Unit 4, Chapter 7 & Chapter 18 pp 531-573. Subnets & Subnetting Subnetwork or Subnet – separate part of an organizations network that is identifiable

Data Link Control Protocols Data Link Control Protocols & Transmission Media& Transmission Media

Unit 4, Chapter 7 & Chapter 18 pp 531-573

Subnets & Subnetting

Subnetwork or Subnet – separate part of an organizations network that is identifiableSecurity and traffic controlSubnet mask – 32 Bit number – ANDed with network portion of address(only 1+1=1)– 1’s = network and 0’s = host– Ex. Class A 255.0.0.0, network info is in the first octet

Default Subnet Masks– Class A = 255.0.0.0– Class B = 255.255.0.0– Class C = 255.255.255.0

Bits in the host octets are used to define subnet(pg 388)– Class C address 206.11.20.81– Subnet mask 255.255.255.224 or /27

• 11111111.11111111.11111111.11100000• 81 = 0101 0001

– Subnet Number 2– Host ID 17

Subnets & Subnetting

Classless Inter-Domain Routing:CIDR Address Prefix and Number of Class C

Addresses

Cisco Learning InstituteNetwork+ Fundamentals and Certification

Copyright ©2005 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Addressing Particulars

/nn Classless Internet Domain Routing– 204.11.20.16/19 or Subnet mask

11111111.11111111.11100000.00000000

Supernetting – several class C addresses into a contiguous address blockDynamic IP address – address assigned when neededStatic – address is configured and does not change(routers…infrastructure equipment)Private networks – 10.0.0.0, 172.16.0.0,192.168.0.0

Subnetting Example

Step Example Rules

Address 8.1.4.5 None

Mask 255.255.0.0 None

Number of network bits 8 Always defined by Class A,B,C

Number of Host Bits 16Always defined by the number of binary 0s in the

mask

Number of Subnet Bits 8 32 - (Network size + host size)

Total 32 Network + Host + Subnet

Domain Names

Mnemonic for IP address (WWW.MSN.COM)Domain Name Services(DNS) used to translate or resolve name to addressHierarchical 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 systemsDeveloped by Defense Advanced Research Projects Agency (DARPA)Direct or point-to-point communicationsConnection oriented communicationFull Duplex – communication in both direction3 way hand shake to start communications & End Communications– Start:->SYN,<-SYN+ACK,->ACK – End: ->FIN+ACK,<-FIN+ACK,->ACK

TCP HEADER

TCP Header Information

TCP/IP Header:Stop-and-Go (left) versus Sliding Window Flow Control

(right)



TCP/IP Header:Sliding Window Flow Control in

Operation



User Datagram Protocol

Simple protocolConnectionlessNo error checkingNo sequencingNo HandshakingExamples: Ping, DNS, VOIP, TFTP

UDP Header:UDP Diagram Format




UDP Header:IP Header Field Information




TCP/UDP Port Number:Selected Well-Known Port Numbers




Port TCP UDP Protocol

20 FTP Data21 FTP Control22 SSH (Secure Shell)23 Telnet25 SMTP53 DNS69 TFTP80 HTTP

TCP/UDP Port Number:Selected Well-Known Port Numbers




Other Protocols

Address Resolution Protocol (ARP)Dynamic Host Configuration ProtocolFile Transfer Protocol/Trivial File Transfer ProtocolHypertext Transfer Protocol & Hypertext Transfer Protocol over Secure Sockets Layer or Transfer Layer SecurityPost 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
























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 AccessDefinition: 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 placePredeterminedSettings on a device (Modem)– Parity– Transmission Speed

Flow ControlStop-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 01111110 must be uniqueAddress Field – 8 or 16 bitsFrame 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. dynamicallyb. historicallyc. manuallyd. inherited

Review Questions

2. Polling systems require several stations on the circuit to act as master stations.a. Trueb. False

Review Questions

3. The simplest form of flow control is called___________________.a. stop and wait flow controlb. give and get flow controlc. first in first out flow controld. 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

phenomenonb. is one of the most difficult problems to work aroundc. occurs in spikesd. delays some frequencies more than others

Review Questions

5. What does the term “sliding window” relate to? a. Multiplexingb. Stop and waitc. Flow controld. Full duplexe. None of the above

Review Questions

6. How “big” is an IPv6 Internet address?a. 32 bitsb. 32 bytesc. 20 octetsd. 128 bitse. 128 bytes

Review Questions

7. What is the main objective of the IPv6 proposal to the TCP/IP protocol suite?a. Reduce user responseb. Update TCP/IP to remain compatible with new

technologyc. Allow for more Internet addressesd. Add a fiber optic specification to TCP/IP suitee. 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. 8b. 16 c. 14d. 32

Review Questions

9. What does the “time-to-live” field (8bits) do in an IP header?a. Prevents infinite loopsb. Sets Frame Priorityc. Records the transmission time for tracert functionsd. Error checkinge. Frame sequence numbering

Review Questions

10. The part of the message that contains the destination address is called the ______ .a. Zipb. Textc. Trailerd. Headere. Flag

Homework

Assignment: Due Next Week– Review:

• Chapter 7, pp. 158-182• Chapter 18, pp. 531-538

– Read:• Chapter 10, pp. 248-282• Chapter 11, pp. 286-314

– 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.

Documents

Unit 4, Chapter 7 & Chapter 18 pp 531-573. Subnets & Subnetting Subnetwork or Subnet – separate part of an organizations network that is identifiable