## How Long Is An Ipv6 Address?

Parts of the IPv6 Address – An IPv6 address is 128 bits in length and consists of eight, 16-bit fields, with each field bounded by a colon. Each field must contain a hexadecimal number, in contrast to the dotted-decimal notation of IPv4 addresses. In the next figure, the x’s represent hexadecimal numbers.

## What is the longest IPv6 length?

IPv6 addresses are normally written as eight groups of four hexadecimal digits, where each group is separated by a colon (:). So that’s 39 characters max.

### How long is an IPv6 address 32?

IPv6 is the successor to the first addressing infrastructure of the Internet, Internet Protocol version 4 (IPv4). In contrast to IPv4, which defined an IP address as a 32-bit value, IPv6 addresses have a size of 128 bits.

#### Are IPv6 addresses 16 bytes long?

IPv6 addresses – IPv6 addresses are 128 bits or 16 bytes. This results in enough IP addresses to connect the entire universe to the internet. Many times over! IPv6 addresses are not expressed as decimal, but as hexadecimal numbers. Which is in fact more convenient. Expressing IPv6 addresses as decimal numbers would make then way to long.

### Why is IPv6 128 bits?

Why is ipv6 128bit and not 64bit? The two are unrelated. The decisions around how to structure IPV6 are myriad. There’s a lot of info at the, Basically, the 128-bit address space of IPv6 gives us such a massive address space that we are unlikely to ever use all of it (2^128 addresses, or 3.4*10^38).

The larger address space also allows for a better hierarchical model of addressing, because CIDR and similar “hacks” are no longer necessary for routing. The address space allows a separation of a 64 bit host address and 64 bit network address, and host address can be self-configured. With more space, we have more addresses, and it’s easier to organize them efficiently.

IPv4 is kind of like a cluttered 1-bedroom apartment, and IPv6 is a giant warehouse in which we can set up everything in a much more organized fashion. : Why is ipv6 128bit and not 64bit?

#### Why is IPv6 so large?

Will IPv6 addresses run out eventually? – In practical terms, no. There are 2^128 or 340 trillion, trillion, trillion IPv6 addresses, which is more than 100 times the number of atoms on the surface of the Earth. This will be more than sufficient to support trillions of Internet devices for the forseeable future.

### Why is IPv6 not used?

1. IPv6 was not designed to be IPv4 compatible – When IPv6 was designed, compatibility with IPv4 was not on the requirements list. A solution to communicate with devices that still run on IPv4 was not provided. This means that each IPv6 address needs an IPv4 address.

#### How long is an IPv4 address?

An IPv4 address is 32 bits. An IP Address is shown as 4 decimal numbers representing 4 bytes: d.d.d.d where d = decimal number (0 – 255). High order bits are the network identifier and lower order bits are the host identifier.

### Does IPv6 use 32-bit or 64 bit?

IPv6 uses 128-bit (2 128 ) addresses, allowing 3.4 x 10 38 unique IP addresses. This is equal to 340 trillion trillion trillion IP addresses.

#### How long is an IPv6 address 128?

Parts of the IPv6 Address – An IPv6 address is 128 bits in length and consists of eight, 16-bit fields, with each field bounded by a colon. Each field must contain a hexadecimal number, in contrast to the dotted-decimal notation of IPv4 addresses. In the next figure, the x’s represent hexadecimal numbers.

## Why is there no IPv5?

Caught in the Middle – IPv5 was not really assigned, but it was understood to be associated with a separate experimental protocol for streaming that saw limited use. In 1979, IEN 119 (Internet Experiment Notes were used instead of RFCs for non-ARPANET developments) defined Internet Stream Protocol (ST), which worked alongside Stream Control Message Protocol (SCMP).

RFC 1190 – Experimental Internet Stream Protocol, Version 2 (ST-II) from 1990 and RFC 1819 – Internet Stream Protocol Version 2 (ST2) Protocol Specification – Version ST2+ from 1995 revised ST. The protocol itself was an experiment for resource reservation that provided Quality of Service (QoS) for multimedia applications that involved real-time communications, including video and voice.

The plan was not to replace IPv4 with ST2, but rather have IPv4 for regular packets and ST2 for packets containing real-time data. When ST/ST2 was encapsulated in IPv4 packets, the Protocol Number field had a value of 5, just like packets encapsulating ICMP contain a value of 1 in the Protocol Number field, packets encapsulating Transmission Control Protocol (TCP) segments contain a value of 6 in the Protocol Number field, and packets that contain User Datagram Protocol (UDP) datagrams contain a value of 17 in the Protocol Number field.

1. When ST/ST2 was not encapsulated in IPv4 packets, it used the value of 5 in the Version Number field in its own header, but never was thought of or referred to as IPv5.
2. When IPv6 was designed, to avoid any confusion, IPv5 was skipped, and the name of the protocol went to IPv6.
3. ST2 saw usage for distributed simulations and videoconferencing in the Terrestrial Wideband Network and its replacement, the Defense Simulation Internet.

Its design was incorporated into the core technology for voice call transportation and other real-time streams for Canada’s Iris Digital Communications System. Anything ST related, today, is long obsolete. Here’s a snippet from RFC 1190: 2.2. Concepts and Terminology The ST packet header is not constrained to be compatible with the IP packet header, except for the IP Version Number (the first four bits) that is used to distinguish ST packets (IP Version 5) from IP packets (IP Version 4).

The ST packets, or protocol data units (PDUs), can be encapsulated in IP either to provide connectivity (possibly with degraded service) across portions of an internet that do not provide support for ST, or to allow access to services such as security that are not provided directly by ST. ST uses IP Version Number 5.

When encapsulated in IP, ST uses IP Protocol Number 5. Here’s a snippet from RFC 1819: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ST=5 | Ver=3 |D| Pri | 0 | TotalBytes | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HeaderChecksum | UniqueID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OriginIPAddress | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 10: ST Header – ST is the IP Version Number assigned to identify ST packets.

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The Meaning of IPv6 Addresses – IPv6 stands for Internet Protocol version 6. It’s the latest version of the Internet Protocol, which was developed to accommodate the rapidly growing need for more unique IP addresses. In fact, we are actually running out of IPv4 addresses—and without an alternative—that would be a serious issue.

1. IPv6 is the successor to IPv4 and was designed to supplement and ultimately replace version 4, though total adoption of version 6 is still a ways off.
2. Did you know? : There was an IPv5, but it never caught on.
3. It was designed to be a streaming protocol but used the same addressing type as IPv4.
4. Because it consists of 128-bit hexadecimal digits, IPv6 has near-infinite scalability.

This solves the dwindling IPv4 problem as it allows up to 340 undecillion addresses. Undecilli-what? If you’re having a hard time picturing that number, it looks like this: 340,000,000,000,000,000,000,000,000,000,000,000,000.

## Are IPv6 addresses 256 bits in size?

The correct answer is 128 bits. An IPv6 address has a size of 128 bits.

## Why IPv6 has 64?

IPv6 Subnetting

DHCP6 Prefix Delegation

IPv6 subnetting is easier than IPv4. It’s also different. Want to divide or combine a subnet? All that is needed is to add or chop off digits and adjust the prefix length by a multiple of four. No longer is there a need to calculate subnet start/end addresses, usable addresses, the null route, or the broadcast address.

• IPv6 doesn’t have a subnet mask but instead calls it a Prefix Length, often shortened to “Prefix”.
• Prefix length and CIDR masking work similarly; The prefix length denotes how many bits of the address define the network in which it exists.

Most commonly the prefixes used with IPv6 are multiples of four, as seen in Table IPv6 Subnet Table, but they can be any number between 0 and 128, Using prefix lengths in multiples of four makes it easier for humans to distinguish IPv6 subnets. All that is required to design a larger or smaller subnet is to adjust the prefix by multiple of four.

IPv6 Subnet Table ¶

Prefix Subnet Example Total IP Addresses # of /64 nets
4 x:: 2 124 2 60
8 xx:: 2 120 2 56
12 xxx:: 2 116 2 52
16 xxxx:: 2 112 2 48
20 xxxx:x:: 2 108 2 44
24 xxxx:xx:: 2 104 2 40
28 xxxx:xxx:: 2 100 2 36
32 xxxx:xxxx:: 2 96 4,294,967,296
36 xxxx:xxxx:x:: 2 92 268,435,456
40 xxxx:xxxx:xx:: 2 88 16,777,216
44 xxxx:xxxx:xxx:: 2 84 1,048,576
48 xxxx:xxxx:xxxx:: 2 80 65,536
52 xxxx:xxxx:xxxx:x:: 2 76 4,096
56 xxxx:xxxx:xxxx:xx:: 2 72 256
60 xxxx:xxxx:xxxx:xxx:: 2 68 16
64 xxxx:xxxx:xxxx:xxxx:: 2 64 (18,446,744,073,709,551,616) 1
68 xxxx:xxxx:xxxx:xxxx:x:: 2 60 (1,152,921,504,606,846,976) 0
72 xxxx:xxxx:xxxx:xxxx:xx:: 2 56 (72,057,594,037,927,936) 0
76 xxxx:xxxx:xxxx:xxxx:xxx:: 2 52 (4,503,599,627,370,496) 0
80 xxxx:xxxx:xxxx:xxxx:xxxx:: 2 48 (281,474,976,710,656) 0
84 xxxx:xxxx:xxxx:xxxx:xxxx:x:: 2 44 (17,592,186,044,416) 0
88 xxxx:xxxx:xxxx:xxxx:xxxx:xx:: 2 40 (1,099,511,627,776) 0
92 xxxx:xxxx:xxxx:xxxx:xxxx:xxx:: 2 36 (68,719,476,736) 0
96 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:: 2 32 (4,294,967,296) 0
100 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:x:: 2 28 (268,435,456) 0
104 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xx:: 2 24 (16,777,216) 0
108 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxx:: 2 20 (1,048,576) 0
112 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:: 2 16 (65,536) 0
116 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:x:: 2 12 (4,096) 0
120 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xx:: 2 8 (256) 0
124 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxx:: 2 4 (16) 0
128 xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx 2 0 (1) 0

A /64 is a standard size IPv6 subnet as defined by the IETF. It is smallest subnet that can used locally if auto configuration is desired. Typically, an ISP assigns a /64 or smaller subnet to establish service on the WAN. An additional network is routed for LAN use.

#### Why is 128-bit not used?

CPUs that process 128 bits as a single unit, compared to 8, 16, 32 or 64 bits. As of 2022, there are no 128-bit computers on the market. A 128-bit processor may never occur because there is no practical reason for doubling the basic register size. One of the reasons for migrating from 32-bit to 64-bit computers was memory (RAM) addressing; however, for all practical purposes, there was only a need for a few more bits beyond 32 (see binary values ).

### What are the 3 types of IPv6 addresses?

IPv6 Addressing System Administration Guide, Volume 3 IPv6 addresses are 128-bits long and are identifiers for individual interfaces and sets of interfaces. IPv6 addresses of all types are assigned to interfaces, not nodes (hosts and routers). Because each interface belongs to a single node, any of that node’s interfaces’ unicast addresses can be used as an identifier for the node.

Unicast addresses identify a single interface. Anycast addresses identify a set of interfaces in such a way that a packet sent to an anycast address is delivered to a member of the set. Multicast addresses identify a group of interfaces in such a way that a packet sent to a multicast address is delivered to all of the interfaces in the group.

IPv6 has no broadcast addresses: multicast addresses took over. IPv6 supports addresses that are four times the number of bits as IPv4 addresses (128 vs.32). This is 4 billion times 4 billion times the size of the IPv4 address space. Realistically, the assignment and routing of addresses requires the creation of hierarchies that reduce the efficiency of address space usage, thus reducing the number of available addresses.

1. Nonetheless, IPv6 provides enough address space to last into the foreseeable future.
3. The variable-length field containing these leading bits is called the format prefix (FP).
4. The following table shows the initial allocation of these prefixes.

Table 14-1 Format Prefix Allocations

Allocation Prefix (binary) Fraction of Address Space
Reserved 0000 0000 1/256
Unassigned 0000 0001 1/256
Reserved for NSAP Allocation 0000 001 1/128
Reserved for IPX Allocation 0000 010 1/128
Unassigned 0000 011 1/128
Unassigned 0000 1 1/32
Unassigned 0001 1/16
Aggregate Global Unicast Address 001 1/8
Unassigned 010 1/8
Unassigned 011 1/8
Reserved for Neutral-Interconnect-Based Unicast Addresses 100 1/8
Unassigned 101 1/8
Unassigned 110 1/8
Unassigned 1110 1/16
Unassigned 1111 0 1/32
Unassigned 1111 10 1/64
Unassigned 1111 110 1/128
Unassigned 1111 1110 0 1/512
Site Local Use Addresses 1111 1110 11 1/1024

The allocations support the direct allocation of aggregate global unicast addresses, local-use addresses, and multicast addresses. Space is reserved for NSAP (Network Service Access Point) addresses, IPX (Internetwork Packet Exchange Protocol) addresses, and neutral-interconnect addresses.

• The remainder of the address space is unassigned for future use.
• This remaining address space can be used for expansion of existing use (for example, additional aggregate global unicast addresses) or new uses (for example, separate locators and identifiers).
• Notice that anycast addresses are not shown here because they are allocated out of the unicast address space.

Approximately fifteen percent of the address space is initially allocated. The remaining 85% is reserved for future use.

## Why is IPv4 worse than IPv6?

What is IPv6? – Internet Protocol version 6, or IPv6, is the sixth iteration of the Internet Protocol and was created because the world was in danger of running out of IPv4 addresses. IPv6 works in much the same way as IPv4 – by providing unique, alphanumerical IP addresses needed for devices to send and receive data on the internet.

• However, as you might imagine, an IPv6 address is a lot longer than an IPv4 address, which means you can create a lot more unique IP addresses than you can with IPv4.
• And when we say a lot more, we really mean it.
• IPv6 uses a 128-bit address and can provide 340 undecillion IP addresses, while IPv4 is limited to 4.3 billion IP addresses.

However, IPv6 implementation by ISPs and/or network admins can lead to various leaks and security issues. This way, your personal information can potentially compromised. In this situation, a VPN connection can help you avoid many possible issues. For those interested, an IPv6 address is made up of eight groups of four hexadecimal digits,

• These are separated by colons rather than full stops.
• An example of an IPv6 address looks like this : 2001:0db8:82a3:0000:0000:4a2e:0370:7337 Pros: More unique addresses, supported by new devices, no subnetting problems Cons: Much longer than IPv4, not yet supported by all websites, possible system issues IPv6 was first introduced back in the late 1990s in the hope that it would replace IPv4 before we ran out of IP addresses.

However, the transition from IPv4 to IPv6 has been slow. And the main reason for this is that it costs time and money to upgrade all the routers, servers and switches that have depended on IPv4 for so long. So, while IPv6 is ready to go, it’s taking a long time to roll out.

Routing is made more efficient by reducing the size of routing tables. Support for multicast rather than broadcast allows bandwidth-intensive packet flows to be sent to many destinations at the same time, which saves bandwidth. Auto-configuration means that configuration tasks, such as IP address assignment and device numbering can take place automatically. Security features that provide data integrity, authentication and confidentiality are baked into IPv6.

## Why is IPv6 safer than IPv4?

IPv6 Encryption – While end-to-end encryption was retroactively added to IPv4, it was built into IPv6. Encryption and integrity-checking, currently used by VPNs, is standard in IPv6 for all devices and systems. IPv6 is also more secure for name resolution.

## Does IPv6 reduce speed?

IPv4 vs. IPv6: Speed comparison – How do IPv4 and IPv6 compare when it comes to speed? The security blog Sucuri ran a series of tests in which they found that in direct connections, IPv4 and IPv6 delivered the same speed. IPv4 occasionally won the test.

In theory, IPv6 should be a little faster since cycles don’t have to be wasted on NAT (Network Address Translation). But IPv6 also has larger packets, which may make it slower for some use cases. What really makes a difference at this point is that IPv4 networks are mature and thus highly optimized, more so than IPv6 networks.

So with time and tuning, IPv6 networks will get faster.

#### Why is IPv6 bad for privacy?

A single device within an IPv6 home network can reduce the privacy of every computer, handheld, and other gadget on that network, enabling all devices to be tracked around the internet, even those with IPv6 privacy protections. In a research paper titled “One Bad Apple Can Spoil Your IPv6 Privacy,” Said Jawad Saidi, of the Max-Planck-Institut für Informatik at Saarland University in Germany; Oliver Gasser, also of the MPI-INF; and Georgios Smaragdakis, of TU Delft in the Netherlands describe how the use of legacy IPv6 addressing standard EUI-64, aka Extended Unique Identifier, by just one device potentially degrades privacy to every device on that network.

• Their paper is scheduled to be published next month in ACM SIGCOMM Computer Communication Review, Volume 52, Issue 2.
• IPv6 was introduced in 1998 as the successor to IPv4, the internet addressing protocol that emerged from DARPA in 1981.
• IPv6 is still being rolled out – about 38 percent of those connecting to Google.com currently do so over IPv6 connections.

But IPv6 is necessary to allow new devices to be added to the internet as IPv4 addresses become scarce. Depending on your ISP, router, and so on, you might find that on your home network, your laptops, phones, and other devices have their own local IPv6 addresses, and each have a public-facing IPv6 address when connecting to websites and other stuff online.

These addresses should be regularly swapped out with new ones so that when you visit a website today, and visit it again tomorrow, it’s not clear to the website from your IPv6 address alone that your device has returned, granting you some level of privacy. According to this research, if you have a device on your network with EUI-64, you lose this.

IPv6, the paper explains, relies either on DHCPv6 or stateless address auto-configuration (SLAAC) to assign client addresses. With SLAAC, a router will send a prefix – in a way, the network identifier in an address – to the client, and the client will then select an IPv6 address within that prefix – known as the host part the address, or interface identifier (IID).

1. The IID used to be based on an encoding of the device’s hardware MAC address, known as EUI-64,
2. It subsequently became clear that EUI-64 should be considered harmful to privacy because it exposes hardware identifiers at the network layer.
3. Back in 2007, IPv6 privacy extensions were proposed to randomize the host portion of the address.

And ISPs got into the habit of rotating IPv6 address prefixes as an additional privacy defense. Sadly, some hardware makers – largely Internet-of-Things vendors – missed the memo and still use EUI-64 to generate a device’s IID.

Microsoft Azure DevOps revives TLS 1.0/1.1 with rollback Nominet suspends ‘single digit’ number of Russian dot-UK domain registrars Network operating system Dent 2.0 targets smaller firms IPv6 is built to be better, but that’s not the route to success

What the paper’s authors have found is that it just takes a single device using EUI-64 to deny privacy to every device on the network. Almost a fifth (19 percent) of all end-user prefixes at a large ISP were found to be affected by this privacy leak and, it’s claimed, a slightly smaller percentage (17 percent) can be monitored by large internet companies and hyperscalers.

By analyzing passive data from a large ISP, we find that around 19 percent of end-users’ privacy can be at risk,” the authors state in their paper. “When we investigate the root causes, we notice that a single device at home that encodes its MAC address into the IPv6 address can be utilized as a tracking identifier for the entire end-user prefix — even if other devices use IPv6 privacy extensions.” The paper describes an example involving two devices, a laptop using IPv6 privacy extensions, and a smart TV using EUI-64, both using a home network gateway router with IPv6 connectivity upstream and SLAAC in use.

The diagram below, taken from the paper, is given to illustrate this scenario. Diagram from the paper illustrating the privacy leak, Credit: Saidi et al The TV and the laptop are, on day one, given the same end-user prefix (2001:db80:1111:b000) and then their own host portions to form a public-facing IPv6 address. By the next day, another prefix is generated (2001:db80:3333:fff1) though the EUI-64-based TV gets the same host portion while the laptop gets a fresh one.

The laptop has an entirely new IPv6 address whereas the TV only has a new prefix. If the TV and laptop on day one interact with CDNs and internet giants, and then interact with those providers again on day two, one or more of those large networks can work back from the TV’s unchanged host portion (8e8f:90ff:fe12:3456) and new prefix to link the laptop’s latest IPv6 address with its previous address.

Thus, the laptop can be tracked, with the TV’s host portion effectively becoming a tracking ID. This only works if the TV and the laptop both access the same cloud or CDN providers – such as Google, Meta, or Netflix, or something like a DNS or NTP provider – and if those backends care enough to match up people’s IPv6 addresses and then use that information for something.

It’s perhaps unlikely though the mechanism is there. In the above diagram, CPE refers to the customer premise equipment aka the broadband gateway box. If this doesn’t have the same end-user prefix as the devices on the network, it can’t be tracked via this method. “Since the smart TV is not using privacy extensions, it allows CDNs and other large players in the internet to track not only the smart TV itself, but all devices within that end user prefix,” the paper added.

The MAC address can also be extracted from the EUI-64 portion of the IPv6 address and used to determine the device maker, via the Organization Unique Identifier (OUI) part of the MAC address. Devices not using EUI-64 could not be identified this way, even though they could be tracked using the common IID.

The boffins said about 39 percent of the network prefixes hosting EUI-64 devices correspond to companies making only IoT devices. About 32 percent correspond to companies making various devices, including IoT, computers, and mobile hardware. In this second category, the paper’s authors observe, while Apple enables privacy extensions by default in their products, other vendors do not.

“Unfortunately, at the time of writing, many Linux distributions do not activate privacy extensions by default,” the paper says. “Products using Linux derivatives in their software are likely unknowingly putting their users’ privacy at risk.” The authors speculate that this may be due to the fact that the original privacy extensions specification recommended deactivating them by default, which is no longer the case in the current standard,

#### Why is IPv6 not safe?

Summary: As currently implemented IPv6 networks might actually be less secure than IPv4. This is not because of the design IPv6 but because of inadequate support in firewalls and because network administrators and security specialist have more knowledge dealing with IPv4 than with IPv6.

### How old is IPv6?

table> Internet Protocol Version 6

Communication protocol IPv6 header Abbreviation IPv6 Purpose Internetworking protocol Developer(s) Internet Engineering Task Force Introduction December 1995 ; 27 years ago Based on IPv4 OSI layer Network layer RFC(s) 2460, 8200

Internet Protocol version 6 ( IPv6 ) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet, IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion, and is intended to replace IPv4,

• In December 1998, IPv6 became a Draft Standard for the IETF, which subsequently ratified it as an Internet Standard on 14 July 2017.
• Devices on the Internet are assigned a unique IP address for identification and location definition.
• With the rapid growth of the Internet after commercialization in the 1990s, it became evident that far more addresses would be needed to connect devices than the IPv4 address space had available.

By 1998, the IETF had formalized the successor protocol. IPv6 uses 128- bit addresses, theoretically allowing 2 128, or approximately 3.4 × 10 38 total addresses. The actual number is slightly smaller, as multiple ranges are reserved for special use or completely excluded from use.

The two protocols are not designed to be interoperable, and thus direct communication between them is impossible, complicating the move to IPv6. However, several transition mechanisms have been devised to rectify this. IPv6 provides other technical benefits in addition to a larger addressing space. In particular, it permits hierarchical address allocation methods that facilitate route aggregation across the Internet, and thus limit the expansion of routing tables,

The use of multicast addressing is expanded and simplified, and provides additional optimization for the delivery of services. Device mobility, security, and configuration aspects have been considered in the design of the protocol. IPv6 addresses are represented as eight groups of four hexadecimal digits each, separated by colons.

### What is the maximum length of an IPv6 in bytes?

Fragment Header – The Fragment header is used for IPv6 fragmentation and reassembly services. This header is identified by the value of 44 in the previous headers Next Header field. Figure 24 shows the Fragment header. Figure 24 The Fragment header The Fragment header includes a Next Header field, a 13-bit Fragment Offset field, a More Fragments flag, and a 32-bit Identification field. The Fragment Offset, More Fragments flag, and Identification fields are used in the same way as the corresponding fields in the IPv4 header.

Because the use of the Fragment Offset field is defined for 8-byte fragment blocks, the Fragment header cannot be used for IPv6 jumbograms, In IPv6, only source nodes can fragment payloads. If the payload submitted by the upper layer protocol is larger than the link or path MTU, then IPv6 fragments the payload at the source and uses the Fragment extension header to provide reassembly information.

When an IPv6 packet is fragmented, it is initially divided into unfragmentable and fragmentable parts: The unfragmentable part of the original IPv6 packet must be processed by each intermediate node between the fragmenting node and the destination. This part consists of the IPv6 header, the Hop-by-Hop Options header, the Destination Options header for intermediate destinations, and the Routing header.

The fragmentable part of the original IPv6 packet must only be processed at the final destination node. This part consists of the Authentication header, the Encapsulating Security Payload header, the Destination Options header for the final destination, and the upper layer PDU. Next, the IPv6 fragment packets are formed.

Each fragment packet consists of the unfragmentable part, a fragment header, and a portion of the fragmentable part. Figure 25 shows the fragmentation process for an IPv6 packet. Figure 25 The IPv6 fragmentation process

#### What is the maximum prefix length in IPv6?

The maximum prefix length you can use for an IPv6 address is /128 which essentially is a host address, much the same as using a subnet mask of 255.255.255.255 in IPv4.

#### Is IPv6 is Infinite?

IPv4 provides an addressing capability of approximately 4.3 billion addresses. The Internet Protocol version 6 (IPv6) is more advanced and has better features compared to IPv4. It has the capability to provide an infinite number of addresses.

### Is the length of an IPv6 address 256 bits?

Explanation: An IPv6 address is 128 bits long.