network
Table of Content

IPv6 called IPng(IP next generation)

  • new version
  • successor to IPv4
  • enhancement of IPv4

The shortage of IPv4

1) IPv4 address space is not enough
IPv4 address, 32 bits, in theory can provide 4.3B, address allocation is not balance, US took half of space.
2) backbone router routing table is too huge
3) cannot autoconfig and re-config address
4) cannot solve security issue

The current solution to reduce IPv4 short of address

1) CIDR, supports any length address mask, increased space efficiency of address, but still cannot face the new request due to 32 bits limit.
2) NAT, uses private address inside local network, translates address from local to public, weakness of NAT:
a) broken IP end to end model
b) single point failure
c) not supports end to end security
d) hard to expand or re-allocate network
e) cannot solve short of address issue

IPv6 new feature

1) sample design, transparent, higher efficiency
2) support new mobile business
3) intro end to end security and QoS

IPv6 technical advantage

1) 128 bits long address, provide enough address space
2) new network architecture, improves routing performance
3) IPv6 header simple, flexible, high performance, easy extendable
4) autoconfig, plug-n-use
5) support end to end security
6) mobile feature
7) new flow flag, supported QoS

New with TCP/IPv6

  • Application layer: HTTP,FTP,DNS,DHCPv4 -> HTTP,FTP,DNS,DHCPv6
  • Transport Layer: TCP, UDP ,TCPv6, UDPv6
  • Internet Layer: IPv4, ICMP, IPv6, ICMPv6
  • Link Layer: PPP,ARP -> PPP, ND (Neighbor Discovery)

IP address format

  • IPv4 32 bits, Decimal
  • IPv6 128 bits, Hexadecimal, 8 groups x 4 x 4bits

Binary to Hexadecimal

8 1000
9 1001
A/10 1010
B/11 1011
C/12 1100
D/13 1101
E/14 1110
F/15 1111

IPv6 address format

  • Global routing prefix: n //range to a site
  • Subnet ID: m //link within a site
  • Interface ID: 128 – n – m //unique interface on a link 
    prefix 2001:1111:AAAA ::/48
subnet
2001:1111:AAAA:0001::/64
2001:1111:AAAA:0002::/64
unique host addresses
HOST 1 2001:1111:AAAA:0001:4321:5678:1ABC:2222
HOST 2 2001:1111:AAAA:0001:1234:2134:567C:3262
HOST 3 2001:1111:AAAA:0002:9876:8672:2D43:1111
HOST 4 2001:1111:AAAA:0002:2314:167A:5ABC:7634

IPV6 Address allocation

  • IANA – Internet Assigned Numbers Authority, delegates allocations of IP address blocks /12 prefix to regional Internet registries (RIRs)
  • RIR – Regional Internet Registry, manages the allocation and registration of IP addresses within a particular region of the world with /32 prefix
  • African Network Information Centre (AfriNIC) – Africa
  • American Registry for Internet Numbers (ARIN) – US, Canada, several parts of the Caribbean region
  • Asia-Pacific Network Information Centre (APNIC) – Asia, Australia, New Zealand
  • Latin America and Caribbean Network Information Centre (LACNIC) – Latin America and parts of the Caribbean region
  • Réseaux IP Européens Network Coordination Centre (RIPE) – Europe, the Middle East, and Central Asia

Local Internet Registry (LIB) / ISP assign address to business customers with site prefix of /48, business customer can subnet address to each individual link with /64 prefix.

Assigned prefixed

  • Unspecified 00…0 (128 bits) ::/128
  • Loopback 00…1 (128 bits) ::1/128
  • Multicast 11111111 FF00::/8
  • Link-local unicast 1111111010 FE80::/10
  • Unique local unicast 1111110000 FC00::/7
  • Global unicast (everything else) 2000::/3 – prefix

Categories of IP addresses

IPv4
Unicast, multicast and broadcast
IPv6
Unicast, multicast andanycast(nearest)

IPv6 unicast addressing

1) Global unicast addresses, same as IPv4 public unicast address
2) Unique local unicast addresses (ULA), same as IPv4 private address
3) Link-local unicast addresses, IPv6 auto-configured on an interface allowing hosts on the same subnet to communicate with each other without router
4) IPv4 mapped IPv6 addresses, ::FFFF:x.x.x.x
5) Special addresses
unassigned address 0.0.0.0 ::
Loopback 127.0.0.1 0:0:0:0:0:0:1 OR ::1

IPv6 anycast

anycast address format same as unicast header
anycast sent to nearest interface a set of interfaces

IPv6 multicast

send to a set of interfaces which belong to different nodes
11111111 8 bits, identify multicast
flag 4 bits 000T T=0 permanent multicast by IANA, T=1 anycast
scope, 4 bits
group ID 112 bits

IPv6 6BONE

IPv6 lab network
3ffe:0000::/16

IPv6 header

IPv4 13 fields – IPv6 8 fields
IPv4 20-60 bytes – IPv6 fixed 40 bytes

IPv6 header change

  • remove 5 fields
    header checksum, improves speed
    header length , no need for fixed length
    3 data fragmentation fields removed, use extension header
    Identification, Flags and Fragment offset
    option, no need for fixed IPv6 header
    padding, make sure IPv4 header ends 32 bits edge, no needed for fixed header
  • rename/change 4 fields
    Type of service – Traffic Class field, same as IPv4 TOS
    Protocol type – Next Header field
    Total length – Payload length
    Time to live – Hop limit field
  • new flow label (20bites) in IPv6
    a flow = flow label + address of the source node

IPv6 extension headers

IPv4 option – 20 to 60 bytes options
IPv6 Next Header – extension headers 0 to any
0 hop by hop: examined by every node along the path of the packet, RSVP,MLDv1,Jumbo
60 destination: examined only by a packets destination node(s)
43 routing: all routers
44 fragment: send packet large than would fit in path MTU
51 authentication: authentication and also message integrity, used by IPsec
50 ESP: Encapsulating Security Payload, privacy, used by IPsec
upper layer: final ext header, transport layer protocol such as TCP(6), UDP(17) and ICMP(58)

IPv6 protocol

ICMPv6
IPv6 autoconfig
ND
DHCPv6
DNSv6

ICMPv6

same as IPv4 plus for:
ND Neighbor Discovery
Path MTU Discovery
MLD Multicast Listener Discovery

ping and traceroute based on ICMP

IPv6 next header 58 for ICMPv6 ext header

ICMPv6 type

Error
Destination unreachable (type 1)
Time Exceeded (type 3)
Informational
Echo Request (type 128)
Echo Reply (type 129)

ND protocol

replaced IPv4 protocol:

  • ARP
  • ICMP Router discovery
  • ICMP redirect

ND solved issues

  • Router Discovery: Locate Router
  • Prefix Discovery: Network Prefix
  • Parameter Discovery: MTU
  • Address Auto Configuration: Link local Address
  • Address Resolution: Equivalent to ARP
  • Next hop determination: Determine the next hop router
  • Neighbor Unreachability Detection (NUD): Neighbor reachable
  • Duplicate Address Detection (DAD): Addresses in use
  • Redirect: Better first hop

5 ICMPv6 messages that ND uses

133 Router Solicitation–Request a Router Advertisement message
134 Router Advertisement – Router advertises the 64-bit prefix and parameters for a
link
135 Neighbour Solicitation– any node can contact another node by sending a message
to see if it responds
136 Neighbour Advertisement– response to the original contact message from
someone else
137 Redirect– A router can inform any node that there is a better first-hop node on the
path to a given destination

IPv6 interface ID assignment

  • Manually (similar to IPv4)
  • DHCP (similar to IPv4) but in addition, introduce DHCPv6
  • auto-configured from a 64-bit EUI-64 which is expanded from a 48-bit MAC address (e.g., Ethernet address) (New for IPv6)
  • auto-generated pseudo-random number (New for IPv6)

Stateful autoconfiguration

  • DHCPv4
  • DHCPv6
  • DHCP server required

Stateless autoconfiguration

  • New for IPv6
  • Allows hosts to configure their own IPv6 address
  • Minimal configuration of routers
  • No DHCP server are required

Stateless autoconfig address

Link local Prefix + EUI-64 format
FE80::290:27FF:FE17:FC0F

EUI-64 address

MAC 48 bits EUI-64 bits
1st 0002 local
insert FFFE in middle of MAC

IPv6 auto-config address

IPv6 two NDP messages, namely router solicitation (RS) and router
advertisement (RA) messages to discover the IPv6 prefix used on a LAN.

DHCPv6

DHCP Servers provide:

  • IPv6 addresses
  • DNS server addresses

Hosts sends DHCPv6 requests to a reserved mutlicast address:
FF02::1:2 All_DHCP_Relay_Agents_and_Servers

DNSv6

DNS maps names IP addresses
DNS is an application layer protocol and uses UDP port 53

DNSv6 – populating the DNS servers with “quad-A” records for name-to-IPv6 address resolutions and with PTR records for IPv6 address to name resolutions

DNS extensions for IPv6

  • New DNS resource record AAAA
  • New textual representation in PTR record
  • IP6.arpa domain
  • New DNS queries
    Experimental or deprecated
  • A6 and DNAME records
  • Binary Labels type
  • IP6.int domain

IPv4/v6 Transition and coexistence

  1. Dual-stack techniques – This allows IPv4 and IPv6 to coexist in the same
    devices and networks.
  2. Tunneling techniques – This allows the transport of IPv6 traffic over the existing
    IPv4 infrastructure.
  3. Translation techniques – This allows IPv6-only nodes to communicate with IPv4-
    only nodes.

Dual stack

host or router has support for both IPv4 and IPv6 protocol versions
When both the IPv4 and IPv6 stacks are enabled, the node can use both protocols.

Tunneling

carry IPv6 traffic over an IPv4 infrastructure
The tunneling process involves three steps:

  • Encapsulation at the tunnel entry point
  • Decapsulation at the tunnel exit point
  • and tunnel management.
    Tunnel Types:
  • MCT Manually configured tunnel
  • 6to4 Dynamic 6to4 tunnels
  • ISATAP Intra-site Automatic Tunnel Addressing Protocol
  • Toredo

Translation

Network Address Translation-Protocol Translation (NAT-PT)
native IPv6 hosts and applications to communicate with native IPv4 hosts and applications, and vice versa

Summary of special IPv6 address

  • multicast FF00::/8
  • link local FE80::/10 for autoconfig
  • unique local FC00::/7 private address
  • global 2000::/3
  • autoconfig link local + EUI-64 FE80 + (FFEE in middle of MAC)
  • 6to4 2002::/16 2002 + (IPv4 hex in 2/3 quartet)
  • ISATAP 2001 + (0200 5EFE in 5/6 quartet) + (IPv4 IP hex in 7/8 quartet)
  • Teredo 2001:0::/32