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Understanding IPv6

Understanding IPv6. Dan Schmiedt CU Network Services & Telecommunications. What IS IPv6?. What we currently use is IPv4. IP protocol 5 was the Stream protocol RFC1190. IPv6 is a Layer 3 protocol, j ust like IPv4 or IPX. What does that mean? . The OSI Model: Secret Network Decoder Ring.

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Understanding IPv6

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  1. Understanding IPv6 Dan Schmiedt CU Network Services & Telecommunications

  2. What IS IPv6? • What we currently use is IPv4. • IP protocol 5 was the Stream protocol RFC1190. • IPv6 is a Layer 3 protocol, just like IPv4 or IPX. • What does that mean?

  3. The OSI Model: Secret Network Decoder Ring Layer 8+ … People, Politics, etc Application Layer 7 Firefox, Eudora, Etc Layer 6 Presentation HTML Content Switches: ACE, CSM, CSS Layer 5 Session HTTP, SSH, Telnet, POP, IMAP Layer 4 Transport TCP, UDP, SCTP, SPX Routers Layer 3 Network IPv4, IPv6, IPX Layer 2 Datalink Ethernet, FDDI, ATM Switches Layer 1 Physical Fiber, Twisted Pair Copper, Radio WDM, Hubs

  4. Why IPv6? Another IPX? I have other things to worry about… • IANA’s IPv4 address pool was exhausted on31-Jan-2011, with regional authorities’ (RIRs) spaceexhausting in about a year. • IPv4 will not scale to a fully connected world, even with perfect allocation (not possible): Number of Addresses in IPv4 4,294,967,296 World Population (2003 est.) 6,314,000,000 Number of Addresses in IPv6 340,282,366,920,938,463,463,374,607,431,768,211,456 We need an Internet Protocol that allows for unfettered connectivity from anywhere to anywhere, in any direction …and IPv6 is the only boat we have…

  5. So what? Stuff still works. • What does that really mean? Will IPv4 just stop working one day? • No, but IPv4 addresses are not available for new things. • If we want those new things to talk to us, and if we want to talk to them, IPv6 is the only way. • China, etc?

  6. Yikes, so how do we “convert?” • We don’t. • We simply begin operating in a “dual stack” world. • Workstations and servers will have v4 and v6 addresses. • DNS will resolve names to either A (v4) or AAAA records (v6) • Will be mostly invisible to the user.

  7. Some interesting numbers … • Number of addresses in 130.127/16: 65,536 (2^16) • Number of addresses per typical subnet: 256 (2^8) • Number of addresses CU’s v6 allocation: 19,342,813,113,834,066,795,298,816 (2^84) • Number of addresses per subnet in v6: 18,446,744,073,709,551,616 (2^64)

  8. So … what’s one of these addresses look like? • Since we now have to represent 128 bits, using dotted decimal octets would not be practical. I don’t know about you, but I think this would be unwieldy: 120.254.56.127.130.25.36.78.162.73.221.86.213.34.48.1 • So did everyone else, so that representation is not valid in IPv6….

  9. So … what’s one of these addresses look like? • So, addresses are represented in hexadecimal, with the following rules: • Case-insensitive • Leading zeroes are optional • Successive fields of “0” can be represented as ::, but only once in an address • Example: • 2001:0000:4321:0000:0000:c2d2:b0b0:0123 can be represented as: • 2001:0:4321:0:0:c2d2:b0b0:123 and then further reduced to: • 2001:0:4321::c2d2:b0b0:123

  10. What’s up with the /44 and all? • In an IP address, aprefix tells us about a range of addresses… • In IPv4, we used the “subnet mask” to tell us what part represented the network… • In IPv6, we just say how many bits of the address are the network part, like so: • <address>/<prefix length> • 2620:103:a000:a001::1/64 The remainder is the node part of the address…

  11. Types of addresses … • In IPv6, a network interface will have multiple IPv6 addresses. • I’ll mention a few of the more common ones…

  12. Unicast: Link-local • Used for local, non-routed communication. • Quasi-implemented in IPv4 169.254/16 scheme, RFC 3927, Apple and MS… • In IPv6, it’s simply the prefix fe80:: fe80:: 217:f2ff:fec8:e40b • … Pre-pended to the interface identifier. • This address is used to receive router advertisements, etc.

  13. Unicast: global unicast • Used for communication on the Internet. • Uses the prefix 2000::/3. • At Clemson, on IPv4, we know this as 130.127.0.0/16 … • At Clemson, on IPv6, this is 2620:103:A000::/44 So, our prefix (48 bits)… Plus site subnets (16 bits)… Plus the host part (64 bits)… 2620:103:a000 :a001: 217:f2ff:fec8:e40b … Gives us a globally routable IPv6 address!!

  14. Permanent multicast addresses FF01::1 All nodes on the interface FF02::1 All nodes on the link FF01::2 All routers on the interface FF02::2 All routers on the link FF05::2 All routers in the site FF02::1:FFXX:XXXX Solicited node (next slides)

  15. Unicast: Other addresses… • Unspecified… • Just like IPv4, all zeroes • Represented as :: • Loopback • Used for a host to represent itself • ::1

  16. Other types of addresses: • Unique Local addressing: Addresses start with FD • Similar to 192.168’s, 172.19’s, 10.’s • 6to4: starts with 2002, transitional, tunnels=bad. • NAT64: starts with 64:ff9b, embeds IPv4 address in IPv6 address. Also transitional

  17. How are addresses assigned? • Addresses can be assigned statically: • … Or automatically via autoconf, RFC2462, a stateless automatic configuration mechanism… • … Or dynamically via DHCPv6, RFC3315, a managed dynamic allocation system similar to the DHCP we know today.

  18. Interface identifier… • The IEEE came up with a way to make a 64-bit “EUI-64 identifier” out of a 48-bit MAC address for automatic configuration. 00 17 f2 c8 e4 0b 00 17 f2 ff fe c8 e4 0b X= 0 if non-unique MAC adress X=1 if unique MAC address 000000X0 02 17 f2 ff fe c8 e4 0b This can be used for the host part of an IPv6 address… Which is then combined with a prefix, obtained via router advertisement … 2620:103:a000:a001: 0217:f2ff:fec8:e40b (future MACs will be 64 bits) To make a complete IPv6 address!

  19. For Example… :Take a look at my workstation’s wired interface: Linklocal Autoconf global Scope Statically configured global

  20. So, how do I start using it? • … the same way you use IPv4!

  21. Next Steps at Clemson • Enable IPv6 on all CU network devices. • Enable IPv6-capable DNS. • Enable IPv6 on Server and Client computers. • Insist that new applications be able to use IPv6. • Clemson IPv6 “Task Force”

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