Distance Vector

What is the main difference between distance vector and link-state routing algorithms?

Distance vector routing is decentralized and uses local information, while link-state routing uses global information about all nodes.

What does a node's distance vector contain?

Estimated costs to travel to each known destination in the network.

When does a node update its distance vector?

When the cost of visiting a direct neighbor changes or when it receives an updated distance vector from a direct neighbor.

What is the purpose of the Bellman-Ford equation in distance vector routing?

It helps to calculate the least-cost path for each destination.

What is iBGP used for in BGP routing?

iBGP is used for routing within a single Autonomous System (AS).

What is eBGP used for in BGP routing?

eBGP is used for routing between different Autonomous Systems (AS).

Why are AS-PATH and NEXT-HOP BGP attributes important?

They help in determining the path and next-hop for routing decisions in BGP.

What is the count to infinity problem in distance vector routing?

It occurs when nodes continuously update their distance vectors with incorrect information, leading to infinite loops.

What is poisoned reverse in distance vector routing?

It is a technique where a node tells its neighbor that the distance to a certain node is infinite to prevent incorrect routing information.

How does a node recalculate costs when it receives a new distance vector?

It recalculates the cost to each destination using the new distance vector and updates its own if the new cost is lower.

What is the initialization step in the distance vector algorithm?

Setting the initial costs to directly connected neighbors and infinity for all other destinations.

What happens during the first iteration of the distance vector algorithm?

Nodes share their distance vectors with neighbors and update their own based on received information.

What is the significance of convergence in distance vector routing?

Convergence occurs when all nodes have consistent distance vectors, reflecting the true least-cost paths.

What is the role of direct neighbors in distance vector routing?

Direct neighbors provide the necessary distance vector updates for a node to calculate its own costs.

What is the maximum number of iterations needed to find the least-cost path in distance vector routing?

It can vary based on network changes, but typically it converges quickly unless there are significant changes.

What is the impact of a cost increase between two nodes in distance vector routing?

It may require multiple iterations for the network to converge to the new least-cost paths.

What is the purpose of the distance vector table?

To keep track of the estimated costs to reach each destination from the node.

How does distance vector routing ensure that updates are sent only when necessary?

Nodes only send updates when their distance vector changes due to neighbor updates or cost changes.