Lesson 2 Introduction to IPv6

Lesson Objectives Limitations of IPv4 and modern day Internet Features of IPv6 Differences between IPv4 and IPv6 IPv6 terminology Case for IPv6 deployment

Limitations and some solutions of IPv4 Exponential growth since 1991 large routing tables Need for simpler configuration Requirement for security at the IP level Need for better support for real-time delivery of data—also called quality of service (QoS) Possible solutions Class to classless (CIDR) Network Address Translation (NAT) Separated attached component: IPsecV4, IP mobile, …

Consequences of the Limited IPv4 Address Space: NATs Dest. Addr.: 157.60.13.9 Src. Addr.: 192.168.0.10 Dest. TCP port: 80 Src. TCP port: 1025 Dest. Addr.: 157.60.13.9 Src. Addr.: 131.107.47.119 Dest. TCP port: 80 Src. TCP port: 5000 Host NAT 192.168.0.10 NAT Web server Internet 131.107.47.119 157.60.13.9 Dest. Addr.: 192.168.0.10 Src. Addr.: 157.60.13.9 Dest. TCP port: 1025 Src. TCP port: 80 Dest. Addr.: 131.107.47.119 Src. Addr.: 157.60.13.9 Dest. TCP port: 5000 Src. TCP port: 80 NAT

NAT additional (NAT editors) Problems with NAT added: TCP, UDP is stored elsewhere in the payload E.g., FTP use PORT command with embedded IPv4 address TCP or UDP is not used to identify the data stream Point-to-Point Tunneling Protocol (PPTP) use a Generic Routing Encapsulation (GRE) and the Call ID field of the GRE identifies the data stream.

NATs and Peer-to-Peer Applications Host A Host A can initiate a session with Host B and Host C However, Host A can not inform Host C of Host B. Modification is to make peer-to-peer application to be NAT-aware, And NAT itself. Host C NAT Internet Host B Intranet

Features of IPv6 New header format Large address space Efficient and hierarchical addressing and routing infrastructure Stateless and stateful address configuration Built-in security Better support for QoS New protocol for neighboring node interaction Extensibility

Differences Between IPv4 and IPv6 Feature IPv4 IPv6 Address length 32 bits 128 bits IPSec support Optional Required QoS support Some Better Fragmentation Hosts and routers Hosts only Packet size 576 bytes 1280 bytes Checksum in header Yes No Options in header Yes No Link-layer address resolution ARP (broadcast) ARP (Group) Multicast membership IGMP Multicast Listener Discovery (MLD) Router Discovery Optional Required Uses broadcasts Yes No Configuration Manual, DHCP Automatic, DHCP DNS name queries Uses A records Uses AAAA recordsDNS reverse queries Uses IN-ADDR.ARPA Uses IP6.INT

IPv6 Terminology Additional subnets Neighbors Host Host Host Bridge Intra-subnet router Router LAN segment Link Subnet Additional subnets Network

Node, any device that runs IPv6 includes routers and hosts. Link, one or more LAN segments bounded by routers Subnet, one or more links that use the same 64-bit IPv6 address prefix. Also called network segment Network, two or more subnets connected by routers

Neighbors, nodes connected to the same link. Interface, a physical or logical attachment of a node to a link Link MTU: Max. Transfer Unit Path MTU

The Case For IPv6 Deployment IPv6 solves the address depletion problem IPv6 solves the international address allocation problem IPv6 restores end-to-end communication IPv6 uses scoped addresses and address selection IPv6 has more efficient forwarding IPv6 has built-in security and mobility

Review Limitations of IPv4 and modern day Internet Features of IPv6 Differences between IPv4 and IPv6 IPv6 terminology Case for IPv6 deployment