transition from ipv4 to ipv6 - ucy · designing goals of ipv6 (1/3) 6 ece 654 advance computer...

Transition from IPv4 to IPv6

Argyrou Ioannis

Overview

ECE 654 Advance Computer Networks 2

Internet Protocol

Motivation

Designing goals of IPv6

Differences between IPv4 and IPv6

Transition Mechanisms

Problems on IPv4-IPv6 transition

Conclusions

References

Internet Protocol (IP)


“The Internet Protocol (IP) is the principal communications

protocol used for relaying datagrams across an internetwork

using the Internet Protocol Suite. Responsible for routing

packets across network boundaries, it is the primary protocol

that establishes the Internet” (Wikipedia).

IP in the Open Systems Interconnection

(OSI) Layer


IP has the task of delivering

datagrams from the source host

to the destination host solely

based on the addresses. For this

purpose, IP defines datagram

structures that encapsulate the

data to be delivered. It also

defines addressing methods that

are used to label the datagram

source and destination.

Motivation


The primary motivating factor in creating the next

version of the Internet Protocol, IPv6, is the relatively

small address space of the IPv4 for the current and future

size of the Internet.

The IPv4 address exhaustion already became real.

03/02/2011, IANA (Internet Assigned Numbers Authority)

Unallocated Address Pool was exhausted.

19/04/2011, APNIC (Asia-Pacific Network Information

Centre) unallocated address pool was exhausted.

Other RIRs (Regional Internet Registry), unallocated address

pool does not exhausted now, however, it should be a matter

of time.

Designing Goals of IPv6 (1/3)


As the only problem of the IPv4 was the problem of addressing and the transition to the next generation protocol IPv6 IS a big deal and something done rarely, people think to update a number of other respects as well.

The designing goals of the IPv6 include:

Larger Address Space: IPv6 had to provide more addresses for the growing Internet.

Better Management of Address Space: It was desired that IPv6 not only include more addresses, but a more capable way of dividing the address space and using the bits in each address.



Elimination of “Addressing Kludges”: Technologies like Network Address Translator (NAT) are effectively “kludges” that make up for the lack of address space in IPv4. IPv6 eliminates the need for NAT and similar workarounds, allowing every Transfer Control Protocol/Internet Protocol (TCP/IP) device to have a public address.

Easier TCP/IP Administration: The designers of IPv6 hoped to resolve some of the current labor-intensive requirements of IPv4, such as the need to configure IP addresses. Even though tools like Dynamic Host Configuration Protocol (DHCP) eliminate the need to manually configure many hosts, it only partially solves the problem.

Modern Design For Routing: In contrast to IPv4, IPv6 will allow Internet backbone designers to create a flexible and expandable global routing hierarchy.



Better Support for Multicasting: Multicasting, the ability to send a single packet to multiple destinations, was an option under IPv4 from the start, but support for it has been slow in coming. So is part of the base specification in IPv6.

Better Support for Security: IPv4 was designed at a time when security wasn't much of an issue, because there were a relatively small number of networks on the Internet, and their administrators often knew each other. Today, security on the public Internet is a big issue, and the future success of the Internet requires that security concerns be resolved.

Better Support for Mobility: When IPv4 was created, there really was no concept of mobile IP devices. The problems associated with computers that move between networks led to the need for Mobile IP. IPv6 builds on Mobile IP and provides mobility support within IP itself.

Differences between IPv4 and IPv6 (1/6)


Address space

IPv6 addresses are 128-bits long instead of 32-bits.

Header

IPv6 header format simplifies

the header fields with 40 bytes

fixed length and allows faster

packet processing (because

there is no checksum

calculation). One or more

extension header can be added

before the encapsulated

payload. These headers provide

flexibility and efficiency in IPv6

datagram.



Security

In IPv4 the IP Security Protocol is used which is not different in

principle to IPv6 but is very complex and difficult to use.

IPv6-enabled nodes must support the IP Security Protocol,

therefore IPv6 nodes are more secure. It also includes security

features, such as payload encryption, authentication of the

communication and data integrity safeguards, in its

specifications.

Another advantage of IPv6 over IPv4 is IP spoofing, which is

known to be one of the most common forms of denial-of-

service-attack. With IPv4 is impossible for a server to

determine weather packets are being received from a

legitimate end node, while an IPv6 server is able to.



Mobility Support

IPv4 has difficulties managing mobile computers for several reasons:

A mobile computer needs to make use of a forwarding address at each new point of attachment to the internet.

Informing any agent in the routing infrastructure about the mobile node’s new location requires good authentication facilities.

It is unlikely in IPv4 that mobile nodes would be able to inform their communication partners about any change in location.

The objective of mobile IPv6 is to allow a mobile node to move from link to link while retaining the same home IPv6 address. IPv6 Neighbor Discovery (ND) protocol and Address Auto configuration allows hosts to operate in any location without a special support. The performance is improved because of traffic optimization. The flexible address structure is well suited for roaming. The mobility comes in the form of Mobile IP, and unlike mobile IPv4, Mobile IPv6 avoids triangular routing and is therefore as efficient as normal IPv6.



IP Configuration As in IPv4, the IP configuration was manual or DHCP, IPv6 includes a plug-

and-play mechanism that facilitates the connection of equipment to the network. Auto configuration works together with the DHCP and the Domain Name Server (DNS), so the system administrator is not forced to configure every workstation and PC manually. The address is a combination of routing part and a host ID. The auto configuration mechanism reads the MAC address and composes a network wide valid ID.

Quality of Service (QoS) support IPv6 packet format contains a new 20-bit traffic-flow identification field

that will be of great value to vendors who implement QoS network functions. The QoS implementation is set up so that routers can identify packets belonging to an individual QoS flow. Furthermore, QoS instructions are included in the IPv6 packet header. This means that the packet body can be encrypted, but QoS will still function because the header portion containing the QoS instructions is not encrypted. This will make it possible to send streaming audio and video over the Internet with IPSec encryption, but in a manner that guarantees adequate bandwidth for real-time playback.



Routing

Is the process by which systems decide where to send a packet.

Routing protocols on a system “discover” the other systems on

the local network.

Routing in IPv6 is almost identical to IPv4 routing under

Classless Inter-Domain Routing (CIDR). The only difference is

that the addresses are 128-bit IPv6 addresses instead of 32-bit

IPv4 addresses. With very straightforward extensions, all of

IPv4's routing algorithms can be used to route IPv6.

IPv6 also includes simple routing extensions

Provider selection that is based on policy, performance, cost, and so on

Host mobility, route to current location

Auto-readdressing, route to new address



Routing Protocols Description

Routing Information Protocol (RIP) Interior Gateway Protocol (IGP) that

routes IPv4 packets and maintains a

routing table. IPv4 distance vectoring

that routes IPv4 packets and advertises

its routing table to neighbors

Internet Control Message Protocol

(ICMP) Router Discovery

Used by hosts to discover the addresses

of operational routers on the subnet

Routing Information Protocol, next

generation (RIPng) Protocol

IGP that routes IPv6 packets and

maintains a routing table

Neighbor Discovery (ND) Protocol Advertises the presence of an IPv6

router and discovers the presence of

IPv6 hosts on a network

Open Shortest Path First (OSPF)

protocol

Is a link state routing protocol that runs

as an IGP to a single autonomous system.

Transition Mechanisms


The transition between the IPv4 and the IPv6 will be a

long process during both protocols coexist and also it is

unreasonable to expect that many millions of IPv4 nodes

will be converted overnight.

That’s why some mechanisms where designed:

Dual Stack mechanism

Tunneling mechanism

Translation mechanism

Transition Mechanisms-Dual Stack

Mechanism


Allows IPv4 and IPv6 to coexist in the same hosts and routers

for supporting interoperability between IPv4 and IPv6.

IPv6 nodes which provide a complete IPv4 and IPv6

implementations are called “IPv6/IPv4 nodes” or “dual stack

nodes”. IPv6/IPv4 nodes have the ability to send and receive

both IPv4 and IPv6 packets.

Transition Mechanisms-Tunneling

Mechanism


IPv6 packets are transmitted over IPv4 network via IPv6 tunnel.

Data is carried through an IPv4 tunnel using encapsulation, in

which IPv6 packet is carried inside an IPv4 packet.

Transition Mechanisms-Translation

Mechanism


Allows IPv6 nodes only to communicate with IPv4 nodes only.

As a node with IPv4 address cannot understand a node with

IPv6 address a translator is needed for the communication

between the two.

Translation mechanism maps addresses between IPv4 and IPv6

using some protocols in the gateway to translate internet

protocols.



Packet Interception

Pretend as RA/DHCP (Routing Advertisement/DHCP) Server

Interception of ICMP (Internet Control Message Protocol) by

Firewall

Inappropriate Network Operation

Instable operation for DNS (Domain Name Server) Server

response

Tunnel network and lack of peer/path

To transmit data and conserve quality must have enough IPv6 peer

partners.



Unconsciousness on fault tolerant design

Bad TCP Error reaction

If a node gets a hard error/reset request from destination node, the

node stalls and connect to the next IP address.

If a node gets a soft error, a delay occurred because of retransmission.

Bad IPv6 address resolution with DNS

DNS server makes fault in name resolution or it takes a lot of time to

response. That’s why sometimes user can’t access a web page or wait

for while using a web browser.

Did you know?


The reason why the successor to IPv4 is version 6 and

not version 5 is because version number 5 was used to

refer to an experimental protocol called the Internet

Stream Protocol, which was never widely deployed.

Two phases of IPv6.

Conclusions


IPv6 is a very capable protocol replacement for IPv4.

IPv6 does not suffer the address space limitations that

plague IPv4.

It adds many features enhancements.

The design of IPv6 lends itself to a straightforward,

phased transition from IPv4 and work is already underway

on a global IPv6 backbone.

IPv6 should provide robust connectivity for many years to

come.

References


M. K. Sailan, R. Hassan, A. Patel, “A comparative Review of IPv4

and IPv6 for Research Test Bed”, 2009, IEEE.

J. G. Jayanthi, S. A. Rabara, “Transition and Mobility Management

in the Integrated IPv4 and IPv6 Network”, 2010, IEEE.

H. Afifi, L. Toutain, “Methods for IPv4-IPv6 Transition”, 1999,

IEEE.

R. Hiromi, H. Yoshifuji, “Problems on IPv4-IPv6 network

Transition”, 2005,IEEE.

http://www.tcpipguide.com/free/t_InternetProtocolIPIPv4IPngI

Pv6andIPRelatedProtocol.htm

http://tools.ietf.org/html/draft-matsuhira-sa46t-motivation-01

http://en.wikipedia.org/wiki/Internet_Protocol

http://www.tcpipguide.com/free/t_InternetProtocolIPIPv4IPngIPv6andIPRelatedProtocol.htm

http://www.tcpipguide.com/free/t_InternetProtocolIPIPv4IPngIPv6andIPRelatedProtocol.htm










http://en.wikipedia.org/wiki/Internet_Protocol

Thank you!

Questions?


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