Routing

Question 1

Router

Answer 1

• hardware or software that forwards packets based on their destination IP
• work at the network layer

Question 2

MLS

Answer 2

Multilayer switch

- works at multiples layers of the OSI modem

Question 3

how a router works

Answer 3

• packets come to router for handling
• strips off any layer 2 information
• drops ip packet into queue
• inspects each packets ip destination and sends the packet out the correct port

Question 4

routing table

Answer 4

• tells the router where to send packets

- keeps track of destination ip’s, subnet masks, gateways, and interfaces

Question 5

routing table destination LAN IP

Answer 5

a defined network id. every id directly connected to one of the routers ports is always listed here

Question 6

routing table gateway

Answer 6

the ip address for the next hop router (where the packets go)

• if the network id is not directly connected to the router, packets go to gateway
• if no gateway needed, will say 0.0.0.0 or On-link

Question 7

routing table interface

Answer 7

tells the router which of its ports to use

Question 8

zero in a routing table

Answer 8

means anything

Question 9

default route in routing table

Answer 9

tells the router exactly what to do with eveyr incoming packet unless another line in the routing table gives another route

Question 10

view routing table windows CLI

Answer 10

“route print” or “netstat -r”

Question 11

view routing table in Linux or Mac OS?

Answer 11

netstat -r

Question 12

metric

Answer 12

relative value that defines the “cost” of using a route

- router will always use the route with the lowest metric

Question 13

NAT

Answer 13

network address translation
- replaces the source ip address of a computer with the source ip address from the outside router interface on outgoing packets

Question 14

SNAT

Answer 14

Static NAT

- maps a single routable (not private) IP address to a single machine

Question 15

DNAT

Answer 15

Dynamic NAT

- many computers can share a pool of routable IP addresses that number fewer than the computers

Question 16

dynamic routing protocols

Answer 16

routers ability to update their routes dynamically

Question 17

hop

Answer 17

each time a packet goes through a router

Question 18

common criteria for metrics

Answer 18

hop count - number of routers packet passes through
bandwidth -
delay - latency
cost -
MTU - Maximum Transmission Unit - largest frame route can handle

Question 19

distance vector

Answer 19

routing protocols that calculate the total cost to get to a particular network id and compares that cost to all the other routes, then chooses the route with lowest cost

Question 20

convergence

Answer 20

the updating of the routing tablesfor all the routers has completed
also called steady state

Question 21

RIP

Answer 21

Routing Information Protocol

• maximum hop count of 15
• sends out update every 30 seconds
• could not use VLSM
• no authentication

Question 22

RIPv2

Answer 22

Routing Information Protocol v2

• added authentication
• distance vector
• IGP
• supports VLSM and discontiguous subents

Question 23

Autonomous System

Answer 23

one or more networks that are governed by a single dynamic routing protocol within that AS

• does not use IP addressses,
• uses Autonomous System Number (ASN) assigned by IANA (32 bit)
• communicate using BGP

Question 24

BGP

Answer 24

Border Gateway Protocol

• hybrid routing protocol
• advertise information passed to them from different AS edge routers
• will ignore bad routes
• policies for limiting which and how other routers may access an ISP
• route aggregation (simplies routing tabls into manageable levels)
• path vector
• used on internet, connects AS’s

Question 25

Link State Dynamic Routing Protocol

Answer 25

announces and forwards indiviudal route changes as they appeared instead of at intervals

Question 26

OSPF

Answer 26

Open Shortest Path First - most commonly used IGP - designed to work within a single AS - converges faster & more efficient than RIP - supports authentication - shortest path first (prevets loops) - version 2 for IPv4 - version 3 for IPv6 - link state

Question 27

How does OSPF work?

Answer 27

- send out "Hello Packets" looking for other OSPF routers - after two adjacent routers form a neighborship through hello packets, they exchange information about route3rs and networks through LSA packets (Link State Advertisement) - if a route goes down, quickly recomputes a new route with stores LSAs - metric is cost (proprontional to bandwidth)

Question 28

IS-IS

Answer 28

Intermediate System to Intermediate System - extremely similar to OSPF - uses areas and send-only updates to routing tables - works from IPv6 from the start - standard for ISPs - link state dynamic routing protocol

Question 29

EIGRP

Answer 29

Enhance Interior Gateway Protocol - hybrid protocol - advanced distace vector protocol - cisco

Question 30

RIPv1

Answer 30

Distace vector IGP old; only used variable subnets within an ALS

Question 31

route redistribution

Answer 31

takes routes of one protocol (like RIP) and announces those routes over another protocol (like OSPF)

Question 32

cisco cable

Answer 32

Rollover or YOST cable

Question 33

settings to connect to serial port in PUTTY

Answer 33

9600 baud 8 bits data 1 stop bit no parity

Question 34

what don't you do with a new router

Answer 34

plug it into an existing network

Question 35

NMS

Answer 35

network management software | - an advanced tool to manage multiple devices

Question 36

Trace a route in Windows CLI

Answer 36

tracert

Question 37

Trace a route in Mac/Linux

Answer 37

traceroute

Question 38

do routers use the same type of connection for all routes

Answer 38

no

Question 39

What technology allows you to share a single public IP address with many computers?

Answer 39

Port address translation

Question 40

Distance vector routing protocols such as RIP rely on what metric to determine the best route?

Answer 40

hop count

Question 41

What is area 0 called in OSPF

Answer 41

backbone