Q1. What is the Internet and the relationship between routers?
Answer: the first now behold, what is the Internet?Computers will be able to exchange messages, connect to the Internet is sent from one computer to another. When computer-Internet receiving the message, you need to find out how to deliver to.
Next, how the Internet give messages? The Internet is routers and protocols.Routers are hardware-device to one task: redirect packets. Protocols are the rules that decide to forward packets paths.Routers and Internet protocols must be able to move between messages.
Q2. what router?
Answer: the router is a network device that forwards packets to their destinations by the per-item. it points out how mail mails processing premises.
Is the sender's and recipient's addresses.The postal Office uses e-mail messages are delivered to the following postal Office, which is closer to that of the receiver is delivered to the recipient's address. Mail Stop after more than one recipient.
-Computer messages are transported in a package called into smaller parts. Each packet contains the sender's IP address and the recipient's IP address. Routers use the package recipient address to deliver the next-hop router that is closer to the target. The package will be delivered to more than one Stop after the recipient.
Q3.How to connect hosts and routers?
Answer: the hosts from a local network connected to the Internet Gateway routers, the gateway router. is connected to the core routers.The Internet has made many gateway routers and core routers in the middle of the border.Gateway routers often use a variety of different types of interface technologies and security features. Core routers to focus forward packets at high speed.Routers use the routing table for forwarding packets decisions. Topology has clear companion aniation.
Q4. routing table properties
Answer: the Routing table is router core data structure.It contains (destination address, the next item in the interface). When the router receives the packet, it uses the package recipient address compare routing table destination addresses.If a match is found, the router sends the packet to the "next hop" to the interface. If a match is not found, the router will drop the packet.
For example, the R1 's routing table contains 3 entries:
-(100.4.5.6, Port1). It means to forward packets to join 100.4.5.6 Port1.
-(150.1.2.3, Port2). It is to forward packets to join Port2 150.1.2.3.
-(222.111.44.33, Port2).It means to forward packets to join Port2 222.111.44.33.
Q5.How to build the routing tables?
Answer: this Is to build the routing tables in two ways:
(A)) static routing table.The network administrator configure the routing table for each router manually.It was common for 20 years ago, when the number of routers is small.
B) dynamic routing table.Routers use routing protocols to find a network topology, routing paths and execution shall be calculated in the routing paths.Two popular routing protocols are the OSPF and RIP.See simulations OSPF and RIP.
Q6. how big is the routing table?
Answer: approximately 4.2 billion IP addresses (an IP address is 32 bits. 2 ^ 32 is approximately 4.2 billion.)Have more than one routing table can hold. non-multiple routes.
This animation we want readers of the main ideas and use routers individual IP addresses Actually routing tables use the routing tables. network address, not a single IP address for more information, please go to the next tutorial..
Q7. what network address?
Answer: the network address is similar to a ZIP Code/postal code. the same zip code has thousands of street addresses. Mail your mail to sort their postal code, and emails are delivered to the next hop to him, the last post office, e-mail, zip/postal code. shall be forwarded to the street addresses.
Routers forward packets to the destination IP address. but the actual search is done by using the IP address of the network address portion may be hundreds or thousands of hosts use the same network address. see the guidance at the IP address of the series: the network address.
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