CCNA Guide to Cisco Networking Chapter 3 TCPIP

CCNA Guide to Cisco Networking Chapter 3: TCP/IP And IP Addressing

Objectives • Discuss the origins of TCP/IP • Understand the different classes of IP addresses • Configure and verify IP addresses • Subdivide an IP network • Identify and discuss the different layer functions of TCP/IP

Objectives (continued) • Describe the functions performed by protocols in the TCP/IP protocol suite, including ICMP, UDP, TCP, ARP, and RARP • Use ping and trace and describe their functions • Understand advanced routing concepts such as CIDR, summarization, and VLSM

Origins Of TCP/IP • United States Department of Defense (Do. D) – Advanced Research Projects Agency (ARPA) – Create a WAN to survive an nuclear attack • Advanced Research Projects Agency Network (ARPANET) – – University of California at Santa Barbara (UCSB) University of California at Los Angeles (UCLA) Stanford Research Institute University of Utah

Overview Of The TCP/IP Protocol Suite • Application Layer – – – – – File Transfer Protocol (FTP) Trivial File Transfer Protocol (TFTP) Network File System (NFS) Simple Mail Transfer Protocol (SMTP) Telnet rlogin Simple Network Management Protocol (SNMP) Domain Name System (DNS) Hypertext Transfer Protocol (HTTP)

Overview Of The TCP/IP Protocol Suite (continued) • Transport Layer – Ports • Well Known Port numbers – TCP three-way handshake • Initial sequence numbers • Expectational acknowledgement • Reset packet (RST) – TCP sliding windows • Flow control with sliding windows, buffering, congestion avoidance

Overview Of The TCP/IP Protocol Suite (continued) • Internetwork Layer – Internet Protocol (IP) • IPv 4 and IPv 6 – Internet Control Message Protocol (ICMP) • Echo request, echo reply, and TTL – Address Resolution Protocol (ARP) • ARP table, ARP request, ARP reply, and TTL – Reverse Address Resolution Protocol (RARP) • RARP server and RARP client

Overview Of The TCP/IP Protocol Suite (continued) • Network Interface Layer – Combines OSI Physical and Data Link layers – MAC addresses – Network card drivers – Specific physical interfaces

Ping Utility

Ping Utility (continued)

Ping Utility (continued)

The Trace Utility

IP Addressing • MAC to IP address translation • IP classes – Internet Assigned Numbers Authority (IANA) – American Registry of Internet Numbers (ARIN) – Internet Corporation for Assigned Names and Numbers (ICANN) – Class A – Class B – Class C – Class D – Class E – Private IP ranges

IP Addressing (continued)

IP Addressing (continued)

IP Addressing (continued)

IP Addressing (continued)

IP Addressing (continued)

Subnet Addressing • Default class subnet masks – Class A subnet mask is 255. 0. 0. 0 1111. 00000000 – Class B subnet mask is 255. 0. 0 11111111. 0000 – Class C subnet mask is 255. 0 11111111. 0000 • Boolean ANDing operation • Subnet addresses • Broadcast addresses

Broadcast Types • Flooded broadcasts – 255 • Directed broadcast – 129. 30. 255

Subdividing IP Classes

Subnet Masking

Subnet Masking (continued)

Subnet Masking (continued)

Learning To Subnet

Learning To Subnet (continued) • Breakdown of 255. 244 subnet mask – – – – 0 (binary 0000) — unusable 32 (binary 00100000) 64 (binary 01000000) 96 (binary 01100000) 128 (binary 10000000) 160 (binary 10100000) 192 (binary 11000000) 224 (binary 11100000) — unusable

Learning To Subnet (continued)

Learning To Subnet (continued)

Subnetting Formulas • 2 y – 2 = # of usable subnets (where y is the number of bits borrowed) • 2 x – 2 = # of usable hosts per subnet (where x is the number of bits remaining in the host field after borrowing)

Subnetting Formulas (continued)

Subnetting Formulas (continued)

CIDR • Classless Inter-Domain Routing (CIDR) • Developed to slow the exhaustion of IP Addresses • Provide efficient use of IP addresses and address ranges • Subnetting and supernetting

Summarization • Also known as route aggregation • Move subnet mask bits left of the default boundary • Combine several default class networks

Variable Length Subnet Masks

Variable Length Subnet Masks (continued)

Variable Length Subnet Masks (continued)

IPv 4 Versus IPv 6 • Internet Protocol version 4 is the most widely used – 32 -bit structure – 232 available addresses • Internet Protocol version 6 is not common but used – 128 -bit structure – 2128 available addresses

Understanding Packet Transmission • • • Routers on the network Network to network Dynamic or static tables Transmitting packets to remote segments Routing packets

Understanding Packet Transmission (continued)

Understanding Packet Transmission (continued)

Understanding Packet Transmission (continued)

Understanding Packet Transmission (continued)

Working With Hexadecimal Numbers

Summary • TCP/IP is more than just the Transmission Control Protocol/Internet Protocol; it is an entire suite of protocols that provides data transportation, management, and diagnostic capabilities for networks that use it • TCP/IP was started by the Defense Advanced Research Projects Agency (DARPA) • That group was charged with developing a national communication system that could survive a nuclear war • Later, its network, ARPANET, was turned over to the public, especially universities • From there, the Internet grew into what it is today, a large worldwide commerce and communications network

Summary (continued) • TCP/IP maps to a four-layer network model: Application, Transport, Internetwork, and Network Interface • The Application layer in the TCP/IP model covers the Application, Presentation, and Session layers of the OSI reference model • TCP/IP Transport layer maps directly to the OSI Transport layer • The Internetwork layer of the TCP/IP model maps directly to the Network layer of the OSI model • Network Interface layer of the TCP/IP model is equivalent to the Data Link and Physical layers of the OSI model

Summary (continued) • The TCP and UDP protocols reside at the Transport layer of the TCP/IP networking Model • UDP is an unreliable and connectionless communications protocol that does not guarantee packet delivery • TCP is a reliable and connection-oriented protocol that guarantees packet delivery • TCP uses a three-way handshake to establish a communications link between two points before data transfer • TCP also uses a sliding window to control the flow of packets and the number of acknowledgments between the two hosts

Summary (continued) • Both TCP and UDP use port numbers from 1 to 65, 535 to establish their communications between two points • Ports with numbers 1023 and under are Well Known Port numbers, as defined in RFC 1700 • These ports describe common Internet services that hosts can use to contact public servers for specific types of services, such as Web, FTP, and telnet • The Internet Protocol (IP) resides at the Internetwork layer, it provides the logical address that can be passed through a router • The subnet mask allows networks to be divided into subnetworks

Summary (continued) • You can use the ping utility with IP and ICMP to diagnose and troubleshoot network connections • Use the trace utility with IP to determine all the hops that a packet makes along its path to a remote TCP/IP host • Address Resolution Protocol (ARP) and Reverse ARP (RARP) reside in the Internetwork layer • These protocols allow the TCP/IP host to map the IP address to a MAC address

Summary (continued) • The MAC address is the final leg of communication between hosts • Packets are transmitted via the MAC address to the destination host once the packets arrive at the destination network or subnetwork • The Internet Corporation for Assigned Names and Numbers (ICANN) and the American Registry of Internet Numbers (ARIN) work together to subdivide and issue addresses for Internet clients • Three classes of addresses (A, B, and C) are available to organizations • Class A addresses are for governments worldwide

Summary (continued) • Class B addresses are assigned to medium to large companies and universities • Class C addresses are assigned to organizations and people who require an IP address but do not meet the criteria to have a Class A or B address • Class D addresses are used for multicasting information • Multicasting allows anyone with the correct setup to broadcast a simultaneous transmission to multiple computers • Class E addresses are used for experimentation and research

Summary (continued) • The subnet mask divides the network portion of the IP address from the host portion of the address • The network or subnetwork IP address must always have zeros for the host identifier portion • IP addresses that identify TCP/IP hosts must be nonzero in the host portion • When the host portion of an IP address is all binary ones, the address is a broadcast address

Summary (continued) • Routing tables can be created manually and dynamically • Network administrators manually create static routing tables • A manual table requires more administrative overhead but gives the administrator greater control over the routing process • Dynamic updates are provided through routing protocols • The routing protocols allow the routers to be updated automatically

Summary (continued) • Advanced routing protocols such as RIP version 2, OSPF, and EIGRP support variable length subnet masking (VLSM) • VLSM allows network administrators to better allocate their IP address space by using different subnet masks on their subnetworks • Classful routing protocols such as RIP version 1 and IGRP do not support VLSM • They require the same subnet mask on every subnet

Summary (continued) • IPv 6 is the latest version of IP addressing • Unlike the 32 -bit IPv 4 addresses that are in use today on most networks, IPv 6 addresses are 128 bits long and are expressed in hexadecimal • It is expected that vendors and networkers will slowly convert to IPv 6 in the next several years

Summary (continued) • The hexadecimal numbering system is also known as base 16 because there are 16 available numerals • The numerals include all of the numbers 0– 9 as well as the letters A–F • For example, the letter A represents the decimal number 10 and the letter F represents the decimal number 15 • Hexadecimal numbers are found in MAC addresses and IPv 6 addresses, and are often used in computer and networking applications