IP addressing involves assigning unique addresses to devices on a network. The document discusses:
- The structure of IP addresses and how they are represented in dotted decimal notation.
- The limitations of the original classful IP address system and how subnetting and CIDR were developed to address these issues by allowing more flexible assignment of address prefixes.
- How IP Version 6 was created to replace IPv4 and expand the available address space as IPv4 addresses were becoming exhausted.
this is a presentationon ip and cidr.pptBlackHat41
The document discusses IP addressing and related concepts. It covers the structure of IP addresses, classful IP addresses and their limitations, subnetting to add hierarchy and flexibility, and CIDR which abandons classes and allows arbitrary prefix lengths to improve efficiency and reduce routing tables. It also mentions IPv6 which was developed to replace IPv4 due to its limited 32-bit address space.
The document discusses IP addresses and IPv6 addresses. It provides information on the structure of IP addresses, subnetting, CIDR notation, and IPv6 addressing. Some key points include:
- An IP address identifies a device on a network and has two parts - a network prefix and host number. Subnetting splits the host number into a subnet number and smaller host number.
- CIDR notation specifies the length of the network prefix to efficiently allocate address space. IPv6 addresses are 128-bit for a huge number of available addresses compared to IPv4.
- IPv6 introduces new address types like multicast for groups and anycast to select one group member. Provider-based addressing allocates IPv6
IP addresses are a unique identifier for devices connected to a network. They allow for the delivery of data packets across networks. The structure of IP addresses includes a network prefix that identifies the network and a host number that identifies the specific device. Techniques like subnetting, CIDR, and IPv6 were developed to address the limited available IPv4 address space and allow for more efficient allocation and routing of IP addresses.
The document discusses IP addressing and IPv6. It defines what an IP address is, how it is written in dotted decimal notation, and its structure including the network prefix and host number. It describes problems with the original IP address classification scheme and how subnetting and CIDR addressed these. It also summarizes IPv6, including its 128-bit address size which vastly increases the available address space compared to IPv4.
IP addresses are 32-bit identifiers that identify devices on a network. They have two parts: a network prefix that identifies the network and a host number that identifies the specific device. Subnetting and CIDR allow more efficient use of IP addresses by allowing network administrators to divide large address blocks into smaller subnets. IPv6 uses 128-bit addresses to vastly increase the available address space and introduces other changes to improve on IPv4.
The document discusses IPv4 addressing and subnetting. It begins by explaining the need for a network layer and describing IPv4 addressing fundamentals like address classes and notations. It then covers topics like subnet masks, CIDR notation, private IP ranges for NAT, and address depletion issues in IPv4. The document provides examples of subnetting Class C addresses using different subnet mask values. It also gives practice examples of subnetting Class B addresses.
IPv4 addresses are 32-bit numbers represented in dotted decimal notation with four octets separated by periods. The network portion and host portion of an address depend on its class. There are five classes: Class A has a 7-bit network ID and 24-bit host ID; Class B a 14-bit network ID and 16-bit host ID; Class C a 21-bit network ID and 8-bit host ID. Class D is for multicasting with the high-order bits set to 1110, and Class E is reserved for experimental purposes.
The document provides an overview of key concepts in the network layer, including:
- The network layer is responsible for moving data between sending and receiving endpoints by encapsulating transport segments into datagrams.
- The two main functions of the network layer are forwarding, which moves packets through routers, and routing, which determines the path packets take from source to destination.
- IP addresses are 32-bit identifiers assigned to network interfaces that allow endpoints to communicate and routers to forward packets. IP addresses use hierarchy and prefixes to scale routing across large networks like the Internet.
this is a presentationon ip and cidr.pptBlackHat41
The document discusses IP addressing and related concepts. It covers the structure of IP addresses, classful IP addresses and their limitations, subnetting to add hierarchy and flexibility, and CIDR which abandons classes and allows arbitrary prefix lengths to improve efficiency and reduce routing tables. It also mentions IPv6 which was developed to replace IPv4 due to its limited 32-bit address space.
The document discusses IP addresses and IPv6 addresses. It provides information on the structure of IP addresses, subnetting, CIDR notation, and IPv6 addressing. Some key points include:
- An IP address identifies a device on a network and has two parts - a network prefix and host number. Subnetting splits the host number into a subnet number and smaller host number.
- CIDR notation specifies the length of the network prefix to efficiently allocate address space. IPv6 addresses are 128-bit for a huge number of available addresses compared to IPv4.
- IPv6 introduces new address types like multicast for groups and anycast to select one group member. Provider-based addressing allocates IPv6
IP addresses are a unique identifier for devices connected to a network. They allow for the delivery of data packets across networks. The structure of IP addresses includes a network prefix that identifies the network and a host number that identifies the specific device. Techniques like subnetting, CIDR, and IPv6 were developed to address the limited available IPv4 address space and allow for more efficient allocation and routing of IP addresses.
The document discusses IP addressing and IPv6. It defines what an IP address is, how it is written in dotted decimal notation, and its structure including the network prefix and host number. It describes problems with the original IP address classification scheme and how subnetting and CIDR addressed these. It also summarizes IPv6, including its 128-bit address size which vastly increases the available address space compared to IPv4.
IP addresses are 32-bit identifiers that identify devices on a network. They have two parts: a network prefix that identifies the network and a host number that identifies the specific device. Subnetting and CIDR allow more efficient use of IP addresses by allowing network administrators to divide large address blocks into smaller subnets. IPv6 uses 128-bit addresses to vastly increase the available address space and introduces other changes to improve on IPv4.
The document discusses IPv4 addressing and subnetting. It begins by explaining the need for a network layer and describing IPv4 addressing fundamentals like address classes and notations. It then covers topics like subnet masks, CIDR notation, private IP ranges for NAT, and address depletion issues in IPv4. The document provides examples of subnetting Class C addresses using different subnet mask values. It also gives practice examples of subnetting Class B addresses.
IPv4 addresses are 32-bit numbers represented in dotted decimal notation with four octets separated by periods. The network portion and host portion of an address depend on its class. There are five classes: Class A has a 7-bit network ID and 24-bit host ID; Class B a 14-bit network ID and 16-bit host ID; Class C a 21-bit network ID and 8-bit host ID. Class D is for multicasting with the high-order bits set to 1110, and Class E is reserved for experimental purposes.
The document provides an overview of key concepts in the network layer, including:
- The network layer is responsible for moving data between sending and receiving endpoints by encapsulating transport segments into datagrams.
- The two main functions of the network layer are forwarding, which moves packets through routers, and routing, which determines the path packets take from source to destination.
- IP addresses are 32-bit identifiers assigned to network interfaces that allow endpoints to communicate and routers to forward packets. IP addresses use hierarchy and prefixes to scale routing across large networks like the Internet.
This document provides an introduction to IP addressing and subnetting. It discusses key topics including IP addresses and versions IPv4 and IPv6, network classes in IPv4, subnet masks, private addresses, Classless Inter-Domain Routing (CIDR), gateway addresses, and subnetting including variable length subnet masks. Examples are provided to illustrate subnetting networks and determining valid subnets, broadcast addresses, and host ranges.
CIDR was introduced to address the exhaustion of IPv4 address space and inefficient allocation of large address blocks. It allows for flexible subnet masks and routing based on the longest prefix match. IPv6 vastly expands the available address space to accommodate future growth. Packet forwarding in both protocols works by routers looking up the destination IP address in their forwarding table to determine the outgoing interface for each packet.
The document discusses classful IP addressing and subnetting. It begins by explaining classful IP addressing and its issues with flexibility, efficiency, and router table entries. It then introduces subnetting as a way to create a hierarchical network structure and better allocate addresses. The key points are that subnetting splits the host ID portion of an IP address into subnet ID and host ID bits, and that a subnet mask specifies this split and is used by routers to determine the network and subnet portions of an IP address. Examples are provided to illustrate how subnet masks are determined and how subnets, subnet addresses, and host addresses are designated for a given network address range.
IPv4 addresses identify devices on the internet and consist of 32 bits represented by 4 octets separated by periods. Addresses include a network ID and host ID portion, with the division determined by the address class (A, B, C, etc). Class A uses 8 network bits and 24 host bits, Class B uses 16 network bits and 16 host bits, and Class C uses 24 network bits and 8 host bits. Subnetting and CIDR allow networks to be further subdivided to introduce subnets and supernetting.
IP addresses have a structure that includes a network prefix and host number. Subnetting splits the host number portion into a subnet number and smaller host number, creating a three-layer IP address hierarchy of network, subnet, and host. This allows organizations to independently manage multiple internal networks while keeping subnet structure invisible externally, improving efficiency of IP address usage and reducing router complexity.
The document discusses key concepts about the network layer, including:
1) The network layer is responsible for transporting data segments from the sending host to the receiving host by encapsulating segments into datagrams. Network layer protocols exist in every host and router.
2) The main functions of the network layer are forwarding, which moves packets through routers from input to output, and routing, which determines the best path from source to destination using routing algorithms.
3) Network layers can provide either a connection-oriented service using virtual circuits, which require call setup, or a connectionless service using datagrams as in the Internet protocol.
This document provides an introduction to IPv6, including:
- IPv4 is running out of addresses due to its 32-bit size, while IPv6 uses a 128-bit address which provides vastly more addresses.
- IPv6 features include larger addresses, more efficient headers, extension headers for additional functions, and stateless autoconfiguration to simplify address assignment.
- Key changes from IPv4 include larger and more hierarchical addresses, removal of optional fields and checksums, and addition of traffic class and flow label fields.
This document provides an overview of IP addressing and subnetting concepts. It begins with an introduction to why IP addresses are written in bits and the dotted decimal notation format. It then covers why IP addresses are necessary to route data on the internet and how they incorporate network and host addresses. The document discusses classes of IP networks (A, B, C) and how many bits can be borrowed from each class to create subnets. It also defines subnet masks, network addresses, broadcast addresses, and how supernetting can expand the host field to create larger networks. The key purpose is to explain the core components of IP addressing and subnetting to understand how networks, subnets, and hosts are identified.
The document discusses IPv4 addressing and subnetting. It describes the original IPv4 classful addressing scheme which divided addresses into classes A, B, and C based on the first octet. It explains how each class defined the number of network and host bits. It then introduces subnetting which allows networks to be divided into smaller subnets using a subnet mask, and describes how this led to classless addressing with variable length subnet masks.
IPv4 and IPv6 are network layer protocols that route packets between networks through multiple hops. The network layer addresses devices, routes packets, and interconnects different subnets. Routers use routing tables to forward packets towards their destination network based on the destination address. Fragmentation allows packets to be split into smaller pieces if their size exceeds the maximum transmission unit on a link. This allows packets to traverse heterogeneous networks with different MTU sizes.
IPv4 is an internet protocol that uses 32-bit addresses divided into a network prefix and host number. Addresses are assigned by IANA and expressed in dotted decimal notation. IPv4 addresses were originally divided into classes A, B, and C but are now commonly assigned using CIDR which allows for variable length subnet masks and more efficient address space usage.
Basics of Network Layer and Transport LayerRubal Sagwal
This document provides an overview of computer networks, focusing on the network, transport, and application layers. It discusses IPv4 and IPv6 packet structure, addressing, and protocols like ICMP, IGMP, TCP, and UDP. Specifically, it examines IPv4 and IPv6 addressing schemes, packet headers, classes of addresses, subnetting, and IPv6 advantages over IPv4. It also describes functions of protocols like ICMP for error reporting and queries, and IGMP for multicast group management.
The document discusses the Internet Protocol (IP) which is the cornerstone of the TCP/IP architecture and allows all computers on the Internet to communicate. There are two main versions of IP - IPv4, the currently used version, and IPv6 which is intended to replace IPv4 and includes improvements like longer addresses. IP addresses are 32-bit for IPv4 and 128-bit for IPv6. Strategies like private addressing and Classless Inter-Domain Routing (CIDR) help conserve the limited number of available IP addresses.
This document discusses IP addresses and their structure. It covers the following key points in 3 sentences:
IP addresses have both a network prefix that identifies a network and a host number that identifies a specific device. Subnetting allows an organization to split the host number portion of an IP address into a subnet number and a smaller host number, creating a three-level address hierarchy. The traditional class-based IP address system had problems with inefficient address allocation and inflexible network sizes that motivated the development of subnetting and Classless Inter-Domain Routing (CIDR).
IP addressing and subnetting allows networks to be logically organized and divided. The key objectives covered include explaining IP address classes, configuring addresses, subnetting networks, and advanced concepts like CIDR, summarization, and VLSM. Transitioning to IPv6 is also discussed as a way to address the depletion of IPv4 addresses and improve security.
IP addresses are numeric identifiers assigned to devices connected to a network. IPv4 uses 32-bit addresses represented in dotted decimal notation, while IPv6 uses 128-bit addresses represented by 8 groups of hexadecimal digits separated by colons. IP addresses have two parts - a network portion allocated by ISPs and a host portion assigned to individual devices. IPv4 classes (A, B, C, D, E) determine how many bits are used for the network vs host portions. IPv6 supports a much larger address space and easier auto-configuration compared to IPv4.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
This document provides an introduction to IP addressing and subnetting. It discusses key topics including IP addresses and versions IPv4 and IPv6, network classes in IPv4, subnet masks, private addresses, Classless Inter-Domain Routing (CIDR), gateway addresses, and subnetting including variable length subnet masks. Examples are provided to illustrate subnetting networks and determining valid subnets, broadcast addresses, and host ranges.
CIDR was introduced to address the exhaustion of IPv4 address space and inefficient allocation of large address blocks. It allows for flexible subnet masks and routing based on the longest prefix match. IPv6 vastly expands the available address space to accommodate future growth. Packet forwarding in both protocols works by routers looking up the destination IP address in their forwarding table to determine the outgoing interface for each packet.
The document discusses classful IP addressing and subnetting. It begins by explaining classful IP addressing and its issues with flexibility, efficiency, and router table entries. It then introduces subnetting as a way to create a hierarchical network structure and better allocate addresses. The key points are that subnetting splits the host ID portion of an IP address into subnet ID and host ID bits, and that a subnet mask specifies this split and is used by routers to determine the network and subnet portions of an IP address. Examples are provided to illustrate how subnet masks are determined and how subnets, subnet addresses, and host addresses are designated for a given network address range.
IPv4 addresses identify devices on the internet and consist of 32 bits represented by 4 octets separated by periods. Addresses include a network ID and host ID portion, with the division determined by the address class (A, B, C, etc). Class A uses 8 network bits and 24 host bits, Class B uses 16 network bits and 16 host bits, and Class C uses 24 network bits and 8 host bits. Subnetting and CIDR allow networks to be further subdivided to introduce subnets and supernetting.
IP addresses have a structure that includes a network prefix and host number. Subnetting splits the host number portion into a subnet number and smaller host number, creating a three-layer IP address hierarchy of network, subnet, and host. This allows organizations to independently manage multiple internal networks while keeping subnet structure invisible externally, improving efficiency of IP address usage and reducing router complexity.
The document discusses key concepts about the network layer, including:
1) The network layer is responsible for transporting data segments from the sending host to the receiving host by encapsulating segments into datagrams. Network layer protocols exist in every host and router.
2) The main functions of the network layer are forwarding, which moves packets through routers from input to output, and routing, which determines the best path from source to destination using routing algorithms.
3) Network layers can provide either a connection-oriented service using virtual circuits, which require call setup, or a connectionless service using datagrams as in the Internet protocol.
This document provides an introduction to IPv6, including:
- IPv4 is running out of addresses due to its 32-bit size, while IPv6 uses a 128-bit address which provides vastly more addresses.
- IPv6 features include larger addresses, more efficient headers, extension headers for additional functions, and stateless autoconfiguration to simplify address assignment.
- Key changes from IPv4 include larger and more hierarchical addresses, removal of optional fields and checksums, and addition of traffic class and flow label fields.
This document provides an overview of IP addressing and subnetting concepts. It begins with an introduction to why IP addresses are written in bits and the dotted decimal notation format. It then covers why IP addresses are necessary to route data on the internet and how they incorporate network and host addresses. The document discusses classes of IP networks (A, B, C) and how many bits can be borrowed from each class to create subnets. It also defines subnet masks, network addresses, broadcast addresses, and how supernetting can expand the host field to create larger networks. The key purpose is to explain the core components of IP addressing and subnetting to understand how networks, subnets, and hosts are identified.
The document discusses IPv4 addressing and subnetting. It describes the original IPv4 classful addressing scheme which divided addresses into classes A, B, and C based on the first octet. It explains how each class defined the number of network and host bits. It then introduces subnetting which allows networks to be divided into smaller subnets using a subnet mask, and describes how this led to classless addressing with variable length subnet masks.
IPv4 and IPv6 are network layer protocols that route packets between networks through multiple hops. The network layer addresses devices, routes packets, and interconnects different subnets. Routers use routing tables to forward packets towards their destination network based on the destination address. Fragmentation allows packets to be split into smaller pieces if their size exceeds the maximum transmission unit on a link. This allows packets to traverse heterogeneous networks with different MTU sizes.
IPv4 is an internet protocol that uses 32-bit addresses divided into a network prefix and host number. Addresses are assigned by IANA and expressed in dotted decimal notation. IPv4 addresses were originally divided into classes A, B, and C but are now commonly assigned using CIDR which allows for variable length subnet masks and more efficient address space usage.
Basics of Network Layer and Transport LayerRubal Sagwal
This document provides an overview of computer networks, focusing on the network, transport, and application layers. It discusses IPv4 and IPv6 packet structure, addressing, and protocols like ICMP, IGMP, TCP, and UDP. Specifically, it examines IPv4 and IPv6 addressing schemes, packet headers, classes of addresses, subnetting, and IPv6 advantages over IPv4. It also describes functions of protocols like ICMP for error reporting and queries, and IGMP for multicast group management.
The document discusses the Internet Protocol (IP) which is the cornerstone of the TCP/IP architecture and allows all computers on the Internet to communicate. There are two main versions of IP - IPv4, the currently used version, and IPv6 which is intended to replace IPv4 and includes improvements like longer addresses. IP addresses are 32-bit for IPv4 and 128-bit for IPv6. Strategies like private addressing and Classless Inter-Domain Routing (CIDR) help conserve the limited number of available IP addresses.
This document discusses IP addresses and their structure. It covers the following key points in 3 sentences:
IP addresses have both a network prefix that identifies a network and a host number that identifies a specific device. Subnetting allows an organization to split the host number portion of an IP address into a subnet number and a smaller host number, creating a three-level address hierarchy. The traditional class-based IP address system had problems with inefficient address allocation and inflexible network sizes that motivated the development of subnetting and Classless Inter-Domain Routing (CIDR).
IP addressing and subnetting allows networks to be logically organized and divided. The key objectives covered include explaining IP address classes, configuring addresses, subnetting networks, and advanced concepts like CIDR, summarization, and VLSM. Transitioning to IPv6 is also discussed as a way to address the depletion of IPv4 addresses and improve security.
IP addresses are numeric identifiers assigned to devices connected to a network. IPv4 uses 32-bit addresses represented in dotted decimal notation, while IPv6 uses 128-bit addresses represented by 8 groups of hexadecimal digits separated by colons. IP addresses have two parts - a network portion allocated by ISPs and a host portion assigned to individual devices. IPv4 classes (A, B, C, D, E) determine how many bits are used for the network vs host portions. IPv6 supports a much larger address space and easier auto-configuration compared to IPv4.
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
The chapter Lifelines of National Economy in Class 10 Geography focuses on the various modes of transportation and communication that play a vital role in the economic development of a country. These lifelines are crucial for the movement of goods, services, and people, thereby connecting different regions and promoting economic activities.
Beyond Degrees - Empowering the Workforce in the Context of Skills-First.pptxEduSkills OECD
Iván Bornacelly, Policy Analyst at the OECD Centre for Skills, OECD, presents at the webinar 'Tackling job market gaps with a skills-first approach' on 12 June 2024
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
This presentation was provided by Racquel Jemison, Ph.D., Christina MacLaughlin, Ph.D., and Paulomi Majumder. Ph.D., all of the American Chemical Society, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
2. IP Addresses
• Structure of an IP address
• Classful IP addresses
• Limitations and problems with classful IP addresses
• Subnetting
• CIDR
• IP Version 6 addresses
3. IP Addresses
Application data
TCP Header
Ethernet Header Ethernet Trailer
Ethernet frame
IP Header
version
(4 bits)
header
length
Type of Service/TOS
(8 bits)
Total Length (in bytes)
(16 bits)
Identification (16 bits)
flags
(3 bits)
Fragment Offset (13 bits)
Source IP address (32 bits)
Destination IP address (32 bits)
TTL Time-to-Live
(8 bits)
Protocol
(8 bits)
Header Checksum (16 bits)
32 bits
4. IP Addresses
Application data
TCP Header
Ethernet Header Ethernet Trailer
Ethernet frame
IP Header
0x4 0x5 0x00 4410
9d08 0102 00000000000002
128.143.137.144
128.143.71.21
12810 0x06 8bff
32 bits
5. What is an IP Address?
• An IP address is a unique global address for a network
interface
• An IP address:
- is a 32 bit long identifier
- encodes a network number (network prefix)
and a host number
6. Dotted Decimal Notation
• IP addresses are written in a so-called dotted decimal
notation
• Each byte is identified by a decimal number in the range
[0..255]:
• Example:
10001111
10000000 10001001 10010000
1st Byte
= 128
2nd Byte
= 143
3rd Byte
= 137
4th Byte
= 144
128.143.137.144
7. • The network prefix identifies a network and the host number
identifies a specific host (actually, interface on the network).
• How do we know how long the network prefix is?
– The network prefix is implicitly defined (see class-based
addressing)
– The network prefix is indicated by a netmask.
Network prefix and Host number
network prefix host number
8. • Example: ellington.cs.virginia.edu
• Network id is: 128.143.0.0
• Host number is: 137.144
• Network mask is: 255.255.0.0 or ffff0000
• Prefix notation: 128.143.137.144/16
» Network prefix is 16 bits long
Example
128.143 137.144
9. The old way: Classful IP Adresses
• When Internet addresses were standardized (early 1980s),
the Internet address space was divided up into classes:
– Class A: Network prefix is 8 bits long
– Class B: Network prefix is 16 bits long
– Class C: Network prefix is 24 bits long
• Each IP address contained a key which identifies the class:
– Class A: IP address starts with “0”
– Class B: IP address starts with “10”
– Class C: IP address starts with “110”
10. The old way: Internet Address Classes
Class C network id host
1
1 0
Network Prefix
24 bits
Host Number
8 bits
bit # 0 1 23 24
2 31
3
Class B 1 network id host
bit # 0 1 15 16
2
Network Prefix
16 bits
Host Number
16 bits
0
31
Class A 0
Network Prefix
8 bits
bit # 0 1 7 8
Host Number
24 bits
31
11. Class D multicast group id
1
1 1
bit # 0 1 2 31
3
0
4
Class E (reserved for future use)
1
1 1
bit # 0 1 2 31
3
1
4
0
5
The old way: Internet Address Classes
• We will learn about multicast addresses later in this course.
12. Problems with Classful IP Addresses
• The original classful address scheme had a number
of problems
Problem 1. Too few network addresses for large
networks
– Class A and Class B addresses are gone
Problem 2. Two-layer hierarchy is not appropriate
for large networks with Class A and Class B
addresses.
– Fix #1: Subnetting
13. Problems with Classful IP Addresses
Problem 3. Inflexible. Assume a company requires 2,000
addresses
– Class A and B addresses are overkill
– Class C address is insufficient (requires 8 Class C
addresses)
– Fix #2: Classless Interdomain Routing (CIDR)
14. Problems with Classful IP Addresses
Problem 4: Exploding Routing Tables: Routing on the
backbone Internet needs to have an entry for each network
address. In 1993, the size of the routing tables started to
outgrow the capacity of routers.
– Fix #2: Classless Interdomain Routing (CIDR)
15. Problems with Classful IP Addresses
Problem 5. The Internet is going to outgrow the 32-
bit addresses
– Fix #3: IP Version 6
16. Subnetting
Subnetting
• Problem: Organizations
have multiple networks
which are independently
managed
– Solution 1: Allocate one or
more Class C address for
each network
• Difficult to manage
• From the outside of the
organization, each network
must be addressable.
– Solution 2: Add another
level of hierarchy to the
IP addressing structure
University Network
Medical
School
Library
Engineering
School
17. Basic Idea of Subnetting
• Split the host number portion of an IP address into a
subnet number and a (smaller) host number.
• Result is a 3-layer hierarchy
• Then:
• Subnets can be freely assigned within the organization
• Internally, subnets are treated as separate networks
• Subnet structure is not visible outside the organization
network prefix host number
subnet number
network prefix host number
extended network prefix
18. • Routers and hosts use an extended network prefix (subnet
mask) to identify the start of the host numbers
* There are different ways of subnetting. Commonly used netmasks for university
networks with /16 prefix (Class B) are 255.255.255.0 and 255.255.0.0
Class B network host
16 bits
with
subnetting
host
Subnet
mask
(255.255.255.0)
network subnet
Network Prefix (16 bits)
1
1111111111111111111111100000000
0
10
Extended Network Prefix (24 bits)
Subnet Masks
19. • Each layer-2 network (Ethernet segment, FDDI segment) is
allocated a subnet address.
128.143.17.0 / 24
128.143.71.0 / 24
128.143.7.0 / 24
128.143.16.0 / 24
128.143.8.0 / 24
128.143.22.0 / 24
128.143.136.0 / 24
Typical Addressing Plan for an Organization that
uses subnetting
128.143.0.0/16
20. Advantages of Subnetting
• With subnetting, IP addresses use a 3-layer hierarchy:
» Network
» Subnet
» Host
• Improves efficiency of IP addresses by not consuming an
entire Class B or Class C address for each physical network/
• Reduces router complexity. Since external routers do not
know about subnetting, the complexity of routing tables at
external routers is reduced.
• Note: Length of the subnet mask need not be identical at all
subnetworks.
21. CIDR - Classless Interdomain Routing
• IP backbone routers have one routing table entry for each
network address:
– With subnetting, a backbone router only needs to know one entry for
each Class A, B, or C networks
– This is acceptable for Class A and Class B networks
• 27 = 128 Class A networks
• 214 = 16,384 Class B networks
– But this is not acceptable for Class C networks
• 221 = 2,097,152 Class C networks
• In 1993, the size of the routing tables started to outgrow the
capacity of routers
• Consequence: The Class-based assignment of IP addresses
had to be abandoned
22. CIDR - Classless Interdomain Routing
• Goals:
– Restructure IP address assignments to increase efficiency
– Hierarchical routing aggregation to minimize route table
entries
• CIDR (Classless Interdomain routing) abandons the notion of
classes:
Key Concept: The length of the network id (prefix) in the IP
addresses is kept arbitrary
• Consequence: Routers advertise the IP address and the
length of the prefix
23. CIDR Example
• CIDR notation of a network address:
192.0.2.0/18
• "18" says that the first 18 bits are the network part of the
address (and 14 bits are available for specific host
addresses)
• The network part is called the prefix
• Assume that a site requires a network address with 1000 addresses
• With CIDR, the network is assigned a continuous block of 1024 addresses
with a 22-bit long prefix
25. CIDR and Address assignments
• Backbone ISPs obtain large block of IP addresses space and
then reallocate portions of their address blocks to their
customers.
Example:
• Assume that an ISP owns the address block 206.0.64.0/18, which
represents 16,384 (214) IP addresses
• Suppose a client requires 800 host addresses
• With classful addresses: need to assign a class B address (and
waste ~64,700 addresses) or four individual Class Cs (and introducing 4
new routes into the global Internet routing tables)
• With CIDR: Assign a /22 block, e.g., 206.0.68.0/22, and allocated a
block of 1,024 (210) IP addresses.
26. CIDR and Routing Information
206.0.64.0/18
204.188.0.0/15
209.88.232.0/21
Internet
Backbone
ISP X owns:
Company X :
206.0.68.0/22
ISP y :
209.88.237.0/24
Organization z1 :
209.88.237.192/26
Organization z2 :
209.88.237.0/26
27. CIDR and Routing Information
206.0.64.0/18
204.188.0.0/15
209.88.232.0/21
Internet
Backbone
ISP X owns:
Company X :
206.0.68.0/22
ISP y :
209.88.237.0/24
Organization z1 :
209.88.237.192/26
Organization z2 :
209.88.237.0/26
Backbone sends everything
which matches the prefixes
206.0.64.0/18, 204.188.0.0/15,
209.88.232.0/21 to ISP X.
ISP X sends everything which
matches the prefix:
206.0.68.0/22 to Company X,
209.88.237.0/24 to ISP y
Backbone routers do not know
anything about Company X, ISP
Y, or Organizations z1, z2.
ISP X does not know about
Organizations z1, z2.
ISP y sends everything which matches
the prefix:
209.88.237.192/26 to Organizations z1
209.88.237.0/26 to Organizations z2
28. Example
Belongs to:
Cable & Wireless USA 207.0.0.0 - 207.3.255.255
11001111 00000010
207 2
01011000
88
10101010
170
11001111 00000010 01011000 00000000
Belongs to:
City of Charlottesville, VA: 207.2.88.0 - 207.2.92.255
11001111 00000000 00000000 00000000
You can find about ownership of IP addresses in
North America via http://www.arin.net/whois/
• The IP Address: 207.2.88.170
29. CIDR and Routing
• Aggregation of routing table entries:
– 128.143.0.0/16 and 128.144.0.0/16 are represented as
128.142.0.0/15
• Longest prefix match: Routing table lookup finds the
routing entry that matches the the longest prefix
What is the outgoing interface for
128.143.137.0/24 ?
Prefix Interface
128.0.0.0/4 interface #5
128.128.0.0/9 interface #2
128.143.128.0/17 interface #1
Routing table
30. IPv6 - IP Version 6
• IP Version 6
– Is the successor to the currently used IPv4
– Specification completed in 1994
– Makes improvements to IPv4 (no revolutionary changes)
• One (not the only !) feature of IPv6 is a significant increase in
of the IP address to 128 bits (16 bytes)
• IPv6 will solve – for the foreseeable future – the
problems with IP addressing
31. IPv6 Header
Application data
TCP Header
Ethernet Header Ethernet Trailer
Ethernet frame
IPv6 Header
version
(4 bits)
Traffic Class
(8 bits)
Flow Label
(24 bits)
Payload Length (16 bits)
Next Header
(8 bits)
Hop Limits (8 bits)
Source IP address (128 bits)
32 bits
Destination IP address (128 bits)
32. IPv6 vs. IPv4: Address Comparison
• IPv4 has a maximum of
232 4 billion addresses
• IPv6 has a maximum of
2128 = (232)4 4 billion x 4 billion x 4 billion x 4 billion
addresses
33. Notation of IPv6 addresses
• Convention: The 128-bit IPv6 address is written as eight 16-
bit integers (using hexadecimal digits for each integer)
CEDF:BP76:3245:4464:FACE:2E50:3025:DF12
• Short notation:
• Abbreviations of leading zeroes:
CEDF:BP76:0000:0000:009E:0000:3025:DF12
CEDF:BP76:0:0:9E :0:3025:DF12
• “:0000:0000:0000” can be written as “::”
CEDF:BP76:0:0:FACE:0:3025:DF12 CEDF:BP76::FACE:0:3025:DF12
• IPv6 addresses derived from IPv4 addresses have 96 leading zero bits.
Convention allows to use IPv4 notation for the last 32 bits.
::80:8F:89:90 ::128.143.137.144
34. IPv6 Provider-Based Addresses
• The first IPv6 addresses will be allocated to a provider-based
plan
• Type: Set to “010” for provider-based addresses
• Registry: identifies the agency that registered the address
The following fields have a variable length (recommeded length in “()”)
• Provider: Id of Internet access provider (16 bits)
• Subscriber: Id of the organization at provider (24 bits)
• Subnetwork: Id of subnet within organization (32 bits)
• Interface: identifies an interface at a node (48 bits)
Registry
ID
Provider
ID
010
Subscriber
ID
Interface
ID
Subnetwork
ID
35. More on IPv6 Addresses
• The provider-based addresses have a similar flavor as CIDR
addresses
• IPv6 provides address formats for:
– Unicast – identifies a single interface
– Multicast – identifies a group. Datagrams sent to a
multicast address are sent to all members of the group
– Anycast – identifies a group. Datagrams sent to an anycast
address are sent to one of the members in the group.