Auto Configuration Neighbour Discovery Extension Headers No fragmentation (PMTUD) In built L3 security (IPSec) Efficient Mobility Multicast enabled QoS enabled Only visible solution for address depletion Tethering is the use of a communication device as a modem for another device Telematics is the science of sending, receiving and storing information via telecommunication devices 22

23 The Inevitable IPv6 just allows the growth to continue. Even if another IP application is never invented, we still need IPv6 just to sustain the growth of what we already have. For ISPs and Service Providers, transition is inevitable, It is essential that we; Get Proper Exposure to the concepts Build our Competencies To face the inevitable migration in the near future. Demand for IPv6 Global demand for IPv6 is mostly dominated by Asian regions Biased IPv4 allocation (70% allocated for N.America) Soaring Population in Asia Immerging new economies Japan will be the 1 st to complete migration Demand for IPv6 from customers, mostly corporate, would arise due to one or more of the following Learning & adapting Interest in / experiment with new technology Global Partner/Mother Companies migrating to IPv6 New Corporate Applications running on IPv6 Fresh networks based on IPv6 23

24 Demand for IPv6 There is no widespread demand for IPv6 right now. No one is panic-implementing IPv6. IPv6 has little or no market adoption to make serious commercial sense due to the following facts. No clear model for Profitability Lack of a Migration strategy IPv4 will Continue to co-exist for a long time, until the last IPv4 user has migrated to IPv6 Emerging economies still architecting their IPv4 networks Concerns about seamless Coexistence with IPv4 No Penalty for Late migration No Content No Customers Users Perspective Operating Systems are ready for IPv6 Windows XP, VISTA, 7 Solaris, Unix & Linux Networking Devices are Ready Most (including Cisco, Juniper, Nortel, Huawei, etc.) are ready for IPv6 Autoconfiguration of User Networks No manual configuration needed Network defined configuration Automatic Tethering for home devices etc. No DHCP required No NAT required Each device will have its own unique public IP address IP Portability & Mobility Anywhere anytime (Ubiquitous) networking 24

25 Where are we? ARPANET Deploys IP Bone is borned Bone de-activated 2030?? IPv4 Only IPv4 Only Experimental IPv6. Majority: IPv4 traffic. Some IPv6. Next: Majority: IPv6 traffic. Some IPv4. IPv6 only!? Now: IPv4 + IPv6 Live EXPERIMENTAL + SOME IPV6 Where are we? Original Plan Ref: Geoff Huston, Chief Scientist, APNIC. APNIC 24, Sep 2007 Revised Plan 25

26 IPv4 Only V4+DS V4+DS+V6 DS+V6 V6 only Transition Migration Path Dual Stack Source: IP in Action, Iljitsch van Beijnum Transition - Phases Phase-1: Initial Dual-stack (V6-over-V4) Phase-2: Intermediate Phase-3: Completion with V4 shutdown (V4-over-V6) 26

27 IPv6-IPv4 Interworking IPv6 is not backward compatible with IPv4 But can communicate with a translation mechanism Allows native IPv6 hosts and applications to communicate with native IPv4 hosts and applications, and vice versa Easy-to-use transition and co-existence solution Transition Technical Team Learning IPv6 Planning the Transition Share Experience with Task Force Members Setting up Discovery Lab End of Learning Phase Enable IPv6 on Infrastructure Start the Transition Phase out IPv4 27

28 Transition Options & Barriers Options available for the migration (most popular) Dual stack IPv4/IPv6 IPv6 Tunneled over IPv4 IPv6 over MPLS or Native IPv6 The transition to IPv6 is not an easy task since IPv6 is not backward compatible with IPv4. Careful Planning Proper Transition Mechanisms Additional Investment in Upgrading Equipment Legacy equipment, OSs & Applications will remain running IPv4 until replaced IPv6 Advantages Subjects IPv4 IPv6 IPv6 Advantages Address Space 2^32 Addresses Configuration Manual or use DHCP Broadcast / Multicast Anycast support Network Configuration Uses both Not part of the original protocol Mostly manual and labor intensive 2^128 Addresses Universal Plug and Play (UPnP) with or without DHCP No broadcast and has different forms of multicast Explicit support of anycast Facilitate the re-numbering of hosts and routers 79 Octillion times the IPv4 address space Lower Operation Expenses and reduce error Better bandwidth efficiency Allows new applications in mobility, data center Lower operation expenses and facilitate migration QoS support ToSusing DIFFServ Flow classes and flow labels More Granular control of QoS Security Mobility Uses IPsec for Data packet protection Uses Mobile IPv4 IPsec becomes the key technology to protect data and control packets Mobile IPv6 provides fast handover, better router optimization and hierarchical mobility Unified framework for security and more secure computing environment Better efficiency and scalability; Work with latest 3G mobile technologies and beyond. 28

29 Advantages of IPv6 Lessons Learnt from IPv4 are used by IPv6 to provide New Features & Functionality Auto Configuration Neighbour Discovery Extension Headers No fragmentation (PMTUD) In built L3 security (IPSec) Efficient Mobility Multicast enabled QoS enabled (IPv4 has also provided many of the features as add-ons) Advantages: Room for many levels of structured hierarchy and routing aggregation Easy address auto-configuration Easier address management and delegation than IPv4 Ability to deploy end-to-end IPsec (NATs removed as unnecessary) Test What is the main reason for having IPv6? How long is an IPv4 address? (in bits) How long is an IPv6 address? (in bits) How many unique v4 addresses? How many unique v6 addresses? Is IPv6 header size variable? What is the size of IPv6 header? How many fields are there in IPv6 header? When will IPv4 run-out? How much IPv4 is left unused? Will IPv6 replace IPv4 totally? Is IPv6 & IPv4 naturally inter-operable? What is the recommended IPv6 LAN subnet address allocation size? What advantages does IPv6 offer? What is the IPv6 equivalent to IPv4 DNS A-Record? 29

30 Supplementary Slides IPv4 Address Types CIDR address block Description /8 Current network (only valid as source address) /8 Private network /8 Loopback /16 Link-Local /12 Private network /24 Reserved (IANA) /24 TEST-NET-1, Documentation and example code /24 IPv6 to IPv4 relay /16 Private network /15 Network benchmark tests /24 TEST-NET-2, Documentation and examples /24 TEST-NET-3, Documentation and examples /4 Multicasts (former Class D network) /4 Reserved (former Class E network) Broadcast 30

31 Your IP: 2402:D000:a3::2 IPv6 Enabled 31