This document provides an overview of IPv6 including addressing, routing, autoconfiguration, transition technologies, and Linux implementation. Key points covered include IPv6 address formats and types, stateless and stateful autoconfiguration using ICMPv6 and DHCPv6, static and adaptive routing protocols like RIPng and OSPFv3, DNS record formats, and dual stack and tunneling transition technologies. It also reviews how to configure an IPv6 router using the radvd daemon on Linux systems.

1. IPv6 Introduction

2. Agenda
• IPv6 Addressing
– What is IPv6
– ICMPv6 (Stateless)
– DHCPv6 (Stateful)
• IPv6 Routing
– Static Routing
– Adaptive Routing
• IPv6 Service
– DNSv6
– IPv6 to IPv4 Transition
• Linux IPv6 Implementation

3. IPv4/IPv6 Protocol Stack

4. What is IPv6
• IPv4 (32bits) → IPv6 (128 bits)
– 2001:0db8:1a2b:0015:0000:0000:1a2f:0000
• 2001:db8:1a2b:15:0:0:1a2f:0
– (0 can ignore)
• 2001:db8:1a2b:15::1a2f:0
– multiple “0” block can combine to :: (only once)
• Prefix is network address
– 2001:0:0:b3::1234/64
• Address type
– Unicast
– Multicast [Multicast Listener Disscovery]
– Anycast (router only)

5. IPv6 Unicast Address
• Unicast address type
– Global
• Unique
• Start 001x+ network addr + 64 bits interface addr
– Local Link
• Cannot pass through Router
• fe80:: + 64 bits interface addr / 10
• EUI-64 (transfer MAC to IPv6 interface address)
– 7th
bit change to complementation
– Add FFFE in the 3th and 4th
• 00:ab:cd:12:34:56 → 02ab:cdff:fe12:3456
• IPv6 address method
– manual, auto-configuration (stateless, stateful)

6. IPv6 Auto Configuration

7. Stateless Auto Configuration
• ICMPv6 ()
– Fault management
• Ping6
• traceroute6
– Multicast Listener Discovery (MLDv2)
• Replace IGMPv3
– Neighbor Discovery
• Router Solicitation (RS)
• Router Advertisement (RA)
• Neighbor Solicitation (NS)
• Neighbor Advertisement (NA)
• Redirect

8. Router Advertisement Header
• M
– 1 : get Prefix from DHCP server
– 0 : get Prefix from Router
• O
– 1 : get DNS from DHCP server
– 0 : get DNS from Router

9. ICMPv6 Router Discovery

10. ICMPv6 Router Discovery

11. ICMPv6 Address Resolution

12. ICMPv6 Address Resolution

13. Stateful Auto Configuration
• DHCPv6 (RFC 3315)
– DHCPv6 client can request multiple IPv6 address
– 4-way messages exchange (Stateful)
• M=1, O=0
• Solicit(C) / Advertise(S) / Request(C) / Reply(S)
– 2-way messages exchange (Stateless)
• Information-request(C) / Reply (S)
• DHCP Roles
• M=0, O=1
– Client
– Server
– Relay Agent

14. DHCPv6 working

15. Auto Configuration Process
• Allows a host to create a unicast address from:
– Its MAC address
– Prefixes sent by neighbor routers
• Several steps:
– Link-local addresses creation
– Duplicate addresses detection (DAD)
– Discover the routers on-link (RS/RA)
– " Configure hosts global addresses
– Configure other parameters: default router, link MTU, …
• Addresses are not automatically registered in the DNS
– Need for DNS Dynamic Update (RFC 2136 and RFC 3007)

16. Auto Configuration Flowchart

17. IPv6 Routing
• Routing Algorithm
– Increase throughput
– Decrease average delay

18. Routing Type
• Static routing (Peer to Peer, Host)
– The same as IPv4
• Specify source, destination, distance
• Adaptive routing (Router to Router)
– Distance Vector Concept
• RIPng (RFC2080)
– Link-State Concept
• OSPFv3 (RFC 5340)

19. Distance Vector Concept

20. Link-State Concept

21. Distance Vector Routing v.s.
Link-State
Routing

22. IPv6 Routing Protocols

23. RIPng
• Same as IPv4
– Distance vector, radius of 15 hops, split horizon, and
– poison reverse
– Based on RIPv2
• Updated features for IPv6
– IPv6 prefix, next-hop IPv6 address
– Uses the multicast group FF02::9 for RIP updates
– Uses IPv6 for transport
– Updates are sent on UDP port 521
• Named RIPng

24. OSPFv3
• Based on OSPFv2, with enhancements
• Distributes IPv6 prefixes
• Runs directly over IPv6
• Ships in the night with OSPFv2
• Adds IPv6-specifific attributes:
– 128-bit addresses
– Link-local address
– Multiple addresses and instances per interface
– Authentication (now uses IPsec)
– OSPFv3 runs over a link, rather than a subnet

25. DNSv6
• Domain Name System version 6
– Mapping Domain name and IP
• Client / Server Architecture
• Application
– ISC BIND-9.2.2 (Linux)
• Support IPv4 & IPv6 DNS query
• AAAA records
• renumbering
– Windows Server 2008

26. IPv6 to IPv4 Transition
• Dual Stack
– Support IPv4 & IPv6 on the same time
– IPv4 only, IPv6 only, Dual Stack
– Need one IPv4 and one IPv6 address

27. IPv6 to IPv4 Transition
• Tunneling
– Add IPv4 header

28. IPv6 to IPv4 Transition
• Translator
– Network Address Translation – Protocol
Translation
– Like IPv4 NAT
– IPv4 Address pool + sock port number
– It is deprecated on 2007/7

29. Linux IPv6 implementation
• IPv6 Addressing
– Linux 2.6.x ~
• ipv6 protocol stack, ip6tables, …
– DHCPv6 (ISC DHCP-4.1.2)
• IPv6 Routing
– IPv6 router (radvd-1.1.5)
• ICMPv6 RA, ipv6 routing
– IPv6 routing protocol (quaga-0.98)
• BGP4, BGP4+, OSPFv2, OSPFv3, RIPv1, RIPv2, RIPng
• IPv6 Service
– DNSv6 (bind-9.2.2), Tunnel Broker (gogoc), NTP (ntp-
4.2.4), SMTP (mailx-12.4), SNMP (netsnmp-5.2.1),
PPP(ppp-2.4.4), WWW(boa-0.94.13), …

30. How to enable IPv6 Router
(radvd)
# yum search radvd // search radvd
# yum install radvd // install radvd
# vi /etc/radvd.conf // edit configuation
interface eth0
{
AdvSendAdvert on;
MinRtrAdvInterval 3;
MaxRtrAdvInterval 10;
prefix 2001:db8:0:f101::1/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr on;
};
};
# echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
# echo 1 > /proc/sys/net/ipv6/conf/default/forwarding
#service radvd start

31. Reference
• http://www.ngnet.it/e/ipv6proto/ipv6-proto-
6.php
• http://www.ipv6.hinet.net/index.html
• http://www.rd.ipv6.org.tw/
• IPv6 應用及路由實務 - 訓練教材
• http://www.ithome.com.tw/itadm/article.ph
p?c=66363&s=6
• http://interop.ipv6.org.tw/index.php