Routing Flashcards

1
Q

Router

A
  • hardware or software that forwards packets based on their destination IP
  • work at the network layer
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2
Q

MLS

A

Multilayer switch

- works at multiples layers of the OSI modem

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3
Q

how a router works

A
  • 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
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4
Q

routing table

A
  • tells the router where to send packets

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

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5
Q

routing table destination LAN IP

A

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

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6
Q

routing table gateway

A

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
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7
Q

routing table interface

A

tells the router which of its ports to use

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8
Q

zero in a routing table

A

means anything

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9
Q

default route in routing table

A

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

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10
Q

view routing table windows CLI

A

“route print” or “netstat -r”

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11
Q

view routing table in Linux or Mac OS?

A

netstat -r

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12
Q

metric

A

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

- router will always use the route with the lowest metric

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13
Q

NAT

A

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

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14
Q

SNAT

A

Static NAT

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

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15
Q

DNAT

A

Dynamic NAT

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

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16
Q

dynamic routing protocols

A

routers ability to update their routes dynamically

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17
Q

hop

A

each time a packet goes through a router

18
Q

common criteria for metrics

A

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

19
Q

distance vector

A

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

20
Q

convergence

A

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

21
Q

RIP

A

Routing Information Protocol

  • maximum hop count of 15
  • sends out update every 30 seconds
  • could not use VLSM
  • no authentication
22
Q

RIPv2

A

Routing Information Protocol v2

  • added authentication
  • distance vector
  • IGP
  • supports VLSM and discontiguous subents
23
Q

Autonomous System

A

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
24
Q

BGP

A

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
25
Q

Link State Dynamic Routing Protocol

A

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

26
Q

OSPF

A

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
27
Q

How does OSPF work?

A
  • 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)
28
Q

IS-IS

A

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
29
Q

EIGRP

A

Enhance Interior Gateway Protocol

  • hybrid protocol
  • advanced distace vector protocol
  • cisco
30
Q

RIPv1

A

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

31
Q

route redistribution

A

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

32
Q

cisco cable

A

Rollover or YOST cable

33
Q

settings to connect to serial port in PUTTY

A

9600 baud
8 bits data
1 stop bit
no parity

34
Q

what don’t you do with a new router

A

plug it into an existing network

35
Q

NMS

A

network management software

- an advanced tool to manage multiple devices

36
Q

Trace a route in Windows CLI

A

tracert

37
Q

Trace a route in Mac/Linux

A

traceroute

38
Q

do routers use the same type of connection for all routes

A

no

39
Q

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

A

Port address translation

40
Q

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

A

hop count

41
Q

What is area 0 called in OSPF

A

backbone