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Department of Computer Networking Application CHAPTER 14 INTERNETWORKING 1 The first section 2 Exercises 3 Online lecture

INTRODUCTION An internet must provide a link between networks, routing and delivering data between processes on computers of different networks while accommodating several variations among those networks. CHAPTER 14 INTERNETWORKING

PRINCIPLES OF INTERNETWORKING A simple internet An internetwork or internet carries the concept of networking one step further down the road to universal connectivity by joining multiple networks or types of network into one large, uniform communications system. An internet is the connection of two or more networks of any type. The most common implementation is the connection of several packet switching networks by using TCP/IP protocols and routers. CHAPTER 14 INTERNETWORKING

TCP/IP PROTOCOL SUITE A comparison of the layers of the OSI Reference Model and the TCP/IP protocol stack. CHAPTER 14 INTERNETWORKING A protocol is the collection of practices, policies, and procedures that are mutually agreed upon between users so they are able to communicate. Just as two people need a common language or rules for communication when they speak to one another, so two hosts (in TCP/IP, any two computers from PCs to mainframe) need protocols or rules of behavior and conventions when sending messages to one another.

REQUESTS FOR COMMENT(RFC) CHAPTER 14 INTERNETWORKING All of the protocols in the TCP/IP suite are defined by documents called RFCs. Whenever a person conceives a new idea or improved capability, he or she writes an RFC, which is then published on the Internet. The RFC is assigned a number by which it will always be known, and reviewers respond with comments and constructive criticism. The RFC is revised and after programmers have tested it, it becomes an official standard.

INTERNET PROTOCOL (IP) CHAPTER 14 INTERNETWORKING IP is responsible for the basic connectivity between networks, though it is not concerned whether data arrive without errors. That is handled by other protocols, such as TCP. The current version of IP is Internet Protocol version 4, (IPv4). A newer version, called IPv6, is a bigger and more versatile "brother” that many Internet sites are starting to implement.

Classful IP Addressing The range of decimal values in the first eight bits of each address class. CHAPTER 14 INTERNETWORKING

Comparison of Class A, B, and C addresses CHAPTER 14 INTERNETWORKING

Division of five classes indicated by the first four bits of the address CHAPTER 14 INTERNETWORKING

Subnetting and Subnet Masks Default subnet masks CHAPTER 14 INTERNETWORKING

Default subnet mask applied to a Class C address A subnet mask applied to a Class C address CHAPTER 14 INTERNETWORKING

A sample Converting decimal numbers to binary CHAPTER 14 INTERNETWORKING

Classless Inter-Domain Routing (CIDR) CHAPTER 14 INTERNETWORKING Another option for dealing with the decreasing number of addresses used by most IPv4 Internet sites is CIDR. CIDR is very closely related to subnetting. Use of the original IPv4 system of classes resulted in the waste of many addresses.

DOMAIN NAME SYSTEM (DNS) Top Level Domains The following is a list of the top level domains:.com: commercial organizations.edu: educational institutions, today usually limited to 4-year colleges and university.net: network providers.org: nonprofit organizations.int: organizations established by international treaty.gov: US Federal Government agencies.mil: US military CHAPTER 14 INTERNETWORKING

DOMAIN NAME SYSTEM (DNS) Top Level Domains The following is a list of the top level domains: CHAPTER 14 INTERNETWORKING.int: organizations established by international treaty.org: nonprofit organizations.net: network providers.edu: educational institutions.com: commercial organizations.gov: US Federal Government agencies.mil: US military

DOMAIN NAME SYSTEM (DNS) Top Level Domains The following is a list of the top level domains:.com: commercial organizations.edu: educational institutions, today usually limited to 4-year colleges and university.net: network providers.org: nonprofit organizations.int: organizations established by international treaty.gov: US Federal Government agencies.mil: US military CHAPTER 14 INTERNETWORKING

A DNS tree The domain name system CHAPTER 14 INTERNETWORKING

14.8 INTERNET PROTOCOL VERSION 6 (IPV6) The hexidecimal syste m CHAPTER 14 INTERNETWORKING

A comparison of the IPv4 and IPv6 header structures CHAPTER 14 INTERNETWORKING

14.9 TRANSMISSION CONTROL PROTOCOL (TCP) TCP is a connection-oriented end-to-end service CHAPTER 14 INTERNETWORKING

Opening handshake CHAPTER 14 INTERNETWORKING

Sender and receiver events CHAPTER 14 INTERNETWORKING

Flow control: sliding window CHAPTER 14 INTERNETWORKING

A closing handshake A TCP header CHAPTER 14 INTERNETWORKING

14.11 SOCKETS AND CLIENT-SERVER COMMUNICATION The relationships between TCP/IP and UDP layers CHAPTER 14 INTERNETWORKING

14.12 OTHER PROTOCOLS Address Resolution Protocol (ARP) Dynamic Host Configuration Protocol (DHCP) File Transfer Protocol(FTP) and Trivial File Transfer Protocol(TFTP) HTTP and Secure Hypertext Transfer Protocol (HTTPS) Internet Control Message Protocol (ICMP) Post Office Protocol, v3(POP3) and Internet Message Access Protocol, v4(IMAP4) Simple Mail Transfer Protocol (SMTP) CHAPTER 14 INTERNETWORKING

14.12 OTHER PROTOCOLS Address Resolution Protocol (ARP) Dynamic Host Configuration Protocol (DHCP) File Transfer Protocol(FTP) and Trivial File Transfer Protocol(TFTP) HTTP and Secure Hypertext Transfer Protocol (HTTPS) Internet Control Message Protocol (ICMP) Post Office Protocol, v3(POP3) and Internet Message Access Protocol, v4(IMAP4) Simple Mail Transfer Protocol (SMTP) CHAPTER 14 INTERNETWORKING

14.13 INTERNETWORKING TOOLS AND APPLICATIN Name Server Lookup (nslookup) Output from nslookup CHAPTER 14 INTERNETWORKING

Whois Output from nslookup CHAPTER 14 INTERNETWORKING

Ping Ping is one of the most widely available tools in the TCP/IP suite Output from ping CHAPTER 14 INTERNETWORKING

Traceroute Output from traceroute CHAPTER 14 INTERNETWORKING

课后习题 D 、 What is the default subnet mask for a Class C network? （ ）. D A 、 B 、 C 、 Show Answer Reset Next × × × √ Exercises CHAPTER 14 INTERNETWORKING

课后习题 C 、 Which of the following binary numbers is the equivalent of the decimal number 206? （ ） C D 、 A 、 B 、 Show Answer Reset Next × × × √ CHAPTER 14 INTERNETWORKING Exercises

课后习题 A 、 Which of the following decimal numbers is the equivalent of the binary number ? （ ） A D 、 203 B 、 197 C 、 192 Show Answer Reset Next × × × √ Exercises CHAPTER 14 INTERNETWORKING

课后习题 B 、 The dotted decimal IP address is the equivalent of the following binary address: ( ) B D 、 A 、 C 、 Show Answer Reset Next × × × √ Exercises CHAPTER 14 INTERNETWORKING

课后习题 B 、 flow control 5. What does the term “sliding window” relate to? ( ) B D 、 full duplex A 、 multiplexing C 、 queuing Show Answer Reset Next × × × √ Exercises CHAPTER 14 INTERNETWORKING

课后习题 6. An ________ is the connection of two or more networks of any type. internet Answer Exercises 7. _____________ are the individual networks that are interconnected in an internet and may maintain their own. subnetworks Answer 8. ________ define all of the protocols in the TCP/IP Suite. RFCs Answer CHAPTER 14 INTERNETWORKING

课后习题 9. The TCP/IP __________ layer makes sure that packets have no errors and that they arrive in the correct order. transport Answer Exercises 10. The IP address type designed for the largest networks is class ____. A Answer CHAPTER 14 INTERNETWORKING