Slide 1IPv4 and IPv6IPv6 at a GlanceUnderstanding the format of IPv6 AddressIPv6 Address NotationSlide 6Rule 1: Leading 0’sRule 2: Double colon :: equals 0000…0000Rule 2: Double colon :: equals 0000…0000Rule 2: Double colon :: equals 0000…0000Network PrefixesIPv6 AddressesSlide 13Global Unicast IPv6 AddressesSlide 15Slide 16Slide 17Slide 18Subnetting IPv6Slide 20Slide 21Slide 22Slide 23Slide 24TopologySlide 26Slide 27Slide 28Slide 29Slide 30Slide 31Pinging a Global Unicast IPv6 AddressesConfiguring Dynamic IPv6 AddressesIPv4 Dynamic AddressesWith IPv6 it begins with the Router AdvertisementRouter AdvertisementSLAAC (Stateless Address Autoconfiguration)Router Advertisement – Option 1Dynamic Interface IDEUI-64 (Extended Unique Identifier – 64)EUI-64Slide 42What about Stateful DHCPv6?Link-Local Unicast IPv6 AddressesSlide 45Slide 46Slide 47IOS uses EUI-64 to Create Link-Local AddressesSlide 49Configuring Static Link-Local AddressesSlide 51Pinging a Link-Local AddressMulticast IPv6 AddressesIPv6 MulticastIPv6 MulticastAssigned Multicast AddressesSlide 62Internet Control Message Protocol (ICMPv6)Neighbor Discovery Protocol Uses ICMPv6Router Solicitations and Router AdvertisementsNeighbor Solicitations and Neighbor AdvertisementsNeighbor CacheNeighbor CacheIPv6 Static RoutesMaking a Router an IPv6 RouterIPv6 Static RoutesOur TopologyIPv6 Address ConfigurationVerifying IPv6 InterfacesIPv6 Routing Table: Directly Connected NetworksIPv6 Routing Table: Local AddressesSlide 77IPv6 Routing Table Static RoutesSlide 79Static Route using a Link-Local Next-Hop AddressIPv6 & IPv4 Co-existence Dual Stack – Tunneling – NAT64IPv4 & IPv6 Dual StackTunnelingNAT64NAT64NAT64An Introduction to IPv6 Slides – adapted from a presentation by Rick GrazianiIPv4 and IPv6•IPv6 is more than just larger address space.•It was a chance to make some improvements on the IP protocol.IPv6 at a Glance •Next Header = Protocol field in IPv4.–Indicates the data payload type (TCP, UDP, ICMPv6)•Hop Limit = TTL (Time to Live) in IPv4. –Number of router hops before packet is discarded.•Routers do not fragment IPv6 packets unless it is the source of the packet.•Use of a Link-Local Address.•ICMPv6 is more robust than ICMPv4.•SLAAC (Stateless Address Autoconfiguration) for dynamic addressing.Understanding the format of IPv6 AddressIPv6 addresses are 128-bit addresses represented in:Eight 16-bit segments or “hextets” (not a formal term)Hexadecimal (non-case sensitive) between 0000 and FFFFSeparated by colonsReading and subnetting IPv6 is easier than IPv4!IPv6 Address NotationOne Hex digit = 4 bits2001:0DB8:AAAA:1111:0000:0000:0000:0100/642001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 010016 bits116 bits216 bits316 bits416 bits516 bits616 bits716 bits8How many addresses does 128 bits give us?340 undecillion addesses or …340 trillion trillion trillion addresses or … “50 billion billion billion addresses for every person on earth” 2001:0DB8:AAAA:1111:0000:0000:0000:0100/642001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 010016 bits16 bits16 bits16 bits 16 bits16 bits16 bits16 bitsTwo rules for reducing the size of written IPv6 addresses. The first rule is: Leading zeroes in any 16-bit segment do not have to be written.2001 : 0DB8 : 0001 : 1000 : 0000 : 0000 : 0ef0 : bc002001 : DB8 : 1 : 1000 : 0 : 0 : ef0 : bc002001 : 0DB8 : 010d : 000a : 00dd : c000 : e000 : 00012001 : DB8 : 10d : a : dd : c000 : e000 : 12001 : 0DB8 : 0000 : 0000 : 0000 : 0000 : 0000 : 0500 2001 : DB8 : 0 : 0 : 0 : 0 : 0 : 500 Rule 1: Leading 0’sThe second rule can reduce this address even further:Any single, contiguous string of one or more 16-bit segments consisting of all zeroes can be represented with a double colon.FE80 : 0000 : 0000 : 0000 : 0000 : 0000 : 0000 : 0001 FE80 : : 1 FE80::1Rule 2: Double colon :: equals 0000…0000Second Rule First RuleOnly a single contiguous string of all-zero segments can be represented with a double colon. Both of these are correct…FE80 : 0000 : 0000 : 0000 : 0014 : 0000 : 0000 : 0095FE80 :: 14 : 0 : 0 : 95ORFE80 : 0 : 0 : 0 : 14 :: 95Rule 2: Double colon :: equals 0000…0000Using the double colon more than once in an IPv6 address can create ambiguity because of the ambiguity in the number of 0’s. FE80::14::95This is bad! It is a mistake as it is not clear what it meansFE80:0000:0000:0000:0014:0000:0000:0095 ?FE80:0000:0000::0014:0000:00000000:0095 ?FE80:0000:0014:0000:0000:0000:0000:0095 ?Rule 2: Double colon :: equals 0000…0000IPv4, the prefix—the network portion of the address—can be identified by a dotted decimal netmask or bitcount.255.255.255.0 or /24IPv6 prefixes are always identified by bitcount (prefix length). Prefix length notation: 3ffe:1944:100:a::/64 16 32 48 64 bitsNetwork PrefixesIPv6 AddressesIPv6 AddressingMulticastUnicastAnycastAssigned Solicited NodeGlobal UnicastUnspecifiedLoopbackEmbedded IPv4Link-LocalUnique LocalFF00::/8FF02::1:FF00:0000/104::/128::1/1282000::/33FFF::/3FE80::/10FEBF::/10FC00::/7FDFF::/7::/80Global Unicast IPv6 AddressesInterface IDSubnet IDGlobal Routing PrefixGlobal Unicast Address (GUA)001Range: 2000::/3 0010 0000 0000 0000 :: to 3FFF::/3 0011 1111 1111 1111 ::•Global unicast addresses are similar to IPv4 addresses•Routable•Unique IANA’s allocation of IPv6 address space in 1/8th sectionsInterface IDSubnet IDGlobal Routing PrefixGlobal Unicast Address (GUA)001Range: 2000::/3 0010 0000 0000 0000 :: to 3FFF::/3 0011 1111 1111 1111 ::•Global unicast addresses are equivalent to IPv4 public addresses•Except under very specific circumstances, all end users will have a global unicast address•Terminology: •Prefix equivalent to network address•Prefix length equivalent to subnet mask in IPv4•Interface ID equivalent to host portionTypical Global Unicast AddressIPv4 Unicast Address 32 bitsNetwork portion Host portionSubnet portion/?IPv6 Global Unicast Address 128 bitsGlobal Routing PrefixInterface ID16-bit Fixed Subnet ID/64•64-bit Interface ID = 18 quintillion (18,446,744,073,709,551,616) devices/subnet•16-bit Subnet ID = 65,536 subnets/48Interface IDSubnet IDGlobal Routing Prefix/64 Global Unicast Addresses and the 3-1-4 rule2001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 0100 3 + 1 = 4 (/64) :
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