IPv6 Migration

Copyright © 2010 All Rights Reserved

IPv6 Migration The Impact to the Network Infrastructure as a

result of Implementing IPv6

SEIS 645-01

Research by:

Ed Grams

Eric Hunsberger

Jayesh Naithani

Jess Walczak

12/7/2010

Copyright © 2010 All Rights Reserved 2

Contents Abstract ......................................................................................................................................................... 4

IPv6 Overview ............................................................................................................................................... 4

Important features of IPv6 ........................................................................................................................ 4 Physical Layer ................................................................................................................................................ 5

Transmission media .................................................................................................................................. 5 Data Link Layer .............................................................................................................................................. 6

Impact to Connecting Devices................................................................................................................... 6 Use of VLANs and Gateways for IPv6 and IPv4 Co-existence ................................................................... 6 WAN: Transitioning to IPv6 ....................................................................................................................... 6 Impact to Link-Layer Technologies ........................................................................................................... 7

Ethernet ................................................................................................................................................ 7

Bridged .................................................................................................................................................. 7

Switched ................................................................................................................................................ 8

Bluetooth .............................................................................................................................................. 8

Frame Relay........................................................................................................................................... 8

ATM ....................................................................................................................................................... 9

Network Layer ............................................................................................................................................... 9

Physical Addresses .................................................................................................................................... 9 IP Address ................................................................................................................................................ 10 Cast addresses ......................................................................................................................................... 10 Port Address ............................................................................................................................................ 11 Classless Addressing ................................................................................................................................ 11 Configuring Addresses ............................................................................................................................ 11 Subnets.................................................................................................................................................... 11 NAT-PT .................................................................................................................................................... 12 Inter-networking ..................................................................................................................................... 12 IPv6 Datagram format ............................................................................................................................. 13 Path MTU Discovery ................................................................................................................................ 13 Fragmentation ......................................................................................................................................... 14 Routing and Forwarding .......................................................................................................................... 15 Unicast Routing and Protocols ................................................................................................................ 15 Intradomain ............................................................................................................................................ 15 Interdomain ............................................................................................................................................ 16

Transport Layer ........................................................................................................................................... 16

Checksum requirement ........................................................................................................................... 16 User Datagram Protocol (UDP) ............................................................................................................... 16 Transmission Control Protocol (TCP) ...................................................................................................... 16 Internet Message Control Protocol (ICMP) ............................................................................................. 17

ICMPv6 ................................................................................................................................................ 17

Protocols combined ............................................................................................................................ 17

Neighbor Discovery ............................................................................................................................. 17


Quality of Service and Congestion Control ............................................................................................. 18 Flows and Flow Labels ......................................................................................................................... 18

Traffic Class ......................................................................................................................................... 18

Integrated Services ............................................................................................................................. 18

Network Address Translation ............................................................................................................. 19

Differentiated services ........................................................................................................................ 19

Security ................................................................................................................................................... 19 IPSEC.................................................................................................................................................... 19

ISAKMP and IKE ................................................................................................................................... 20

AH ........................................................................................................................................................ 20

ESP ....................................................................................................................................................... 20

Application Layer ........................................................................................................................................ 20

Multimedia .............................................................................................................................................. 21 DNS Changes, DHCP ................................................................................................................................ 21

Interoperability ........................................................................................................................................... 21

Dual Stack ................................................................................................................................................ 21 Tunneling................................................................................................................................................. 22 Header Translation .................................................................................................................................. 22

Conclusion ................................................................................................................................................... 23

References .................................................................................................................................................. 24


Abstract

In this paper we will describe the effect and impact of implementing and migrating to an IPv6 capable

network. Our goal is to combine the understanding of the IPv6 protocol and related specifications when describing

its impact to the overall network infrastructure. An important and related goal is to describe the migration to IPv6

in terms of concepts and information we have learned in our Data Communications and Networking class about the

five (5) layer TCP/IP protocol suite.

Our goal is not to present a paper describing a network migration strategy from IPv4 to IPv6. We will not

provide details about the various interoperability strategies between IPv4 and IPv6. Any differences between the

two protocol versions will be noted to illustrate and emphasize the impact to network operation and efficiencies as

a result of the implementation and migration.

IPv6 Overview IPv6 is the new version of the Internet Protocol and has been designed as an evolutionary rather that a

revolutionary step-up from the IPv4 standard. Certain IPv4 functionality that worked well was

preserved, certain functionality that was either under used or did not work efficiently was removed

and/or made optional, and some new, improved, and necessary functionality was added [A1].

IPv6 can be installed as a normal software upgrade in most Internet devices today, and is interoperable

with the IPv4 standard. It is designed to run well on high performance networks such as Gigabit

Ethernet, ATM, Frame Relay, and others, as well as on low bandwidth networks, such as wireless

networks. And it provides a starting point for some new Internet functionality such as extended

addressing, improved security, and better quality of service (QoS) capabilities. [A2]

Important features of IPv6 The large address space offered by IPv6 is its most important feature and, because of the problem of

rapid addresses depletion with IPv4, the primary reason for migration. The availability of additional

important features such as higher scalability, better data integrity, improved QoS capabilities,

autoconfiguration capabilities for dynamically connecting devices, and improved routing and end-to-end

connectivity also come along with IPv6. [A3].

Substantial increase in IP address space: The address size for IPv6 has increased to 128 bits.

This solves the problem of the limited 32 bit address space in IPv4.

[A4]

Simplified header format: The IPv6 header has a fixed length of 40 bytes. Some fields of the

IPv4 header have been removed or made optional leading to faster packet handling and lower

processing costs.


[A5]

Additional support for extension headers and options: Extension headers are optional and are

only inserted between the IPv6 header and the message payload. Forwarding IPv6 packets is

very efficient. IPv6 options can be of arbitrary length, providing the ability to be used for

functions that were not practical or possible with IPv4. Options can be encoded with actions

that routers or hosts should perform if the option is unknown, and this facilitates the

incremental deployment of additional functionality dynamically into an existing network without

the danger of disruption [A1].

Improved security: Support for authentication and privacy is provided and required in IPv6.

Besides extensions for support data integrity, extensions exist to also support message

encryption and confidentiality.

Flow labeling capability: Packets that belong to the same traffic flow can be labeled by senders

to provide special handling, real-time service, and improved QoS.

Support for autoconfiguration: Multiple forms of plug and play configurations of node

addresses, and complete support for DHCP facilities is possible via autoconfiguration with IPv6.

Simple and flexible transition from IPv4: Existing IPv4 hosts and routers can be upgraded to

IPv6 at any time independent of each other, while IPv6 host and routers can be installed at

anytime without any prerequisites or prior preparation. Additionally, IPv4 routers can continue

to operate using existing addresses while co-existing with IPv6 routers on a network.

Physical Layer

Transmission media The transmission media, be it air, copper, fiber optic or some other type of media used for

communication has no impact on the IPv6 protocol. By the time the IPv6 communication has traversed

the layers of the network it is bits and signals, and transmission across the media essentially process the

same. When the discussion grows to include the fact that IPv6 allows for more devices to connect to a

network, and utilize the transmission media, there will likely be bandwidth concerns. For example, a

network with 10 devices connected and transmission media of copper has a certain speed per user.

Convert it to IPv6 and now there are 1000 devices on that same copper media, the speed per user may

be impacted.


Data Link Layer In this section we discuss the impact of IPv6 to data link layer connecting technologies, both hardware

and software, and some addressing related considerations when transitioning a WAN from IPv4 to IPv6.

Impact to Connecting Devices Connecting devices such as hubs, repeaters, bridges, and two layer switches operate at the Data Link

layers and below. They work with data frames that contain MAC source and destination addressees

which are completely independent from IPv6 [A2].

Connecting devices such as routers and three-layer switches operate at the Network layer, while

gateways operate on all five layers. These devices route data packets that contain source and

destination logical addresses. These devices cannot route packets unless they understand the IPv6

protocol. Older hardware designed for the efficient forwarding of just the IPv4 packets will not be

suitable for supporting IPv6, and will require a complete hardware update or a firmware update at the

least. Also, as a result of larger address size for IPv6, routing tables and caches on routers now need to

be bigger and re-structured to be optimized for IPv6. Routers need to use better routing protocols such

as Open Shortest First Protocol (OSFP) and Routing Information Protocol (RIP) and be able to support

the optional IPv6 header extensions, such as the Routing Header, for streamlining the packet forwarding

process.

Use of VLANs and Gateways for IPv6 and IPv4 Co-existence A couple of connecting technologies are involved when interoperating between IPv4 and IPv6 enabled

networks.

VLANS create broadcast domains, and can be used in networks for the purpose of traffic segregation.

Enterprises migrating from IPv4 can utilize the VLAN technique to provide a gradual approach to

introducing IPv6 capable switch-router equipment into their networks, without requiring changes to

their existing IPv4 configuration. [D1]

An application level gateway operates in the application layer and acts as an intermediate system

between two internetworks. The application level gateway converts the network layer address

information found inside the application payload between two hosts exchanging information. They are

often used as a translating technology to connect host nodes between IPv4 and IPv6.

WAN: Transitioning to IPv6 As with many cases, in a pure IPv6 network, the WAN addressing would have the ability to allow a

device to connect to another device directly, without any translation being necessary. When the

discussion moves to a WAN that operates between IPv4 and IPv6, there are more considerations.

Translation schemes are required to allow IPv4 and IPv6 protocols to interoperate. Since it will be some

time until a pure IPv6 world exists, the best advice to give network administrators is to understand their

WAN use model and plan accordingly. This means that in a first implementation, the larger support

would be to convert IPv4 devices to connect to the IPv6 network as it is likely the administrator will be

able to upgrade their network long before IPv4 devices cease to have a need for access [C1].


As the model matures towards IPv6 devices, and IPv4 devices become the minority, the support would

also shift towards an IPv6 biased implementation. Many organizations and network administrators

have lifecycle management in which devices are swapped out for more capable devices. It would be

logical to reason the replacement of equipment over a lifecycle will lend itself to implementing against a

network model that roadmaps the transition from IPv4 bias to IPv6 bias [C1].

Impact to Link-Layer Technologies IPv6 is defined to work over most of the data link layer technologies such as Ethernet, Frame Relay,

ATM, FDDI, PPP, Bluetooth, and Token-Ring. The rules and packet sizes for the transport of IPv6

datagrams differ depending upon the topology. Key points are how IPv6 packets are encapsulated in

the data link layer protocol unit, how IPv6 multicasts and unicasts are directed on the local link, and how

the IPv6 interface identifiers are derived from link layer addresses.

In this section we describe IPv6 over Ethernet, a common wired Local Area Network (LAN) technology;

IPv6 over Bluetooth a wireless LAN technology; and IPv6 over Frame Relay and Asynchronous Transfer

Mode (ATM), two common virtual-circuit Wide Area Network (WAN) technologies

Ethernet

[A3]

The transmission of IPv6 over Ethernet is quite straightforward. The IPv6 packet is transmitted as a

payload of the Ethernet frame. The default Maximum Transmission Unit (MTU) size is 1500 bytes. A

data link node is autoconfigured by concatenating the link local prefix FE80::/64 with the the 64 bit

Extended Unique Identifier of the node interface. The identifier is based on the MAC Ethernet Address

of the interface. Ethernet has protocol field in the frame format to help identify the type of protocol in

the frame payload. IPv6 datagrams are identified with 0x86DD in the protocol field. A neighbor’s

Ethernet address is discovered through the neighbor discovery procedure. Finally IPv6 multicast

addresses are constructed by concatenating the 2-byte prefix 3333 (hex) and the last four bytes of the

IPv6 address [A3].

Bridged

There is no difference between the forwarding of IPv4 packets versus the forwarding of IPv6 packets

specifically in regards to a bridged Ethernet configuration since bridging logic never looks at any IP

addresses contained in the packet. Instead, bridging being a data link protocol is only concerned with

the MAC Ethernet addresses of the source and destination nodes when making its decision to either

drop the packet or to forward the packet on across the bridge. [C2]


Switched

The only real difference that IPv6 has in regards to Layer 2 Ethernet switching is in the area of

multicasting. The difference is mainly that in IPv6 the Ethernet framing uses a different MAC destination

address prefix, 0x3333, which avoids the problem of increasing packet collisions that is inherent in IPv4

multicasting. [C3]

Bluetooth

Bluetooth is a wireless LAN technology. The connection of Bluetooth devices to a central device has

been called a Personal Area Network (PAN). A prime example would be that of a BlackBerry and a

laptop that are connected together via Bluetooth. The laptop, in this example, is connected to a WAN

and is using IPv6. There is communication between the WAN and the BlackBerry happen through the

laptop. In an IPv6 world, the BlackBerry and the Laptop could both have connection to the WAN as long

as the WAN had a Bluetooth access point. There is a good presentation on the need for Bluetooth to

support IPv6 to allow for these devices to access the internet [C4]. Since the IPv6 address allows for

unique device identification, it makes sense to have WAN access provide Bluetooth. Network

administrators will have to consider what Bluetooth means to their network and, much like with the

WAN discussion, they will have to determine a model for supporting Bluetooth as the technology and

devices mature.

Frame Relay

Frame Relay is a connection-oriented, high-speed network technology used in WANs. It operates in the

physical and data link layers, and can be used as a backbone network to provide services to protocols

that already have a network layer protocol. [D2]

(source: http://technet.microsoft.com/en-us/library/bb726928.aspx)

- Frame format for the transmission of IPv6 packets over Frame Relay: Frame Relay devices are

configured to have a maximum frame size of at least 1600 octets and the default IPv6 Maximum

Transmission Unit (maximum packet size) is 1592 octets. The IPv6 frame encapsulation format allows a

virtual circuit to carry IPv6 packets. The Frame Relay header has a 1 byte field called the Next Level

Protocol ID (NLPID), which contains the value 0x8E indicating the IPv6 protocol.


- Method of forming IPv6 link local addresses on Frame Relay links: The IPv6 link-local addresses

for an IPv6 Frame Relay interface is formed by appending the interface identifier, as described in the

Network Layer Physical Addresses section described later, to the prefix .

- Mapping of IPv6 addresses to Frame Relay addresses: The procedure of mapping IPv6 addresses

to link-layer addresses follows the specification for Neighbor Discovery, which is discussed in more detail

later in this paper.

ATM

ATM is a connection oriented high speed network technology that is used in both LANs and WANs.

An ATM network is used in Permanent Virtual Circuit (PVC) mode to connect exactly two nodes. An

IPv6/ATM interface has only one neighbor on each link. All IPv6 multicast and broadcast operations

collapse down to an ATM level unicast operation. PVCs do not have link-layer addresses, so the link-

layer address option is not used in neighbor discovery messages. All IPv6 unicast and multicast packets

sent over ATM are encapsulated using the LLC/SNAP encapsulation standard by an encapsulating service

called Application Adaption Layer (AAL5), and the Ethertype field is set to the value 0x86DD for IPv6.

The default MTU size for an ATM PVC link is 9180 bytes. [D3]

When an ATM network is used in Switched Virtual Circuit (SVC) mode, unicast packets are transmitted

using the same method as described for PVC. For the transmission of multi cast packets, the OUI field in

the encapsulation header is set to 0x000005E and the Ethertype field to 0x0001.

[D4]

Network Layer

Physical Addresses The physical address, also known as the MAC address, for any given device can be included in the IPv6

address. The standard physical address has a length of 48 bits and is commonly referred to as the IEEE

802 MAC Address. The Interface identifier of the IPv6 address is 64 bits and is commonly referred to as

the 64 bit Extended Unique Identifier (EUI-64). [D5] To include the MAC address in the interface

identifier portion of the IPv6 address, a few steps have to be taken. The first step is the physical address

has to be split into two 24 bit pieces. The first 24 bit section is the Organizationally Unique Identifier

(OUI) which is given to companies that create network using devices. The second 24 bit section is the

device identifier, which is the particular network using device the company created. The two 24 bit

sections of the MAC address then have a hexadecimal 0xFFFE placed in between them. The final step is

the 7th bit (from the left) is set to a one (1), this makes the identifier a universal identifier. The final

notation is referred to as modified EUI-64. [D6]


The following diagram, as found on The TCP/IP Guide website [D7] does a great job showing this

process:

This is commonly used in IPv6 autoconfiguration between two devices. This can occur within a local

network or globally depending on the prefix used. IPv6 prefixes will be discussed later.

IP Address The IPv6 address is 128 bits long whereas IPv4 had a 32 bit address size. An IPv6 address is divided into

eight groups of four hexadecimal digits. Example: 2001:ab49:0987:1120::4011:f542:21f0. The ::

represents contiguous groups of four zeros. The IPv6 address is divided into two parts: a 64 bit network

prefix and a 64 bit interface identifier. The Network Address Translator (NAT) has been traditionally

used to deal with the diminishing number of IPv4 address. In theory, a true IPv6 network would

eliminate the need for the use of NATs, however, as the scope of this document suggests, the

networked world is a long ways from a true and pure IPv6 network. [D8] The Network Address

Translation with Protocol Translation (NAT-PT) has been introduced to assist with the, potentially years

long, transition to a true IPv6 networked world. The actual translation of IPv4 to IPv6 addresses will be

covered in the Interoperability with IPv4 section.

Cast addresses The IANA is responsible for the address management of IPv6 addresses. Per their address space

allocation, they had defined the following addresses [D9]

2000::/3 – Global Unicast

FC00::/7 – Unique Local Unicast

FE80::/10 – Link Local Unicast

FF00::/8 – Multicast


Each of the addresses divides the network prefix into sections in order to direct the cast traffic. A

generic way to look at this section break down is the first 64 bits are broken into two sections. Section

one is n bits long and is the routing prefix (global, local, etc). The second section is m bits long and

defines the subnet for the cast traffic. The remaining bits, 128 – n – m are the interface ID, or the node

that is being cast to. In the cases of multicast transmissions, the interface ID is likely set as zero or

omitted altogether which will send it to all interface IDs on the defined subnet or subnets. There is

another address, called a loopback address, defined as 0:0:0:0:0:0:0:1, and can be used by an IPv6 node

to send a packet to itself [D10]. One helpful piece of information regarding localhost is: in IPv4 it is the

address 127.0.0.1, for IPv6 it is the loopback address of ::1.

Port Address With IPv4, the port address was identified by using a colon and the port number. Since IPv6 has colons

as part of its address structure, the question comes up of how ports are dealt with. The answer is

surprisingly simple: the same, with a slight exception. Take the IPv6 address of

2001:a3f5:4480:f399:1c5d:7822:ee44:0001 and a port of 80. To represent this notation we simply add

brackets to the IPv6 address and then the colon and the port [D11]. Entered in a browser window, this

would look like: http://[2001:a3f5:4480:f399:1c5d:7822:ee44:0001]:80/

Classless Addressing Classless addressing in IPv6 is essentially the same as with IPv4. The IP address uses the / notation to

determine the address range. As expected, this can be a large number such as /48 since IPv6 has 128

bits versus the 32 bits with IPv4. One important notation to be aware of is the :: notation. This notation

signifies a series of 0 addresses. For example: 2001:e34f:5591:4739:eedc::2e44/90 is short for

2001:e34f:5591:4739:eedc:0:0:2e44/90. While this example is unlikely, it is still worth noting that it

could occur [D9]. A classless address of /90 would land in the middle of a 0 address range.

Configuring Addresses There are two ways to configure addresses with IPv6. The first is the nodes automatically create their

local-link addresses. This works with Router Advertisement and Neighbor Discovery messages to avoid

address collision. IPv6 can also automatically configure 6to4 tunnels, Intrasite Automatic Tunnel

Addressing Protocol (ISATAP) and address routes to off-link routers, given the off-link address prefix has

been advertised by a router. The second method for configuring addresses is manually, which according

to Microsoft in their products is not needed due to the local-link scope always being automatically

configured [D12]. It is probably safe to assume that not all software and hardware manufacturers

provide this local-link auto configuration, so it is best to understand the capabilities of the network and

choose an addressing configuration scheme that best fits.

Subnets Dividing a network into subnets has traditionally been a good way for network administrators to control

traffic between various areas of their networks. With IPv6 there exists the potential to access a device

directly from anywhere on the internet. The question then can be raised: do network administrators

need to segment their networks into subnets if all devices can be resolved down to a single address?

http://[2001:a3f5:4480:f399:1c5d:7822:ee44:1]/


This answer depends on the administrators approach to security and access control. Good security and

segmentation practices would require that yes, a network should have subnets.

Breaking the IP address into subnets is relatively easy. Per the IPv6 specification, the 16 bits from the

49th to the 64th are for defining subnets [D13]. Given the following IP address, the bytes in red are the

subnet bits: 2001:a3f5:4480:0000:1c5d:7822:ee44:0001. If an administrator had a need for 15 subnets,

the mask for the subnets would be: FFFF:FFFF:FFFF:FFF0 allowing for addresses 1 – F for each subnet.

For example, the first four subnets would look like:

Subnet one: 2001:a3f5:4480:0001

Subnet two: 2001:a3f5:4480:0002

Subnet three: 2001:a3f5:4480:0003

Subnet four: 2001:a3f5:4480:0004

Granted, the 64 bits of unique device identification will most likely far exceed the number of possible

devices in any given subnet. Administrators can mask further into the unique device identification

portion to provide smaller subnet definitions if desired. [D14]

NAT-PT Network Address Translation –Protocol translation in a pure IPv6 environment is not needed as there

are plenty of addresses to assign out to devices and still have the ability to provide a unique address to

all devices in the world. For networks that have to provide interoperability between IPv4 and IPv6

network devices, a NAT-PT table would be used. The translation table would look much like the NAT

tables that divide and isolate IPv4 networks with the difference that the table would have IPv6

addresses included for those translations. Cisco systems shows the following command line output of a

NAT-PT mapping that illustrates the concept well [D15]:

1 - ipv6 nat v4v6 source 192.168.30.1 2001:0db8:0::2

2 - ipv6 nat v6v4 source 2001:0db8:bbbb:1::1 10.21.8.10

3 - ipv6 nat prefix 2001:0db8:0::/96

Line 1 shows the mapping from an IPv4 address to a IPv6 address. Line 2 shows a mapping from IPv6 to

IPv6 and line 3 shows the router prefix.

Inter-networking The topic of Inter-networking changes depending on the IPv6 implementation context being used for

the discussion. In a pure IPv6 network, the connection from device to device and network to network

adheres to the IPv6 standard and communication happens as it would with any other type of inter-

networking. When the context of inter-networking shifts to an IPv4 and IPv6 blend of device and

network interaction, translation protocols have to be agreed upon so communication can flow from

network to network. This statement of protocol agreement is true for even a pure IPv6 network. To

limit the scope of this discussion, and to avoid a fifty page research paper with great depth on the topic

of inter-networking, the general rule to any kind of inter-networking is to ensure that the boundaries of

the various networks have a defined and agreed upon implementation of the IP protocol. Failure to do


so will result in the inability to communicate, misunderstanding in Quality of Service (QoS) definitions

and great pains for the network administrators [D16].

IPv6 Datagram format The IPv6 datagram header format is shown in the graphic as documented on tcpipguide.com [D17]:

The version for the IPv6 header is 0110 which is binary for a decimal value of 6. The Traffic class relates

to QoS which is discussed later in this research paper. Flow label is used for extended QoS abilities and

to ensure that all routers in the flow path of a datagram network handle the packets the same way,

thereby ensuring proper flow control for different types of network traffic. The payload length contains

the number of bytes in the payload as well as any extension headers that might be included in the

packet. Next header is used in one of two ways. The first is to callout the identity of an extension

header, should one exist. The second use is the same as with IPv4 packets in that specifies the

protocols. Hop limit is self explanatory in that it represents the number of hops allowed before the

packet is dropped. The source address is just as it states, the source address. Finally, the destination

address is the ultimate destination the packet is intended for, not the next intermediate destination or

hop [D17].

Path MTU Discovery A significant change from IPv4 to IPv6 was the consideration of packet fragmentation in the network

layer. IPv4 made provision for the intentional fragmentation of packets by each router along the way,

and while the provision in IPv4 for packet fragmentation may be potentially useful in negotiating

different types of networks, it comes at a cost of router processing power and time along the route and

at the destination. IPv6 explicitly permitted fragmentation only between the origination node and

destination, but not during the intermediate hops. Hop-by-hop fragmentation is considered a bad thing

since it can generate more fragments than end-to-end fragmentation and it should be considered more

inefficient since the loss of a single fragment means all those corresponding fragments must be

retransmitted. This is interesting since unlike most other enhancements in IPv6, the responsibility is

shifted from the router back to the node [D18].


IPv6 tries to avoid fragmentation along its route, but how is it to know how large to make packets that

will make it end-to-end without the need for fragmentation, especially considering that packets could

take varying routes? IPv6 does this through two ways; the first is specifying that any IPv6 node must be

able to transmit a packet sized at 1280 bytes at minimum which reflects the realities that most routers

can handle average IP packets without needing fragmentation (MTU = maximum transmission unit), and

the second is the mechanism of Path MTU Discovery (PMTUD), which adjusts the packet sizes as needed

from any point along the route back to the source [D19].

The operation of PMTUD goes as follows: the source node sends out packets at the size of the MTU of

the first link and the first packet continues on its route until it reaches the destination or a router that

has an MTU sized smaller than the packet size. Then that router drops the packet and sends back to the

source an ICMPv6 Packet Too Big message. The error message contains in it the MTU size of the next

hop link, and so the source node resizes its packets to comply with this new link MTU. Note that this can

occur multiple times in either a unicast or multicast packet stream. Interestingly, when dealing with

multicast source packets, the routes may be different and the smallest MTU reported back affects the

size for all recipients—the lowest common denominator is the rule in this case [D20].

Fragmentation As mentioned earlier, the minimum MTU that routers and physical links were required to handle was

576 bytes in IPv4, while in IPv6 all links must handle a packet size of at least 1280 bytes. This doubling in

size improves efficiency by increasing the ratio of maximum payload to header length, and reduces the

frequency with which fragmentation is required. Within IPv6, source nodes are expected to perform

PMTUD to determine the maximum size of packets to send, and the upper-layer protocol is expected to

limit the payload size. However, if the upper-layer protocol is unable to do so, the sending host may use

the Fragment extension header in order to perform end-to-end fragmentation of IPv6 packets if the

packets must be fragmented [D21].

The method of fragmenting begins at the source node when it inserts a fragmentation header into the

optional part of the standard IP packet header—note that there isn’t anything in a standard IP packet

header about fragmentation unless it is required, lessening the overhead all around. The Fragmentation

header contains the following fields: Next Header, Reserved, Fragment Offset, Res, M Flag, and

Identification fields. The design of this Fragment header is interesting since by shifting the Fragment

Offset field to the left and the M flag (which signifies “More packets coming”) it has become easier to

process than its IPv4 equivalent. The Fragment Offset is a value specifying the number of 8-octet words

to be offset; that value is stored in a 13-bit field. Ignoring the low-order 3 bits of that part of the header

(that is, the 2 reserved bits and the more flag) allows the 13-bit Fragment Offset field to be expressed as

a 16-bit value and interpreted as the number of octets specified by the offset [D22].

Each packet contains essentially two parts. The Unfragmentable Part which is the original IPv6 header

and any extension headers that must be processed by nodes rather than the destination (these

extension headers are options). The Fragmentable Part is therefore everything else which includes

those extension headers that are meant for the destination, along with the upper layers headers, and of

course the data payload. Fragments are created by dividing the Unfragmentable Part up, with each


fragment incorporated into its own packet; the resulting packets duplicate the Unfragmentable Part of

the original packet and add a Fragment Header, resulting in a sequence of packets where each of the

fragment-carrying packets has the same Unfragmentable Part, with the Next Header field of the last

header of that part set to 44, indicating that the next header is a Fragment Header. At the destination,

the process is reversed as fragment packets begin arriving; if all the fragments have not been received

within 60 seconds, the packets that have been received are discarded, and if the first fragment was

received, the receiving node sends an ICMP error message [D23].

Routing and Forwarding Routing is the process in which systems decide where to send a packet. Forwarding is a process used to

determine which path a packet should be sent. Forwarding can originate from two places: from the

source host that is sending the packet to another host or from a router that is an intermediary between

the source host and the destination host. Both use cases require a routing table, which stores

information regarding the source address of the packet and the destination address of the packet.

In both IPv4 and IPv6 use cases, the main difference between protocols is the size of the addresses being

stored in the packet (source and destination) and in the routing table (source and next hop) from 32 bits

to 128 bits. To increase the speed of forwarding between routers, the IPv6 protocol has abandoned the

use of header checksums that the IPv4 protocol offers between nodes as well. Routing is still performed

by looking at the IP address to determining which portion is the network ID and which is the host ID,

despite that IPv6 unicast addresses use a special hierarchical format [D24].

Unicast Routing and Protocols Unicast addressing is defined as one-to-one communication between a host and a destination. Unicast

routing is the mechanism for handling routing for unicast addressing. Since the internet is constantly

changing, routing tables need to be updated dynamically and frequently. To address this issue, routing

protocols were developed and implemented. A routing protocol is a combination of rules and

procedures that let routers in the internet inform each other of changes with themselves and changes

within their neighborhood. Since the internet is so large, routing for the internet needs to be broken

down into separate domains. Each domain is a group of networks and routers which is called an

autonomous system. Routing protocol technologies used within an autonomous system is referred to as

intradomain routing whereas routing used between autonomous systems is interdomain routing. Both

types of routing use different kind of routing protocols which we will discuss further.

Intradomain Intradomain routing uses two different protocol technologies to to update the routing tables: distance

vector routing and link state routing. In distance vector routing, routing is configured based upon the

least-cost or minimum distance between nodes. The Routing Information Protocol (RIP) is as an

implementation of this protocol and the IPv4 protocol has two different versions; RIPv1 and RIPv2.

RIPv1 was the original protocol used for distance vector routing while RIPv2 was introduced to fix the

inefficiencies of RIPv1 (currently used for IPv4) and it also multicasts its information to adjacent routers

instead of broadcasting for better performance. RIPng was introduced for IPv6, which extends the


functionality of RIPv2 while allowing support for IPv6 networking (128 bit addresses). RIPng also no

longer supports authentication on packets and routing table groups [D25].

Linked state routing uses LSAs (linked state advertisements) throughout an autonomous system to

update routing tables. This routing technology uses the Open Shortest Path First protocol (OSPF).

OSPFv2 is the routing protocol used for IPv4 and OSPFv3 is the routing protocol used for IPv6. The main

difference between these two protocols is that OSPFv3 supports IPv6 addressing and also no longer

supports protocol –internal authentication but instead relies on the IPv6 protocol security.

Interdomain Interdomain routing uses only the path vector routing technology to handle updates between

autonomous systems within the internet. Path vector routing is very similar to distance vector routing,

except that each autonomous system acts like a node instead of a host or router. The Border Gateway

Protocol (BGP) is an implementation of this technology, and unlike using network IP address as the other

protocols mentioned previously do, this protocol uses assigned 16-bit integers (ASN numbers) within the

network to identity each autonomous system [D26]. Each system keeps track of other autonomous

systems when router table information is shared. Since systems are tracked by ASNs, there is no

difference in implementation for IPv4 and IPv6.

Transport Layer One of the requirements of the IPv6 protocol is to re-use current UDP and TCP transport protocols as

they are currently defined. The impact to the Transport layer is that it is now mandatory to carry a

transport protocol checksum for both the UDP and TCP transport protocols. This is a direct result of the

removal of the IP packet checksum from the IPv6 message header with the assumption that the layer

above IP must carry and require the checksum.

Checksum requirement All transport protocols such as UDP, TCP, and ICMP, compute the checksum for IPv6 packets. The

transport protocol checksum is calculated over the following fields: Source Address, Destination

Address, Next Header field, Transport-layer payload length [A3].

User Datagram Protocol (UDP) No modifications were done to the UDP protocol for IPv6. With UDP however the checksum is

mandatory when using IPv6, but not when using IPv4.

Transmission Control Protocol (TCP) The TCP protocol has not changed for IPv6. The checksum is still mandatory. The protocol has been

improved and optimized for IPv6, such as improvements in performance as a result of the Selective

acknowledgement (SACK) and Explicit Congestion Notification (ECN) mechanisms [A3].

The ECN mechanism allows routers to signal early detection of congestion to nodes by modifying the

ECN bits in the traffic class field of the IPv6 header. To avoid congestion which in turn results in packet


drops, end nodes supporting ECN decrease their transport window size to participate in the reduction of

network traffic. The ECN mechanism is defined for both IPv6 and IPv4 [A3].

Internet Message Control Protocol (ICMP) ICMP is not a transport protocol like UDP or TCP, but from the perspective of IPv6 it also contains a

checksum which is computed the same way as the transport protocol checksum.

ICMPv6

ICMP in IPv6 is used by intermediate and receiving nodes to inform source nodes about errors and

issues related to the delivery of datagrams. It is similar to ICMP in IPv4, but with a few enhancements

[A2]:

- ICMP is carried in an IPv6 datagram identified by a specific Next Header field - As mentioned before, a checksum is computed - New messages have been defined, for instance, informational messages for Path Maximum

Transmission Unit (MTU) Discovery and Neighbor Discovery. ICMP for V4 message numbers and types have been substantially changed.

- Error reporting messages such as the source-quench message has been eliminated and instead the priority and flow label fields are used for congestion control and discarding of messages. And the packet-too-big error message has been added because in IPv6 fragmentation is the responsibility of the sender.

- Query messages for timestamp request and replay and address-mask request and replay have been eliminated because they are already implemented in other protocols such as TCP and very rarely used in ICMP for IPv4.

- An ICMP error message includes the original datagram within the error packet for easier recovery by the source.

Protocols combined

Also, the Internet Group Management Protocol (IGMP) function that manages multicast group

memberships with IPv4 and the Address Resolution Protocol/Reverse Address Resolution Protocol

(ARP/RARP) that is used to map Data Link layer addresses to IP addresses and vice versa, has been

included in ICMP for IPv6 [E1].

Neighbor Discovery

A new protocol, Neighbor Discovery, has been introduced which uses ICMP for IPv6 messages and

allows IPv6 nodes to:

- determine Data Link layer addresses for Neighbors attached to the same link - find Neighboring routers that can forward their packet - keep track of Neighbors that are reachable - detect changes in Data Link layer addresses

Duplicate address detection (DAD) is used to verify the usability of an address by sending a neighbor

solicitation to its own address. If a neighbor advertisement is received, the address is not used.

With IPv4, there is no means to detect whether a neighbor is reachable or not [A2]. Also, NDP in IPv6 is

insecure and susceptible to malicious interference, and an extension of this protocol called SEcure


Neighbor Discovery (SEND) provides an alternate mechanism for securing NDP with a cryptographic

method that is independent of IPSec [E9].

Quality of Service and Congestion Control Quality of Service is typically defined as a mechanism that provides distinction of traffic types,

So that it can be classified and administered differently throughout the network [A3]. The IPv6 protocol

does not impose a specific mechanism for QoS, but offers enough flexibility to support multiple QoS

mechanisms. A number of QoS specific service elements in the IP Base and Extension headers can be

used in different ways and combinations to provide QoS. IPv6 uses the Integrated Services and

Differentiated Services traffic policing strategies for QoS the same way as IPv4. Few differences do exist

such as the use of the IPv6 flow label, network address translation, and hardware processing issues [A3].

(source: Cisco IPv6 QoS at-a-glance)

Flows and Flow Labels

A flow is a sequence of packets from a particular source to a particular destination. The flow requires

special handling by intermediate routers, which is communicated by routers using other protocols. The

20 bit Flow Label field in the IPv6 header can be used by a source to request special handling by other

IPv6 routers. A router that does not support the flow label functions is required to set the field to all

zeros when sending a packet, pass it unchanged when forwarding packets, and ignore when receiving a

packet. Additionally, routers do not need to inspect the application payload which results in efficient

QoS processing [A2].

Traffic Class

The Traffic Class field in the IPv6 header enables a source to identify the desired delivery priority of the

packets. The bits of this field hold two values. The 6 most-significant bits are used for differentiated

services (DS) and the remaining two bits are used for ECN (Explicit Congestion Control). The priority

values are divided into ranges: traffic where the source provides congestion control and non-congestion

control traffic. [E2]

Integrated Services

Integrated services are implemented by having the source node start a RSVP (Resource Reservation

Protocol) reservation through the path to a destination node. Each router along the path processes the


reservation, and when the destination is reached an acknowledgment is sent back to the source node

confirming the reservation. The Next Header field in the IPv6 basic header indicates, with a value of

zero, a hop-by-hop extension header following the basic header. The Option-Type field indicates a

Router Alert which means every router that receives the packet should look inside it. The IPv6 packet

structure provides many more features such as chaining of extension headers, use of Next Header to

indicate next payload type, hop-by-hop options and option types [A3].

Network Address Translation

Network Address Translation (NAT) disables the use of QoS, and creates artificial boundaries. Since IPv6

has no NAT this limitation does not exist and QoS can be applied to larger domains. With IPv6 true end-

to-end QoS policy implementations are closer to reality [A3].

Differentiated services

Differentiated services are identical to IPv4. Differentiated services mark packets so that routers in the

network process packets differently. In IPv6 the packets are marked by setting bits in the IPv6 header

Traffic Class field. The Traffic Class fields directly map to the Diffserv (DS) bits on the Type of Service

(TOS) field in the IPv4 header [A3].

Security As discussed, the IPv6 protocol has been introduced to replace IPv4 due to the consumption of all

available IPv4 addresses. Part of the design of IPv6 has been geared towards adding security features to

aid in protecting network traffic. IPSEC is a standard that encompasses many of the security features.

This section will discuss IPSEC, the various protocols and modes is supports as well as some overall

security concerns and implementation practices that are recommend for organizations using IPv6

capable hardware and software. The IPv6 protocol addresses many of the security issues with the IPv4

protocol. While not all attacks have been resolved, some of them have been made more difficult to

achieve. A prime example of this is network scans to determine vulnerable addresses. With IPv6 the

sheer number of possible addresses makes this attack a very lengthy process.

IPSEC

As defined by the Internet Engineering Task Force (IETF), “IPSEC is designed to provide interoperability,

high quality, cryptographically-based security for IPv4 and IPv6.” *E3] IPv6 was designed with IPSEC in its

architecture, while it is an optional extension that can be used, if desired, in IPv4. IPSEC provides end-to-

end security and operates in the Internet Layer. Since IPv4 is optional, considerations must be taken

when determining how to connect IPv6 and IPv4 networks together. IPv4 to IPv6 connection points

must be able to assimilate the appropriate packets to traverse through the IPSEC implementation on the

IPv6 network. Similarly, the IPv6 to IPv4 connection points must to be able to either adapt the packets

to the IPv4 IPSEC implementation, if required, or to disassemble the packets and reassemble for the IPv4

network. Regardless of which state exists, measures must be taken to ensure the security level of the

network is maintained through these connections.


ISAKMP and IKE

IPSEC implementations include Internet Security Association and Key Management Protocol (ISAKMP)

and Internet Key Exchange (IKE). ISAKMP defines the framework with which the Security Associations

(SA) will be generated. The framework provides payload formats, negotiations of the SA and the

mechanism by which the IKE is performed. IKE, as its name implies, is a protocol used for exchange keys

between nodes on a network that have a requirement to communicate securely. A feature of IKE is the

automatic negotiation of the SA and a secure communication channel. This eliminates manual pre-

configurations which can be both costly and timely. [E4] The ISAKMP has what is called an identity. The

identity can be either an IP address or name. It is worth mentioning that both ends of a connection

have to have the same type of identity setup, IP or name, or the IKE could fail should a DNS not be able

to resolve the identity for both ends. [E5]

AH

The Authentication Header (AH) provides important security features such as authentication and

integrity for the entire packet being sent. [E6] Authentication is important as there is a need to be sure

the sender is both identifiable and verifiable. Integrity is important for ensuring the data being sent, has

not been modified. It is important to note that authentication and integrity are not the same as

confidentiality. The implementation of the AH does not provide any level of data encryption, therefore

the actual data portion of the packet is readable, should it be intercepted. The AH is inserted for use in

the Network layer, and before any headers or information for the Transport layer. Lastly, the AH in IPv6

protects both the header and the payload whereas in IPv4, only the payload is protected.

ESP

Like AH, Encapsulating Security Payload (ESP) provides authentication and integrity. Unlike AH, ESP also

provides confidentiality and anti-replay mechanisms. The ESP, however, does not protect the IP header,

as AH does. This is true with the exception of tunneling where the entire packet is encapsulated in

another packet used for the tunnel. [E7] Similar to the discussion around IPSEC, the use of AH and ESP

between IPv6 and IPv4 requires careful implementation to ensure data integrity and security are

maintained. Ensuring the IPv4 and IPv6 implementations of IPSEC are the same, helps mitigate many of

the concerns. The ESP can be implemented in both cases and remain intact from end to end, providing

that overall data confidentiality. The AH and ESP can be used together which can help protect the traffic

information of the network communication in transit. [E8]

Application Layer To fully understand the impact the IPv6 protocol has on the TCP/IP Application Layer, we must first

understand (briefly) the Application Layer itself. The Application Layer is highest layer in the TCP/IP

stack, and is solely concerned with the user’s view of a network. Common examples of Application

Layer protocols are FTP, HTTP, POP, SSH and Telnet. Since the Application Layer treats the Transport

Layer as a “black box” to create network communication between devices, information regarding the

connection between the two devices is abstracted away from the Application Layer. Since the IP

protocol is isolated in the Network Layer, any migration made from IPv4 and IPv6 will go unnoticed in

the Application Layer. This means that any change from IPv4 to IPv6 will have no impact on the


Application Layer in almost all cases. The only exceptions to this rule are application protocols that

embed internet-layer addresses such as FTP and NTPv3 [F1]. The FTP extensions, as specified in RFC

2428 "FTP Extensions for IPv6 and NATs", work with both IPv4 and IPv6.

Multimedia The IPv6 protocol does not affect the process of encoding or streaming of multimedia. The multi-media

server software that is responsible for streaming data will need to be updated to support streaming data

over IPv6. A benefit from using IPv6 will be increased network capacity and faster delivery of real time

data since routers no longer need to translate addresses between sub-nets and home networks. Certain

characteristics of IPv6, such as the large addressing space reserved for multicast addresses and the

availability of the Priority field and the Flow Label field on the IPv6 header, will improve the support of

multimedia applications, and especially real-time applications [F2].

DNS Changes, DHCP The Domain Name System (DNS) is a distributed database across the Internet which maps host names to

addresses. Modifications were done to DN to support IPv6 addresses [F3]. To support the storage of

IPv6 addresses the several extensions have been defined. A new resource record type is defined to map

a domain name to an IPv6 address. A new domain is defined to support lookups based on the address.

Finally, existing queries that perform additional processing to locate IPv4 addresses have been redefined

to perform additional processing on both IPv4 and IPv6 addresses. [F4]

With IPv6, DHCP is not required to configure hosts with address information. The stateless

autoconfiguration mode will configure hosts with IPv6 addresses.

Interoperability The transition from IPv4 to IPv6 will continue to occur gradually, especially with the large number of

systems that exist in the Internet today. It will need to be done smoothly in order to prevent problems

between IPv4 and IPv6 systems. Three common strategies to help with the transition are briefly

described below [E1].

Dual Stack This technique provides complete support for both protocol versions in hosts and routers. A station

must run IPv4 and IPv6 simultaneously until all the Internet uses IPv6. In this technique, the source host

queries the DNS to determine the version to use when sending a packet. Depending on the version of

the address returned - IPv4 or IPv6 – the source host sends the packet in the corresponding version.


[E1]

Tunneling This technique is used for establishing a point-to-point tunnel between a source and destination host

where IPv6 packets are encapsulated within IPv4 headers in order to carry them over IPv4 routing

infrastructures.

[E1]

Header Translation This technique will be necessary when the majority of hosts on the Internet have moved to IPv6 but

some systems continue to use IPv4. The packet sent to a node within an IPv4 based network has to in

the format that can be understood by it. The header format of the IPv6 packet is converted to an IPv4

format by a combination of Application Level Gateways (ALG), and Network Address Translation and

Protocol Translators (NAT-PT), before being sent to the receiving IPv4 node.

[E1]


Conclusion Our paper analyses and describes the impact of implementing IPv6 to the overall network infrastructure.

We have intentionally limited the scope of our research to the information we have learned in class this

semester. Impact to network hardware and components, network area topologies, routing

mechanisms, transport protocols, application, security, quality of service, and performance have been

organized and presented using the structure of the five (5) layer Internet TCP/IP protocol suite –

starting with Layer 1: The Physical Layer, and concluding with Layer 5: The Application Layer.

With the rapid depletion and eventual exhaustion of the global Internet address space using IPv4,

migration to IPv6 is inevitable. Companies and their IT staffs need to fully understand the impact of

implementing IPv6 on their network infrastructure so that they can plan and choose their migration

strategy wisely, and continue to provide uninterrupted, reliable, and cost efficient service to their end

consumers.


References

[A1] S. Bradner, A. Mankin, “The Recommendation for the IP Next Generation Protocol”, Jan 1995 Retrieved

from the World Wide Web on November 12th, 2010 http://www.ietf.org/rfc/rfc1752.txt

[A2] Silvia Hagen, “IPv6 Essentials – Integrating IPv6 into your IPv4 network”, O’Reilly Media, May 2006

[A3] Marc Blanchet, “Migrating to IPv6 – A Practical Guide to Implementing IPv6 in Mobile and Fixed

Networks”, John Wiley & Sons Ltd., 2006

[A4] Retrieved from the World Wide Web on November 12th, 2010

http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd8026003d.pdf

[A5] Retrieved from the World Wide Web on November 12th, 2010

http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd80260042.pdf

[C1] H. Singh, et. Al. “IPv6 CE router requirements” Internet Engineering Task Force August 2010 Retrieved

from the World Wide Web on November 12th, 2010 http://tools.ietf.org/html/draft-ietf-v6ops-ipv6-cpe-

router-07

[C2] Retrieved from the World Wide Web on December 3rd, 2010

http://docwiki.cisco.com/wiki/Source-Route_Bridging

[C3] Retrieved from the World Wide Web on December 3rd, 2010

http://www.juniper.net/techpubs/software/junos/junos91/swconfig-multicast/layer-2-frames-and-

multicast.htmli/Transparent_Bridging

[C4] Carlos Perez “IPv6 and Bluetooth” French IPv6 Worldwide Summit November 2006 Retrieved from the

World Wide Web on November 12th, 2010

http://www.v6summit.com/Conference/Presentations/MOBILITY_PEREZ.pdf

*D1+ T. Chown “Use of VLANs for IPv4-IPv6 Coexistence in Enterprise Networks” Networking Working Group

June 2006 Retrieved from the World Wide Web on November 12th, 2010 http://www.ietf.org/rfc/rfc4554.txt

*D2+ A. Conta “Transmission of IPv6 Packets over Frame Relay Networks Specification” Network Working

Group May 1999 Retrieved from the World Wide Web on November 12th, 2010

http://tools.ietf.org/html/rfc2590

*D3+ G. Armitage et. Al. “IPv6 over ATM Networks” Network Working Group January 1999 Retrieved from the

World Wide Web on November 12th, 2010 http://tools.ietf.org/html/rfc2492

[D4] http://www.eurescom.eu/~public-web-deliverables/P1100-series/P1113/D1/31_diflink.html#3

[D5] C. Kozierok “The TCP/IP Guide – Ipv6 Addressing” Retrieved from the World Wide Web on November

12th, 2010 http://www.tcpipguide.com/free/t_IPv6InterfaceIdentifiersandPhysicalAddressMapping.htm

[D6] F. Donze “IPv6 Autoconfiguration” The Internet Protocol Journal, Volume 7, Number 2 June 2004

Retrieved from the World Wide Web on November 12th, 2010

http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-2/ipv6_autoconfig.html

[D7] C. Kozierok “The TCP/IP Guide Retrieved from the World Wide Web on November 12th, 2010

http://www.tcpipguide.com/free/diagrams/ipv6eui64.png

http://www.ietf.org/rfc/rfc1752.txt

http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd8026003d.pdf

http://www.cisco.com/en/US/technologies/tk648/tk872/technologies_white_paper0900aecd80260042.pdf

http://tools.ietf.org/html/draft-ietf-v6ops-ipv6-cpe-router-07

http://tools.ietf.org/html/draft-ietf-v6ops-ipv6-cpe-router-07

http://docwiki.cisco.com/wiki/Source-Route_Bridging

http://www.juniper.net/techpubs/software/junos/junos91/swconfig-multicast/layer-2-frames-and-multicast.htmli/Transparent_Bridging

http://www.juniper.net/techpubs/software/junos/junos91/swconfig-multicast/layer-2-frames-and-multicast.htmli/Transparent_Bridging

http://www.v6summit.com/Conference/Presentations/MOBILITY_PEREZ.pdf




http://www.eurescom.eu/~public-web-deliverables/P1100-series/P1113/D1/31_diflink.html#3

http://www.tcpipguide.com/free/t_IPv6InterfaceIdentifiersandPhysicalAddressMapping.htm

http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-2/ipv6_autoconfig.html

http://www.tcpipguide.com/free/diagrams/ipv6eui64.png


[D8+ C. Aoun, et. Al. “Reasons to Move the Network Address Translator - Protocol Translator (NAT-PT) to

Historic Status” Network Working Group July, 2007 Retrieved from the World Wide Web on November 12th,

2010 http://tools.ietf.org/html/rfc4966

[D9] “Internet Protocol Version 6 Address Space” Internet Assigned Numbers Authority (IANA) Retrieved from

the World Wide Web on November 12th, 2010 http://www.iana.org/assignments/ipv6-address-space/ipv6-

address-space.xml

[D10] R. hinden et. Al. “IP Version 6 Addressing Architecture” Network Working Group February 2006

Retrieved from the World Wide Web on November 12th, 2010 http://tools.ietf.org/html/rfc4291

[D11] B. Posey “Crash Course in IPv6” Windows Networking – Network Protocols November 2006 Retrieved

from the World Wide Web on November 12th, 2010

http://www.windowsnetworking.com/articles_tutorials/Crash-Course-IPv6-Part1.html

[D12] “Methods for Configuring IPv6 Addresses” Microsoft April 2010 Retrieved from the World Wide Web

on November 12th, 2010 http://msdn.microsoft.com/en-us/library/aa920446.aspx

[D13] M. Clark “How To Subnet IPv6” Internet Retrieved from the World Wide Web on November 12th, 2010

http://www.clarksys.com/blog/2009/03/12/howto-subnet-ipv6/

[D14] J. Lambert “IPv6 Subnet Masking” Exabyte.com Retrieved from the World Wide Web on November

12th, 2010 http://www.exabyte.net/lambert/subnet/ipv6_subnet_masking.htm

[D15] “Cisco IOS IPv6 Configuration Guide – Implementing NAT-PT for IPv6” Cisco November 2002 Retrieved

from the World Wide Web on November 12th, 2010

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-

nat_trnsln_ps6350_TSD_Products_Configuration_Guide_Chapter.html

[D16] D. Teare “Designing Cisco Networks” Cisco Press July 1999 Retrieved from the World Wide Web on

November 12th, 2010 http://docwiki.cisco.com/wiki/Internetworking_Basics

[D17] C. Kozierok “The TCP/IP Guide – IPv6 Datagram Main Header Format” Retrieved from the World Wide

Web on November 12th, 2010 http://www.tcpipguide.com/free/t_IPv6DatagramMainHeaderFormat.htm

[D18] Pete Loshin, “IPv6: Theory, Protocol, and Practice, 2nd Edition”, Morgan Kaufmann, December 2003

[D19] Silvia Hagen, “IPv6 Essentials – Integrating IPv6 into your IPv4 network”, O’Reilly Media, May 2006

[D20] Charles M. Kozierok, “IPv6 Datagram Size, Maximum Transmission Unit (MTU), Fragmentation and

Reassembly”, Version 3.0, September 2005

http://www.tcpipguide.com/free/t_IPv6DatagramSizeMaximumTransmissionUnitMTUFragment.htm


[D22] Silvia Hagen, “IPv6 Essentials – Integrating IPv6 into your IPv4 network”, O’Reilly Media, May 2006


[D24] http://www.tcpipguide.com/free/t_IPv6DatagramDeliveryandRouting.htm

[D25] http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-routing/html/ripng-

overview.html


http://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xml

http://www.iana.org/assignments/ipv6-address-space/ipv6-address-space.xml


http://www.windowsnetworking.com/articles_tutorials/Crash-Course-IPv6-Part1.html

http://msdn.microsoft.com/en-us/library/aa920446.aspx

http://www.clarksys.com/blog/2009/03/12/howto-subnet-ipv6/

http://www.exabyte.net/lambert/subnet/ipv6_subnet_masking.htm

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-nat_trnsln_ps6350_TSD_Products_Configuration_Guide_Chapter.html

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-nat_trnsln_ps6350_TSD_Products_Configuration_Guide_Chapter.html

http://docwiki.cisco.com/wiki/Internetworking_Basics

http://www.tcpipguide.com/free/t_IPv6DatagramMainHeaderFormat.htm

http://www.tcpipguide.com/free/t_IPv6DatagramSizeMaximumTransmissionUnitMTUFragment.htm

http://www.tcpipguide.com/free/t_IPv6DatagramDeliveryandRouting.htm

http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-routing/html/ripng-overview.html

http://www.juniper.net/techpubs/software/junos/junos64/swconfig64-routing/html/ripng-overview.html


[D26] http://www.bgp4.as

[E1] Behrouz A. Ferouzan , “Data Communications and Networking”, McGraw Hill, 2007

*E2+ “IPv6 Packet”, http://en.wikipedia.org/wiki/IPv6_packet

[E3] S. Kent, K. Seo “Security Architecture for the Internet Protocol” Network Working Group December 2005

http://tools.ietf.org/html/rfc4301.txt

[E4] D. Maughan et. Al. “Internet Security Association and Key Management Protocol (ISAKMP) NEtowrk

Working Group November 1998 http://www.ietf.org/rfc/rfc2408.txt

[E5] “Internet Key Exchange Security Protocol” Cisco Retrieved from the World Wide Web on November 12th,

2010 http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/isakmp.html

[E6] “Authentication Header” Microsoft TechNet Retrieved from the World Wide Web on November 12th,

2010 http://technet.microsoft.com/en-us/library/cc959507.aspx

[E7] S.Kent, R. Atkinson “IP Encapsulating Security Payload (ESP) Network Working Group November 1998

Retrieved from the World Wide Web on November 12th, 2010 http://www.ietf.org/rfc/rfc2406.txt

[E8] D. Parker “IPSEC (IP Security)” Windows Networking – Network Protocols February 2006 Retrieved from

the World Wide Web on November 12th, 2010 http://www.windowsnetworking.com/articles_tutorials/IPSec-

IP-Security-Part1-ESP.html

[E9] Secure Neighbor Discovery Protocol http://en.wikipedia.org/wiki/Secure_Neighbor_Discovery_Protocol

[F1] http://en.wikipedia.org/wiki/IPv6

[F2] David Childers, “How will IPv6 Change Internet Multimedia Streaming” Retrieved from the World Wide

Web on November 12th, 2010 http://ezinearticles.com/?How-Will-IPV6-Change-Internet-Multimedia-

Streaming&id=2275641

[F3] S. Thomson, C. Huitema “DNS Extensions to Support IP version 6” Retrieved from the World Wide Web

on November 12th, 2010 http://www.faqs.org/rfcs/rfc1886.html)

[F4] Charles M. Kozierok, The TCP/IP Guide Retrieved from the World Wide Web on November 12th, 2010

http://www.tcpipguide.com/free/t_DNSChangesToSupportIPVersion6.htm

http://www.bgp4.as/

http://tools.ietf.org/html/rfc4301.txt


http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/isakmp.html

http://technet.microsoft.com/en-us/library/cc959507.aspx


http://www.windowsnetworking.com/articles_tutorials/IPSec-IP-Security-Part1-ESP.html

http://www.windowsnetworking.com/articles_tutorials/IPSec-IP-Security-Part1-ESP.html

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

http://en.wikipedia.org/wiki/IPv6

http://ezinearticles.com/?How-Will-IPV6-Change-Internet-Multimedia-Streaming&id=2275641

http://ezinearticles.com/?How-Will-IPV6-Change-Internet-Multimedia-Streaming&id=2275641

http://www.faqs.org/rfcs/rfc1886.html

http://www.tcpipguide.com/free/t_DNSChangesToSupportIPVersion6.htm

Documents

IPv6 Migration