ECCS3631: Unit 4 - Routing Protocols

What is the primary function of a router?

To forward packets between different networks.

What table do routers use to determine forwarding decisions?

The routing table.

What does a “next hop†in a routing table represent?

The IP address of the neighboring router to forward packets to.

What is the difference between static and dynamic routing?

Static routes are manually configured, dynamic routes are learned automatically.

What is an Autonomous System (AS)?

A collection of routers under one administrative domain. 4-2 Administrative Distance & Metrics

What does Administrative Distance (AD) measure?

The trustworthiness of a routing source.

What is the AD of a directly connected route?

0

What is the AD of a static route?

1

What is the AD of RIP?

120

What is the AD of OSPF?

110

Which protocol metric is based on hop count?

RIP.

Which protocol metric is based on cost (bandwidth)?

OSPF.

What does an AD of 255 mean?

The route is considered invalid. 4-3 RIP

What type of routing protocol is RIP?

Distance-vector.

What metric does RIP use?

Hop count.

What is the maximum hop count in RIP?

15 (16 = unreachable).

What is the RIP update interval?

30 seconds.

Which RIP version supports VLSM and CIDR?

RIP v2.

Which algorithm does RIP use?

Bellman-Ford. 4-4 OSPF

What type of routing protocol is OSPF?

Link-state.

What algorithm does OSPF use?

Dijkstra’s Shortest Path First (SPF).

What metric does OSPF use?

Cost (based on bandwidth).

What is OSPF’s default administrative distance?

110

What is OSPF Area 0 called?

The backbone area.

What is an ABR in OSPF?

Area Border Router â€" connects one area to Area 0.

What is an ASBR in OSPF?

Autonomous System Boundary Router â€" connects OSPF to external routing protocols.

Which OSPF packet is used to form neighbor adjacencies?

Hello packet.

How often does OSPF send Hello packets on broadcast networks?

Every 10 seconds. 4-5 BGP (Basic)

Where is BGP mainly used?

For inter-domain routing on the Internet.

What does an Autonomous System (AS) represent in BGP?

A group of networks under a single administrative control. 4-6 General / Comparisons

Which is easier to configure for small networks: static or dynamic routing?

Static routing.

Which is more scalable: static or dynamic routing?

Dynamic routing.

Which protocol is best for small networks with few routers?

RIP.

Which protocol is best for large enterprise networks?

OSPF.

Which protocol is most widely used on the Internet?

BGP.

Which type of routing (link-state or distance-vector) shares entire topology information?

Link-state.

Which type of routing (link-state or distance-vector) shares only distance and direction?

Distance-vector.

What is the key benefit of dynamic routing over static routing?

It automatically adapts to topology changes.