Routing ( Static & Dinamis)

Routing is the process of directing packets from the source node to destination node on the network that berbeda.Mendapatkan packet to the next hop router they need to perform two basic activities: tekaddan path packet switching.
Path determination
Involve reviewing all the paths to the destination network and selecting the optimal route. To determine the optimal route, information is entered into the route table, which includes information such as network destination, next hop, and related metrics.
Packet switching
Involve physical changes to the packet's destination address to that of the next hop (logical destination address of the source package and will remain the same).
Routers need to know information to route packets
• The destination address.
• Neighbor routers.
• Possible routes to all remote networks.
• The best route for each network.
• How to maintain and verify routing information.
Routers learn about remote networks from neighbor routers or administrator. The router then builds a routing table that tells how to get to the remote network. Routes are either directly connected, static, or dynamic. Static routes entered by the administrator. Dynamic routes learned from neighboring routers using routing protocols. In dynamic routing, routers update each other on a specified interval. Changes cause the router to update all other routers. If the router receives a packet with the destination network is not in the routing table, it will discard the packet.

STATIC ROUTING


The process of manually adding a route in the routing table of each router. Administrators configure the destination network, the next hop, and appropriate metrics. The route does not change until the network administrator changes it.
Profit
• No overhead on the router CPU.
• No use of bandwidth between the links.
• Security (only the administrator added the route).
Shortage
• The administrator must really understand the internetwork and how each router is connected.
• If the new network is added, the administrator must update all routers.
• Not practical on a large network because the time-intensive.
Examples of static routes
Router3 routes (config) # ip 192.168.1.0 255.255.255.0 serial0 permanent

DINAMIC ROUTING

Routes dynamically adjust to changes in the internetwork environment automatically. When there is change in the network, the router begins to converge with re-calculate the route and distribute route update. Route update messages spread through the network, which causes other routers to recalculate their routes. The process continues until all routes have been gathered. Using the protocol for finding and updating routes in the routing table. It uses CPU time and consumes bandwidth between the links. Routing protocol defines the rules used by the router when they communicate with each other.
There are two types of routing protocols in the internetwork, Interior Gateway Protocol (IGP) and Exterior Gateway Protocol (EGP). IGP is used within the network in the same administrative domain. EGPs are used to communicate between domains.
Routers to route the lines that formed automatically by the router itself according to the configuration are made. If there are changes in inter-network topology, the router will automatically create a new routing.
Pros:
• Dynamic Routing will always update and menenntukan jalur2nya in its routing table.
• Dynamic Routing not only create the best path to a different network, dynamic roting will also determine the new path is good if the goal is not te
rsedia (if the topology changes).
• Automatically divides its routing information to other routers and adapt to the changing topology of the arrangement tenpa s
eorang network admin.
weaknesses:
• Dynamic routing will be a burden in terms of processes in the CPU bandwidth usage of routers and network links.
When using dynamic routing:
Static routing is usually used for large-scale networks.


The IP Routing Process
The IP Routing Process
The IP routing process is fairly direct when a datagram's destination is located on a neighboring network. In this kind of situation, a router would follow a simple procedure

First, when a workstation wants to send a packet to a destination host, in this instance 160.1.0.1 transmitting to 160.2.0.4, host 160.1.0.1 checks the destination IP address. If it determines the address isn't on the local network, it must then be routed. Next, 160.1.0.1 calls on ARP to obtain the hardware address of its default gateway. The IP address of the default gateway is configured in machine 160.1.0.1's internal configuration, but 160.1.0.1 still needs to find the hardware address of the default gateway, and sends out an ARP request to get it. IP then proceeds to address the packet with the newly obtained destination hardware address of its default router. The information utilized for addressing the packet includes:
• Source hardware address 1
• Source IP address 160.1.0.1
• Destination hardware address 5
• Destination IP address 160.2.0.4
IP, on the receiving router with the hardware address of 5, establishes that it is not the final, intended recipient by inspecting the packet's destination IP address, which indicates it must be forwarded to network 160.2. Then, IP uses ARP to determine the hardware address for 160.2.0.4. The router then puts the newly identified hardware address into it's ARP cache for easy reference the next time it's called upon to route a packet to that destination.