Quick Study Revision Points: Routing Algorithms and Protocols

Routing Algorithms:

1. Definition: Routing algorithms determine the best path for data packets to travel from a source to a destination in a computer network.

2. Shortest Path Routing: Algorithms like Dijkstra's algorithm and Bellman-Ford algorithm calculate the shortest path based on the number of hops or link costs.

3. Distance Vector Routing: Routing protocols like RIP (Routing Information Protocol) use distance vectors to determine the best path, considering factors like hop count and metrics.

4. Link-State Routing: Protocols like OSPF (Open Shortest Path First) use link-state databases and SPF (Shortest Path First) algorithm to find the shortest path, considering link costs and network topology.

OSPF (Open Shortest Path First):

1. Definition: OSPF is an interior gateway protocol (IGP) used for routing within an autonomous system (AS). It is a link-state routing protocol that calculates the shortest path using the Dijkstra algorithm.

2. Purpose: OSPF enables efficient routing by considering link costs, network traffic, and providing fast convergence in large networks.

3. Features:

   • Hierarchical Design: OSPF supports a hierarchical design with areas, reducing the amount of routing information exchanged.

   • Scalability: OSPF can handle large networks with thousands of routers and adapt to changes in network topology.

   • Fast Convergence: OSPF has mechanisms like incremental SPF calculation and fast link failure detection for quick convergence.

BGP (Border Gateway Protocol):

1. Definition: BGP is an exterior gateway protocol (EGP) used for routing between autonomous systems (AS). It is a path-vector protocol that makes routing decisions based on network policies and attributes.

2. Purpose: BGP enables routing between different autonomous systems and helps in determining the best path based on various factors like path length, policies, and network performance.

3. Features:

   • Policy-Based Routing: BGP allows network administrators to define routing policies based on factors like AS path length, community strings, and route attributes.

   • Scalability: BGP can handle the large-scale internet routing table and is designed to adapt to changes in network topology.

   • Path Selection: BGP uses path attributes like AS path, next-hop, and local preference to select the best path for routing.

Study Revision Points: Network Topologies and Protocols

Network Topologies:

1. Definition: Network topologies describe the physical or logical arrangement of devices and connections in a computer network.

2. Bus Topology: Devices are connected to a single cable, and data is broadcasted to all devices on the network.

3. Star Topology: Devices are connected to a central hub or switch, and data is transmitted through the hub.

4. Ring Topology: Devices are connected in a closed loop, and data travels in one direction around the ring.

5. Mesh Topology: Each device is connected to every other device, providing multiple paths for data transmission.

Ethernet:

1. Definition: Ethernet is a widely used networking technology that defines the physical and data link layer specifications for wired LAN (Local Area Network) connections.

2. IEEE 802.3 Standard: Ethernet follows the IEEE 802.3 standard and uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) for media access control.

3. Ethernet Frames: Data is transmitted in Ethernet frames, which consist of source and destination MAC addresses, payload, and error checking fields.

Wi-Fi:

1. Definition: Wi-Fi is a wireless networking technology that allows devices to connect to a local area network without using physical cables.

2. IEEE 802.11 Standard: Wi-Fi networks adhere to the IEEE 802.11 standard, which specifies the protocols and mechanisms for wireless communication.

3. Wi-Fi Modes: Wi-Fi