Computer hardware and software
Tunneling IPv6 over IPv4 infrastructure
Section 1: Introduction
While the IPv4 Internet Protocol was to provide an efficient service for over 20 years,
but the new Internet protocol, IPv6, more efficiency, as sufficiently
Concerning IP addresses, enhanced security and mobility. In fact, it is good, the performance benefits we get IPv6 can rate compare IPv4. We can get to upgrade existing IPv4 infrastructure for next generation Internet Protocol (IPv6) and advantages of using transition mechanisms.
When IPv4 was developed, most of the networks had lymph years of low-bandwidth, high latency and high error rate. The most common applications of this time were FTP, e-mail, and so on.In the early 1990s, the computer industry with the entry of personal computers (PC) market expanded. The Internet has also developed and e-business and e-commerce has begun. Market demand is the most important factor in the Internet Revolution. Since the rapid growth of the Internet has been detected in the early 1990s, it was
shows that the IPv4 address space would be completed by the end of the century. In this
In that regard, mechanisms such as Network Address Translator (NAT) has extended the life of IPv4, but it was not solution.Today logic of the market seems very different than it was in the 1980s. As well as FTP and email are still popular today, but also new applications such as video conferencing, VoIP, e-commerce, mobile phones, etc., have the />
Engineering Task Force (IETF) for a new Internet protocol, which we call /> IPv6.
Process, the two protocols to coexist for many years to come. To facilitate the transition, the IETF (Internet Engineering Task Force) has established a working group called ngtrans (Next Generation Transition) that specifies the mechanisms to ensure interoperability between IPv4 and IPv6 support. In particular, the group focused on two major issues:
• How to communicate with IPv4 IPv6 terminals terminals.
• How IPv6 over an IPv4 network can communicate with transport so that IPv6 “islands” of IPv4 Internet connected.
The second problem, which is very important in the initial phase of the />
as
transportation: provision will be joined in future by the issue of reciprocity
IPv4 to IPv6. However, the discussion on this issue have been postponed until the presence of IPv6 is an important point on the Internet
.
The work on these problems has resulted in a number of transition mechanisms, each of which led to a certain range of uses and applications.
Section 2:
IP Overview
Internet Protocol is a set of techniques used by many hosts for transmitting data over
the Internet. The current version of the Internet protocol is IPv4, the 32-bit addressing system offers.
Internet Protocol is a “best effort” system, which means that no information package sent
more it is guaranteed to its destination in the same condition it was sent to achieve. Often />
Protocols are in tandem with the Internet Protocol for data used for one reason or
others have a very high accuracy.
Each device connected to a network, be it a local area network (LAN) or Internet
is in a range of Internet protocol. This address is used to uniquely identify the device under all other devices connected to the WAN.
2.1: Characteristics of
IP
IP is a connectionless protocol. That is, it has no concept of a job or session.
Each packet is treated as a whole in itself. IP is a bit like a postal worker sorting
Letters. He does not care whether a package is a lot. He simply streets
Packages, one at a time, at the following location on the delivery route.
IP is also immaterial whether a package must be objective, or
reached
if the packets arrive in the original order. There is no information in a packet
identified as part of a sequence or as belonging to a specific task. Therefore, IP
can not say whether the packets were lost or received out of order. IP is a
unreliable protocol. Any mechanisms to ensure that data is sent intact and correct by higher protocols provided in the suite.
2.2: IP Routing
How does a packet with an IP address on a computer on the other side of the world is
the way to his goal? The basic mechanism is very simple.
In a LAN, every host sees every packet that is sent from all other hosts on the LAN.
Usually it is just something to do with this package, if it is directed, or if
The goal is a broadcast address.
A router is different. A router examines every packet and compares />
Address with an address table that holds in memory. If it finds an exact match, it
forwards the packet to an address with the entry in the table refers. This
associated address, the address of another network in a point-to-point, or
It may be the address of the next hop router.
If the router does not find a game, it goes through the table, this time in search of
Match the network ID part of the address. Even if a match is found, the
Packet is sent to the address associated with this entry.
If a match is not found, the router looks to see if a default address of the next section
to present. If so, the packet is sent there. If no default address is present, the router sends
an ICMP “host unreachable” or “network unreachable” message to the sender. If
You are seeing this message, it usually indicates a failed router at some point in the
Network.
The most difficult part of the job of a router is not the way it packages roads, but the way he built his
Table. In the simplest case, the router table is static: to be read from a file at startup.
This is adequate for simple networks. You do not even need a separate piece of kit for
this is because the function integrated IP routing.
Dynamic routing is more complicated. A router table built his charisma
Calls ICMP router to respond to the other router. Routing protocols
be used to discover the shortest path to a location. Routes are regularly updated
Response to the market and the availability of a route. However, details />
blow it all works is beyond the scope of this report.
2.3: The Future of the Internet
As we see the Internet is a serious problem in recent years. With its
tremendous growth and limitations in the design and equipment, it will be a
Problem, if no free addresses are available for connecting to new hosts or
Assignment to a new device. At this time, no new Web servers are installed, no
Multiple users can be set up for accounts with suppliers and more new machines to access the Internet or playing online games.
Several solutions have been made to solve the problem. A popular approach is
not assign a unique address assigned to each user’s computer, but
the “private” addresses, and hide several machines behind a servant />
unique address. This technique is called "Network Address Translation or NAT. It
has problems as the machines hidden behind the global address list can not be accessed,
and after this, opening connections to be used in online games,
Peer-to-peer networking, and etc., is not possible.
Another approach to the problem of Internet addresses is unusual get rid
Internet Protocol old man with his limited capacities of address, and use a new
Protocol that does not have these limitations. Protocol, or indeed a series of
Minutes of computers is connected to the Internet as used today, known as
TCP / IP (Transmission Control Protocol / Internet Protocol) and version 4 currently
Use has all the problems described above.
Jump to a different protocol version that does not have these problems />
requires a new version is available. And indeed, there is a better version.
Internet Protocol Version 6 (IPv6) provides future research in the address space,
and other features such as privacy, encryption, and better support of
Mobile computing as well.
Assuming a basic knowledge of operating IPv4 today, this report is intended
as an introduction to IPv6. Change of address formats and name
Resolution be recorded. Then it is shown how to use a IPv6 /> simple, but
efficient transition mechanism called 6to4.
Section 3: IPv6 vs. IPv4
When people say to migrate from IPv4 to IPv6, the question you usually hear, “Why?”.
There are actually some good reasons to move to the new version:
• Large address space
• Support for mobile devices
• Integrated security
3.1: Bigger address space />
IPv4. During today’s Internet architecture is based on 32-bit address width, the new base
Version has a 128-bit technology for addressing. Based on advanced />
Space should, solutions such as NAT no longer be used. This enables complete, full IP connectivity for IP-based machines of today and future mobile devices such as PDAs and mobile phones all benefit from full access to IP over GPRS and UMTS.
3.2: Mobility />
necessary support to the mobility and the implementation of this Protocol is “Mobile
IP is one of the requirements for each IPv6 stack. If we IPv6 is so
have the support of roaming between different networks with a global notification when
We go from one network and enter another. Support for roaming is possible with
IPv4, but there are a number of circles, which are bound to order things have to get
to work. In IPv6 there is no need for that support for mobility was one of the
Design requirements for IPv6.
3.3:
Security
Besides support for mobility, security was another requirement for the successor of
Internet Protocol version today. As a result, IPv6 protocol stacks needed for
include IPsec. IPsec allows authentication, encryption and compression of IP traffic.
Apart from application-level protocols such as SSL or SSH, all IP traffic between two
Nodes can be treated without adjusting any applications. The advantage is that all
Applications on a machine can benefit from encryption and authentication, and
Policy can be configured by the host (or network) basis, the application or a service.
Section 4: IPv6 />
IPv6 addressing properties is presented in this section.
4.1: Multiple addresses
In IPv4, a host usually has a range of IP addresses per network interface or />
if the IP stack supports. Very rare applications like web servers result
Machines with more than one IP number.
In IPv6 is different. For each interface, it is not just a />
Address, but there are two other addresses that are of interest: the link-local address,
and address local site. The address of the link-local prefix FE80:: / 64 and
Host bits are built from eui64 address of the interface. The link-local address is used
the hosts and routers on the same network to the addresses not
visible or accessible to different subnets. If you like, there is a choice between
mapped using global addresses from the supplier, or by using site-local addresses [16].
Site-local addresses are assigned network address fec0:: / 10 and subnets and hosts
can be used as well as supplier networks are addressed assigned. The only difference is that
Addresses are not visible from outside machines, as they are on a />
Network and Site-local addresses are physical in a different thread. As in the case
IPv4 network can be used to site-local addresses, but need not. IPv6 is
more likely to have hosts assigned a link local and global IP address.
Site-local
Addresses are now rare, and can not replace />
Addresses, if global connectivity is required.
4.2: Multicasting />
the most common way is to talk to a host through direct talks with its unicast address.
In the IPv4 unicast address “normal” IP address is assigned to a single host, with
all address bits assigned. The broadcast address used to treat all hosts on the same
IP subnet, the network bits in the network address is specified, and all bits to “1″
which can easily mask the network and operations on bits. Multicast addresses are used to achieve a number of hosts on the same multicast group, which machines are broadcast over the Internet. Machines must join multicast groups
be assigned specifically to participate, and there are specific numbers for IPv4 multicast addresses from the subnet 224 / 8. Multicast is not widely used in IPv4, and only a few applications it.In IPv6 unicast addresses are the same as used in IPv4, no surprise of all
Network and host bits are assigned to identify the target network and machine.
The emissions are not part of IPv6 in the way they were in IPv4, it comes into play multicasting. Addresses in the ff:: / 8 network for multicast applications, reserved, and there are replacing two special multicast addresses, broadcast addresses from IPv4. One is the address “all routers” multicast, the others are “all hosts”.
More information on IPv6 are usually the way they were proposed by the IETF RFCs, but we decided to use Microsoft Windows 2003 platform to perform the tests. By their early stages of development, the IPv6 protocol stack in Windows 2003 are still many problems such as fragmentation problems, no support
for IPSec, a security device natives, etc. …
Microsoft has two different implementations of IPv6 for Windows NT 5.0 and Windows 2003 stack. The old battery as “Microsoft Research IPv6 version 1.4″ is known, works in two NT 4.0 and Win2K, announced the new battery as
“Microsoft IPv6 Technology Preview for Windows 2003 running on Windows 2003. Both batteries have existing IPv4 stack to install it.
Once installed, in addition to the Windows environment, support for IPv6, it
creates a new set of routines, such as “ping6″, “tracert6″ are the same />
and so a programmer who can apply more IPv4 can learn how
to make a simple request, and IPv6.
Internet Protocol Version 6 is designed as an upgrade to the development of the Internet
Protocol (IPv4) and in fact coexist with the older IPv4 for some time. IPv6 is designed so that the Internet is a steady growth, both in terms of the number of connected computers and the total amount of data traffic is transmitted, it’s like 128-bit address FFFF will be: FFFF: FFFF: FFFF and it supports up to
340,282,366,920938,463,463,374,607,431,768,211,456 addresses.in single Table1, we see the advantages of IPv6 over IPv4.
The IPv6 header is always present and has a fixed size of 40 bytes. The fields of the
IPv6 header are described briefly below.
The fields in the IPv6 header are:
Version – 4 bits are used to specify the version of IP, and set to 6
.
Traffic Class – Indicates the class or the priority of the IPv6 packet. The size of this field
8 is bits.The Traffic Class field contains a similar functionality as the IPv4 Type
Services Division.
Flow Label – Indicates that this packet belongs to a particular sequence of packets
between a source and destination, the special treatment of />
Router. The size of this field is 20 bits. Label Flow is used for />
House connections, like those of real-time data (voice and video) is required. For
Handling of the default router flow label is set to 0. There can be multiple flows between a source and destination, as distinguished by separate zero flow length Labels.Payload – Specifies the length of the IP payload. The size of this field is 16 bits. The Payload Length field contains the header extension and the upper layer PDU. With 16 bits, a payload of up to 65,535 bytes IPv6 are given. For payload lengths greater than 65,535 bytes, the Payload Length field is set to 0 and Jumbo Payload option is used in />
Next Header - Indicates the header of the first extension (if applicable) or log
in the upper layer PDU (such as TCP, UDP, or ICMPv6). The size of this field is 8
Bits. To give an upper layer protocol over the Internet layer, the />
Values in the IPv4 Protocol field are used here employed.
Extension header – zero or more extension headers can be present and
different length. Further a field header in the IPv6 header indicates the upcoming expansion
header.Within each extension header is another Next Header field that indicates the
next extension header. The top row shows the final extension />
(Such as TCP, UDP, or ICMPv6) in the upper-layer protocol data unit included.
The headers in IPv6 headers and extension to replace the current IPv4 IP header with options. The new extension header format allows IPv6 to be increased to meet future needs and capabilities. Unlike options in the IPv4 header, IPv6 extension headers can have change the maximum size and not expand to accommodate all />
for IPv6 communication is needed.
Hop Limit – Indicates the maximum number of links on which the IPv6 packet />
Travel before it thrown away. The size of this field is 8 bits. Hop is the limit />
TTL in IPv4, except that there is no historical relationship to the amount of time
(In seconds) that the packet to the router in the queue. If the limit is 0 hop, the
packet is discarded and an ICMP time expired message to the source address sent.
Address source and stores the IPv6 address of the originating host. The size is 128 bits.
Destination Address – Stores the IPv6 address of the target host is running. The
Size of this field is 128 bits. In most cases, the destination address on the />
the destination address.
However, if a Routing header extension is present, the destination address
Set to the next router interface in the list of discovered route.
Section 5: Transition Mechanisms
Since IPv6 finally begin to mature, it is obvious that the methods of modernization of the
Internet must be found. One idea would be to disable the entire Internet in 12 hours,
Upgrade the network infrastructure includes routers, protocol stacks, … and turn the
Internet by 6 clock and hope that everything works well and correctly.
It is not realistic due to the fact that it cost more money than imaginable,
Time is too short, and nothing ever works as good as it is in theory.
have developed more gradual transition policies that occur probably during
over 10 years. Some transition mechanisms are:
Dual-stack
SIIT – Stateless IP / ICMP Translator
HIIA – Allocation of IPv4 addresses to IPv6 hosts World
NAT – Protocol Translator – scaling and DNS issues, and has a single point of failure problem
Tunnel Broker – Dynamic Tunnel access servers, but has problems of authentication and scale
6-to-4 mechanism – dynamic stateless tunnels over IPv4 infrastructure to connect to 6 – />
Allows you to use the existing infrastructure manually configure />
O host-host tunneling
o Router-router tunneling
o Host-router and vice versa Tunneling
5.1: Dual Stack:
The basic approach to allow for all communications is the />
where each new host, server, router or other equipment at the IP layer to support both protocols. In this way communication between the terminals IPv6
is direct, while a terminal IPv4/IPv6 communicate with a terminal needs to do only IPv4 in IPv4 can. This approach is not particularly burdensome for the hosts and servers, because it’s a software update that no significant impact on the system. Nevertheless, maintaining the main drawback of this approach, the need to
Multi-protocol network with a dual routing infrastructure, which increases the workload of administrators. In addition, stacking the widespread use of dual-IP-model will not be possible if the address space exhaustion reached the point that new IPv4 addresses can be assigned.
To overcome these problems, several solutions for interoperability between IPv4 and IPv6-only networks have been defined that the communication from end to end between heterogeneous terminals:
• Dual-stack IP devices, ALG perform protocol translation at the border between the non-homogeneous networks using application proxies on two servers stack implemented.
• NAT-PT (Network Address Translator – Protocol Translator). Devices, the address and protocol translation run on the border between the non-homogeneous networks at the IP level
• Dual Stack Transition Mechanism or DSTM, which proposes to use the IP dual-stack approach based on IPv4 addresses dynamically assigned, if necessary, and the use of IPv4 to IPv6 tunnel through the local IPv6 network from access by the external IPv4 network.
Although this transition mechanisms the same mistakes that similar mechanisms are proposed for the integration of the various IPv4 networks, they offer a significant advantage for the future. Thus, while mechanisms for IPv4 is final and can not happen without such a switch to IPv6 is critical to the coexistence of IPv4 and IPv6, which should end once the work to ensure full IPv6 Internet.
IPv6 was delivered with migration techniques to cover every possible example IPv4 upgrade, but many were ultimately rejected by the technology community, and today we find ourselves with a small number of practical approaches.
Dual-stack IPv4 and IPv6 running involves simultaneously. End nodes and routers / switches run both protocols, and if IPv6 communication is possible that the protocol is preferred.
A common dual-stack migration strategy is to make the transition from the core
Board. These allow two TCP / IP stacks on routers heart of WAN, router and firewall perimeter, then, while farm routers and finally the desktop access routers. After the network supports IPv6 and IPv4 protocols, the process of dual protocol stacks on the servers and computers on board
Systems.
Another approach is to use the tunnel to carry a log to another. These tunnels
IPv6 packets and encapsulate them to accept IPv4 packets through parts of the network, not be sent to IPv6 upgrade.
Other techniques, such as Network Address Translation protocol (NAT-PT)
simply translate IPv6 packets into IPv4 packets. This translation techniques are
complicated than IPv4 NAT because the protocols were different techniques formats.Translation head be used as a last resort. preferable with dual stack and tunneling techniques is
with NAT-PT.
It will be easier to try to do everything in a dual-stack mode, remove the
IPv4 over time. Currently, there are not many systems being developed for IPv6 communication, but there are many systems that run dual-stack mode. Operating systems from Microsoft, for example, have a double-layer architecture, which makes for a smooth operation of these protocols. Therefore, those plans for the conversion maximization of the use of double stack and reduce the amount of the tunnel. It should also
be mentioned, is not on the dual-stack of the final state. We must not forget that />
Migration to IPv6 is the final destination.
Dual Stack IPv4/IPv6
In the 1990 network industry uses the term “Switch when you can, route where you have to.” But over time, close the performance gap between routing and switching. For IPv6 transitions the new name is “dual stack, where one tunnel, where you have to.”
5.2: IPv6 over IPv4 tunnels:
IPv6 over IPv4 tunnel is a mechanism to facilitate the transition by the two IPv6
.
