IP protocol family

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This part includes:
• IP protocol family
• IPv6
Chapter 2 IP protocol family
Author: Mark A. sportack
This chapter includes:
• TCP/IP Model
• Understand the I p Protocol
• Understand the Transmission Control Protocol (t c p)
• Understand User Datagram Protocol (u d p)
T c p/I p has become synonymous with describing I p-based communication. In addition to popularity, few people know that it actually refers to the whole
Each protocol has its own functions and limits. This chapter discusses the structure and functions of various protocols in the I p protocol family.
Yes.
9.1 TCP/IP Model
Like other network protocols, t c p/I p has its own reference model used to describe the functions of each layer. However
Other protocols are different. t c p/I p model is available only after the Protocol component is developed. Therefore, the t c p/I p Model
T c p/I p Reference Model and o s I reference model are compared as shown in Figure 9-1.
Figure 9-1 Comparison Between TCP/IP model and OSI model
Part iii I p and related Protocols
O s I Reference Model Layer
Description
T c p/I p
Layer description
Process/Application Layer
Host to host Layer
Network access layer
O s I level Number
Application Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer
7
6
5
5
3
2
1
Internet Layer
As shown in Figure 9-1, the t c p/I p Reference Model achieves all the same functions in the o s I model. Important differences
They have different layers of granularity. The o s I model is more accurate to the layer, while the t c p/I p model uses a wider layer definition.
9.1.1 anatomy of the TCP/IP Model
The t c p/I p protocol stack consists of four functional layers: Process/application layer, host to host layer, Internet layer, and network access layer. This
The Layer 4 is roughly relative to the Layer 7 in the o s I Reference Model.
1. Process/Application Layer
The application layer protocol provides remote access and resource sharing. Applications familiar to readers include te l n e t, f t p, s m t p, h t p,
Many other applications reside and run at this layer, and rely on the underlying functions. Similarly, you need
Any application for communication (including the software developed by the user and purchased in the store) is also described at this layer of the model.
2. Host to host Layer
The host-to-host layer of I p corresponds to the Session Layer and transmission layer of the o s I Reference Model. This layer supports the following features:
To segment the application data transmitted over the network, perform a mathematical check to ensure the integrity of the collected data.
Multiplexing (transmission and receiving) data streams with simultaneous data transmission ). This means that the host-to-host layer can identify special applications and
Sort the received data in sequence.
The current host-to-host layer includes two protocol entities: Transmission Control Protocol (t c p) and User Datagram Protocol (u d p ).
Another protocol is being defined, which is targeted at the increasing transaction-oriented needs. This Protocol is called a transaction/event.
Service Control Protocol (tr a n s a c t I o n/transmission control protocol, T/T C P ).
3. Internet Layer
The Internet layer of I P V 4 consists of the protocols and processes required for communication between two hosts. This means that the data packet must be
It is routable. The Internet layer (I p) is responsible for data packet routing.
The Internet layer must also support other routing management functions. It must provide resolution and
Reverse resolution. These features are provided by one-on-one protocol for I p, as discussed in chapter 5th.
The Internet layer must support routing and routing management. These functions are provided by external peer-to-peer protocols.
By agreement. These protocols include the Internal Gateway Protocol (I g P) and the external Gateway Protocol (e g P), which are identified as peer-to-peer.
It is important because they reside at the network layer, but are not inherent in the I p protocol components. In fact, there are many ways
The protocol can discover and compute routes in the Multi-Route Protocol address structure. Example package of the routing protocol used for other address Structures
Including I p x and a p L E TA L K.
4. network access layer
The network access layer provides all functions for physical connection and transmission. The o s I model divides this layer of functionality into two layers: physical
Layer and data link layer. Since it is created after the same name protocol, the t c p/I p Reference model combines two layers because of various
The I p protocol is terminated on the Internet layer. I p assumes that all underlying functions are provided by LAN or serial port connection.
9.1.2 protocol components
Although it is generally identified as "t c p/I p", there are several different protocols in the I p protocol component. Including:
• IP-Internet protocol.
• TCP-reliable host-to-host layer protocol.
• UDP-best-effort forwarding of the host to the host layer protocol.
• ICMP-multi-layer protocols designed to control, test, and manage functions in the I p network.
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Various I c m p protocols extend from the host layer to the process/application layer. The relationship between these protocols is 9-2.
Note that applications resident in the process/Application Layer (such as te l n e t, f t p, and many other applications) must be considered as I p protocol.
Components are inherent components. However, since these are applications rather than protocols, they are not in this Chapter
Discussion.
Figure 9-2 TCP/IP is actually a protocol group, not just a protocol
9.2 understand Internet Protocol (IP)
The I p Protocol has become the most important Internet protocol in the world. Because the I p Protocol is open, others such as o s I,
A p l e ta l k, and even I p x will eventually be eliminated by I p. The function of I p is defined by the data in the I p header structure. I p header structure and functions,
It is most defined by a series of R f c documents and a series of documents published when I e t f was created. R f c 7 9 1 published in September,
This is the basic documentation for today's I p version.
I p has been evolving, thanks to the unremitting efforts of I e t f. Many new features and functions are available in subsequent R f c documents.
Expansion, however, all of these are built on the basis of r f c 7 9 1. In terms of structure, the current I p version is 4. New Version
6. almost completed. However, only I P V 4 is the current standard and is widely accepted. For more information about I P V 6, see chapter 0.
9.2.1 IPv4 Structure
Figure 9-3 shows the I p header structure and the size of each domain. The I p header has the following fields:
• The first four digits in the version-I p header identify the operation version of I p, such as version 4 or version 6.
• Internet header length-the following four digits in the header include the header length, in the unit of 3 or 2 digits.
• Service type-one of the following bytes contains a series of labels that ensure priority (compared with other I p reports
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Application Protocol
(F t p. h t p, etc)
Application Protocol
(T f t p. d n s, n f s, etc)
T c p I c m p U D p
I p
Data link layer and Physical Layer
Absolute priority), latency, throughput, and number of packets. The priority indicates three characters long, and the delay,
Throughput and reliability indicate each 1-bit length. The remaining two are reserved for future use.
Figure 9-3 The IP header structure shows the functional domains supported by many IP addresses
• Total length-the total length of a packet, in bytes, of a 1-6-bit domain. The maximum valid value range is
65 535 bytes.
• ID (I d e n t I f I e r)-each I p packet is assigned a unique one-6-bit identifier to identify the segmentation of the datagram.
• Fragmentation flag-the next domain contains three 1-bit flag that identifies whether a packet can be segmented.
And whether these domains are used. The first part is retained and always set to 0. The second part identifies whether the packet can be segmented. If this
0 indicates that the content can be segmented. If it is equal to 1, it cannot be segmented. The third digit is only 0 in the second digit.
. If this bit is equal to 0 (data can be divided into multiple packets), this bit identifies whether this packet is a series
The last segment of the column, or whether the receiving application still wants more segments. 0 indicates that the message is the last one.
• Fragment off e S t-the 8-bit domain indicates the offset of the segmented packet to the beginning of the entire packet. This
The number of values increases progressively in 6 4 bits.
• T l-I p packets cannot be permanently roaming in the wide area network. It must be limited to a certain t l. 8
The t l of BITs adds 1 to each hop. After reaching its maximum limit, packets are considered to be unreachable.
Then an I c m p packet is generated and sent back to the source machine. messages that cannot be forwarded are discarded.
• Protocol-eight-bit protocols that indicate I p headers, such as V I n e s, t C P, and U D p.
• Checksum (c h e c k s u m)-the checksum is a 6-Bit Error Detection domain. Each gateway on the target machine and network must be reinstalled.
Calculate the checksum of the packet header, just like what the same machine does. If the data has not been changed
The results should be the same. This domain also notifies the target host of the amount of data received.
• Source I p address-source computer I P address.
• Destination I p address-destination computer I P address.
• Fill-to ensure that the length of the I p header is an integer multiple of three or two digits, fill in an additional 0.
These header fields indicate that the Internet layer of I P V 4 is not connected: the forwarding device in the network can freely determine the packets transmitted through the network.
. It also does not provide any upper-layer protocols such as the response, throttling, and ordering functions provided by t c p. Neither can I p.
It is used to guide the data in the I p packet to the correct target application. These functions are left to upper-layer protocols, such as t c p and u d p.
9.2.2 What do IP addresses do?
The I p packet header contains all necessary information that makes some important network functions possible, including:
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4-digit
IP version
Current No.
3-bit Optimization
Level 1
1 positive
Regular & low
Latency
1 positive
Regular & high
Throughput
1 positive
Regular & high
Reliable bit
Dual warranty
Stay
4-digit Header
Length
2 bytes
Total packets
Length
Two bytes
Unique report
Text mark
Two bytes
Checksum
Domain
Three
Segmentation
Flag
One word
Segment
Offset Field
One byte
Survival
Inter-Domain
One byte
Protocol mark
Recognition Domain
Four bytes
Destination
Address
Four bytes
Source Address
Variable
Long fill
Charge
Word
Server
Service
Type label
Zhi
• Addressing and Routing
• Segmentation and restructuring
• Data corruption detection and correction during transmission
1. Addressing and Routing
One of the most obvious features of I p is that it can send packets to a specific destination. Connect the vrouters in the source and destination Networks
Use the destination I P address to determine the optimal network path.
Similarly, the I p packet also includes the source machine address. The source address appears because the target machine may communicate with the source machine.
2. Segmentation and reorganization
Sometimes a segment of application data cannot be completely included in an I p packet; they must be segmented into two or more packets.
When a segment occurs, I p must be able to restructure the packet (no matter how many packets need to reach their destination ).
The important point is that the source and target machines must understand and follow the same Segmentation Data Process. Otherwise, the reorganization is to report
It is impossible to divide text forwarding into multiple segments. When the data is restored to the same format on the source machine
Successfully reorganized. The segment marker in the I p header identifies the segment data.
Note that the data for reorganizing segments is very different from the data for unordered frames that are re-ordered. Re-sorting is TCP
Function.
3. Damage message Compensation
The last major function of I p is to detect and compensate messages that are damaged or lost during transmission. There are many ways
One packet can be damaged: radio frequency interference (R f I) and electromagnetic interference (e m I) are two obvious interference factors.
When a packet arrives at the destination in a different bit mode from the source machine when it is created, it is deemed that the packet is damaged.
There are many causes for packet loss. Network Congestion will lead to packet t l timeout and the packet t l timeout is detected.
The device will simply discard the packets. In another case, the packet is subject to e m I or R f I interference, which may make the header information uninterested.
. In this case, packets will also be discarded.
When messages cannot be forwarded or are unavailable, the router must notify the source machine. The I p header contains the I P address of the source machine.
It is possible to know the source machine. Although I p does not include the retransmission mechanism, a notification to the source host may cause retransmission.
Machines play an important role.
4. IP conclusion
Despite these features, you must acknowledge that I p is only an Internet Protocol. In order to make it play a role, it must be in line with the Transport Association
(Layer 4 in o s I) and the data link layer protocol (Layer 2 in the o s I Reference Model) work together. Although this book does not discuss data links
But the rest of this chapter will discuss two transport protocols that depend on the I p connection. They are t c p and u d p.
9.3 understand the Transmission Control Protocol (TCP)
T c p is the transport layer protocol (Layer 4 in the o s I Reference Model). It uses I p to provide reliable application data transmission. T C P
Establish link-oriented communication between two or more hosts. T c p supports multi-data stream operations and provides throttling and error control,
It even completes the re-sorting of unordered incoming packets. The transfer control protocol is also implemented through a series of publicly published I e t f documents.
. This repeated development process reached the vertices when r f c 7 9 3 was published in September, along with the rfc791 IP address,
Rfc793 TCP has been continuously expanded over the past 8 years, but this work has not been fully completed. Therefore, r f c's internal
Only the core content of t c p is retained.
9.3.1 TCP Header Structure
Like I p, the function of T C P is limited by the information carried in its header. Therefore, understanding the mechanisms and functions of t c p requires understanding
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Content in the t c p header. Figure 9-4 shows the t c p header structure and the size of each field.
Figure 9-4 The TCP Header structure shows the fields on which TCP can work normally.
The t c p protocol header consists of at least 2 0 bytes, including the following fields:
• T c p Source Port-1 6-bit source port domain contains the initial communication port number. The function of the source port and the source I P address is
Identifies the return address of the message.
• T c p destination port-1 6-bit destination port domain defines the purpose of transmission. This port indicates the message receiving computer.
Application address interface.
• T c p serial number-3 two-digit serial number is used by the receiver computer, and the packet of the segment is restructured into the initial form. In Motion
Some packets in the status routing network may use different routes, so the packets will arrive in disorder. This serial number
The domain can compensate for inconsistencies during transmission.
• T c p response no.-t c p uses a 3-2-bit response (a c k) domain to identify the first byte of the next packet to be received.
It is not intuitive to respond to something that has not happened, but the source computer that receives the c k message will know that the specified segment has
Received. The number that identifies each a c k is the serial number of the Response Message. This field is only available when the c k flag is set.
Valid.
• Data offset-This 4-bit field contains the size of the t c p header, in units of 3 2-bit data structure or "word.
• Reserved-6-bit constant 0 domain. Define new usage reserved for the future.
• Flag-6-digit flag domain, each of which can enable a control function. These six marks are: emergency sign,
Indicates the response mark, push, reset connection mark, synchronize serial number mark, and complete data sending mark. These signs,
U r G, a c k, p s h, r s t, s y n, and f I n are arranged sequentially. Considering their previous advantages
Can be described, the meaning of these signs is easy to understand.
• Window size-the destination uses a 6-bit domain to tell the source host the size of each tb c p data segment it wants to receive.
• The Checksum-t c p header also contains a one-6-bit error check domain-"checksum" domain. Source host computing based on data content
A value. The target host must perform the same calculation. If the received content has not been changed, two calculation results are returned.
It should be exactly the same, which proves the validity of the data.
• Emergency-the Emergency pointer field is an optional 1-6-bit pointer pointing to the last byte position in the segment, which only
Valid only when the u r g flag is set. If the u r g flag is not set, the emergency domain is filled. Source and purpose
Devices in the network between hosts must accelerate the processing of data segments marked as emergency.
• Option-the variable length domain ID Option with at least one byte (if any) is valid. If no option is available
The one-byte field equals 0, indicating the end Of the option field. If this byte is equal to 1, no operation is required. Value 2 indicates the following
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Two bytes
T c p Source
Port Number
Two bytes
U d p object
Port
No.
Four bytes
T c p Shun
Serial number
4 bytes
T c p answer
Application No.
4-digit
Data bias
Shift
Six bits
Zhi
6-digit warranty
Stay
Two words
Window
Large ports
Small
Two bytes
Checksum
Domain
Two words
Tight connection
Urgent
Needle
Option
Domain (most
1-Character
Section)
Variable
Long fill
Charge
1 digit
F I n
1-bit
Step
1 digit
R S T
1 digit
P S H
1 digit
A C K
1 digit
U r g
The four bytes include the maximum segment length (maximum segment size, m s) of the source machine ). M s is the data domain
The maximum data volume, source and target machines, must be consistent.
• Data-Technically speaking, it is not part of the t c p header, recognizing that the application data segment is in the emergency pointer and/or option field
But before filling in the domain, it is very important. The domain size is the maximum ms, and Ms can be used on the source and target machines.
Negotiation. The data segment may be smaller than m s, but it cannot be larger than m s.
• Fill-unlike what its name implies, fills always exist for mathematical purposes in data communication. The purpose is
Ensure Space predictability; timing and standard size. Add extra zeros to this domain to ensure that the t c p header is 3 or 2 bits.
Integer multiple.
9.3.2 what does TCP do?
T c p plays several important roles in communication sessions. It can be considered as a connection between multiple applications and networks. Its Merits
Can include:
• Multiplexing of multiple application data.
• Test the integrity of the received data.
• Sequentially receives data in disorder.
• Respond to successfully received data.
• Rate-Adaptive Traffic Control (via t c p window size ).
• Timing function.
• Retransmission of corrupted or lost data during transmission.
1. multiplexing data streams
T c p is the interface between your application and many network communication protocols. Because, in fact, no one has heard that t c p is limited
Therefore, t c p must be able to receive multiple application data at the same time. t c p packages them into data segments and then transmits them
To I p. Similarly, t c p must be able to receive data from multiple applications at the same time.
T c p must track the application that records the incoming packets to be forwarded. This can be achieved through the port. Therefore, the source
It is very useful to reach an agreement on the universal application port set between the machine and the target machine. Unfortunately there are so many running on I p
In fact, some form of consistency cannot be achieved for the ports corresponding to these applications. Therefore, I a n A, that is, the current
The I c A N is accelerating the standardization of at least some available port numbers.
Many applications are common, so they are widely known, which can simplify the tasks of I C A N. In this way,
I c a n can assign port numbers to these applications. Any user can expect the host that can process I p packets to recognize them.
The listener port examples include:
• Port 8 0 (Hypertext Transfer Protocol, h t p ).
• Port 11 9 (network news transmission protocol, n t p ).
• Port 6 9 (plain text file transfer protocol, t f t p ).
Because there are 1 0 2 4 well-known ports (from 0 to 1 0 2 3), it is impossible to list them all. T c p and u d p
For a complete list of worker ports, see r f c 1 7 0 0.
If you note that the port domain contains a one-6-bit binary number. Therefore, there are 65 535 possible ports
. And 0 ~ 1 0 2 3 is a common port. A port number larger than 1 0 2 3 is usually called a high port number. For high ports
No. I c A N is not managed. Therefore, I p should not be excluded from non-well-known applications for communication. They can be selected
Any high port number is used for communication.
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In Section t c p, both the source application port number and the target port number are available. Another commonly used term is socket, although T C P
There is no socket field in the header. A socket is composed of the specific application port number residing on the host and the machine I P address. Therefore,
Socket describes the unique host and application. ":" Separates two numbers. For example, socket 1 0. 1. 1 9: 6 6 6 identifies the master
The application on Host 1 0. 1. 1. 1 9. Its port number is 6 6 6 (d o m port number ).
2. Test Data Integrity
The data encapsulated in the t c p segment is computed by t c p and the result is put in the validation and domain of the t c p header. I
Once the data arrives at the destination, the same mathematical calculation is performed on the received data. The resulting result should be the same as that stored in the t c p header.
Results are the same. If the two are the same, there is reason to believe that the data has not been changed. Otherwise, a request must be sent to the source host.
It resends a copy of the data.
3. Sort again
The packets arriving at the destination are often out of order. There are many reasons, such
In the network, the routing protocol is likely to select different routes through the network for packets. This will cause the data segment to arrive in disorder. Another
In this case, packets may be lost or damaged during transmission. Therefore, the data sequence required to receive the application is discarded.
The t c p protocol of the target machine caches the received data segments until they are correctly re-ordered.
You can complete this task by checking the serial number field in the t c p header. The re-sorting is based on the received data of this domain pair.
Mathematical sorting of segments.
4. Traffic Control
The source and target machines in the t c p session are called peer entities. Each pair of equal entities has streaming data to their physical buffer.
. Traffic control uses the t c p window size. The window size of the source and target machines communicates with each other through the t c p header.
When any host is drowned by the received data, the rate of the sender is reduced. This can be done by notifying the new window size
If the server buffer is fully filled, it will send a response message about the last received data.
The window size is 0. This will effectively stop sending until the congested machine can clear its buffer. Each
A section must be answered. You can use the response to reset the window size greater than 0 to start sending.
Although this simple mechanism can effectively adjust the data streams between two machines, it can only ensure the communication end
Will not be lost by the received data. The window size does not consider the network congestion. Network Congestion
The arrival time of the message to the destination is longer than normal. Therefore, congestion management must be a function of network time. T c p passed
The use of timers enables congestion management.
5. Timing Mechanism
T c p uses timing control for several key functions. Each time a data segment is transmitted, a timer is set. Assume that
When the timer stops before receiving the response (that is, to 0), the data segment is considered to have been lost. Therefore, it will be re-transmitted. Timing
You can indirectly manage network congestion by slowing down the transmission rate when timeout occurs. Theoretically, when timeout occurs
Therefore, t c p cannot manage network congestion well, but it will reduce its impact on congestion.
The source machine periodically queries the maximum window size of the target host using a persistence (p e r s I s t) timer. In ideal world
The p e r s I s t timer is never required because each response contains the window size. However, sometimes the network is indeed lost
Data. If a buffer overflow problem occurs on a machine and a zero-window response is returned, the transmission node stops sending messages.
Send. However, if the response in non-zero window size in the descending order is lost, the sending session will be in a dangerous situation. P e r s I s t timer passed
Periodic query window size to ensure that this situation does not occur. If the query still cannot get the window size, t c p protocol
Will reset the connection.
Another timing mechanism is called Maximum Segment life time (m s l ). M s l enables t c p machines
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It identifies the replaced datagram that has been transmitted over the network for a long time and receives the aborted Ms.
Abandoned.
6. Receive response
If a c k is set, the target t c p machine must connect to the received data to make a response. Considering that t c p is almost
It is always used in reliable mode, so it is rare that a c k is not set.
The unresponded data segment is considered to have been lost during transmission and re-transmitted. Retransmission must be performed on the source and target machines
.
9.4 understand User Datagram Protocol (UDP)
The User Datagram Protocol is another host-to-host layer protocol of I p (corresponding to the transport layer of the o s I Reference Model ). U d p lift
For a basic, low-latency data transmission. To understand that u d p is such a simple protocol, the reader
You only need to compare the r f c 7 6 8 (u d p function, initial Specification Description of data structure and mechanism) with other r f c.
R f c 7 6 8 short content: only 3 pages long. In other R f c documents, three pages can only contain content tables!
The simplicity of u d p makes u d p not suitable for some applications, but provides link-oriented functions for others that are more complex and self-contained.
Is suitable. Other situations that may use u d p include: data exchange in the forwarding route table, system information, and network monitoring.
Control data exchange. These types of switching do not require throttling, response, rescheduling, or any functionality provided by t c p.
9.4.1 UDP header Structure
Figure 9-5 shows the structure of the u d p header and the size of each domain:
Figure 9-5 The UDP header structure shows the simplicity of UDP forms and functions
The u d p protocol header has the following structure:
• U d p Source Port-1 6-bit source port is the connection number on the source computer. Source Port and source I P address as the packet
Return address.
• U d p destination port number-1 6-bit destination port number is the connection number on the destination host. The destination port number is used
The packets of the target machine are forwarded to the correct application.
• U d p checksum-checksum is a one-6-bit error check domain, which is calculated based on the message content. Destination computer
Execute the same mathematical computation on the source host. The difference between the two calculated values indicates that the message encountered an error during transmission.
• U d p information length-Information length field 1 6 characters long, tell the target computer information size. This domain is calculated for the purpose
Another mechanism is provided to verify the effectiveness of information.
9.4.2 what can UDP do?
Very few! U d p is designed as a valid and minimal transport protocol. This is directly reflected in its header structure. It
Only include sufficient information used to forward data packets to an appropriate application (port number) and perform certain error checks.
U d p does not provide any advanced features supported by t c p. No Timing Mechanism, flow control or congestion management mechanism, response,
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Two-byte u d p Source
Port Number
2-byte u d p objective
Port Number
Two-byte checksum and two-byte message
Message Length
Accelerated transmission of emergency data, or any other function. U d p transfers the datagram in the best way possible. Transmission for some reason
Failed. The datagram is discarded and is not re-transmitted.
9.4.3 TCP and UDP
T c p and u d p are different transport layer protocols designed to do different things. The commonality between the two is that I p is used as its
Network Layer Protocol. The main difference between t c p and u d p is reliability. T c p is highly available, while u d p is a simple
Single, best-effort datagram forwarding protocol. This basic difference implies that t c p is more complex and requires a large amount of functional overhead. However
U d p is simple and efficient.
U d p is often considered unreliable because it does not have any reliability mechanism of t c p. U d p is not reliable because
It does not have the receiving and Response Mechanism of t c p, the order of arrival data in disorder, or even the connection to receive damaged packets
Retransmission mechanism. That is to say, u d p does not guarantee that the data will arrive at the target end without being damaged! Therefore, u d p is most suitable for sending small messages.
(That is, separate packets) t c p is more suitable for scenarios where data is divided into multiple packets and the data stream needs to be adjusted.
It is necessary to make a compromise between the reliability of u d p and the advantages of u d p. U d p is a small, resource-saving transport layer protocol.
Its operation is much faster than t c p. Therefore, it is suitable for emerging time-related applications such
Audio and real-time visual meetings.
U d p can also be well applied to other network functions, such as updating the transmission route table between routers or the transmission network
Manage/monitor data. Although these functions are critical to the operability of the network, if reliable t c p transmission is used
This mechanism has a negative impact on the network. Unreliable protocols do not mean that u d p is useless protocol, it only means that the design uses
To support different application types.
Conclusion 9.5
T c p/I p protocol components (including u d p and I c m p) are suitable for fast-growing user and application communication for nearly 2 0 years. That
These protocols have been constantly updated to keep up with the evolving pace of technology and meet the requirements of I n t e r n t from semi-private research machines
To meet the evolving needs of public commercial facilities.
I n t e r n e t commercialization has brought unprecedented growth in I n t e r n t users. In turn, this also causes more addresses and new
I n t e r n e t service type needs. Therefore, the lack of I P V 4 prompted people to develop a new Protocol version. The new version is called I p.
Version 6 (I p v 6), but often referred to as the Internet Protocol: the Next Generation (I p n g ). I P V 6 will be discussed in detail in chapter 0.
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