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chapter_1_-_internet_networks_and_tcp-ip:1-3_networking_basics [2013/01/22 15:51]
cellbiol
chapter_1_-_internet_networks_and_tcp-ip:1-3_networking_basics [2013/10/16 14:59] (current)
cellbiol
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 +~~NOCACHE~~
 ===== 1-3: Networking Basics ===== ===== 1-3: Networking Basics =====
  
-From the previous sections, it should now be clear that routers play a key role in regulating and making possible the data flow on the Internet based on the TCP/IP standards. Indeed some routers are big, costly, complex pieces of hardware located in key nodes of the world network (Figure 1-8). +From the previous sections, it should now be clear that routers play a key role in regulating and making possible the data flow on the Internet based on the TCP/IP standards. Indeed some routers are big, costly, complex pieces of hardware located in key nodes of the world network (Figure 1-3-1). 
  
-== Figure 1-8: The Avaya ERS 8600 router ==+== Figure 1-3-1: The Avaya ERS 8600 router ==
 //Image source: [[http://​en.wikipedia.org/​wiki/​Router_(computing)|Wikipedia]]//​ //Image source: [[http://​en.wikipedia.org/​wiki/​Router_(computing)|Wikipedia]]//​
  
 {{ :​chapter_1_-_internet_networks_and_tcp-ip:​ers-8600.jpeg?​200 |}} {{ :​chapter_1_-_internet_networks_and_tcp-ip:​ers-8600.jpeg?​200 |}}
  
-However, inexpensive,​ light weight routers are now available, from many different manufacturers,​ that allow the easy creation of an home or office Local Area Network, and the connection of this LAN to the Internet (Figure 1-9). This second step is optional, it is perfectly possible, with such routers, to create a private LAN not connected to the internet. Some models will allow the creation of more than one LAN (for example a private LAN reserved to lab members and a guest LAN, with a printer and internet access), but we will not discuss this here.+However, inexpensive,​ light weight routers are now available, from many different manufacturers,​ that allow the easy creation of an home or office Local Area Network, and the connection of this LAN to the Internet (Figure 1-3-2). This second step is optional, it is perfectly possible, with such routers, to create a private LAN not connected to the internet. Some models will allow the creation of more than one LAN (for example a private LAN reserved to lab members and a guest LAN, with a printer and internet access), but we will not discuss this here.
  
-== Figure 1-9: Home routers ==+== Figure 1-3-2: Home routers ==
 //Image source: [[http://​www.cellbiol.com/​bioinformatics_web_development|cellbiol.com]]//​ //Image source: [[http://​www.cellbiol.com/​bioinformatics_web_development|cellbiol.com]]//​
  
 {{ :​chapter_1_-_internet_networks_and_tcp-ip:​home_routers.png |}} {{ :​chapter_1_-_internet_networks_and_tcp-ip:​home_routers.png |}}
  
-Home routers have several ethernet ports on the back. Typically 5 for smaller models (Figure 1-9). One of these ports have the purpose of connecting the router to the Internet. The other 4 allow the connection of network devices such as computers, printers, scanners, network drives (for storage and backups) and more. All these devices of course support TCP/IP. In addition to connecting the devices via ethernet cables, more devices (or all the devices) can be connected through a wireless connection. From the network point of view there is no particular difference between a device connected by wireless and a device connected by cable. They are both connected to the router and belong to the same LAN.+Home routers have several ethernet ports on the back. Typically 5 for smaller models (Figure 1-3-2). One of these ports have the purpose of connecting the router to the Internet. The other 4 allow the connection of network devices such as computers, printers, scanners, network drives (for storage and backups) and more. All these devices of course support TCP/IP. In addition to connecting the devices via ethernet cables, more devices (or all the devices) can be connected through a wireless connection. From the network point of view there is no particular difference between a device connected by wireless and a device connected by cable. They are both connected to the router and belong to the same LAN.
  
-In a typical scenario, the router is configured as DHCP server, which means it will provide a LAN IP address to any device that is connected to it, either by a wire or wirelessly (Figures 1-10 and 1-12). This address is a local address, only visible INSIDE the LAN. This address, that might be something like 192.168.1.24,​ is not a public internet address, this is a crucial concept to understand in this discussion.+In a typical scenario, the router is configured as DHCP server, which means it will provide a LAN IP address to any device that is connected to it, either by a wire or wirelessly (Figures 1-3-3 and 1-3-4). This address is a local address, only visible INSIDE the LAN. This address, that might be something like 192.168.1.24,​ is not a public internet address, this is a crucial concept to understand in this discussion.
  
  
-== Figure 1-10: Creating and connecting a network to the internet through a router ==+== Figure 1-3-3: Creating and connecting a network to the internet through a router ==
 //Image source: [[http://​www.cellbiol.com/​bioinformatics_web_development|cellbiol.com]]//​ //Image source: [[http://​www.cellbiol.com/​bioinformatics_web_development|cellbiol.com]]//​
  
 {{ :​chapter_1_-_internet_networks_and_tcp-ip:​creating_and_connecting_a_network_to_the_internet.png |}} {{ :​chapter_1_-_internet_networks_and_tcp-ip:​creating_and_connecting_a_network_to_the_internet.png |}}
  
-The router configuration can be fine-tuned in the router administration interface. This is accessible from any computer connected to the router, for example through a ethernet cable connecting the computer to one of the LAN ethernet ports on the router. No internet connection is required at this time, just a cable between the computer and the router. The router admin interface is accessed through a browser, by typing the IP address of the router (Figure 1-11). +The router configuration can be fine-tuned in the router administration interface. This is accessible from any computer connected to the router, for example through a ethernet cable connecting the computer to one of the LAN ethernet ports on the router. No internet connection is required at this time, just a cable between the computer and the router. The router admin interface is accessed through a browser, by typing the IP address of the router (Figure 1-3-4). 
  
-== Figure 1-11: A NETGEAR router administration interface ==+== Figure 1-3-4: A NETGEAR router administration interface ==
 //Image source: snapshot// //Image source: snapshot//
  
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-Please note that the router, at the end of the day, will have 2 different IP addresses (see Figure 1-10), one "for the inside"​ of the LAN - the router will be the gateway of the LAN so this is known as the gateway address - , another one for the Internet. To connect to the admin interface of the router we need to type the internal/​gateway address. This will typically be something like 192.168.1.1,​ that is, on the LAN, the router will reserve the number 1 (the last number in the IP address) for himself. It can then assign one of the other 244 addresses available (from 192.168.1.2 to 192.168.1.225) to any device that is connected to the router'​s LAN.+Please note that the router, at the end of the day, will have 2 different IP addresses (see Figure 1-3-3), one "for the inside"​ of the LAN - the router will be the gateway of the LAN so this is known as the gateway address - , another one for the Internet. To connect to the admin interface of the router we need to type the internal/​gateway address. This will typically be something like 192.168.1.1,​ that is, on the LAN, the router will reserve the number 1 (the last number in the IP address) for himself. It can then assign one of the other 244 addresses available (from 192.168.1.2 to 192.168.1.225) to any device that is connected to the router'​s LAN.
  
 Devices inside the LAN can see each other through their internal LAN addresses, the ones assigned to each by the router when they were connected. You can think of a LAN as a "small Internet",​ where the same rules and protocols (TCP/IP of course) apply, as in the "​real"​ Internet. Inside a big LAN (say a department or Faculty LAN) you could have web servers, mail servers, FTP servers and all the goodies you might expect on the Internet, even if the LAN is totally disconnected from the Internet. All the services (for example websites) would be available only to those connected to the LAN. Such model is sometimes referred to as an "​[[http://​en.wikipedia.org/​wiki/​Intranet|Intranet]]",​ and it is commonly found within organizations of every kind, including academic and research centers. Devices inside the LAN can see each other through their internal LAN addresses, the ones assigned to each by the router when they were connected. You can think of a LAN as a "small Internet",​ where the same rules and protocols (TCP/IP of course) apply, as in the "​real"​ Internet. Inside a big LAN (say a department or Faculty LAN) you could have web servers, mail servers, FTP servers and all the goodies you might expect on the Internet, even if the LAN is totally disconnected from the Internet. All the services (for example websites) would be available only to those connected to the LAN. Such model is sometimes referred to as an "​[[http://​en.wikipedia.org/​wiki/​Intranet|Intranet]]",​ and it is commonly found within organizations of every kind, including academic and research centers.
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 ==== Chapter Sections ==== ==== Chapter Sections ====
 +<box 100% left round blue | **Chapter 1**>
 +<​html>&​nbsp;</​html>​
   * [[chapter_1_-_internet_networks_and_tcp-ip:​start|Introduction]]   * [[chapter_1_-_internet_networks_and_tcp-ip:​start|Introduction]]
   * **1-1**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-1_data_transmission_on_the_internet|Data Transmission on the Internet]]   * **1-1**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-1_data_transmission_on_the_internet|Data Transmission on the Internet]]
   * **1-2**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-2_the_tcp-ip_family_of_internet_protocols|The TCP/IP Family of Internet Protocols]]   * **1-2**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-2_the_tcp-ip_family_of_internet_protocols|The TCP/IP Family of Internet Protocols]]
-  * **1-3**: Networking Basics+  * **1-3**: ​[[chapter_1_-_internet_networks_and_tcp-ip:​1-3_networking_basics|Networking Basics]]
   * **1-4**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-4_domain_name_server|Domain Name Servers: DNS, matching network IP addresses to domain names]]   * **1-4**: [[chapter_1_-_internet_networks_and_tcp-ip:​1-4_domain_name_server|Domain Name Servers: DNS, matching network IP addresses to domain names]]
  
 [[:​start|Back to main index]] [[:​start|Back to main index]]
 +</​box>​
chapter_1_-_internet_networks_and_tcp-ip/1-3_networking_basics.1358887877.txt.gz · Last modified: 2013/01/22 15:51 by cellbiol