IPv6 The Big Move: Transition and Coexistent Frenil V. Dand

Introduction

• IPv6 (Internet Protocol version 6) is the successor to IPv4

• IPv4 is base on 32bits, with that its possible to express 4,294,967,296 different values. Over half a billion of those are unusable. Giving us 3.7 billion possible addresses

• 5% of IPv4 are reaming • IPv4 will run out by end 2011• IPv6 supports about 340 undecillion (1036) addresses 340,282,366,920,938,463,463,374,607,431,786,211,456

• IPv6 adoption has been slowed and IPv4 exhaustion has bee prolonged by NAT (Network Address Translation)

http://www.ipv6forum.com/

Advantages of IPv6

• Trillions of times more addresses.• Easy to configure (Neighbor discovery and Stateless

autoconfig)• Compatible with 3G and features that support greater

mobility• Supports ad hoc networking• More efficient usage of broadband, via Jumbograms

and Flow Label• Leaner Headers (six removed and one new filed).• More secure with mandatory IPSec• Better Quality of Service (QoS)• Allowing for many new possibilities

IPv6 Headers

How does IPv6 work?

• New 128-bit addressing represented by eight 16 bit hex components divided by colons, X:X:X:X:X:X:X:X

• Last 64 bits are used for interface ID• e.g. 2001:0DB8:C003:0001:0000:0000:0000:F00D• Can be represented in shorter format by removing leading

zeros e.g. 2001:DB8:C003:1:0:0:0:F00D• Further reduction by removing consecutive fields of zeros

using the double-colon :: option• Double-colon can be used only once, because multiple

occurrences would lead to ambiguity• e.g. 2001:DB8:C003:1::F00D

• Addresses are organized in a hierarchical manner to facilitate:

- Scaling

- Aggregation

- Routing• Aggregation is achieved by address prefix and the

organization of addresses into two levels- public topology and interface identifier

• Smaller routing tables allows for increase routing efficiency

• IPv6 supports three address types:

- Unicast Addresses: one-to-one (global, link local, unique local, compatible)

- Multicast Addresses: one-to-many (also replaces broadcast addresses)

- Anycast Addressed: one-to-nearest (allocated from Unicast)

IPv6 Global Unicast Address

Generic Division of Unicast

Field Name Size (bits) Description

Prefix “n”Global Routing Prefix: The network

ID or prefix of the address, used for routing.

Subnet ID “m”Subnet Identifier: A number that

identifies a subnet within the site.

Interface ID “128-n-m”

Interface ID: The unique identifier for a particular interface (host or other device). It is unique within the specific prefix and subnet.

• Unicast will be used for majority of the traffic• One-eighth of address is assigned to it• 2001:0DB8:C003:0001:0000:0000:0000:F00D

IPv6 Multicast and Anycast• Multicasting allows for single device to send data to

group of recipient • Format Prefix of 1111 1111

• Always begins with FF

Four bits are reserved for Flags.Currently, first 3 of them are set to zero (unused)

Last bit is Transient. Transient can be zero or one:

If T set to Zero, then multicast address is well-known permanently assigned

If T set to One, then multicast address is not permanently assigned

Scope ID(16 different values from 0 to 15)

Currently defined values (in decimal) 0 = Reserved 1 = Node-Local Scope 2 = Link-Local Scope 5 = Site-Local Scope 8 = Organization-Local Scope 14 = Global Scope 15 = Reserved

• Anycast addresses are new to IPv6• Cross between unicast and multicast • Allows datagrams to be sent to whichever router in a

group of equivalent router is closest

Unicast

• Send this to one address

Multicast

• Send this to every member of this group

Anycast

• Send this to any member of this group

• Send this to closest member of this group

Autoconfiguration and Renumbering

• By default IPv6 host can configure a link-local address for each interface

• Router discovery allows host to determine addresses of routers, additional addresses, and other configuration parameters

• Address autoconfiguration can only be performed on multicast-capable interfaces

• 6 steps device takes for stateless autoconfiguration

1. Link-Local Address Generation- device generates a link-local address

2. Link-Local Address Uniqueness Test- node tests to ensure the address in not duplicated

3. Link-Local Address Assignment- device assigns the link-local address to its IP interface

4. Router Contact- node next attempts to contact local router for more information on continuing the configuration

5. Router Direction- router provides direction to the node on how to proceed

6. Global Address Configuration- host will configure itself with its globally unique Internet address

IPv6 Transition and Coexistence

• Very long and difficult process• IPv4 and IPv6 incompatible• Various technologies• Three categories :

– Dual Stack– Tunneling– Translation

• Dual Stack is a network stack that supports both IPv4 and IPv6 while sharing most of the code

• To work effectively must be implemented on all routers in network

• Works by using two addressing schemes in parallel• Requires more resources

• Tunneling is technique which consists of encapsulating

• Allows IPv6 packets over IPv4 networks• Require dual-stack at end of tunnel• Three main tunneling techiques:

– IPv6 over IPv4 (6over4)– IPv6 to IPv4 (6to4) automatic tunneling– Tunnel Broker

• Three step of tunneling are:– Encapsulation– Descapsulation– Tunnel management

• 6over4– Embeds IPv4 in IPv6– Not auto; needs network admin for end point

• 6to4 automatic tunneling– Tunnel endpoint doesn’t require administrator– IPv4 embedded in the last 32 bits– IPv6 packets send over IPv4 network

• IPv6 Tunnel Broker– 3rd party service or a vendor

• Teredo is extension of basic 6to4– Provides IPv6 connectivity behind NAT– Uses 3rd party relay service – Vista and Windows 7 running Teredo– Easy for average Internet users

• Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) similar to 6over4– Automatic encapsulation by using virtual IPv6– Used in enterprise network

• IPv4/IPv6 Translation– Once considered as a last resort– Not simple as it sounds– Based on Stateless IP/ICMP and Network address

translation– Only option of IPv6 transition that entirely remove

IPv4 addresses.– Single-stack approach

• 6rd– IPv6 Rapid Deployment– Big move help in residential consumer– Allows ISP to designate relay– Requires home hardware to support 6rd– Encapsulation of IPv6 inside IPv4 and send to ISP

Conclusion

• Not a overnight process• Interoperability key• IPv6 is going to internet and world of

communications to the next level• Japan, China and other countries in Asia-Pacific

are already deploying and using IPv6• 2008 Beijing Olympics was the widest use of IPv6• Refrigerators can order groceries and taxis can

detect rain and message to headquarters• And let’s not forget iPad, iPhone, and Android’s• DOD and Federal Government already running

IPv6

The End

Questions?