dynamic routing

What is static routing?

Manually configured routes using ip route.

What is dynamic routing?

Routers automatically discover and adapt to paths using protocols.

Which routing method is more scalable?

Dynamic routing.

Which routing method adapts automatically to network changes?

Dynamic routing.

Which routing method is simpler for small networks?

Static routing.

What is a network route?

Route to an entire subnet (mask < /32).

Give an example of a network route.

192.168.4.0/24.

What is a host route?

Route to a single IP (/32 mask).

Give an example of a host route.

10.0.12.1/32.

How to configure a static host route?

ip route 255.255.255.255 .

What is an adjacency in dynamic routing?

Neighbor relationship between routers to exchange routes.

What do routers advertise?

Their connected networks and learned routes.

What happens if a link fails?

Routers remove invalid routes and switch to backups.

What mechanism prevents dead-end traffic in dynamic routing?

Automatic adaptation.

What are Interior Gateway Protocols (IGPs)?

Protocols that share routes within one Autonomous System (AS).

Name examples of IGPs.

RIP, EIGRP, OSPF, IS-IS.

What are Exterior Gateway Protocols (EGPs)?

Protocols that share routes between Autonomous Systems (ASs).

Give an example of an EGP.

BGP.

What are distance vector protocols?

Protocols that share routing tables with neighbors (‘routing by rumor’).

Name examples of distance vector protocols.

RIP, EIGRP.

What are link state protocols?

Protocols that build full network topology maps using Link State Advertisements (LSAs).

Name examples of link state protocols.

OSPF, IS-IS.

What are path vector protocols?

Protocols that share AS path information for inter-AS routing.

Give an example of a path vector protocol.

BGP.

What is a metric in routing?

Value used to determine the best path within a protocol.

Which protocol uses hop count as a metric?

RIP.

Which protocol uses cost based on bandwidth as a metric?

OSPF.

Which protocol uses bandwidth + delay as a metric?

EIGRP.

Which protocol uses AS path as a metric?

BGP.

What is ECMP?

Equal Cost MultiPath, load balancing across multiple equal-cost routes.

When does ECMP occur?

Same destination, same prefix length, same metric.

How does traffic flow in ECMP?

Traffic is distributed across equal-cost paths.

What is Administrative Distance (AD)?

Cisco value ranking route trustworthiness.

Which Administrative Distance is most preferred?

Lowest value.

What is the AD for connected routes?

0.

What is the AD for static routes?

1.

What is the AD for EIGRP summary routes?

5.

What is the AD for external BGP routes?

20.

What is the AD for internal EIGRP routes?

90.

What is the AD for OSPF routes?

110.

What is the AD for RIP routes?

120.

What is the AD for external EIGRP routes?

170.

What is the AD for internal BGP routes?

200.

What is the AD for unknown routes?

255 (unreachable).