HIT3723Sample Exam Solutions

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Swinburne University of Technology Faculty of ICTHIT3713 Internetworking Routing S1 !1!

Swinburne University of Technology

Faculty of Infor"ation an# Co""unication Technologies

HIT3713 Internetwork RoutingSe"ester 1$ !1!

PART A

Note: There is only one correct answer for each question.

Q1. For the #iagra" below an# the configuration shown which one of the following state"ents

about what router % will a#vertise to router & is correct'

(a) % will a#vertise 1!(1((!)3 to &(

(b) % will a#vertise 1!(1(3(!)* to &(

(c) % will a#vertise 1!(1((!)* to &(

(d) % will a#vertise 1!(1(*(!)* to &(

Mars(!" #1)

Q2. +hat action #oes an ,I-R. Router take when it cannot fin# a feasible successor for anetwork'

(a) It transitions fro" active to /assive state for that network an# 0ueries its neighbors

(b) It transitions fro" /assive to active state for that network an# 0ueries its neighbors(

(c) It ea"ines the routing table for a net best /ath(

(d) It ea"ines the to/ology table for a net best /ath(

Mars(!" #1)

Router $ip route 10.1.4.0 255.255.255.0 10.1.1.10

!

interface serial 0

ip summary-address eigrp 10.1.2.0 255.255.254.0

!

router eigrp 100

redistribute static 1000 1 255 1 1500

network 10.2.2.2 0.0.0.1

network 10.1.2.0 0.0.0.255

eigrp stub connected 1%.1.&.%'&


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Q". The #iagra" below shows ,I-R. running over a "ulti/oint fra"e relay connection(

%asic connectivity is establishe# an# then the following co""an#s are given on the

res/ective routers2

HQ(config) interface serial 0/0

HQ(config-if)bandwidth 128 East(config)# interface serial 0/0

East(config-if)# bandwidth 64

est(config)# interface serial 0/0

est(config-if)# bandwidth 64

How "uch ban#wi#th on the Serial !)! interface on H is reserve# for ,I-R. traffic to ,ast over

this "ulti/oint fra"e relay connection'

(a) 3(

(b) 4*(

(c) 15(

(d) 6one of the above(Mars(!" #1)

Q4. &n a#"inistrator ty/es in the co""an# router osf 1 an# receives the error "essage2

“O" process 1 cannot start#

+hat shoul# be #one to correctly set u/ S.F'

(a) ,nsure that an interface has been configure# with an I. a##ress an# is u/(

(b) ,nsure that an interface has been configure# with an I. a##ress(

(c) ,nsure that I. classless is enable# on the router((d) ,nsure that the interfaces can /ing their #irectly connecte# neighbours(


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Mars(!" #1)

Q5. In the #iagra" below$ S.F has been configure# on all routers in the network$ an# &rea 1

has been configure# as a 6SS&(

+hich state"ent concerning 6SS& &rea 1 is correct'

(a) 6o re#istribute# routes can a//ear in &rea 1$ only su""ary routes

(b) Re#istribute# RI. an# ,I-R. routes will a//ear in &rea 1( They will be a#vertise# via

ty/e 8 9S&s(

(c) nly re#istribute# RI. routes will a//ear in &rea 1( They will be a#vertise# via ty/e 7

9S&s(

(d) nly re#istribute# ,I-R. routes will a//ear in &rea 1( They will be a#vertise# via ty/e 7

9S&s(

Mars(!" #1)

Q*. In an IS:IS 9&6 environ"ent$ what ha//ens when the #esignate# IS router crashes'

(a) & new election /rocess occurs i""e#iately$ establishing a new ;IS until a router with a

higher /riority or 6,T? is'

(a) &n 6S&. a##ress with 6S,9 value of >!!?( It refers to the router itself an# consists of an

&rea I; an# a Syste" I;(


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(b) &n 6S&. a##ress with an inter:#o"ain /art @I;.A an# #o"ain:s/ecific /art @;S.A(

(c) &n 5 to ! byte a##ress consisting of an &rea I; an# a Syste" I;(

(d) & H,B translation of the #otte# #eci"al I. a##ress notation an# /a##e# out with eros(

Mars(!" #1)

Q,. +hat #oes the use of the co""an#$ isis circuit-type$ allow the a#"inistrator to achieve in

the situation shown below'

(a) Faster convergence when interfacing with other routing /rotocols(

(b) Re#uce the area sie(

(c) Increase the s/ee# of the #ata transfer by selecting a har#ware out/ut(

(d) Increase the efficiency by saving "e"ory an# ban#wi#th(

Mars(!" #1)

Q-. +hat #oes the route:"a/ below #o for the network shown' &ssu"e that these are all of the

configuration state"ents relating to route:"a/s on router +est( Choose the "ost correct

alternative(

West(config)#access-list 1 permit 192.1!.1." ".".".255

West(config)#access-list 2 permit 12.1.1." ".".".255

West(config)#route-map $%&1 permit 1"

West(config-route-map)#matc' ip address 1

West(config-route-map)#set interface serial""

West(config-route-map)#eit

West(config)#route-map $%&2 permit 2"

West(config-route-map)#matc' ip address 2West(config-route-map)#set interface serial"1


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West(config-route-map)#eit

(a) 6othing(

(b) ;irects traffic #estine# for the internet fro" network 1D(145(1(! out serial !)!(

(c) ;irects traffic #estine# for the internet fro" network 17(14(1(! out serial !)1(

(d) %oth @bA an# @cA above(

Mars(!" #1)

Q1%. +hat is the safest way to /erfor" route re#istribution'

(a) The safest way is to re#istribute routes in one #irection only(

(b) The safest way is to re#istribute routes on all of the boun#ary routers within a network(

(c) The safest way is to re#istribute routes in one #irection only an# on only one boun#ary

router within the network((d) The safest way is to re#istribute routes in both #irections an# on all of the boun#ary

routers within the network(

Mars(!" #1)

Q11. In /olicy:base# routing$ what #oes a /er"it state"ent of a route "a/ i"/ly'

(a) &llow the traffic if it "atches the criteria s/ecifie# by the "atch state"ent(

(b) ;ro/ all traffic if no "atch is foun# in the route "a/ state"ents(

(c) Route the traffic base# on the #efine# /olicy if it "atches the criteria s/ecifie# by the

"atch state"ent(

(d) Route the traffic through the gateway of last resort if no "atch is foun# in the route "a/

state"ents(

Mars(!" #1)

Q1&. +hich of the following /roble"s can route re#istribution cause'

(a) Routing loo/s(

(b) Subo/ti"al routing(

(c) ;ifference in routing infor"ation #ue to #iffering convergence ti"es of routing /rotocols(

(d) &ll the above(

Mars(!" #1)

Q1". +hat is %-. synchroniation'

(a) It is the synchroniation of e%-. routes with i%-. routes(

(b) It is the synchroniation of %-. attributes between %-. neighbours(

(c) It is the synchroniation of %-. routes between %-. neighbours(


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(d) It is the synchroniation of I-. routing infor"ation with %-. routing infor"ation

Mars(!" #1)

Q1. Router 1 is connecte# to networks 17(14(1(!)4 an# 17(14(1(4*)7( n the basis of the

/artial out/ut given below$ which state"ent is correct' *1#s'o+ running-config ,

router eigrp1""

net+or 12.1."."

distribute-list prefi /0$% out

auto-summary

,

ip prefi-list /0$% se 1" permit 12.1.1."2

(a) Router R1 will a#vertise both routes(

(b) Router R1 will #eny the 17(14(1(!)4 route while /er"itting the 17(14(1(4*)7 route to

be a#vertise#(

(c) Router R1 will #eny the 17(14(1(4*)7 route while /er"itting the 17(14(1(!)4 route to

be a#vertise#(

(d) Router R1 shoul# be reconfigure# with an &C9 instea# of an i/ /refi:list co""an#(

Mars(!" #1)

Q1. +hen a %-. neighbour #oes not share a co""on subnet$ what is re0uire# to gain

connection

(a) Configure %-. "ulti:ho/ with e%-.(

(b) Configure %-. "ulti:ho/ with i%-.(

(c) Cannot establish /eering(

(d) It is not necessary to share a co""on subnet for %-. /eering(

Mars(!" #1)

Q1*. In %-. when a router is /eering)neighbouring its state "ay cycle between active an# i#le(

The neighbour "ay not know how to get back to this router( +hich one of the following is

not a reason for this cycling(

(a) The neighbour #oes have a route to the source I. a##ress of the %-. o/en /acket

generate# by this router

(b) The neighbour is /eering with the wrong a##ress

(c) The neighbour #oes not have a nei/hbour state"ent for this router

(d) The &S nu"bers are "isconfigure# (

Mars(!" #1)


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Q1+. Refer to the #iagra" an# the given configuration below( Routers RT& an# RT% are running

%-. but the session is in the active state( +hich one of the following alternatives gives the

co""an#@sA that "ust be a##e# to establish the %-. session'

'ostname *3

,

interface loopbac "

ip address 1".1".1".2 255.255.255.255

,interface serial ""

ip address 12.1.1".2 255.255.255.252

,

interface serial "1

ip address 12.1.1". 255.255.255.252

,

router bgp 52""

neig'bor 1".1".1".1 remote-as 5""

neig'bor 1".1".1".1 update-source loopbac "

neig'bor 1".1".1".1 ebgp-multi'op 1

(a) networ 1%.1%.1%.%

(b) no synchroni0ation

(c) i route 1%.1%.1%.1 &.&.&.& s%'%

i route 1%.1%.1%.1 &.&.&.& s%'1

(d) nei/hbor 1%.1%.1%.1 net#ho#self

Mars(!" #1)

Q1,. How "any I. "ulticast a##resses "a/ to a layer


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(d) &ll of the above(

Mars(!" #1)

Q&%. +hat techni0ues are use# to allow I.v* to work with I.v4'

(a) .&T:E.6

(b) Tunnelling

(c) High stack

(d) .arallel stack with a "ulti/lee# out/ut(

Mars(!" #1)

Q&1. -iven the I.v4 a##ress of 112!!!!2!&%C2%&%,2!!!!2!!!!2!!!12*!!!$ what is the"ost efficient way to write the a##ress'

(a) 112!2!&%C2%&%,2!2!2!!!12*!!!

(b) 112!2!&%C2%&%,2!2!212*!!!

(c) 112!2&%C2%&%,2212*!!!

(d) 1122&%C2%&%,2212*(

Mars(!" #1)

2nd of PART A


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Part $

$1.

(a)

State all of the tables that are use# in the ,I-R. routing /rocess( ,/lain how these tables areuse# to buil# the final table use# to #eter"ine the /ath selection of #ata /ackets( Show the correct

se0uence in which tables are built an# how they /rovi#e the infor"ation for the net table(

Mars ("!*3-)

The network shown illustrates router Cs ,I-R. tables( Routers & an# % have establishe# a neighbor

relationshi/ with router C( %oth routers & an# % have /aths to network 1!(1(1(!)*$ a"ong "any others

that are not shown( Router & has an ,I-R. "etric of 1!!! for 1!(1(1(!)*$ so router & a#vertises

1!(1(1(!)* to router C with a "etric of 1!!!( Router C installs the route to 1!(1(1(!)* via router & in its

,I-R. to/ology table with an a#vertise# #istance of 1!!!(

Router % has network 1!(1(1(!)* with a "etric of 18!! in its I. routing table$ so router % a#vertises

1!(1(1(!)* to router C with an a#vertise# #istance of 18!!( Router C /laces the route to 1!(1(1(!)*network via router % in the ,I-R. to/ology table with an a#vertise# #istance of 18!!(

Router C has two entries to reach 1!(1(1(!)* in its to/ology table( The ,I-R. "etric for router C to reach

both routers & an# % is 1!!!( This cost @1!!!A is a##e# to the res/ective a#vertise# #istance fro" each

router$ resulting in the feasible #istances fro" router C to reach network 1!(1(1(!)* shown in the figure(

Router C chooses the least:cost feasible #istance$ which is !!!$ via router &$ an# installs it in the I.

routing table as the best route to reach 1!(1(1(!)*( The ,I-R. "etric in the routing table is e0ual to the

feasible #istance fro" the ,I-R. to/ology table( Router & is the successor for

the route to 1!(1(1(!)*(

(b) -iven the following #iagra"2


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,I-R.

&S 1!!

Can une0ual loa# balancing be achieve# in the #iagra" above when sen#ing #ata fro" RT& to

RT;' ,/lain your answer in #etail$ ie if yes e/lain how an# if not e/lain why not(

Mars(1!3*)

&nswer

6

The reason is that the F; for the /ath &:; is !( &lso the R; or &; fro" C:; is ! ie not less than F;(

Hence there is no other /ath to ; which follows the rules in ;U&9( If it was less than ! woul# use the

variance co""an#(

,I-R. config on Router &2

A

C

B

D

10

30

10

20

192.168.16.0

192.168.17.0

192.168.18.0

192.168.19.0

192.168.20.0

10.1.1.2

10.2.2.2


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$&.

iA The following #is/lays the routing table of an S.F router in a stan#ar# area(

The first colu"n in#icates that the routes are S.F routes( The secon# colu"n #is/lays an I&$ ,

or nothing( +hat ty/e of S.F routes #o these in#icate'

Mars (")

• The in#icates that the route co"es fro" within the S.F area

• The I& in#icates a route that has co"e fro" another area

• The , in#icates that the route has originate# fro" a non:os/f area or is an eternal route

iiA The following #is/lays the sa"e routing table but the .SF area ty/e has been change#(

+hat ty/e of S.F area has been configure# to /ro#uce the above routing table' +hat has

ha//ene# to the , route'

Mars ()

• The area has been configure# as a stub(

• ,ternal routes are no longer visible in the routing table$ but are converte# to an intra:area efault

route( This is because a stub area #oes not acce/t ty/e 8 9S& an# these are converte#

•

•

• a ty/e 3 9S&(


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iiiA The following #is/lays the sa"e routing table$ with so"e further changes "a#e to the &%R

router

+hat has cause# the change in the routing table'Mars (&)

• The 17(31(11(! network has been su""arise# at the &%R(

ivA The following now shows the sa"e routing table with one further change to the &%R router(

,/lain what has cause# this final change to the routing table'

Mars (")

• The area is now configure# as totally stubby(

• &ll routes fro" beyon# the area are now only accessible fro" the inter:area #efault route(


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@vA For the #iagra" shown below i#entify the ty/e of su""ariation that nee#s to take /lace at router

& an# ;'

Mars (")

Su""ary #ress n)w "ask

&rea ! range n)w "ask

$". -iven the following out/ut$ answer the 0uestions by co"/leting the table below(

Mars(1!1!1!1!1!&!")31%!1(config)# ro"ter isis!1(config-ro"ter)# net 4$0001$1111$1111$1111$00 !1(config-ro"ter)# interface fastethernet 0/0 !1(config-if)# i% ro"ter isis!1(config-if)# isis %riorit& 100 !1(config-if)# interface loo%bac' 0 !1(config-if)# i% ro"ter isis

!2(config)# ro"ter isis!2(config-ro"ter)# net 4$0001$2222$2222$2222$00 !2(config-ro"ter)# interface fastethernet 0/0 !2(config-if)# isis %riorit& 10 !2(config-if)# i% ro"ter isis!2(config-if)# interface loo%bac' 0 !2(config-if)# i% ro"ter isis

!(config)# ro"ter isis!(config-ro"ter)# net 4$0001$$$$00 !(config-ro"ter)# interface fastethernet 0/0 !(config-if)# i% ro"ter isis!(config-if)# isis %riorit& 0

!(config-if)# interface loo%bac' 0 !(config-if)# i% ro"ter isis

&rea a##ress R1 Syste" I; R Syste" I; R3 Syste" I; 6S,9

0001 1111.1111.1111 2222.2222.2222 3333.3333.3333 00

+hich Router is ;IS +hy'

R1 %ecause it has a /riority of 1!!

C

,;%&


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$. The network shown in the #iagra" below is connecte# an# configurations are /lace# on each of

the routers with the various routing /rotocols(

Re#istribution is configure# between S.F an# ,I-R. on R( It is necessary to filter R3s 9oo/backs 8

an# 3! networks fro" getting re#istribute# into ,I-R. on R( Configure

an access list that "atches these two network a##resses an# a route "a/ that #enies base# on a "atch for

that access list( Show your co""an#s below(


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$. The network shown below is connecte# an# both i%-. an# e%-. are configure# to allow the

users in &S4*81 to have a backu/ /ath to the Internet Service .rovi#er @IS.A( 6ote that only the

loo/back networks have been a#vertie# through %-.(

The following out/ut is observe# on the IS. router(

IS.Gs'o+ ip bgp

%-. table version is 3$ local router I; is 1D(145(1!!(1

Status co#es2 s su//resse#$ # #a"/e#$ h history$ vali#$ best$ i :internal

rigin co#es2 i : I-.$ e : ,-.$ ' : inco"/lete 6etwork 6et Ho/


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(b) ,/lain the /ur/ose of the update-source co""an# in %-.(

Mars(")

The udate#source o/tion of the nei/hbor co""an# overri#es the #efault source I. a##ress use# for

%-. /ackets( It is necessary to tell the router which I. a##ress to use as the source a##ress for all %-.

/ackets if you want to use a loo/back interface instea# of the /hysical interface( @3


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Mars (")

• + subnet prefi! representing the networ, to which the interface is connected. The subnet prefi! is a fi!ed

6-bit length for all current definitions.

• + local identifier sometimes called a to,en which uni/uel# identifies the host on the local networ,. The

local identifier is alwa#s 6- bits and is d#namicall# created based on a#er 2 media and encapsulation. %n

the simple case of an $thernet medium the local identifier is usuall# deri)ed from the $%-8 +address.

(b) %roa#cast a##ressing in I.v* results in several /roble"s( +hat are these /roble"s' How #oes

I.v4 get aroun# this issue'

Mars (&!"3)

• %roa#casts generate a nu"ber of interru/ts in every co"/uter on the network$ which involves

every #evice to /rocess the /acket to see if it is for that #evice( @1 "arkA

• In the etre"e case broa#casts can trigger "alfunctions that co"/letely halt an entire network(

This is known as a broa#cast stor" @1 "arkA

• I.v4 has re/lace# broa#casts with "ulticast a##ressing(


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(a) 9ist the two ty/es of trees(

5ource 6istribution Trees 7 si"/lest for" of "ulticast #istribution tree$ with the root at the source an#

branches for"ing a tree towar# the receivers( S.T @shortest /ath treeA is i#entifie# by the notation @S$-A

where S N I. a##ress of source an# - N "ulticast grou/ a##ress(

5hared 6istribution Trees 7 share a co""on root calle# a >ren#evous /oint? @R.A /lace# at a chosen

/oint in the network( The source traffic is sent to the R.$ which then forwar#s the traffic to reach all

receivers( 6otation is @$-A where N all sources an# - N "ulticast grou/ a##ress( @


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HIT3723Sample Exam Solutions

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