Unit 4, Chapter 7 & Chapter 18 pp

Subnets & Subnetting Subnetwork or Subnet – separate part of an organizations network that is identifiable Security and traffic control Subnet mask –32 Bit number –ANDed with network portion of address(only 1+1=1) –1 ’ s = network and 0 ’ s = host –Ex. Class A , network info is in the first octet

Default Subnet Masks –Class A = –Class B = –Class C = Bits in the host octets are used to define subnet(pg 388) –Class C address –Subnet mask or / = –Subnet Number 2 –Host ID 17 Subnets & Subnetting

Classless Inter-Domain Routing: CIDR Address Prefix and Number of Class C Addresses Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

Addressing Particulars /nn Classless Internet Domain Routing – /19 or Subnet mask Supernetting – several class C addresses into a contiguous address block Dynamic IP address – address assigned when needed Static – address is configured and does not change(routers … infrastructure equipment) Private networks – , ,

Subnetting Example StepExampleRules Address None Mask None Number of network bits8Always defined by Class A,B,C Number of Host Bits16 Always defined by the number of binary 0s in the mask Number of Subnet Bits832 - (Network size + host size) Total32Network + Host + Subnet

Domain Names Mnemonic for IP address ( Domain Name Services(DNS) used to translate or resolve name to address Hierarchical Structure –Local –Corporate –Global Top Level Domain (.com,.edu,.net,.org ….) Internet Corporation for Assigned Names and Numbers (ICAAN) Root Servers – Contain IP addresses of all TLD registries

Transmission Control Protocol Can communicate between hosts with diverse hardware and operating systems Developed by Defense Advanced Research Projects Agency (DARPA) Direct or point-to-point communications Connection oriented communication Full Duplex – communication in both direction 3 way hand shake to start communications & End Communications –Start:->SYN, ACK –End: ->FIN+ACK, ACK

TCP HEADER

TCP Header Information

TCP/IP Header: Stop-and-Go (left) versus Sliding Window Flow Control (right) Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

TCP/IP Header: Sliding Window Flow Control in Operation Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

User Datagram Protocol Simple protocol Connectionless No error checking No sequencing No Handshaking Examples: Ping, DNS, VOIP, TFTP

UDP Header: UDP Diagram Format Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

UDP Header: IP Header Field Information Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

TCP/UDP Port Number: Selected Well-Known Port Numbers Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. PortTCPUDPProtocol 20FTP Data 21FTP Control 22SSH (Secure Shell) 23Telnet 25SMTP 53DNS 69TFTP 80HTTP

TCP/UDP Port Number: Selected Well-Known Port Numbers Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

Other Protocols Address Resolution Protocol (ARP) Dynamic Host Configuration Protocol File Transfer Protocol/Trivial File Transfer Protocol Hypertext Transfer Protocol & Hypertext Transfer Protocol over Secure Sockets Layer or Transfer Layer Security Post Office Protocol v3 (POP3) & Internet Message Access Protocol v4 (IMAP4) Simple Mail Transfer Protocol

Internet Tools Name Server Lookup (nslookup) –Determine IP address of a host system Whois –Determine name from an IP address Ping –Troubleshooting tool –Is the node there, is it alive, how much time …. Traceroute –Determine route packet takes to remote host

PING and Tracert: Example 1 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

PING and Tracert: Example 2 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

PING and Tracert: Example 3 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

PING and Tracert: Example 4 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

PING and Tracert: Example 5 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

PING and Tracert: Example 6 Cisco Learning Institute Network+ Fundamentals and Certification Copyright ©2005 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

Data Link Layer Functions Data Link –Communication Startup How will communications be started –Character Identification and framing What constitutes a character and what is a control character –Message (PDU) identification What is a message –Line Control signaling for successful transmission, line turn around, whether receiving terminal can accept more data –Error Control What scheme to use, what to do when an error is detected –Termination

Line Access Definition: Data Terminal Equipment (DTE) - That part of a data station that serves as a data source, data sink or both and provides data communication control functions Methods to attain access to a circuit (Line Access) – Contention Systems Listen,,wait/send Small systems, few nodes or fast circuit – Polling Roll Call Polling –Master with polling list –Queries stations if they need to transmit Fast Select Polling –Polls several stations at one time, only stations waiting to send respond Hub Polling –Each DTE does part of the Master Station function –Nothing to send, pass on to the next stations – Token Passing Similar to Hub Polling, includes token

Communication Parameters Established prior to communications taking place Predetermined Settings on a device (Modem) –Parity –Transmission Speed

Flow Control Stop-and-Wait (left) versus Sliding Window Flow Control (right)

High-Level Data Link Control (HDLC) Frames 3 types –Supervisory (Control) –Information (Data) –Unnumbered 2 Frame Formats –Normal –Extended Flag field must be unique Address Field – 8 or 16 bits Frame Flow (Page 180) –Initiation Phase –Data Transfer Phase –Disconnect Phase

Review Questions 1. Predetermined communication parameters are those that are set __________ by switches or specified as parameters in software. a. dynamically b. historically c. manually d. inherited

Review Questions 2. Polling systems require several stations on the circuit to act as master stations. a. True b. False

Review Questions 3. The simplest form of flow control is called___________________. a. stop and wait flow control b. give and get flow control c. first in first out flow control d. first in last out flow control

Review Questions 4. Background noise (white noise) on a circuit ______________________. a. is rarely a problem because it is a known, predictable phenomenon b. is one of the most difficult problems to work around c. occurs in spikes d. delays some frequencies more than others

Review Questions 5. What does the term “ sliding window ” relate to? a.Multiplexing b.Stop and wait c.Flow control d.Full duplex e.None of the above

Review Questions 6. How “ big ” is an IPv6 Internet address? a. 32 bits b. 32 bytes c. 20 octets d. 128 bits e. 128 bytes

Review Questions 7. What is the main objective of the IPv6 proposal to the TCP/IP protocol suite? a. Reduce user response b. Update TCP/IP to remain compatible with new technology c. Allow for more Internet addresses d. Add a fiber optic specification to TCP/IP suite e. Force the acceptance of the hexadecimal numbering system

Review Questions 8. What is the size, in bits, of the Net_ID field in a Class B Internet address? a. 8 b. 16 c. 14 d. 32

Review Questions 9. What does the “ time-to-live ” field (8bits) do in an IP header? a. Prevents infinite loops b. Sets Frame Priority c. Records the transmission time for tracert functions d. Error checking e. Frame sequence numbering

Review Questions 10. The part of the message that contains the destination address is called the ______. a. Zip b. Text c. Trailer d. Header e. Flag

Homework Assignment: Due Next Week –Review: Chapter 7, pp Chapter 18, pp –Read: Chapter 10, pp Chapter 11, pp –Complete: Assignment 4.1: Chapter Multiple Choice; Chapter 18 Multiple Choice Assignment 4.2: Subnet Homework B Assignment 4.3 Draw OSI Model again, this time include the Hardware of each layer.