Ipv6 Technology Overview Tutorial- Part I Tutorial- Part I
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IPv6 Technology Overview Tutorial - Part I Speaker: Byju Pularikkal Customer Solutions Architect, Cisco Systems Inc. 1 Acronyms/Abbreviations DOCSIS = Data-Over-Cable Service Interface RS = Router Solicitation Specification RA = Router Advertisement CMTS = Cable Modem Termination System UDP = User Datagram Protocol DS = Downstream DUID = DHCP Unique Identifier US = Upstream DNS = Domain Name System CM = Cable Modem CPE = Customer Premises Equipment IPv6 = Internet Protocol version 6 ICMPv6 = Internet Control Message Protocol ND = Neighbor Discovery version 6 NS = Neighbor Solicitation DHCPv6 = Dynamic Host Configuration Protocol for HFC = Hybrid Fiber Coaxial IPv6 EUI = Extended Unique Identifier MSO = Multiple Services Operator SMB = Small Business TFTP = Trivial File Transfer Protocol PDA = Personal Digital Assistant ToD = Time of Day NAT = Network Address Translation MDD = Mac Domain Descriptor CIDR = Classless Interdomain Routing APM = Alternative Provisioning Mode DAD = Duplicate Address Detection SNMP = Simple Network Management Protocol SLA = Subnet Level Address ASM = Anysource Multicast VPN = Virtual Private Network SSM = Source Specific Multicast ARP = Address Resolution Protocol SLAAC = Stateless Addres Autoconfiguration eSAFE = Embedded Service/Application Functional Entity MLD = Multicast Listener Discovery . 2 Tutorial-1: Agenda Structure of IPv6 Protocol IPv4 and IPv6 Header Comparison IPv6 Extension Headers IPv6 Addressing Addressing Format Types of IPv6 addresses ICMPv6 and Neighbor Discovery Router Solicitation & Advertisement Neighbor Solicitation & Advertisement Duplicate Address Detection Multicast in IPv6 DHCP & DNS for IPv6 DNS with IPv6 DHCPv6 Overview . 3 Tutorial-2: Agenda Routing in IPv6 RIPng OSPFv3 BGP-4 Extensions for IPv6 Multi-Topology IS-IS Tunneling Automatic 6 to 4 Tunnels ISATAP IPv6 for DOCSIS Overview IPv6 Drivers in Broadband Access Networks CMTS & CM Requirements for IPv6 MSO CPE Address Assignment Strategies . 4 The Structure of IPv6 Protocol 5 IPv4 and IPv6 Header Comparison IPv4 Header IPv6 Header Type of Version IHL Total Length Version Traffic Class Flow Label Service Fragment Identification Flags Payload Length Next Header Hop Limit Offset Time to Live Protocol Header Checksum Source Address Source Address Destination Address Options Padding Legend Destination Address - Field name kept from IPv4 to IPv6 - Fields not kept in IPv6 - Name and position changed in IPv6 - New field in IPv6 . 6 IPv6 Header New Field—Flow Label (RFC 3697) 20-Bit Flow Label Field to Identify Specific Flows Needing Special QoS IPv6 Header Flow classifiers had been based on Version Traffic Class Flow Label 5-tuple: Source/destination address, Next Payload Length Hop Limit protocol type and port numbers of Header transport Some of these fields may be unavailable due to fragmentation, Source Address encryption or locating them past extension headers With flow label, each source chooses its own flow label values; routers use source addr + flow label to identify Destination Address distinct flows Flow label value of 0 used when no special QoS requested (the common case today) . 7 Extension Headers Base header IPv6 Base Header Next Header = 0 st (40 octets) 1 Extension Header 0 or more Next Header… = 43 IPv6 Extension Headers Last Extension Packet Header Next Header = 17 Data Next Header = 17 Ext Hdr Length Ext Hdr Data . 8 Extension Header Order Extension Headers Should Be Constructed in the Following Sequence and Should Be Sequenced in this Order: Hop-by-Hop header (0) Destination options header (w/ routing header) (60) Routing header (43) Fragment header (44) Authentication header (51) ESP header (50) Mobility header (135) Destination options header (60) ICMPv6 (58) No Next header (59) Upper-layer header (Varies— TCP=6, UDP=17) . 9 MTU Issues Minimum link MTU for IPv6 is 1280 octets (vs. 68 octets for IPv4) => on links with MTU < 1280, link-specific fragmentation and reassembly must be used Implementations are expected to perform path MTU discovery to send packets bigger than 1280 Minimal implementation can omit PMTU discovery as long as all packets kept ≤ 1280 octets A hop-by-hop option supports transmission of “jumbograms” with up to 2 32 octets of payload; payload is normally 2 16 . 10 IPv6 Addressing 11 IPv6 Addressing . 12 IPv6 Addressing . 13 Addressing Format Representation 16-bit hexadecimal numbers Numbers are separated by (:) Hex numbers are not case sensitive Abbreviations are possible Leading zeros in contiguous block could be represented by (::) Example: 2001:0db8:0000:130F:0000:0000:087C:140B 2001:0db8:0:130F::87C:140B Double colon only appears once in the address . 14 Addressing Prefix Representation Representation of prefix is just like CIDR In this representation you attach the prefix length Like v4 address: 198.10.0.0/16 V6 address is represented the same way: 2001:db8:12::/48 Only leading zeros are omitted. Trailing zeros are not omitted 2001:0db8:0012::/48 = 2001:db8:12::/48 2001:db8: 1200 ::/48 ≠ 2001:db8:12::/48 . 15 IPv6 Address Representation Loopback address representation 0:0:0:0:0:0:0:1=> ::1 Same as 127.0.0.1 in IPv4 Identifies self Unspecified address representation 0:0:0:0:0:0:0:0=> :: Used as a placeholder when no address available (Initial DHCP request, Duplicate Address Detection DAD) . 16 IPv6—Addressing Model Addresses are assigned to interfaces Change from IPv4 mode: Interface “expected” to have multiple addresses Addresses have scope Link Local Unique Local Global Unique Local Link Local Global Addresses have lifetime Valid and preferred lifetime . 17 Addressing Some Special Addresses Type Binary Hex Aggregatable Global 001 2 or 3 Unicast Address Link Local Unicast 1111 1110 10 FE80::/10 Address FC00::/7 Unique Local Unicast 1111 1100 FC00::/8(registry) Address 1111 1101 FD00::/8 (no registry) Multicast Address 1111 1111 FF00::/8 . 18 Types of IPv6 Addresses Unicast Address of a single interface. One-to-one delivery to single interface Multicast Address of a set of interfaces. One-to-many delivery to all interfaces in the set Anycast Address of a set of interfaces. One-to-one-of-many delivery to a single interface in the set that is closest No more broadcast addresses . 19 Global Unicast Addresses Provider Site Host 3 45 Bits 16 Bits 64 Bits Global Routing Prefix SLA Interface ID 001 (2) 011 (3) Global Unicast Addresses Are: Addresses for generic use of IPv6 Structured as a hierarchy to keep the aggregation . 20 Unique-Local 128 Bits Global ID 40 Bits Interface ID 1111 110 Subnet ID FC00::/7 16 Bits 7 Bits Unique-Local Addresses Used for: Local communications Inter-site VPNs Not routable on the Internet . 21 Link-Local 128 Bits Remaining 54 Bits Interface ID 1111 1110 10 FE80::/10 10 Bits Link-Local Addresses Used for: Mandatory Address for Communication between two IPv6 device (like ARP but at Layer 3) Automatically assigned by Router as soon as IPv6 is enabled Also used for Next-Hop calculation in Routing Protocols Only Link Specific scope Remaining 54 bits could be Zero or any manual configured value . 22 IPv6 Multicast Address IP multicast address has a prefix FF00::/8 (1111 1111); the second octet defines the lifetime and scope of the multicast address 8-bit 4-bit 4-bit 112-bit 1111 1111 Lifetime Scope Group-ID Lifetime Scope 1 0 If Permanent Node 2 Link 1 If Temporary 5 Site 8 Organization E Global . 23 Some Well Known Multicast Addresses Address Scope Meaning FF0 1:: 1 Node-Local All Nodes FF0 2:: 1 Link-Local All Nodes FF0 1:: 2 Node-Local All Routers FF0 2:: 2 Link-Local All Routers FF0 5:: 2 Site-Local All Routers FF0 2:: 1:FFXX:XXXX Link-Local Solicited-Node Note that 02 means that this is a permanent address and has link scope More details at http://www.iana.org/assignments/ipv6-multicast- addresses . 24 Multicast Mapping over Ethernet IPv6 Multicast FF02 0000 0000 0000 0000 0001 FF17 FC0F Address Corresponding 33 33 FF 17 FC 0F Ethernet Address Multicast Prefix for Ethernet Multicast Mapping of IPv6 multicast address to Ethernet address is: 33:33:<last 32 bits of the IPv6 multicast address> . 25 Solicited-Node Multicast Address For each unicast and anycast address configured there is a corresponding solicited-node multicast This is specially used for two purpose, for the replacement of ARP, and DAD Used in neighbor solicitation messages Multicast address with a link-local scope Solicited-node multicast consists of prefix + lower 24 bits from unicast, FF02::1:FF: . 26 Anycast Anycast Address Assignment Anycast allows a source node to transmit IP datagrams to a single destination node out of a group destination nodes with same subnet id based on the routing metrics Only routers should respond to anycast addresses Routers along the path to the destination just process the packets based on network prefix Routers configured to respond to anycast packets will do so when they receive a packet send to the anycast address . 27 Anycast Address Subnet Router Anycast Address (RFC 4291) 128 bits n bits (128-n) bits Prefix 00000 Reserved Subnet Anycast Address (RFC 2526) 128 bits Prefix 111111 X111111… 111 Syntactical the same Anycast ID as a Unicast address 0 If EUI-64 Format X = Is one-to-nearest 1 If Non-EUI-64 Format 7 bits type of address Has a current limited use Use Example: Mobile IPv6 Home-Agent Anycast Address . 28 IPv6 Prefix Allocation Hierarchy and Policy Example IANA 2001::/3 AfriNIC APNIC ARIN LACNIC RIPE NCC ::/12 to::/23 ::/12 to::/23 ::/12 to::/23 ::/12 to::/23 ::/12 to::/23 ISP ISP ISP ISP ISP ISP ISP ISP ISP ISP ISP /32 ISP /32 ISP /32 ISP /32 ISP /32 /32 /32 /32 /32 /32 /32 /32 /32 /32 /32 Site Site Site Site Site Site Site Site Site Site Site /48 Site /48 Site /48 Site /48 Site /48 /48 /48 /48 /48 /48 /48 /48 /48 /48 /48 . 29 IPv6 Address Allocation Process Partition of Allocated IPv6 Address Space .