Wide Area Networks

Question 1

What are three WAN topologies

Answer 1

Point to Point Network, Hub & Spoke Network, Full Mesh Networks

Question 2

What does single/dual and homed/multihomed represent

Answer 2

Single/dual = 1/2 or more connections, homed/multihomed = 1/2 or more ISPs

Question 3

Tell me about Border Gateway Protocol

Answer 3

Path Vector routing protocols, uses path attributes to select path,

Question 4

What is MPLS

Answer 4

Multiprotocol Layer Switching - Assigns labels to packets and the MPLS cloud makes forwarding decisions based on the labels (instead of ip)

Question 5

How does MPLS encapsulate its label

Answer 5

Label is 20 bits and inserted between Layer 2 Header and Layer 3 header in a packet

Question 6

What is the GRE Tunnel Theory

Answer 6

Generic routing encapsulation tunnel, a type of tunnel that can encapsulate multiple layer 3 protocols (single hop) GRE tunnel doesn’t have security but IPsec can do those things

Question 7

What is a multipoint GRE

Answer 7

allows a single router interface to have multiple GRE tunnels

Question 8

What is PPP

Answer 8

Layer 2 encapsulation used on leased lines, supports authentication, compression, error checking & connection, logical multilink

Question 9

What is PAP, CHAP, and how are they different

Answer 9

PAP sends password over in clear text while CHAP sends password hashed up

Question 10

What is LCP

Answer 10

Link control protocol, protocol used by PPP to setup, maintain, and tear down a connection

Question 11

What is NCP

Answer 11

Network control protocol, protocol used to negotiate the configuration of protocols over a PPP link (whether that be ip, cdp, etc)

Question 12

What is PPPoE

Answer 12

PPP over ethernet, carries 8 byte header within ethernet frame, commonly used with DSL client and Service Provider connections

Question 13

What is the default encapsulation of an interface

Answer 13

HDLC, High Level Data Link Control Protocol

Question 14

What side has the clocking, DCE or DTE

Answer 14

Data Circuit Terminating Equipment or DCE

Question 15

What type of routing protocol is EIGRP

Answer 15

Advanced distance vector, as is RIP

Question 16

What type of routing protocol is BGP

Answer 16

path vector routing protocol

Question 17

How does BGP choose a route

Answer 17

Weight - BGP likes the path with the highest weight, Local preference - BGP selects the one with highest local preference value, Aggregate preferred over network, Shortest AS_Path is used as a tie breaker

Question 18

What’s the flow of a packet through a MPLS system

Answer 18

Customer Premise Equipment CPE connects to MPLS Cloud, Edge Label Switch Router adds label to packet, LSR or Label Switch Routers with MPLS forward based on labels

Question 19

What is a DMVPN

Answer 19

Dynamic Multipoint VPN, allows for a DMVPN tunnel to be created between two hosts

Question 20

What is the Next Hop Resolution Protocol

Answer 20

Allows the interface at one end of the GRE tunnel to discover the IP address of the device at the other end of the tunnel

Question 21

What is the administrative distance of a connected interface

Answer 21

0

Question 22

What is the administrative distance of a static route

Answer 22

1

Question 23

What is the administrative distance of external BGP

Answer 23

20

Question 24

What is the administrative distance of Internal EIGRP

Answer 24

90

Question 25

What is the administrative distance of IGRP or interior gateway routing protocol

Answer 25

100

Question 26

What is the administrative distance of OSPF

Answer 26

110

Question 27

What is the administrative distance of IS-IS

Answer 27

115

Question 28

What is the administrative distance of external EIGRP

Answer 28

170

Question 29

What is the administrative distance for RIP

Answer 29

120

Question 30

What does RIP use to determine metric

Answer 30

Hop count

Question 31

What does OSPF use to determine metric

Answer 31

Cost

Question 32

What does EIGRP use to determine metric

Answer 32

Bandwidth, delay