Path determination for traffic passing through a network cloud occurs at the network layer (layer 3). The path determination feature allows a router to evaluate the available paths to a destination and establish the preferred processing of a packet. Using routing services network topology information when evaluating network paths. This information can be configured by the network administrator or can be collected through dynamic processes running on the network. The network layer ensures optimal end-to-end packet delivery across interconnected networks. The network layer uses the IP routing table to send packets from the source network to the destination network. Once the router has determined which path to use, it proceeds to forward the packet. The router forwards the packet it accepted on one interface to another interface or port that reflects the best path to the packet's destination. Routing is the process a router uses to forward packets to the destination network. A router makes decisions based on the destination IP address of a packet. All devices along the way use the destination IP address to direct the packet in the right direction. The destination IP address allows the packet to ultimately arrive at its destination. To make the right decisions, routers must learn the direction to remote networks. When routers use dynamic routing, the direction to remote networks is learned from other routers. When static routing is used, a network administrator manually configures information on remote networks. Because static routes must be configured manually, any changes to the network topology require the network administrator to add and remove static routes to accommodate the changes. In a large network, this manual maintenance of routing tables can require considerable administrative time. On small networks with very few modifications possible, static routes require very little maintenance. Static routing does not have the scalability of dynamic routing due to additional administrative requirements. However, even in large networks, static routes intended to accomplish a very specific purpose are often configured in combination with a dynamic routing protocol. Although dynamic routing protocols can automatically determine routes, they must still be initially enabled and configured by a network administrator to accomplish this. So, routing concepts therefore have four sections:
1. The process of routing packets from source to destination
2. Addressing.
3. Path selection and packet switching
4. Routed and Routing Protocols
In summary, routing is the functionality that allows data to be routed from point A to
a point B located in a remote network. Routing, carried out by routers, is based on the address
Destination IP contained in the received packet.
- Teacher: Dr. Mohammed yousri SILAA