2.1 Dynamic Routing

Question 1

What is dynamic routing and how does it differ from static routing?

Answer 1

Dynamic routing allows routers to automatically discover and share route information, unlike static routing which requires manual configuration.

Transcript: “Dynamic routing will have the routers handle this process for you… automatically discover these routes…” (0:25–0:34)

Question 2

What are the benefits of using dynamic routing in large networks?

Answer 2

It reduces manual configuration, automatically updates routes when changes occur, and scales better for large environments.

Transcript: “If you have tens or even hundreds of routers… a more automated way… automatically know where the new route is.” (0:13–0:57)

Question 3

What are the resource requirements of dynamic routing?

Answer 3

Dynamic routing consumes CPU and memory, and may require monitoring to ensure routers can handle the overhead.

Transcript: “This will require some CPU and memory inside of the router…” (1:04–1:19)

Question 4

What happens when a dynamic routing protocol like EIGRP updates a routing table?

Answer 4

Routers exchange route information in real-time, updating their tables without user input.

Transcript: “Router one receives that update and then updates its own routing table…” (2:15–2:19)

Question 5

How do routers share updates in dynamic routing?

Answer 5

Routers use multicast or direct communication to send updates and adjust thier tables accordingly.

Listen for subnet information.
Provide subbnet information to other routers
Determin the best path based on this information.

Transcript: “These are very often sent directly from router to router… with a multicast.” (3:15–3:26)

Question 6

What factors affect how different dynamic routing protocols choose routes?

Answer 6

Factors include link state, number of hops, speed, and protocol-specific metrics.

Transcript: “Routing decisions… based on the state of the link… number of hops… speed…” (4:30–4:50)

Question 7

What is EIGRP and what are its key features?

Answer 7

EIGRP (Enhanced Interior Gateway Routing Protocol) is a Cisco-centric dynamic routing protocol that’s easy to configure, converges quickly, and minimizes network traffic.

Partially proprietrary to Cisco

Transcript: “You would turn on EIGRP in your Cisco router… converge relatively quickly… minimize network traffic.” (6:00–6:30)

Question 8

What is OSPF and why is it widely used?

Answer 8

OSPF (Open Shortest Path First) is a vendor-neutral, link-state routing protocol used in controlled networks (Autonomous Systems).

Link-state protocol: routing is based on the connectivity between routers; each link has a “cost”, throughput, reliability, round-trip time; low cost and fastest path wins, identical costs are load balanced

Transcript: “This is the Open Shortest Path First routing protocol… where you have complete control of those systems.” (6:43–7:02)

Question 9

How does OSPF determine the best route?

Answer 9

OSPF uses link cost based on bandwidth, uptime, and delay–lower cost means better route.

Transcript: “OSPF… assign costs… lowest cost and fastest path is the best route.” (7:33–7:59)

Question 10

What is BGP and what is it used for?

Answer 10

BGP (Border Gateway Protocol) is an external routing protocol used to dynamically route traffic between Autonomous Systems, especially on the Internet.

Transcript: “BGP is the Border Gateway Protocol… dynamically update the routes on the entire internet.” (8:21–8:35)