CS计算机代考程序代写 scheme dns DHCP ITE PC v4.0 Chapter 1

ITE PC v4.0 Chapter 1

Week 8:
IP Addressing- IPv4
Introduction to Networks

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Cisco Networking Academy program
Introduction to Networks
Chapter 8: IP Addressing

Chapter 8
Introduction
IPv4 Network Addresses
Connectivity Verification
Summary

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Chapter 8 Sections

Chapter 8: Objectives
Upon completion of this chapter, you will be able to:
Describe the structure of an IPv4 address.
Describe the purpose of the subnet mask.
Compare the characteristics and uses of the unicast, broadcast, and multicast IPv4 addresses.
Configure global unicast addresses.
Describe multicast addresses.
Use ping and traceroute utilities to test network connectivity.

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3. Chapter 8 Objectives
IP Addressing
Introduction
Addressing is a key function of network layer protocols that enables data communication between hosts, regardless of whether the hosts are on the same network or on different networks. Both Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6) provide hierarchical addressing for packets that carry data.
Designing, implementing and managing an effective IP addressing plan ensures that networks can operate effectively and efficiently.
This chapter examines in detail the structure of IP addresses and their application to the construction and testing of IP networks and subnetworks.

8.1 IPv4 Network Addresses

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8.1 IPv4 Network Addresses

IPv4 Address Structure
Binary Number System

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6/ 8.1.1.2 Binary Number System
IPv4 Network Addresses
IPv4 Address Structure
In IPv4, addresses are 32-bit binary numbers. However, for ease of use by people, binary patterns representing IPv4 addresses are expressed as dotted decimals. This is first accomplished by separating each byte (8 bits) of the 32-bit binary pattern, called an octet, with a dot. It is called an octet because each decimal number represents one byte or 8 bits.
The binary address:
11000000 10101000 00001010 00001010
is expressed in dotted decimal as:
192.168.10.10
In Figure 1, select each button to see how the 32-bit binary address is represented in dotted decimal octets.
But how are the actual decimal equivalents determined?
Binary Numbering System
In the binary numbering system, the radix is 2. Therefore, each position represents increasing powers of 2. In 8-bit binary numbers, the positions represent these quantities:
2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0
128 64 32 16 8 4 2 1
The base 2 numbering system only has two digits: 0 and 1.
When we interpret a byte as a decimal number, we have the quantity that position represents if the digit is a 1 and we do not have that quantity if the digit is a 0, as shown in Figure 1.
Figure 2 illustrates the representation of the decimal number 192 in binary. A 1 in a certain position means we add that value to the total. A 0 means we do not add that value. The binary number 11000000 has a 1 in the 2^7 position (decimal value 128) and a 1 in the 2^6 position (decimal value 64). The remaining bits are all 0 so we do not add the corresponding decimal values. The result of adding 128+64 is 192, the decimal equivalent of 11000000.
Here are two more examples:
Example 1: An octet containing all 1s: 11111111
A 1 in each position means that we add the value for that position to the total. All 1s means that the values of every position are included in the total, therefore, the value of all 1s in an octet is 255.
128 + 64 + 32 + 16 + 8 + 4 + 2 + 1 = 255
Example 2: An octet containing all 0s: 00000000
A 0 in each position indicates that the value for that position is not included in the total. A 0 in every position yields a total of 0.
0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0
A different combination of ones and zeros will yield a different decimal value.

IPv4 Address Structure
Converting a Binary Address to Decimal
Practice

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7/ 8.1.1.3 Converting a Binary Address to Decimal
IPv4 Network Addresses
IPv4 Address Structure
Each octet is made up of 8 bits and each bit has a value, either 0 or 1. The four groups of 8 bits have the same set of valid values in the range of 0 to 255 inclusive. The value of each bit placement, from right to left is 1, 2, 4, 8, 16, 32, 64, and 128.
Determine the value of the octet by adding the values of positions wherever there is a binary 1 present.
If there is a 0 in a position, do not add the value.
If all 8 bits are 0s, 00000000, the value of the octet is 0.
If all 8 bits are 1s, 11111111, the value of the octet is 255 (128+64+32+16+8+4+2+1)
If the 8 bits are mixed, the values are added together. For example, the octet 00100111 has a value of 39 (32+4+2+1).
So the value of each of the four octets can range from 0 to a maximum of 255.
Using the 32-bit IPv4 address, 11000000101010000000101000001010, convert the binary representation to dotted decimal using the following steps:
Step 1. Divide the 32 bits into 4 octets.
Step 2. Convert each octet to decimal.
Step 3. Add a “dot” between each decimal.
Click Play in the figure to see how a binary address is converted to dotted decimal.

IPv4 Address Structure
Converting a Binary Address to Decimal
Practice

Answer = 176
Answer = 255

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8.1.1.3 Converting a Binary Address to Decimal

IPv4 Address Structure
Converting a Binary Address to Decimal

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9/ Section 8.1.1.3 & 8.1.1.4 Converting a Binary Address to Decimal

104
Radix 2 2 2 2 2 2 2 2
Exponent 7 6 5 4 3 2 1 0
Position 128 64 32 16 8 4 2 1
Bit 0 1 1 0 1 0 0 0

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IPv4 Address Structure
Converting from Decimal to Binary (Cont.)

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12/ 8.1.1.6 Converting from Decimal to Binary (Cont.)
IPv4 Network Addresses
IPv4 Address Structure
Follow the conversion steps in the figures to see how an IP address is converted to binary.
Figure 1: Convert 192 to binary.
Figure 2: Convert 168 to binary.
Figure 3: Convert 10 to binary.
Figure 4: Convert 10 to binary.
Figure 5: Combine the converted octets beginning with the first octet.

Cisco Games to Learn Binary Numbering
Binary Game
https://learningnetwork.cisco.com/docs/DOC-1803

Mobile Download
https://learningnetwork.cisco.com/docs/DOC-11119

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IPv4 Subnet Mask
Network Portion and Host Portion of an IPv4 Address
To define the network and host portions of an address, a devices use a separate 32-bit pattern called a subnet mask

The subnet mask does not actually contain the network or host portion of an IPv4 address, it just says where to look for these portions in a given IPv4 address

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14/ 8.1.2.1 Network Portion and Host Portion of an IPv4 Address
IPv4 Network Addresses
IPv4 Subnet Mask
Understanding binary notation is important when determining if two hosts are in the same network. Recall that an IP address is a hierarchical address that is made up of two parts: a network portion and a host portion. But when determining the network portion versus the host portion, it is necessary to look, not at the decimal value, but at the 32-bit stream. Within the 32-bit stream, a portion of the bits makes up the network and a portion of the bits makes up the host.
The bits within the network portion of the address must be identical for all devices that reside in the same network. The bits within the host portion of the address must be unique to identify a specific host within a network. Regardless of whether the decimal numbers between two IPv4 addresses match up, if two hosts have the same bit-pattern in the specified network portion of the 32-bit stream, those two hosts will reside in the same network.
But how do hosts know which portion of the 32-bits is network and which is host? That is the job of the subnet mask.
When an IP host is configured, a subnet mask is assigned along with an IP address. Like the IP address, the subnet mask is 32 bits long. The subnet mask signifies which part of the IP address is network and which part is host.
The subnet mask is compared to the IP address from left to right, bit for bit. The 1s in the subnet mask represent the network portion; the 0s represent the host portion. As shown in Figure 1, the subnet mask is created by placing a binary 1 in each bit position that represents the network portion and placing a binary 0 in each bit position that represents the host portion. Note that the subnet mask does not actually contain the network or host portion of an IPv4 address, it just tells the computer where to look for these portions in a given IPv4 address.
Similar to IPv4 addresses, the subnet mask is represented in dotted decimal format for ease of use. The subnet mask is configured on a host device, in conjunction with the IPv4 address, and is required so the host can determine which network it belongs to. Figure 2 displays the valid subnet masks for an IPv4 octet.

IPv4 Subnet Mask
Network Portion and Host Portion of an IPv4 Address (cont.)

Valid Subnet Masks

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15/ 8.1.2.1 Network Portion and Host Portion of an IPv4 Address (cont.)
IPv4 Network Addresses
IPv4 Subnet Mask
Network Prefixes
The prefix length is another way of expressing the subnet mask. The prefix length is the number of bits set to 1 in the subnet mask. It is written in “slash notation”, a “/” followed by the number of bits set to 1. For example, if the subnet mask is 255.255.255.0, there are 24 bits set to 1 in the binary version of the subnet mask, so the prefix length is 24 bits or /24. The prefix and the subnet mask are different ways of representing the same thing – the network portion of an address.
Networks are not always assigned a /24 prefix. Depending on the number of hosts on the network, the prefix assigned may be different. Having a different prefix number changes the host range and broadcast address for each network.
The figures illustrate different prefixes using the same 10.1.1.0 address. Figure 1 illustrates /24 to /26 prefixes. Figure 2 illustrates /27 to /28 prefixes.
Notice that the network address could remain the same, but the host range and the broadcast address are different for the different prefix lengths. In the figures, you can see that the number of hosts that can be addressed on the network also changes.

IPv4 Subnet Mask
Examining the Prefix Length

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16/ 8.1.2.2 Examining the Prefix Length
IPv4 Network Addresses
IPv4 Subnet Mask
Network Prefixes
The prefix length is another way of expressing the subnet mask. The prefix length is the number of bits set to 1 in the subnet mask. It is written in “slash notation”, a “/” followed by the number of bits set to 1. For example, if the subnet mask is 255.255.255.0, there are 24 bits set to 1 in the binary version of the subnet mask, so the prefix length is 24 bits or /24. The prefix and the subnet mask are different ways of representing the same thing – the network portion of an address.
Networks are not always assigned a /24 prefix. Depending on the number of hosts on the network, the prefix assigned may be different. Having a different prefix number changes the host range and broadcast address for each network.
The figures illustrate different prefixes using the same 10.1.1.0 address. Figure 1 illustrates /24 to /26 prefixes. Figure 2 illustrates /27 to /28 prefixes.
Notice that the network address could remain the same, but the host range and the broadcast address are different for the different prefix lengths. In the figures, you can see that the number of hosts that can be addressed on the network also changes.

IPv4 Subnet Mask
Examining the Prefix Length (cont.)

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17/ 8.1.2.2 Examining the Prefix Length (cont.)
IPv4 Network Addresses
IPv4 Subnet Mask
Network Prefixes
The prefix length is another way of expressing the subnet mask. The prefix length is the number of bits set to 1 in the subnet mask. It is written in “slash notation”, a “/” followed by the number of bits set to 1. For example, if the subnet mask is 255.255.255.0, there are 24 bits set to 1 in the binary version of the subnet mask, so the prefix length is 24 bits or /24. The prefix and the subnet mask are different ways of representing the same thing – the network portion of an address.
Networks are not always assigned a /24 prefix. Depending on the number of hosts on the network, the prefix assigned may be different. Having a different prefix number changes the host range and broadcast address for each network.
The figures illustrate different prefixes using the same 10.1.1.0 address. Figure 1 illustrates /24 to /26 prefixes. Figure 2 illustrates /27 to /28 prefixes.
Notice that the network address could remain the same, but the host range and the broadcast address are different for the different prefix lengths. In the figures, you can see that the number of hosts that can be addressed on the network also changes.

IPv4 Subnet Mask
IPv4 Network, Host, and Broadcast Address

10.1.1.0/24

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18/ 8.1.2.3 IPv4 Network, Host and Broadcast Address
IPv4 Network Addresses
IPv4 Subnet Mask
There are three types of addresses within the address range of each IPv4 network:
Network address
Host addresses
Broadcast address
Network Address
The network address is a standard way to refer to a network. The subnet mask or the prefix length might also be used when referring to network address. For example, the network shown in Figure 1 could be referred to as the 10.1.1.0 network, the 10.1.1.0 255.255.255.0 network or the 10.1.1.0/24 network. All hosts in the 10.1.1.0/24 network will have the same network portion bits.
As shown in Figure 2, within the IPv4 address range of a network, the first address is reserved for the network address. This address has a 0 for each host bit in the host portion of the address. All hosts within the network share the same network address.
Host Address
Every end device requires a unique address to communicate on the network. In IPv4 addresses, the values between the network address and the broadcast address can be assigned to end devices in a network. As shown in Figure 3, this address has any combination of 0 and 1 bits in the host portion of the address but cannot contain all 0 bits or all 1 bits.
Broadcast Address
The IPv4 broadcast address is a special address for each network that allows communication to all the hosts in that network. To send data to all hosts in a network at once, a host can send a single packet that is addressed to the broadcast address of the network, and each host in the network that receives this packet will process its contents.
The broadcast address uses the highest address in the network range. This is the address in which the bits in the host portion are all 1s. All 1s in an octet in binary form, is equal to the number 255 in decimal form. Therefore, as shown in Figure 4, for the network 10.1.1.0/24, in which the last octet is used for the host portion, the broadcast address would be 10.1.1.255. Note that the host portion will not always be an entire octet. This address is also referred to as the directed broadcast.

IPv4 Subnet Mask
First Host and Last Host Addresses

10.1.1.0/24

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19/ 8.1.2.4 First Host and Last Host Addresses
IPv4 Network Addresses
IPv4 Subnet Mask
To ensure that all hosts within a network are assigned a unique IP address within that network range, it is important to identify the first host address and the last host address. Hosts within a network can be assigned IP addresses within this range.
First Host Address
As seen in Figure 1, the host portion of the first host address will contain all 0 bits with a 1 bit for the lowest order or right-most bit. This address is always one greater than the network address. In this example the first host address on the 10.1.1.0/24 network is 10.1.1.1. It is common in many addressing schemes to use the first host address for the router or default gateway address.
Last Host Address
The host portion of the last host address will contain all 1 bits with a 0 bit for the lowest order or right-most bit. This address is always one less than the broadcast address. As seen in Figure 2, the last host address on the 10.1.1.0/24 network is 10.1.1.254.

IPv4 Subnet Mask
Bitwise AND Operation
1 AND 1 = 1 1 AND 0 = 0 0 AND 1 = 0 0 AND 0 = 0

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20/ 8.1.2.5 and 8.1.2.6 Bitwise AND Operation/Importance of ANDing
IPv4 Network Addresses
IPv4 Subnet Mask
To ensure that all hosts within a network are assigned a unique IP address within that network range, it is important to identify the first host address and the last host address. Hosts within a network can be assigned IP addresses within this range.
First Host Address
As seen in Figure 1, the host portion of the first host address will contain all 0 bits with a 1 bit for the lowest order or right-most bit. This address is always one greater than the network address. In this example the first host address on the 10.1.1.0/24 network is 10.1.1.1. It is common in many addressing schemes to use the first host address for the router or default gateway address.
Last Host Address
The host portion of the last host address will contain all 1 bits with a 0 bit for the lowest order or right-most bit. This address is always one less than the broadcast address. As seen in Figure 2, the last host address on the 10.1.1.0/24 network is 10.1.1.254.
20/ 8.1.2.6
IPv4 Network Addresses
IPv4 Subnet Mask
Any address bit ANDed with a 1 bit value from the subnet mask will yield the original bit value from the address. So, a 0 (from the IPv4 address) AND 1 (from the subnet mask) is 0. 1 (from the IPv4 address) AND 1(from the subnet mask) is 1. Consequently, anything ANDed with a 0 yields a 0. These properties of ANDing are used with the subnet mask to “mask” the host bits of an IPv4 address. Each bit of the address is ANDed with the corresponding bit of the subnet mask.
Because all the bits of the subnet mask that represent host bits are 0s, the host portion of the resulting network address becomes all 0s. Recall that an IPv4 address with all 0s in the host portion represents the network address.
Likewise, all the bits of the subnet mask that indicate network portion are 1s. When each of these 1s is ANDed with the corresponding bit of the address, the resulting bits are identical to the original address bits.
As shown in the figure, the 1 bits in the subnet mask will result in the network portion of the network address having the same bits as the network portion of the host. The host portion of the network address will result in all 0s.
For a given IP address and its subnet, ANDing can be used to determine what subnetwork the address belongs to, as well as what other addresses belong to the same subnet. Remember that if two addresses are in the same network or subnetwork, they are considered to be local to each other and can therefore communicate directly with each other. Addresses that are not in the same network or subnetwork are considered to be remote to each other and must therefore have a Layer 3 device (like a router or Layer 3 switch) between them to communicate.
In network verification/troubleshooting, we often need to determine two hosts are on the same local network. We need to make this determination from the perspective of the network devices. Due to improper configuration, a host may see itself on a network that was not the intended one. This can create an operation that seems erratic unless diagnosed by examining the ANDing processes used by the host.

IPv4 Unicast, Broadcast, and Multicast
Assigning a Static IPv4 Address to a Host
LAN Interface Properties
Configuring a Static IPv4 Address

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21/ 8.1.3.1 Assigning a Static IPv4 Address to a Host
IPv4 Network Addresses
IPv4 Unicast, Broadcast, and Multicast
Addresses for User Devices
In most data networks, the largest population of hosts includes the end devices such as PCs, tablets, smartphones, printers, and IP phones. Because this represents the largest number of devices within a network, the largest number of addresses should be allocated to these hosts. These hosts are assigned IP addresses from the range of available addresses in the network. These IP addresses can be assigned either statically or dynamically.
Static Assignment
With a static assignment, the network administrator must manually configure the network information for a host. Figure 1 shows the window for the network adapter properties. To configure a static IPv4 address, choose IPv4 on the network adapter screen, then key in the static address, subnet mask, and default gateway. Figure 2 shows the minimum static configuration: the host IP address, subnet mask, and default gateway.
There are several advantages to static addressing. For instance, they are useful for printers, servers, and other networking devices that do not change location often and need to be accessible to clients on the network based on a fixed IP address. If hosts normally access a server at a particular IP address, it would cause problems if that address changed. Additionally, static assignment of addressing information can provide increased control of network resources. For example, it is possible to create access filters based on traffic to and from a specific IP address. However, static addressing can be time-consuming to enter on each host.
When using static IP addressing, it is necessary to maintain an accurate list of the IP address assigned to each device. These are permanent addresses and are not normally reused.

IPv4 Unicast, Broadcast, and Multicast
Assigning a Dynamic IPv4 Address to a Host
DHCP – The preferred method of assigning IPv4 addresses to hosts on large networks because it reduces the burden on network support staff and virtually eliminates entry errors.

Verification

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22/ 8.1.3.2 Assigning a Dynamic IPv4 Address to a Host

IPv4 Network Addresses
IPv4 Unicast, Broadcast, and Multicast
Dynamic Assignment
On local networks it is often the case that the user population changes frequently. New users arrive with laptops and need a connection. Others have new workstations or other network devices, such as smart phones, that need to be connected. Rather than have the network administrator assign IP addresses for each workstation, it is easier to have IP addresses assigned automatically. This is done using a protocol known as Dynamic Host Configuration Protocol (DHCP), as shown in Figure 1.
DHCP enables the automatic assignment of addressing information such as IP address, subnet mask, default gateway, and other configuration information. The configuration of the DHCP server requires that a block of addresses, called an address pool, is used for assigning to the DHCP clients on a network. Addresses assigned to this pool should be planned so that they exclude any static addresses used by other devices.
DHCP is generally the preferred method of assigning IPv4 addresses to hosts on large networks because it reduces the burden on network support staff and virtually eliminates entry errors.
Another benefit of DHCP is that an address is not permanently assigned to a host but is only “leased” for a period of time. If the host is powered down or taken off the network, the address is returned to the pool for reuse. This feature is especially helpful for mobile users that come and go on a network.
If DCHP is enabled on a host device, the ipconfig command can be used to view the IP address information assigned by the DHCP server, as shown in Figure 2.

IPv4 Unicast, Broadcast, and Multicast
Unicast Transmission
#1 Unicast – the process of sending a packet from one host to an individual host.

In an IPv4 network, the hosts can communicate one of three different ways:
Unicast, Broadcast, and Multicast

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23/ 8.1.3.3 Unicast Transmission
IPv4 Network Addresses
IPv4 Unicast, Broadcast, and Multicast
In an IPv4 network, the hosts can communicate one of three ways:
Unicast – The process of sending a packet from one host to an individual host
. As with all three three types of communication, the IPv4 address of the originating host is placed in the packet header as the source address

Unicast Traffic
Unicast communication is used for normal host-to-host communication in both a client/server and a peer-to-peer network. Unicast packets use the addresses of the destination device as the destination address and can be routed through an internetwork.
Play the animation to see an example of unicast transmission.
In an IPv4 network, the unicast addresses applied to an end device is referred to as the host address. For unicast communication, the addresses assigned to the two end devices are used as the source and destination IPv4 addresses. During the encapsulation process, the source host places its IPv4 address in the unicast packet header as the source address and the IPv4 address of the destination host in the packet header as the destination address. Regardless of whether the destination specified a packet is a unicast, broadcast or multicast; the source address of any packet is always the unicast address of the originating host.
Note: In this course, all communications between devices is unicast communication unless otherwise noted.
IPv4 host addresses are unicast addresses and are in the address range of 0.0.0.0 to 223.255.255.255. However, within this range are many addresses that are reserved for special purposes. These special purpose addresses will be discussed later in this chapter.

IPv4 Unicast, Broadcast, and Multicast
Broadcast Transmission
In an IPv4 network, the hosts can communicate one of three different ways: Unicast, Broadcast, and Multicast.

NOTE: Routers do not forward a limited broadcast!
Directed broadcast
Destination 172.16.4.255
Hosts within the 172.16.4.0/24 network

#2 Broadcast – the process of sending a packet from one host to all hosts in the network.
Directed broadcast
Destination 172.16.4.255
Hosts within the 172.16.4.0/24 network

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24/ 8.1.3.4 Broadcast Transmission
Broadcast – The process of sending a packet from one host to all hosts in the network

As with all three three types of communication, the IPv4 address of the originating host is placed in the packet header as the source address
IPv4 Network Addresses
IPv4 Unicast, Broadcast, and Multicast
Broadcast Transmission
Broadcast traffic is used to send packets to all hosts in the network using the broadcast address for the network. With a broadcast, the packet contains a destination IP address with all ones (1s) in the host portion. This means that all hosts on that local network (broadcast domain) will receive and look at the packet. Many network protocols, such as DHCP, use broadcasts. When a host receives a packet sent to the network broadcast address, the host processes the packet as it would a packet addressed to its unicast address.
Some examples for using broadcast transmission are:
Mapping upper layer addresses to lower layer addresses
Requesting an address
Unlike unicast, where the packets can be routed throughout the internetwork, broadcast packets are usually restricted to the local network. This restriction is dependent on the configuration of the gateway router and the type of broadcast. There are two types of broadcasts: directed broadcast and limited broadcast.
Directed Broadcast
A directed broadcast is sent to all hosts on a specific network. This type of broadcast is useful for sending a broadcast to all hosts on a non-local network. For example, for a host outside of the 172.16.4.0/24 network to communicate with all of the hosts within that network, the destination address of the packet would be 172.16.4.255. Although routers do not forward directed broadcasts by default, they may be configured to do so.
Limited Broadcast
The limited broadcast is used for communication that is limited to the hosts on the local network. These packets always use a destination IPv4 address 255.255.255.255. Routers do not forward a limited broadcast. For this reason, an IPv4 network is also referred to as a broadcast domain. Routers form the boundary for a broadcast domain.
As an example, a host within the 172.16.4.0/24 network would broadcast to all hosts in its network using a packet with a destination address of 255.255.255.255.
Play the animation to see an example of a limited broadcast transmission.
When a packet is broadcast, it uses resources on the network and causes every receiving host on the network to process the packet. Therefore, broadcast traffic should be limited so that it does not adversely affect performance of the network or devices. Because routers separate broadcast domains, subdividing networks with excessive broadcast traffic can improve network performance.

IPv4 Unicast, Broadcast, and Multicast
Multicast Transmission
#3 Multicast – The process of sending a packet from one host to a selected group of hosts, possibly in different networks.
Reduces traffic
Reserved for addressing multicast groups – 224.0.0.0 to 239.255.255.255.
Link local – 224.0.0.0 to 224.0.0.255 (Example: routing information exchanged by routing protocols)
Globally scoped addresses – 224.0.1.0 to 238.255.255.255 (Example: 224.0.1.1 has been reserved for Network Time Protocol)

In an IPv4 network, the hosts can communicate one of three different ways: Unicast, Broadcast, and Multicast.

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25/ 8.1.3.5 Multicast Transmission

Multicast – The process of sending a packet from one host to a selected group of hosts, possibly in different networks
As with all three three types of communication, the IPv4 address of the originating host is placed in the packet header as the source address

Multicast transmission is designed to conserve the bandwidth of an IPv4 network. It reduces traffic by allowing a host to send a single packet to a selected set of hosts that are part of a subscribing multicast group. To reach multiple destination hosts using unicast communication, a source host would need to send an individual packet addressed to each host. With multicast, the source host can send a single packet that can reach thousands of destination hosts. The internetwork’s responsibility is to replicate the multicast flows in an efficient manner so that they reach only their intended recipients.
Some examples of multicast transmission are:
Video and audio broadcasts
Routing information exchange by routing protocols
Distribution of software
Remote gaming
Multicast Addresses
IPv4 has a block of addresses reserved for addressing multicast groups. This address range is 224.0.0.0 to 239.255.255.255. The multicast address range is subdivided into different types of addresses: reserved link local addresses and globally scoped addresses. One additional type of multicast address is the administratively scoped addresses, also called limited scope addresses.
The IPv4 multicast addresses 224.0.0.0 to 224.0.0.255 are reserved link local addresses. These addresses are to be used for multicast groups on a local network. A router connected to the local network recognizes that these packets are addressed to a link-local multicast group and never forwards them further. A typical use of reserved link-local addresses is in routing protocols using multicast transmission to exchange routing information.
The globally scoped addresses are 224.0.1.0 to 238.255.255.255. They may be used to multicast data across the Internet. For example, 224.0.1.1 has been reserved for the Network Time Protocol (NTP) to synchronize the time-of-day clocks of network devices.
Multicast Clients
Hosts that receive particular multicast data are called multicast clients. The multicast clients use services requested by a client program to subscribe to the multicast group.
Each multicast group is represented by a single IPv4 multicast destination address. When an IPv4 host subscribes to a multicast group, the host processes packets addressed to this multicast address and packets addressed to its uniquely allocated unicast address.
The animation demonstrates clients accepting multicast packets.

Types of IPv4 Address
Public and Private IPv4 Addresses
Private address blocks are:
Hosts that do not require access to the Internet can use private addresses
10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
192.168.0.0 to 192.168.255.255 (192.168.0.0/16)

Shared address space addresses:
Not globally routable
Intended only for use in service provider networks
Address block is 100.64.0.0/10

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IPv4 Network Addresses
Types of IPv4 Addresses
Although most IPv4 host addresses are public addresses designated for use in networks that are accessible on the Internet, there are blocks of addresses that are used in networks that require limited or no Internet access. These addresses are called private addresses.
Private Addresses
The private address blocks are:
10.0.0.0 to 10.255.255.255 (10.0.0.0/8)
172.16.0.0 to 172.31.255.255 (172.16.0.0/12)
192.168.0.0 to 192.168.255.255 (192.168.0.0/16)
Private addresses are defined in RFC 1918, Address Allocation for Private Internets, and are sometimes referred to as RFC 1918 addresses. Private space address blocks, as shown in the figure, are used in private networks. Hosts that do not require access to the Internet can use private addresses. However within the private network, hosts still require unique IP addresses within the private space.
Hosts in different networks may use the same private space addresses. Packets using these addresses as the source or destination should not appear on the public Internet. The router or firewall device at the perimeter of these private networks must block or translate these addresses. Even if these packets were to make their way to the Internet, the routers would not have routes to forward them to the appropriate private network.
In RFC 6598, IANA reserved another group of addresses known as shared address space. Similar to RFC 1918 private address space, shared address space addresses are not globally routable. However, these addresses are intended only for use in service provider networks. The shared address block is 100.64.0.0/10.
Public Addresses
The vast majority of the addresses in the IPv4 unicast host range are public addresses. These addresses are designed to be used in the hosts that are publicly accessible from the Internet. Even within these IPv4 address blocks, there are many addresses that are designated for other special purposes.

Types of IPv4 Address
Special Use IPv4 Addresses
Network and Broadcast addresses – within each network the first and last addresses cannot be assigned to hosts
Loopback address – 127.0.0.1 a special address that hosts use to direct traffic to themselves (addresses 127.0.0.0 to 127.255.255.255 are reserved)
Link-Local address – 169.254.0.0 to 169.254.255.255 (169.254.0.0/16) addresses can be automatically assigned to the local host
TEST-NET addresses – 192.0.2.0 to 192.0.2.255 (192.0.2.0/24) set aside for teaching and learning purposes, used in documentation and network examples
Experimental addresses – 240.0.0.0 to 255.255.255.254 are listed as reserved

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There are certain addresses that cannot be assigned to hosts. There are also special addresses that can be assigned to hosts, but with restrictions on how those hosts can interact within the network.
Network and Broadcast Addresses
As explained earlier, within each network the first and last addresses cannot be assigned to hosts. These are the network address and the broadcast address, respectively.
Loopback
One such reserved address is the IPv4 loopback address 127.0.0.1. The loopback is a special address that hosts use to direct traffic to themselves. The loopback address creates a shortcut method for TCP/IP applications and services that run on the same device to communicate with one another. By using the loopback address instead of the assigned IPv4 host address, two services on the same host can bypass the lower layers of the TCP/IP stack. You can also ping the loopback address to test the configuration of TCP/IP on the local host.
Although only the single 127.0.0.1 address is used, addresses 127.0.0.0 to 127.255.255.255 are reserved. Any address within this block will loop back to the local host. No address within this block should ever appear on any network.
Link-Local Addresses
IPv4 addresses in the address block 169.254.0.0 to 169.254.255.255 (169.254.0.0/16) are designated as link-local addresses. These addresses can be automatically assigned to the local host by the operating system in environments where no IP configuration is available. These might be used in a small peer-to-peer network or for a host that could not automatically obtain an address from a DHCP server.
Communication using IPv4 link-local addresses is only suitable for communication with other devices connected to the same network, as shown in the figure. A host must not send a packet with an IPv4 link-local destination address to any router for forwarding and should set the IPv4 time to live (TTL) for these packets to 1.
Link-local addresses do not provide services outside of the local network. However, many client/server and peer-to-peer applications will work properly with IPv4 link-local addresses.
TEST-NET Addresses
The address block 192.0.2.0 to 192.0.2.255 (192.0.2.0/24) is set aside for teaching and learning purposes. These addresses can be used in documentation and network examples. Unlike the experimental addresses, network devices will accept these addresses in their configurations. You may often find these addresses used with the domain names example.com or example.net in RFCs, vendor, and protocol documentation. Addresses within this block should not appear on the Internet.
Experimental Addresses
The addresses in the block 240.0.0.0 to 255.255.255.254 are listed as reserved for future use (RFC 3330). Currently, these addresses can only be used for research or experimentation purposes, but cannot be used in an IPv4 network. Though, according to RFC 3330, they could, technically, be converted to usable addresses in the future.

Types of IPv4 Address
Legacy Classful Addressing

See if updated graphic with top row in text case for consistency.

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Historically, RFC1700, Assigned Numbers, grouped the unicast ranges into specific sizes called class A, class B, and class C addresses. It also defined class D (multicast) and class E (experimental) addresses, as previously presented. The unicast address classes A, B, and C defined specifically-sized networks and specific address blocks for these networks. A company or organization was assigned an entire network from class A, class B, or class C address block. This use of address space is referred to as classful addressing.
Class A Blocks
A class A address block was designed to support extremely large networks with more than 16 million host addresses. Class A IPv4 addresses used a fixed /8 prefix with the first octet to indicate the network address. The remaining three octets were used for host addresses. All class A addresses required that the most significant bit of the high-order octet be a zero. This meant that there were only 128 possible class A networks, 0.0.0.0/8 to 127.0.0.0/8. Even though the class A addresses reserved one-half of the address space, because of their limit of 128 networks, they could only be allocated to approximately 120 companies or organizations.
Class B Blocks
Class B address space was designed to support the needs of moderate to large size networks with up to approximately 65,000 hosts. A class B IP address used the two high-order octets to indicate the network address. The other two octets specified host addresses. As with class A, address space for the remaining address classes needed to be reserved. For class B addresses, the most significant two bits of the high-order octet were 10. This restricted the address block for class B to 128.0.0.0/16 to 191.255.0.0/16. Class B had slightly more efficient allocation of addresses than class A because it equally divided 25% of the total IPv4 address space among approximately 16,000 networks.
Class C Blocks
The class C address space was the most commonly available of the historic address classes. This address space was intended to provide addresses for small networks with a maximum of 254 hosts. Class C address blocks used a /24 prefix. This meant that a class C network used only the last octet as host addresses with the three high-order octets used to indicate the network address. Class C address blocks set aside address space by using a fixed value of 110 for the three most significant bits of the high-order octet. This restricted the address block for class C from 192.0.0.0/24 to 223.255.255.0/24. Although it occupied only 12.5% of the total IPv4 address space, it could provide addresses to 2 million networks.
Figure 1 illustrates how these address classes are divided.
Limits to the Class-based System
Not all organizations’ requirements fit well into one of these three classes. Classful allocation of address space often wasted many addresses, which exhausted the availability of IPv4 addresses. For example, a company that had a network with 260 hosts would need to be given a class B address with more than 65,000 addresses.
Even though this classful system was all but abandoned in the late 1990s, you will see remnants of it in networks today. For example, when you assign an IPv4 address to a computer, the operating system examines the address being assigned to determine if this address is a class A, class B, or class C. The operating system then assumes the prefix used by that class and makes the default subnet mask assignment.

Types of IPv4 Address
Legacy Classful Addressing (cont.)
Classless Addressing
Formal name is Classless Inter-Domain Routing (CIDR, pronounced “cider
Created a new set of standards that allowed service providers to allocate IPv4 addresses on any address bit boundary (prefix length) instead of only by a class A, B, or C address

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Classless Addressing
The system in use today is referred to as classless addressing. The formal name is Classless Inter-Domain Routing (CIDR, pronounced “cider”). The classful allocation of IPv4 addresses was very inefficient, allowing for only /8, /16 or /24 prefix lengths, each from a separate address space. In 1993, the IETF created a new set of standards that allowed service providers to allocate IPv4 addresses on any address bit boundary (prefix length) instead of only by a class A, B, or C address.
The IETF knew that CIDR was only a temporary solution and that a new IP protocol would have to be developed to accommodate the rapid growth in the number of Internet users. In 1994, the IETF began its work to find a successor to IPv4, which eventually became IPv6.
Figure 2 shows the classful address ranges.

Types of IPv4 Address
Assignment of IP Addresses

Regional Internet Registries (RIRs)

For a company or organization to have network hosts, such as web servers, accessible from the Internet, that organization must have a block of public addresses assigned. Remember that public addresses must be unique, and use of these public addresses is regulated and allocated to each organization separately. This is true for IPv4 and IPv6 addresses.
IANA and RIRs
Internet Assigned Numbers Authority (IANA) (http://www.iana.org) manages the allocation of IPv4 and IPv6 addresses. Until the mid-1990s, all IPv4 address space was managed directly by the IANA. At that time, the remaining IPv4 address space was allocated to various other registries to manage for particular purposes or for regional areas. These registration companies are called Regional Internet Registries (RIRs), as shown in the figure.
The major registries are:
AfriNIC (African Network Information Centre) – Africa Region http://www.afrinic.net
APNIC (Asia Pacific Network Information Centre) – Asia/Pacific Region http://www.apnic.net
ARIN (American Registry for Internet Numbers) – North America Region http://www.arin.net
LACNIC (Regional Latin-American and Caribbean IP Address Registry) – Latin America and some Caribbean Islands http://www.lacnic.net
RIPE NCC (Reseaux IP Europeans) – Europe, the Middle East, and Central Asia http://www.ripe.net
ISPs
RIRs are responsible for allocating IP addresses to the Internet Service Providers (ISPs). Most companies or organizations obtain their IPv4 address blocks from an ISP. An ISP will generally supply a small number of usable IPv4 addresses (6 or 14) to their customers as a part of their services. Larger blocks of addresses can be obtained based on justification of needs and for additional service costs.
In a sense, the ISP loans or rents these addresses to the organization. If we choose to move our Internet connectivity to another ISP, the new ISP will provide us with addresses from the address blocks that have been provided to them, and our previous ISP returns the blocks loaned to us to their allocation to be loaned to another customer.
IPv6 addresses can be obtained from the ISP or in some cases directly from the RIR. IPv6 addresses and typical address block sizes will be discussed later in this chapter.

Types of IPv4 Address
Assignment of IP Addresses (Cont.)

Tier 2 ISPs generally focus on business customers.
Tier 3 ISPs purchase their Internet service from Tier 2 ISPs.
Tier 3 ISPs often bundle Internet connectivity as a part of network and computer service contracts for their customers.
ISPs are large national or international ISPs that are directly connected to the Internet backbone.

ISP Services
To get access to the services of the Internet, we have to connect our data network to the Internet using an Internet Service Provider (ISP).
ISPs have their own set of internal data networks to manage Internet connectivity and to provide related services. Among the other services that an ISP generally provides to its customers are DNS services, email services, and a website. Depending on the level of service required and available, customers use different tiers of an ISP.
ISP Tiers
ISPs are designated by a hierarchy based on their level of connectivity to the Internet backbone. Each lower tier obtains connectivity to the backbone via a connection to a higher tier ISP, as shown in the figures.
Tier 1
As shown in Figure 1, at the top of the ISP hierarchy are Tier 1 ISPs. These ISPs are large national or international ISPs that are directly connected to the Internet backbone. The customers of Tier 1 ISPs are either lower-tiered ISPs or large companies and organizations. Because they are at the top of Internet connectivity, they engineer highly reliable connections and services. Among the technologies used to support this reliability are multiple connections to the Internet backbone.
The primary advantages for customers of Tier 1 ISPs are reliability and speed. Because these customers are only one connection away from the Internet, there are fewer opportunities for failures or traffic bottlenecks. The drawback for Tier 1 ISP customers is its high cost.
Tier 2
As shown in Figure 2, Tier 2 ISPs acquire their Internet service from Tier 1 ISPs. Tier 2 ISPs generally focus on business customers. Tier 2 ISPs usually offer more services than the other two tiers of ISPs. These Tier 2 ISPs tend to have the IT resources to operate their own services such as DNS, email servers, and web servers. Other services that Tier 2 ISPs may offer include website development and maintenance, e-commerce/e-business, and VoIP.
The primary disadvantage of Tier 2 ISPs, as compared to Tier 1 ISPs, is slower Internet access. Because Tier 2 ISPs are at least one more connection away from the Internet backbone, they also tend to have lower reliability than Tier 1 ISPs.
Tier 3
As shown in Figure 3, Tier 3 ISPs purchase their Internet service from Tier 2 ISPs. The focus of these ISPs is the retail and home markets in a specific locale. Tier 3 customers typically do not need many of the services required by Tier 2 customers. Their primary need is connectivity and support.
These customers often have little or no computer or network expertise. Tier 3 ISPs often bundle Internet connectivity as a part of network and computer service contracts for their customers. While they may have reduced bandwidth and less reliability than Tier 1 and Tier 2 providers, they are often good choices for small to medium size companies.

Connectivity Verification

ICMP
ICMP (Internet Control Message Protocol)
ICMP messages common to both ICMPv4 and ICMPv6 include:
Host confirmation
Destination or Service Unreachable
Time exceeded
Route redirection
Although IP is not a reliable protocol, the TCP/IP suite does provide for messages to be sent in the event of certain errors, sent using the services of ICMP.

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Connectivity Verification
ICMP
Although IP is not a reliable protocol, the TCP/IP suite does provide for messages to be sent in the event of certain errors. These messages are sent using the services of ICMP. The purpose of these messages is to provide feedback about issues related to the processing of IP packets under certain conditions, not to make IP reliable. ICMP messages are not required and are often not allowed within a network for security reasons.
ICMP is available for both IPv4 and IPv6. ICMPv4 is the messaging protocol for IPv4. ICMPv6 provides these same services for IPv6 but includes additional functionality. In this course, the term ICMP will be used when referring to both ICMPv4 and ICMPv6.
The types of ICMP messages, and the reasons why they are sent, are extensive. We will discuss some of the more common messages.
ICMP messages common to both ICMPv4 and ICMPv6 include:
Host confirmation
Destination or Service Unreachable
Time exceeded
Route redirection
Host Confirmation
An ICMP Echo Message can be used to determine if a host is operational. The local host sends an ICMP Echo Request to a host. If the host is available, the destination host responds with an Echo Reply. In the figure, click the Play button to see an animation the ICMP Echo Request/Echo Reply. This use of the ICMP Echo messages is the basis of the ping utility.
Destination or Service Unreachable
When a host or gateway receives a packet that it cannot deliver, it can use an ICMP Destination Unreachable message to notify the source that the destination or service is unreachable. The message will include a code that indicates why the packet could not be delivered.
Some of the Destination Unreachable codes for ICMPv4 are:
0 – net unreachable.
1 – host unreachable.
2 – protocol unreachable.
3 – port unreachable.
Note: ICMPv6 has similar but slightly different codes for Destination Unreachable messages.
Time Exceeded
An ICMPv4 Time Exceeded message is used by a router to indicate that a packet cannot be forwarded because the Time to Live (TTL) field of the packet was decremented to 0. If a router receives a packet and decrements the TTL field in the IPv4 packet to zero, it discards the packet and sends a Time Exceeded message to the source host.
ICMPv6 also sends a Time Exceeded message if the router cannot forward an IPv6 packet because the packet has expired. IPv6 does not have a TTL field; it uses the hop limit field to determine if the packet has expired.
Route Redirection
A router may use the ICMP Redirect Message to notify the hosts on a network that a better route is available for a particular destination. This message may only be used when the source host is on the same physical network as both gateways.
Both ICMPv4 and ICMPv6 use route redirection messages.

Testing and Verification
Ping – Testing the Local Stack

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Connectivity Verification
Testing and Verification
Ping is a testing utility that uses ICMP echo request and echo reply messages to test connectivity between hosts. Ping works with both IPv4 and IPv6 hosts.
To test connectivity to another host on a network, an echo request is sent to the host address using the ping command. If the host at the specified address receives the echo request, it responds with an echo reply. As each echo reply is received, ping provides feedback on the time between when the request was sent and when the reply was received. This can be a measure of network performance.
Ping has a timeout value for the reply. If a reply is not received within the timeout, ping provides a message indicating that a response was not received. This usually indicates that there is a problem, but could also indicate that security features blocking ping messages have been enabled on the network.
After all the requests are sent, the ping utility provides a summary that includes the success rate and average round-trip time to the destination.
Pinging the Local Loopback
There are some special testing and verification cases for which we can use ping. One case is for testing the internal configuration of IPv4 or IPv6 on the local host. To perform this test, we ping the local loopback address of 127.0.0.1 for IPv4 (::1 for IPv6). Testing the IPv4 loopback is shown in the figure.
A response from 127.0.0.1 for IPv4, or ::1 for IPv6, indicates that IP is properly installed on the host. This response comes from the network layer. This response is not, however, an indication that the addresses, masks, or gateways are properly configured. Nor does it indicate anything about the status of the lower layer of the network stack. This simply tests IP down through the network layer of IP. If we get an error message, it is an indication that TCP/IP is not operational on the host.

Testing and Verification
Ping – Testing Connectivity to the Local LAN

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Connectivity Verification
Testing and Verification
You can also use ping to test the ability of a host to communicate on the local network. This is generally done by pinging the IP address of the gateway of the host. A ping to the gateway indicates that the host and the router interface serving as the gateway are both operational on the local network.
For this test, the gateway address is most often used, because the router is normally always operational. If the gateway address does not respond, a ping can be sent to the IP address of another host on the local network that is known to be operational.
If either the gateway or another host responds, then the local host can successfully communicate over the local network. If the gateway does not respond but another host does, this could indicate a problem with the router interface serving as the gateway.
One possibility is that the wrong gateway address has been configured on the host. Another possibility is that the router interface may be fully operational but have security applied to it that prevents it from processing or responding to ping requests.

Testing and Verification
Ping – Testing Connectivity to Remote

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887/ .3.2.3 Ping – Testing Connectivity to Remote
Connectivity Verification
Testing and Verification
Ping can also be used to test the ability of a local host to communicate across an internetwork. The local host can ping an operational IPv4 host of a remote network, as shown in the figure.
If this ping is successful, the operation of a large piece of the internetwork can be verified. A successful ping across the internetwork confirms communication on the local network, the operation of the router serving as our gateway, and the operation of all other routers that might be in the path between the local network and the network of the remote host.
Additionally, functionality of the remote host can be verified. If the remote host could not communicate outside of its local network, it would not have responded.
Note: Many network administrators limit or prohibit the entry of ICMP messages into the corporate network; therefore, the lack of a ping response could be due to security restrictions.

Testing and Verification
Traceroute – Testing the Path
Traceroute
Generates a list of hops that were successfully reached along the path.
Provides important verification and troubleshooting information.
If the data reaches the destination, then the trace lists the interface of every router in the path between the hosts.
If the data fails at some hop along the way, the address of the last router that responded to the trace can provide an indication of where the problem or security restrictions are found.
Provides round-trip time for each hop along the path and indicates if a hop fails to respond.

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Connectivity Verification
Testing and Verification
Ping is used to test connectivity between two hosts, but doesn’t provide information about the details of devices between the hosts. Traceroute (tracert) is a utility that generates a list of hops that were successfully reached along the path. This list can provide important verification and troubleshooting information. If the data reaches the destination, then the trace lists the interface of every router in the path between the hosts. If the data fails at some hop along the way, the address of the last router that responded to the trace can provide an indication of where the problem or security restrictions are found.
Round Trip Time (RTT)
Using traceroute provides round trip time for each hop along the path and indicates if a hop fails to respond. The round trip time is the time a packet takes to reach the remote host and for the response from the host to return. An asterisk (*) is used to indicate a lost or unreplied packet.
This information can be used to locate a problematic router in the path. If the display shows high response times or data losses from a particular hop, this is an indication that the resources of the router or its connections may be stressed.
IPv4 Time-to-Live (TTL) and IPv6 Hop Limit
Traceroute makes use of a function of the TTL field in IPv4 and the Hop Limit field in IPv6 in the Layer 3 headers, along with the ICMP time exceeded message.
Play the animation in the figure to see how Traceroute takes advantage of TTL.
The first sequence of messages sent from traceroute will have a TTL field value of 1. This causes the TTL to time out the IPv4 packet at the first router. This router then responds with an ICMPv4 message. Traceroute now has the address of the first hop.
Traceroute then progressively increments the TTL field (2, 3, 4…) for each sequence of messages. This provides the trace with the address of each hop as the packets timeout further down the path. The TTL field continues to be increased until the destination is reached or it is incremented to a predefined maximum.
Once the final destination is reached, the host responds with either an ICMP port unreachable message or an ICMP echo reply message instead of the ICMP time exceeded message.

Traceroute – Testing the Path

Ping is used to test connectivity between two hosts but does not provide information about the details of devices between the hosts.
Traceroute (tracert) is a utility that generates a list of hops that were successfully reached along the path.
If the data reaches the destination, then the trace lists the interface of every router in the path between the hosts.
If the data fails at some hop along the way, the address of the last router that responded to the trace can provide an indication of where the problem or security restrictions are found.

Traceroute – Testing the Path
Traceroute works by making use of
the TTL field in IPv4 and the Hop Limit field in IPv6 headers,
the ICMP time exceeded message.

The first sequence of messages sent from traceroute have TTL = 1  time out the IPv4 packet at the 1st router.
This router then responds with an ICMPv4 time exceeded message. Traceroute now has the address of the first hop.

Traceroute then progressively increments the TTL field (2, 3, 4…) for each sequence of messages.
This provides the trace with the address of each hop as the packets timeout further down the path.

The TTL field continues to be increased until the destination is reached, or it is incremented to a predefined maximum.

After the final destination is reached, the host responds with either an ICMP port unreachable message or an ICMP echo reply message

Traceroute – Testing the Path

IP Addressing
Summary
IP addresses are hierarchical with network, subnetwork, and host portions.
An IP address can represent a complete network, a specific host, or the broadcast address of the network.
The subnet mask or prefix is used to determine the network portion of an IP address. Once implemented, an IP network needs to be tested to verify its connectivity and operational performance.
DHCP enables the automatic assignment of addressing information such as IP address, subnet mask, default gateway, and other configuration information.

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Summary
Summary
The Internet of Everything…Naturally!
In this chapter, you learned about how small to medium-sized businesses are connected to networks in groups. The Internet of Everything was also introduced in the beginning modeling activity.
For this activity, choose one of the following:
Online banking
World news
Weather forecasting/climate
Traffic conditions
Devise an IPv6 addressing scheme for the area you chose. Include in your addressing scheme how you would plan for:
Subnetting
Unicasts
Multicasts
Broadcasts
Keep a copy of your scheme to share with the class or learning community. Be prepared to explain:
How subnetting, unicasts, multicasts and broadcasts would be incorporated.
Where your addressing scheme could be used.
How small to medium-size businesses would be impacted by using your plan.
Class Activity – The Internet of Everything…Naturally Instructions

IP Addressing
Summary (cont.)
IPv4 hosts can communicate one of three different ways: unicast, broadcast, and multicast.
The private IPv4 address blocks are: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.
The depletion of IPv4 address space is the motivating factor for moving to IPv6.
Each IPv6 address has 128 bits verses the 32 bits in an IPv4 address.
The prefix length is used to indicate the network portion of an IPv6 address using the following format: IPv6 address/prefix length.

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Summary
Summary
IP addresses are hierarchical with network, subnetwork, and host portions. An IP address can represent a complete network, a specific host, or the broadcast address of the network.
Understanding binary notation is important when determining if two hosts are in the same network. The bits within the network portion of the IP address must be identical for all devices that reside in the same network. The subnet mask or prefix is used to determine the network portion of an IP address. IP addresses can be assigned either statically or dynamically. DHCP enables the automatic assignment of addressing information such as IP address, subnet mask, default gateway, and other configuration information.
IPv4 hosts can communicate one of three different ways: unicast, broadcast, and multicast. Also, blocks of addresses that are used in networks that require limited or no Internet access are called private addresses. The private IPv4 address blocks are: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.
The depletion of IPv4 address space is the motivating factor for moving to IPv6. Each IPv6 address has 128 bits verses the 32 bits in an IPv4 address. IPv6 does not use the dotted-decimal subnet mask notation. The prefix length is used to indicate the network portion of an IPv6 address using the following format: IPv6 address/prefix length.
There are three types of IPv6 addresses: unicast, multicast, and anycast. An IPv6 link-local address enables a device to communicate with other IPv6-enabled devices on the same link and only on that link (subnet). Packets with a source or destination link-local address cannot be routed beyond the link from where the packet originated. IPv6 link-local addresses are in the FE80::/10 range.
ICMP is available for both IPv4 and IPv6. ICMPv4 is the messaging protocol for IPv4. ICMPv6 provides the same services for IPv6 but includes additional functionality.
After it is implemented, an IP network needs to be tested to verify its connectivity and operational performance.

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