1. Lesson 2
Introduction to IPv6

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

3. 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, …

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

5. 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.

6. 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

7. 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

8. 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

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

10. 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

11. 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

12. 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

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