Network Fundamentals Part 1 CS 1 Rick Graziani Cabrillo College.

Network FundamentalsPart 1

Rick Graziani

Cabrillo College

Rick Graziani graziani@cabrillo.edu 2

What is networking?

• Communication!

• An interconnection of computers and other devices including:– Client computers– Servers (computers)– Network Devices

• Hubs and Switches• Routers• Firewall

Most successful networking applications?

What is in a network?

What is a network?

• A computer network is a series of computers and other devices interconnected by communication paths.

• Computer networks include: LANs and WANshttp://www.albany.edu

Ethernet LANs

LAN – Local Area Network

• LAN (Local Area Network) - A network connecting computers at a single site

LAN – Local Area Network

• A LAN:– Operates within a limited geographical area– Controlled by local administration– Allows local users to:

• Share printers• Access local file servers with software and data• Access the Internet

Ethernet LANs

• The most common LAN technology is Ethernet.

• Ethernet allows computers, printers, and other devices, “in the same network”, to be able to communicate.

• For devices to be able to communicate with each other over an Ethernet network, they must be configured with:– IP Address and Subnet Mask on the same network– What??? (We will discuss this shortly)

Creating an Ethernet Network

• To start, your computer must have an Ethernet Network Interface Card (NIC).

• Ethernet NICs have an RJ-45 interface or port.

• Hubs and Switches are used to connect computers, printers and other devices in the Ethernet LAN.

• Ethernet cables, i.e. Cat-5 or Cat-6 cables (Category 5, Category 6) are used to connect computers to the hubs and switches.

• Cat-5 cable connects computer NIC to hub or switch.

Configuring IP (Internet Protocol)

IP Configuration

• To communicate with other computers on your network you need to properly configure:– IP Address (of your computer)– Subnet Mask (of your computer)

• To communicate with computers outside your network you need to properly configure:– Default Gateway IP Address

• To be able to use domain names, like www.cabrillo.edu, instead of IP addresses you need to properly configure:– DNS (Domain Name System)

Server IP Address

IP Configuration: IP Address & Mask

• To communicate with other computers on your network you need to properly configure:– IP Address (of your computer)– Subnet Mask (of your computer)

• IP – Internet Protocol• IP Address is the unique address of

your computer on your network.• Subnet Mask is used by your computer

to figure out what network it belongs to.• Analogy:

– Name: RICKGRAZIANI– Mask: FFFFLLLLLLLL– The Mask tells us which part of

RICKGRAZIANI is the first name (F) and which part is the last name (L).

I am part of the 192.168.1.0 network!

IP Configuration: Default Gateway

• To communicate with computers outside your network you need to properly configure:– Default Gateway IP Address

• Default Gateway or Router: This is the device that connects your network to other networks, including the Internet.

Switch ports that connect to computers on your LAN

DSL or Cable Modem port that connects to your Internet Service Provider

• Any information that needs to be sent to IP Addresses outside your network is sent to the Default Gateway or Router.

To the Internet192.168.1.10

192.168.1.1

IP Configuration: DNS

• To be able to use domain names, like www.cabrillo.edu, instead of IP addresses you need to properly configure:– DNS (Domain Name System)

Server IP Address

207.62.87.54

IP Configuration: DNS• You could use IP Addresses when accessing other computers, but we

would rather use names (domain names).

• Computer networks only understand IP Addresses such as: – 66.94.230.47

• Computer networks do not understand domain names such as:– www.yahoo.com– A domain name is a name that is entered into a computer (e.g. as

part of a website or other URL, or an email address) and then looked up in the global [Domain Name System] which informs the computer of the IP address(es) with that name. (Wikipedia.com)

• People are better with names than numbers, so we would rather use names when:– Accessing a web page: www.yahoo.com– Emailing a friend: Rick.Graziani@cabrillo.edu

• DNS (Domain Name System) servers (computers) are used to translate domain names to IP Addresses.

Hey, 207.62.87.54, what is the IP Address for www.yahoo.com?

It is 66.94.230.47

Yahoo Web Server

Hey, 66.94.230.47, please send me your web page.

Here, 192.168.1.10, here is my web page.

• The details of how DNS works.

• If your DNS server does not know the answer, it will find out for you.

How do I view/edit this information on my computer?

1. Right click

2. Right click

3. TCP/IP, Properties Left click

Setting the IP Configuration Information

• IP information can be configured:– Statically– Dynamically

• Using a DHCP (Dynamic Host Configuration Protocol) Server

IP Configuration: Static Configuration

• Static configuration is when the user or administrator of the computer configures the IP Address, Subnet Mask, Default Gateway and DNS Server information.

IP Configuration: Dynamic Configuration

• Dynamic configuration is when the IP Address, Subnet Mask, Default Gateway and DNS Server information is obtained automatically from a DHCP (Dynamic Host Configuration Protocol) Server.

IP Configuration: Dynamic Configuration

I’m booting up, if there is a DHCP Server out there, I need my IP Configuration Information!

DHCP Server

Here is your IP Address, Subnet Mask, IP Address for the Default Gateway (router), and IP Address for the DNS Server!

The Internet and TCP/IP

What is the Internet?

• The Internet was originally designed by DARPA (Defense Advanced Research Projects Agency) in response to the U.S.S.R. launching Sputnik, the first satellite.

• Out of this came the Internet, a way for computers to communicate from different parts of the world.

• These computers can be any type of computer using any type of operating system, as long as they are using the protocol TCP/IP.

What is TCP/IP? What is a protocol?

• A protocol is nothing more than an agreement or rules to govern a way of communicating.

• The sender and receiver, and everyone in between, must agree on the rules, the protocol.

The actual letter (data) is inside (encapsulated) the envelope.

What is TCP/IP? What is a protocol?

• Protocol: An agreed form of communications.

TCP/IP Transmission Control Protocol / Internet Protocol

• TCP/IP is a suite of protocols.• IP (Internet Protocol) is used for sender and receiver addressing.• Every computer on the Internet or a network must have an IP

address to communicate.

Source IP Address: 192.168.1.10

Destination IP Address 66.94.230.47

This is known as an “IP Packet”

Yahoo Web Server

Destination IP Address: 66.94.230.47

Destination IP Address: 192.168.1.10

192.168.1.1066.94.230.47

Inside envelope: Request for web page

Inside envelope: Web page

Pinging another computer (FYI)

Connecting Networks with Routers

• The Internet, or simply the Net, is the publicly accessible worldwide system of interconnected computer networks.

• Routers are network devices that connect two or more networks together.

• Routers connect networks.

Connecting Networks with Routers

DSL or Cable Modem: No Router

204.180.205.1 Public Address

Hacker can only get to public address and not private address

DSL or Cable Modem

• Routers can help protect your DSL or Cable Modem Network.

DSL or Cable Modem: With a Router

• The router is between your computer (LAN) and your DSL Modem.

• The router is between you and the Internet.

Internet

When using NAT (Network Address Translation, the Router helps hide your network from attackers.

204.180.205.1 Public Address

192.168.1.10 Private Address

Hackers can only get to public addresses and not private addresses

DSL or Cable Modem: With a Router

Internet

Networks: Bandwidth and Connections

• Local Area Networks

• DSL

• Cable Modem

• Leased Lines

• Modems

Bandwidth

• Bandwidth - The amount of information that can flow through a network connection in a given period of time.

• Usually measured in bits per second (bps)– bps: bits per second– Kbps: thousands of bits per second– Mbps: millions of bits per second

Bandwidth

LANs: 10 Mbps or 100 Mbps (or more)

Connection to ISP (Internet Service Provider)Note: Bandwidth depends up provider, location, and service plan.• DSL:

– Download: 600 Kbps to 1.5 Mbps (or more)– Upload: 256 Kbps (or more)

• Cable Modem: – Download: 600 Kbps to 3.0 Mbps (or more)– Upload: 256 Kbps (or more)

• Telephone Modem:– Up to 53 Kbps

• Leased Lines– T1: 1.5 Mbps– T3: 44.736 Mbps

Connection to ISP: DSL

• DSL (digital subscriber line) is a very high-speed connection that uses the same wires as a regular telephone line.

DSL: From HowStuffWorks.com

• Advantages of DSL: – You can leave your Internet connection open and still use the

phone line for voice calls. – The speed is much higher than a regular modem – DSL doesn't necessarily require new wiring; it can use the phone

line you already have. – The company that offers DSL will usually provide the modem as

part of the installation.

• But there are disadvantages: – A DSL connection works better when you are closer to the

provider's central office. – The connection is faster for receiving data than it is for sending

data over the Internet. – The service is not available everywhere.

Connection to ISP: Cable Modem

• A cable modem is a special type of modem that is designed to modulate a data signal over cable television infrastructure.

Connection to ISP: Telephone Modem

• A telephone modem is used to modulate and demodulate (translate) between the digital signals of the computer and the analog signals over the telephone line.

• Maximum bandwidth is only 53 Kbps.

• Need separate phone line if you want to use the phone while connected to the Internet

GOLDMAN: DATACOMM FIG.02-14

DTE DCE

Modulation

Demodulation

digital analog

PSTN Dial-up network

IPv4 and IPv6 Addressing

No handout

IPv4• 32 bits or 4 bytes

• 4,200,000,000 possible addressable nodes• 4 billion possible addresses

Who assigns IP Network Addresses?

• Internet Assigned Numbers Authority (IANA) (http://www.iana.net) is the master holder of the IP addresses.

• Today, the remaining IPv4 address space has been allocated to various other registries to manage for particular purposes or for regional areas. – Regional Internet Registries (RIRs)

Regional Internet Registries (RIR)

• The 5 Regional Internet Registries (RIRs) are:– AfriNIC (African Network Information Centre) - Africa Region

http://www.afrinic.net– APNIC (Asia Pacific Network Information Centre) - Asia/Pacific Region

http://www.apnic.net– ARIN (American Registry for Internet Numbers) - North America Region

http://www.arin.net– LACNIC (Regional Latin-American and Caribbean IP Address Registry) -

Latin America and some Caribbean Islands http://www.lacnic.net– RIPE NCC (Reseaux IP Europeans) - Europe, the Middle East, and Central

Asia http://www.ripe.net

• Most companies or organizations obtain their IPv4 address blocks from an ISP (Internet Service Provider).

ISP (Internet Service Providers)

Private IPv4 Addresses

• In early 1990’s IANA and IETF recognized that the we were running out of IPv4 addresses.

• Long term solution: IPv6

• Short Term solution:– Private Addresses and Network Address Translation

Private IPv4 Addresses

• Private Addresses– 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8)– 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12)– 192.168.0.0 to 192.168.255.255 (192.168.0.0 /16)

• The addresses will not be routed in the Internet– Need NAT (Network Address Translation)

NAT – Network Address TranslationPAT – Port Address Translation

Private Addresses Public Address

• Monday, January 31, 2011 IANA allocated two blocks of IPv4 address space to APNIC, the RIR for the Asia Pacific region (39/8 and 106/8)

• IANA has no more IPv4 network addresses to allocate

• RIR’s Remaining IPv4 addresses

IPv6 addresses are 128-bit addresses represented in:

Eight 16-bit segments or “hextets” (not a formal term)

Hexadecimal (non-case sensitive) between 0000 and FFFF

Separated by colons

One Hex digit = 4 bits

2001:0DB8:AAAA:1111:0000:0000:0000:0100/64

2001 : 0DB8 : AAAA : 1111 : 0000 : 0000 : 0000 : 0100

16 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits 16 bits

How many addresses does 128 bits give us?

340 undecillion addesses or …

340 trillion trillion trillion addresses or …

“IPv6 could provide each and every square micrometer of the earth’s surface with 5,000 unique addresses. Micrometer = 0.001 mm or 0.000039 inches” or….

“A string of soccer balls would wrap around our universe 200 billion times!”

When will RIR’s run out of IPv4 Addresses?

Why do we need to move to IPv6?

Network FundamentalsPart 1

Rick Graziani

Cabrillo College

Network Fundamentals Part 1 CS 1 Rick Graziani Cabrillo College.

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