Internet Infrastructure

• Infrastructure is the physical hardware used to interconnect users and computer.
• Infrastructure includes the transmission media, software used to receive, send, and manage the signals that are transmitted.
• Infrastructure refers to interconnecting software and hardware and not to computers and other devices that are interconnected.
• For some information technology users, infrastructure is viewed as everything that supports the flow and processing of information.

Internet Protocol (IP):

Defintion: The primary network protocol used on the Internet layer of the Internet Protocol Suite, developed (1970s). On the internet and many other networks. IP is often used together with the Transport Control Protocol (TCP) and referred to interchangeably as TCP/IP.

IP used to supports unique addressing for computers on a network. Almost all networks use the Internet Protocol version 4 (IPv4) standard that features IP addresses four bytes (32 bits) shown as 4octets of number from 1-225 represented in decima form instead of binary in length. Internet Protocol version 6 (IPv6) standard features addresses 16 bytes (128 bits) in length.

• IP specifies the format of packets called datagrams, and the addressing scheme. 
• Transmission Control Protocol (TCP), most networks combine IP with higher-level protocol, which establishes a virtual connection between a destination and a source.
• IP consist of two part: network and host/node of network.
• Class of address determines which part belongs to network add and which part belongs node address.

Class A Network

Binary add will start with 0 therefore decimal can be anywhere begin from 1-126.

First octet (8 bits) identify network. For other 3 identify the host.

Class B Network

Binary add will start with 10, so, decimal can be anywhere begin from 128-191.

For decimal 127 reserved for LOPBACK and used for internal testing on local machine.

For the first 2 octet (16bits) identfy network, other 2 octet should be indicate the host.

Class C Network

Binary add will start with 110, so, decimal  can be anywhere begin from 192-223.

For the first 3 octet (24 bits) identify network, other 1 should indicate the host.

Class D Network

Binary add will start with 1110 therefore decimal can be anywhere begin from 224-239.

Its used to support multiasking ( multi layers).

Class E Network

Binary add will starts with 1111 therefore decimal can be anywhere from 240-255.

Its used for experimentation.

DOMAIN NAME SYSTEM (DNS)

· DNS, Internet service that able to translates domain names into IP addresses. Domain names are alphabetic, its will easier to remember. However, Internet is really based on IP addresses. 

·Each time use a domain name, so, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com should be translate to 198.105.232.4.

·The DNS system has own network. If one DNS server not able to translate a particular domain name, its will asks another one, and so on, until the correct IP address is returned.

· The Domain Name System makes it possible to assign domain names to groups of Internet resources and users in a meaningful way, independent of each entity's physical location. 

·Because of this, World Wide Web (WWW) hyperlinks and Internet contact information can remain consistent and constant even if the current Internet routing arrangements change or the participant uses a mobile device.

·Internet domain names are easier to remember than IP addresses. Users take advantage of this when they recite meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates them.

·DNS also stores other types of information, such as the list of mail serversthat accept email for a given Internet domain. By providing a worldwide, distributed keyword-based redirection service, the Domain Name System is an essential component of the functionality of the Internet.

INTERNET ACCESS PROVIDER (ISP)

· An Internet service provider (ISP) is an organization that provides access to the Internet. Internet service providers can be either community-ownedand non-profit, or privately owned and for-profit.

·Access ISPs directly connect clients to the Internet using copper wires,wireless or fiber-optic connections.

·ISP, it refers to a company that provides Internet services, including personal and business access to the Internet. For a monthly fee, the service provider usually provides a software package, username, password and access phone number.

·Equipped with a modem, you can then log on to the Internet and browsethe World Wide Web and USENET, and send and receive e-mail. For broadband access you typically receive the broadband modem hardware or pay a monthly fee for this equipment that is added to your ISP account billing.

·In addition to serving individuals, ISPs also serve large companies, providing a direct connection from the company's networks to the Internet. ISPs themselves are connected to one another through Network Access Points (NAPs). ISPs may also be called IAPs (Internet Access Providers).

HTTP

·HTTP stands for HyperText Transfer Protocol. Hypertext is a multi-linear set of objects, building a network by using logical links (the so calledhyperlinks) between the nodes (e.g. text or words).

·HTTP is the protocol to exchange or transfer hypertext.

·It’s what browsers and web servers rely on for exchanging data so that you can surf the web, browse web pages, search Google, download pictures, and viewing YouTube.

·Developed by W3C and IETF in the last few years of the last century, it’s part of a bigger protocol family created to support the whole Internet, called TCP/IP. As a subset, HTTP’s responsibility is the World Wide Web or WWW.

·By HTTP definition and usage, it’s fundamentally an information exchanging procedure standard between 2 communicating parties or computers, such as the client and the server.

·While you type a URL address in the web browser, the browser will have to know the protocol to use when fetching the remote resource such as a web page or a picture at that address. Failing to do so, as we most of the time would do without the http:// part, the browser will assume HTTP by default and prepend it to the URL address.

A web address representing an access point on the web almost always start with http://, immediately followed by the web page address such as in this one ‘http://www.google.com/’.

·This is the root web site address of Google. And browsing to it, the server located at the address would serve up the home page of Google. This is all beyond the meaning of HTTP however, what this basically means is that, a web address consists of 2 basic parts: Protocol (HTTP) & Address (WWW.GOOGLE.COM).

Wireless Networking

Wireless networking overview

- NETGEAR products conform to the Institute of Electronics Engineers (IEEE).
- 802.11g standard for wireless LANs.
- 802.11 wireless link, data is encoded using direct-sequence spread-spectrum (DSSS) technology, transmitted in the unlicensed radio spectrum at 2.5 GHz.
- 54Mbps is maximum data rate for the 802.11g wireless link, also will automatically back down from 54Mbps when the radio is weak and interference is occur.
- 802.11 standard ( Wireless Ethernet or Wi-Fi ) by the Wireless Ethernet Compatibility Alliance (WECA, see http://www.wi-fi.net), an industry standard group promoting interoperability among 802.11 standard offers two methods for configuring a wireless network- ad hoc infrastructure.


Infrastructure mode


- Wireless access point, the wireless LAN can operate in the infrastructure mode.
- This mode lets you connect wirelessly to wireless network devices within a  area of coverage.


- The access point has one or more antennas that allow you to interact with wireless nodes.
- The wireless access point converts airwave data into wired Ethernet data, acting as a bridge between the wireless LAN and wireless clients.
- Connecting multiple access points via a wired Ethernet backbone can further extend the wireless network coverage.
-  As a mobile computing device moves out of the range of one access point, it moves into the range of another.
- As a result, wireless clients can freely roam from one access point domain to another and still
maintain seamless network connection.




Ad Hoc mode ( Peer-to-peer Workgroup)


- Computers are brought together as needed.
- The network has no structure or fixed points- each node can be set up to communicate with any other node.
- No access point is involved in this configuration.
- This mode enables you to quickly set up a small wireless workgroup and allows workgroup members to exchange data or share printers as supported by Microsoft® networking in the various Windows® operating systems.
- Some vendors also refer to ad hoc networking as peer-to-peer group networking.
- Network packets are directly sent and received by the intended transmitting
and receiving stations.
- As long as the stations are within range of one another, this is the easiest
and least expensive way to set up a wireless network.


Network name - Extended Service Set Identification (ESSI)




- One of two types of Service Set Identification (SSID).
- In an ad hoc wireless network with no access points, the Basic Service Set Identification
(BSSID) is used.
- In an infrastructure wireless network that includes an access point, the ESSID is used, but may still be referred to as SSID.
- An SSID is a 32-character (maximum) alphanumeric key identifying the name of the wireless local
area network.
- Some vendors refer to the SSID as the network name. For the wireless devices in a
network to communicate with each other, all devices must be configured with the same SSID.


Wireless Channel




- IEEE 802.11g/b wireless nodes communicate with each other using radio frequency signals in the
ISM (Industrial, Scientific, and Medical) band between 2.4 GHz and 2.5 GHz.
- Neighboring channels are 5 MHz apart.
- Due to the spread spectrum effect of the signals, a node sending signals using a particular channel will utilize frequency spectrum 12.5 MHz above and below the center channel frequency.
- Two separate wireless networks using neighboring channels (for example, channel 1 and channel 2) in the same general vicinity will interfere with each other.
- Applying two channels that allow the maximum channel separation will decrease the
amount of channel cross-talk and provide a noticeable performance increase over networks with
minimal channel separation.




- The available channels supported by wireless products in various countries are
different.
• Regulations in the United States prohibit using channels greater than channel 11.
• For NETGEAR products sold outside the United States, the wireless region
selection determines which channels are available for use in the product.




- The preferred channel separation between the channels in neighboring wireless networks is
25 MHz (five channels).
- This means that you can apply up to three different channels within your
wireless network. In the United States, only 11 usable wireless channels are available, so we
recommended that you start using channel 1, grow to use channel 6, and add channel 11 when
necessary, because these three channels do not overlap.

WEP Wireless Security

-         The absence of a physical connection between nodes makes the wireless links vulnerable to eavesdropping and information theft.

-         To provide a certain level of security, the IEEE 802.11 standard has defined two types of authentication.:

-          Open System authentication, a wireless computer can join any network and receive any messages that are not encrypted.

The following steps occur when two devices use Open System Authentication:

1. The station sends an authentication request to the access point.

 2. The access point authenticates the station.

 3. The station associates with the access point and joins the network.

-         Shared Key authentication, only those computers that possess the correct authentication key can join the network.

The following steps occur when two devices use Shared Key Authentication:

1. The station sends an authentication request to the access point.

2. The access point sends challenge text to the station.

3. The station uses its configured 64-bit or 128-bit default key to encrypt the challenge text, and it sends the encrypted text to the access point.

4. The access point decrypts the encrypted text using its configured WEP key that corresponds to the station’s default key. The access point compares the decrypted text with the original challenge text. If the decrypted text matches the original challenge text, then the access point and the station share the same WEP key, and the access point authenticates the station.

5. The station connects to the network.

Key Size and Configuration


The IEEE 802.11 standard supports two types of WEP encryption: 40-bit and 128-bit.


- The 64-bit WEP data encryption method allows for a five-character (40-bit) input. 
- 24 factory-set bits are added to the forty-bit input to generate a 64-bit encryption key. (The 24 factory set
bits are not user-configurable). 
- This encryption key will be used to encrypt/decrypt all data transmitted via the wireless interface. 
- Some vendors refer to the 64-bit WEP data encryption as 40-bit WEP data encryption because the user-configurable portion of the encryption key is 40 bits wide.

- The 128-bit WEP data encryption method consists of 104 user-configurable bits. 
-Similar to the 40- bit WEP data encryption method, the remaining 24 bits are factory-set and not user-configurable.
- Some vendors allow pass phrases to be entered instead of the cryptic hexadecimal characters to
ease encryption key entry.
- The 128-bit encryption is stronger than 40-bit encryption, but 128-bit encryption may not be
available outside the United States due to U.S. export regulations.
- When configured for 40-bit encryption, 802.11 products typically support up to four WEP keys.
- Each 40-bit WEP key is expressed as five sets of two hexadecimal digits (0–9 and A–F). For
example, “12 34 56 78 90” is a 40-bit WEP key.
- When configured for 128-bit encryption, 802.11g products typically support four WEP keys, but
some manufacturers support only one 128-bit key. 
- The 128-bit WEP Key is expressed as 13 sets of two hexadecimal digits (0–9 and A–F). For example, “12 34 56 78 90 AB CD EF 12 34 56 78 90” is a 128-bit WEP key.
- Typically, 802.11 access points can store up to four 128-bit WEP keys, but some 802.11 client
adapters can only store one.
- Make sure that your 802.11 access and client adapters configurations match.
-Whatever keys you enter for an access point, you must also enter the same keys for the client
adapter in the same order. 







How to Use WEP Parameters


- WEP data encryption is used when the wireless devices are configured to operate in Shared Key authentication mode. 
- Before enabling WEP on an 802.11 network, you must first consider what type of encryption you require and the key size you want to use.
-There are three WEP Encryption options available for 802.11 products:


• Do Not Use WEP: The 802.11 network does not encrypt data. For authentication purposes, the network uses Open System Authentication.


• Use WEP for Encryption: A transmitting 802.11 device encrypts the data portion of every packet it sends using a configured WEP key. The receiving 802.11g device decrypts the data using the same WEP key. For authentication purposes, the 802.11g network uses Open System Authentication.


• Use WEP for Authentication and Encryption: A transmitting 802.11 device encrypts the data portion of every packet it sends using a configured WEP key. The receiving 802.11 device
decrypts the data using the same WEP key. For authentication purposes, the 802.11 network uses Shared Key Authentication.

WPA Wireless Security

-Wi-Fi Protected Access (WPA) is a specification of standards-based, interoperable security enhancements that increase the level of data protection and access control for existing and future wireless LAN systems.


- WPA offers the following benefits:


• Enhanced data privacy
• Robust key management
• Data origin authentication
• Data integrity protection



How Does WPA Compare to WEP?


- WEP is a data encryption method and is not intended as a user authentication mechanism. 
- WPA user authentication is implemented using 802.1x and the Extensible Authentication Protocol (EAP). 
- Support for 802.1x authentication is required in WPA.
- In the 802.11 standard, 802.1x authentication was optional. Refer to IETF RFC 2284.
- With 802.11 WEP, all access points and client wireless adapters on a particular wireless LAN must use the same encryption key. 
- A major problem with the 802.11 standard is that the keys are
cumbersome to change. 
- If you do not update the WEP keys often, an unauthorized person with a sniffing tool can monitor your network for less than a day and decode the encrypted messages.
- Products based on the 802.11 standard alone offer system administrators no effective method to update the keys.
- For 802.11, WEP encryption is optional. For WPA, encryption using Temporal Key Integrity
- Protocol (TKIP) is required. TKIP replaces WEP with a new encryption algorithm that is stronger than the WEP algorithm, but that uses the calculation facilities present on existing wireless devices to perform encryption operations. 
- TKIP provides important data encryption enhancements
including a per-packet key mixing function, a message integrity check (MIC) named Michael, an extended initialization vector (IV) with sequencing rules, and a re-keying mechanism. 
- Through these enhancements, TKIP addresses all known WEP vulnerabilities.



How Does WPA Compare to IEEE 802.11i?


- WPA is forward-compatible with the IEEE 802.11i security specification currently under development.
- WPA is a subset of the current 802.11i draft and uses certain pieces of the 802.11i draft that were ready to bring to market in 2003, such as 802.1x and TKIP.
- The main pieces of the 802.11i draft that are not included in WPA are secure IBSS (Ad-Hoc mode), secure fast handoff
(for specialized 802.11 VoIP phones), as well as enhanced encryption protocols such as AESCCMP.
- These features are either not yet ready for market or will require hardware upgrades to implement.



What are the Key Features of WPA Security?


The following security features are included in the WPA standard:
• WPA Authentication.
• WPA Encryption Key Management.
– Temporal Key Integrity Protocol (TKIP).
– Michael message integrity code (MIC).
– AES Support.
• Support for a Mixture of WPA and WEP Wireless Clients.


Definition: 802.11a wireless network communication standard. One of the IEEE standards in the 802.11 series.

802.11a and wireless Interference

- 802.11a transmit radio signals in the frequency range above 5 GHz, a part of wireless spectrum regulated in many countries.

- Regulation means 802.11a gear generally avoids signal interference from other consumer wireless products like cordless phones.

- In contrast, 802.11b/g utilizes frequencies inthe unregulated 2.4 GHz range and is more susceptible to radio interference from other devices

Range of 802.11a networks

- Helps improve network performance and reduce interference the range of an 802.11a signal is limited by use of the high 5 GHz frequency. 

- An 802.11a access point transmitter may cover less than one-fourth the area of a comparable 802.11 b/g unit.

- Brick walls and other obstructions affect 802.11a wireless networks to a greater degree than they do comparable 802.11b/g networks.

Network cabling

Type of cable:

Unshielded twisted pair







Coaxial cable

Fiber Optic




Unshielded twisted pair characteristics:

-Unshielded .

-least expensive cable.

-Twisted pairs of .insulated conductors.

-Covered by insulating sheath. 

-Radio and electrical frequency interference (should not be too close to electric motors, fluorescent lights.

Each pair is twisted with a different number of twist per inch to help eliminate interference from adjacent pairs and other electrical devices. 

The tighter the twisting, the higher the supported transmission rate and the greater the cost  per foot.

 Cat5e cable:

-1000Mbps data capacity.

-For runs of up to 90 meters.

-Solid core cable ideal for structural installations (PVC or Plenum).

-Stranded cable ideal for patch cables.

RJ-45 connectors:

-Terminated with RJ-45 connectors (plastic connector).

-RJ - Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. 

-This standard designates which wire goes with each pin inside the connector.

-Best option for school networks.

RJ-45 connectors          

Shielded Twisted Pair (STP) Cable: 

-Shielded twisted pair may be the solution for the interference of UTP connectors.

- Help to extend the maximum distance of the cables

- Available in three different configurations:

Each pair of wires is individually shielded with foil.

There is a foil or braid shield inside the jacket covering all wires (as a group).

There is a shielded around each individual pair, as well as around the entire group of wires (referred to as double twisted pair).

Coaxial Cable:

-Single copper conductor at its center.

-A plastic layer provides insulation between the center conductor and a braided metal shield 

-The metal shield helps to block any outside interference from fluorescent lights, motors, and others computer.

-Difficult to install.

-Highly resistant to signal interference.

-Support greater cable lengths between network devices than twisted pair cable.

-Thick coaxial and thin coaxial.

Thin coaxial:

-Also called thinnet. 

-10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals.

-2 refers to the approximate maximum segment length being 200 meters.

-Maximum segment length is 185 meters.

-popular in school networks, especially linear bus networks.

Thick coaxial :

-Also called thicknet.

-The 5 refers to the maximum segment length being 500 meters.

-has an extra protective plastic cover that helps keep moisture away from the center conductor.

-Great choice when running longer lengths in a linear bus network.

-One disadvantage does not bend easily and is difficult to install.

Coaxial Cable Connecter:

- Common type of connector used is the Bayone-Neill-Concelman (BNC) connector.

Fiber Optic Cable:

-Center glass core surrounded by several layers of protective .

-Transmits light rather than electronic signals eliminating the problem of electrical interference. 

-Environments  a large amount of electrical interference. 

-Made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.

-To transmit signals over much longer distances than coaxial and twisted pair. 

-Carry information at vastly greater speeds.

-Capacity broadens communication possibilities to include services such as video conferencing and interactive services.

-The cost ofvis comparable to copper cabling; however, it is more difficult to install and modify.

-10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals.

-center core of  is made from glass or plastic fibers.

-A plastic coating then cushions the fiber center, and kevlar fibers help to strengthen the cables and prevent breakage.

 single mode :

-Can provide more distance, but it is more expensive.

Multimode :

-larger diameter; however, both cables provide high bandwidth at high speeds.

Specification	Cable Type
10BaseT	Unshielded Twisted Pair
10Base2	Thin Coaxial
10Base5	Thick Coaxial
100BaseT	Unshielded Twisted Pair
100BaseFX	Fiber Optic
100BaseBX	Single mode Fiber
100BaseSX	Multimode Fiber
1000BaseT	Unshielded Twisted Pair
1000BaseFX	Fiber Optic
1000BaseBX	Single mode Fiber
1000BaseSX	Multimode Fiber

 Making connection:

-Cat5e cable

-RJ45 connectors

-Cable stripper

-Scissors

-Crimping tool

Making connection steps:

1.Strip cable end

 - Strip 1 – 1½” of insulating sheath.

-Avoid cutting into conductor insulation.

2.Untwisted wire ends.

-Sort wires by insulation colors.

3.Arrange wires.
-TIA/EIA 568A: GW-G OW-Bl BlW-O BrW-Br

-TIA/EIA 568B: OW-O GW-Bl BlW-G BrW-Br

4.Trim wires to size.
lTrim all wires evenly
lLeave about ½” of wires exposed

5.Attach connector.

-Maintain wire order, left-to-right, with RJ45 tab facing downward.

6.Check.
-Do all wires extend to end?

-Is sheath well inside connector?

7.Crimp test.

-Squeeze firmly to crimp connecter onto cable end (8P)
8. Test.

-Does the cable work?

Installing Cable - some guidelines

When running cable, it is best to follow a few simple rules:

-Always use more cable than you need. Leave plenty of slack.
-Test every part of a network as you install it. Even if it is brand new, it may have problems that will be difficult to isolate later.
-Stay at least 3 feet away from fluorescent light boxes and other sources of electrical interference.
-If it is necessary to run cable across the floor, cover the cable with cable protectors.
-Label both ends of each cable.
-Use cable ties (not tape) to keep cables in the same location together.