Routing is the process by which a router forwards packets to the intended network. A router makes decisions according to the IP address addressed by the packet. All routers use the destination IP address to send packets. In order for the routing decision to be correct, the router must learn how to reach the destination. As routers use routing moving forward, this news is learned from other routers. When using static routing, a network administrator configures information about the network you want to go to manually.
If the routing used is inactive, then the configuration must be done manually, the network administrator must enter or remove the inactive route in case of a topological change. On a large-scale network, if you continue to use inactive routing, it will be very discarded when the network administrator to update the routing table. Therefore, inactive routing is only possible for small-scale networks. While dynamic routing can be applied to large-scale networks and requires more capabilities according to administrators.
To be able to route the expected router.Router is a problem that is used to connect personal computer 1 with others, at the end of the computer can relate to other personal computers because of the IP Address. IP Address is the address that has a personal computer, with the IP Address the computer can connect one another, the IP address that connects between computers must be one of the networks, but with the presence of a personal router computer that has a different segment can connect.
Information a router needs
Destination Address – The destination or address of the host to berouting
Know the origin of the news – Where does the origin (other routers) that can be learned by the router & provide a path to the destination.
Find a route – Which route or path might be taken all the way to the destination.
Route selection – The best route taken to get to the destination.
Maintain routing coverage – A way to keep the path to the destination that has been known &most often traversed.
As we know, the router serves as a network traffic controller or manages the running of IP addresses with different segments. Routers actually have functions or capabilities such as the following:Set frequency paths effectivelySet Messages between two protocol itemsSet Messages between bus &star linear network topologiesSet messages between passing fiber optic cables, coaxial cables or twisted pair cables.
Routers work in the 3rd layer of OSI layer. Usually the router’s task is to send / send packets using the most optimal metric, the router only needs to know the Net-Id (network number) of the data it receives to be forwarded to the intended network. How it works every data packet that arrives, the data packet was opened and then read the header of the data packet and then match or compare into the table in the routing network and forwarded to the intended network through an interface. To find out which network will be passed the router will add (Logical AND) Subnet Mask using the data package.
The direction of the transmitted packet may be learned from the task layer to the 3rd OSI layer i.e. IP address. Routers are always associated as gateways but in fact the gateway should not be a router. Routers still have hardware components and software for example on Cisco router software used called Cisco IOS (Internetworking Operating System). The hardware of a router consists of a CPU e.g. Cisco router 2505 using a 20MHz Processor Motorola 68EC030. In addition, the router also has memory components such as NVRAM, flash RAM, and RAM.
A router is a device that sends data packets over a network or the Internet to its destination, through a process known as routing. Routing processes occur at layer three (network layers such as the Internet Protocol) based on a seven-layer OSI protocol stack.
Router’s main function is to route packets (captions). A router has routing capabilities, is a router can intelligently know where the route of traveling news (packets) will be missed, whether intended for other hosts in the same network or on a different network.
if the packets are intended for the host on another network then the router will forward it to the network earlier. Conversely, if the packets are intended for a single network host then the router will block the packets out.
An illustration of how this router works can be observed in the picture below:
Figure 4.3.The principle of routing work
In the picture above there are two networks connected to a router. The left network connected to port 1 router has network address 192.168.1.0 & right network connected to port 2 according to router using network address 184.108.40.206Computer A sends data to personal computer C, then the router will not forward the data to another network.Once the computer F sends data to E, the router will not forward the data packet to another network.Only when personal computer F sends data to computer B, then the router will damage the data packet to computer B.
The way routers work is similar to using a network bridge, i.e. they can forward network data packets and can also divide the network as several segments or unite network segments. However, routers run on the third layer in the OSI (network layer) model, and use the addressing scheme used in that layer, as does ip addresses. Meanwhile, the network bridge runs in the second layer in the OSI (data-link layer) model, and uses the addressing scheme used at that layer, the MAC address.
Routers are used to connect network segments that run the network protocol (as is the case for connecting IP network segments using the IPX network segment.) In general, routers are smarter than network bridges and can increase network bandwidth, considering that the router does not forward broadcast packets to the intended network.
Static routing is a routing procedure that is done manually by creating routing tables on every router device. On a mini-scale network consisting of only 2 or 3 routers, we are more generic using static routing. Static routing must be configured manually & maintained manually as well because it cannot exchange routing table facts
Dynamic uses other routers. Inactive routing will work well when the routing tables in each network in the internetwork have been manually configured by the network administrator.
Each host in the network must be configured to lead to the default routing or default gateway to fit using the IP address according to the interface on the local router, the router will learn the routing table and choose which route to use to forward the packet.
The workings of static routing can be divided into three parts:The network administrator who configured the routerRouters routing based on news in table routingStatic routing is used to skip data packets4.2. Routing Default
The default route is a route that is believed to be suitable using all destination IP addresses.
With the default route time IP address destination (destination) according to a packet not found in the routing table, then the router will use the default route to forward the packet earlier. The default route works best when there is only one route to a network. the condition of creating default routing is having only one exit lane / 1 gateway to another network.4.3.Routing Dynamics
Dynamic router is a router that has and creates routing tables automatically using listening network traffic and also by cooperating with other routers. Routing protocols regulate routers so that they can communicate with each other and give each other facts using each other and provide routing information that can replace the contents of the forwarding table, depending on the state of the network. In this way, the routers know the state of the last network and are able to forward the data in the right direction. In other words, dynamic routing is the process of automatically filling in routing data on the routing table.