Ccna2 - Chapter 2

Front 1

routing table

Back 1

used to find the best match between the destination IP of a packet and a network address in the routing table.

Front 2

cisco serial connectors for WAN connections

Back 2

EIA/TIA-232, EIA/TIA-449, V.35,X.21, EIA/TIA-530.
A router has a DB-60 port that can support the different standards. This port is also called 5-in-1 serial port.

Front 3

smart serial interface

Back 3

allows for more data to be fowarded across fewer cable pins. The serial end of the smart cable is a 26 pin connector. They support the 5 standards and can be configured as DTE or DCE.

Front 4

ethernet connectors

Back 4

RJ-45 straight cable
switch to router
switch to PC
hub to PC
hub to server

cross over cable
-switch to switch
-PC to PC
-switch to hub
-hub to hub
-router to router
-router to server

Front 5

show interfaces

Back 5

shows the status and gives detailed desc of all interfaces on a router.

Front 6

show ip interface brief

Back 6

to see a portion of the interface information in a condensed format

Front 7

show running-config

Back 7

displays the current configuration that the router is using.

Front 8

message LINK-3_UPDOWN: interface blah changed state to up

Back 8

means the physically the condition is up

Front 9

LINEPROTO-UPDOWN: line protocol on interface changed state to up

Back 9

means that the link layer is operational.

Front 10

clock rate on wan interface

Back 10

if it is not set correctly, the data link layer will not be up

Front 11

unsolicited message from IOS

Back 11

automatic messages sent from the router.

Front 12

separate unsolicited output from input

Back 12

enter configuration mode for the consoled port and add logging synchronous command.

line console 0
logging synchronous

Front 13

routing table entry code c:

Back 13

c means the route is directly connected to the network.

Front 14

ethernet interface on a router

Back 14

has a L2 MAC address .
participates in ARP requests and replies and maintains an ARP table.

Front 15

how does the Router participate in the ARP process

Back 15

If a router has a packet destined for a device on a directly connected netwrk, it checks the arp talbe for an entry with that destination IP address in order to map the MAC address

Front 16

difference in configuring a serial interface vs. ethernet interface

Back 16

interface id
serial port has a clock rate

Front 17

physically connecting a WAN interface
-DTE/DCE crossover cable or
DTE cable connected to DCE cable.

Back 17

The WAN physical layer describes the interface between DTE and DCE equipment. Usually router is the DTE device. Serial interface require a clock signal to control the timing. The service provider will provide the clock which is the DCE end.

Front 18

CDP

Back 18

Cisco Discovery Protocol is a network monitoring and troubleshooting tool.
-access a summary of protocol and address information about cisco devices
- By default, each Cisco device sends periodic messages which are known as CDP advertisements to directly connected Cisco devices.

Front 19

L3 neighbors

Back 19

are devices that share the same network address space

Front 20

L2 neighbor

Back 20

CDP operates on L2 only. CDP neighbors as well as L2 neighbors are devices that are directly connected physically and share the same data link.

Front 21

CDP operation

Back 21

show cdp neighbors
show cdp neighbors detail
-provides information about the neighbor device
- device identifier (name)
- addres slist (upto one network layer addressfor each protocol supported)
- port identifier (name of the local and remote port)
- capabilities list - (device is a router or a switch)
- platform (hardware platform)

Front 22

no cdp run

Back 22

disables CDP globally

Front 23

no cdp enable

Back 23

use CDP but need to stop CDP advertisements on a particular interface.

Front 24

static routes

Back 24

commonly used when routing from a network to a stub network. static routes are configured for connectivity to remote networks that are not directly connected to a router.

Front 25

stub network

Back 25

is a network accessed by a single route

Front 26

ip route

Back 26

arguments
destination network address, subnet mask, next hop ip address and exit interface to determine the outgoing interface.

Front 27

static route code

Back 27

s

Front 28

route fields in [ ]

Back 28

administrative distance and metric for the static route.

Front 29

routing table principle1

Back 29

1. every router makes decisions alone, based on the information it has in its routing table

Front 30

routing table principle 2

Back 30

2. the fact that one router has information in its routing table does not mean the other routers have the same information

Front 31

routing table principle 3

Back 31

routing information about a path from one network to another does not provide routing information about the reverse or return path

Front 32

route resolvability

Back 32

before any packet is forwarded by a router, the routing table process must determine the exit interface to use to forward the packet.
-determine how to reach the next hop IP address by deciding on the exit interface

Front 33

route resolvability

Back 33

every route that references only a next hop IP address and does not reference an exit interface must have the next hop IP Naddress resolved by using another route in the table that has an exit interface

Front 34

directly connected route

Back 34

does not mean the route is a directly connected network or directly connected route.

Front 35

static routes

Back 35

ideal for point to point networks.
- cannot be modified, must be deleted and added again.

Front 36

delete static route

Back 36

no ip route

Front 37

point to point serial network

Back 37

point to point serial nework has only one other device on that network - the router at the other end of the network.

Front 38

ethernet network

Back 38

has many different devices sharing the same multi-access network.

Front 39

how to configure a static route over ethernet network so that it doesn't have to use the recursive lookup of the next hop IP address

Back 39

- configure the static route to include both the exit interface and the next hop IP address

Front 40

static routes with outbound point to point serial network

Back 40

best to have just the exit interface only

Front 41

static routes with outbound ethernet networks

Back 41

best to configure both next hop address and exit interface

Front 42

summarizing static routes

Back 42

-reduces the routing table size
-makes look up process more efficient.

Front 43

route summarization

Back 43

multiple static routes can be summarized if :
- the destination networks can be summarized into a single address
-multiple static routes all use the same exit interface or the next hop IP address

Front 44

how to calculate the summary route

Back 44

write out the networks to summarize
-start with the left most bit
-find all the bits that match.
-when you find the first that doesn't match, stop.

Front 45

default static route

Back 45

is used when
-no other routes in the table match the destination IP address
-when a router has only one other router to which it is connected.

Front 46

default static route format

Back 46

network address is 0.0.0.0
subnet mask is 0.0.0.0
-also called quad-zero route

Front 47

candidate default route

Back 47

is indicated by the code *

Front 48

reasons for a missing route in the table

Back 48

- an interface fails
- service provides drops the connection
-over saturation of links
-wrong configuration

Front 49

steps to troubleshoot a missing route

Back 49

-ping
-traceroute
-show ip route
-show ip interface brief
-show cdp neighbors detail

Front 50

static route admiinistrative distance

Back 50

1

Front 51

difference between attaching a serial interface to a serivce provider production environment and attaching a serial interface to another router in the lab

Back 51

in production environment, serial interface is connected to service provider equipment. Service provides sets the clocking speed. In lab configuration, one router has to provide clocking