Scenarios for Final Preparation
This associate presents three scenarios that can be acclimated to assay best of the concepts
contained in this book. The scenarios are brash to abetment you in final activity for the
Cisco Switching Exam. Case studies are presented with adjustment diagrams and questions
covering abounding switching topics.
This annual emphasizes an all-embracing compassionate of switching concepts, configuration
commands, and adjustment operation. Although the Cisco Switching Exam may not contain
scenarios of this type, this associate will bigger acclimate you by brainwork about the “bigger
picture” of a adjustment and how ceremony switching activity can be applied.
Scenario 14-1
Refer to the arrangement diagram in Figure 14-1 and complete the afterward tasks. Accept that
each of the Catalysts has a MAC abode formed from its one letter name (Catalyst A = aaaa-
aa-aa-aa-aa, Catalyst B = bb-bb-bb-bb-bb-bb, and so on).
1 Accept that all Catalyst switches accept the absence VTP configurations. Which
Catalyst will become a VTP server?
2 Catalyst A is configured with the afterward commands:
set vtp area alpha
set vlan 101 VLAN101
set vlan 102 VLAN102
Which added Catalyst will apprentice of the new VLANs and VTP configuration?
3 To accomplish abiding VTP advice is anesthetized over block links, which VLAN(s) should be
enabled over the trunks amid Catalyst switches?
4 Configure Catalyst A to block alone VLANs 101 and 102 over its 1/1 Gigabit Ethernet
link, application ISL. Let Catalyst B booty the animate block agreement role over the link.
(Port 1/2 will be configured similarly.)
5 Suppose Catalyst A has the afterward commands added to it:
set vtp pruning enable
set vtp pruneeligible 101-110
Will broadcasts on VLAN 101 be beatific beyond the block articulation amid Catalyst A and
Catalyst B?
464 Chapter 14: Scenarios for Final Preparation
Figure 14-1 Arrangement Diagram for Scenario 14-1
6 Which Catalyst will become the basis arch of the Spanning Tree area (assume only
VLANs 101 and 102 are present on all switches)?
7 What command can force Catalyst B to become the basis arch for alone VLANs 101 and 102?
8 Application STP commands, how can Catalyst A anchorage 1/1 be put in the forwarding accompaniment to carry
VLAN 101 traffic, while anchorage 1/2 is put in the forwarding accompaniment for VLAN 102? (This also
means that anchorage 1/1 will be blocking for VLAN 102, and anchorage 1/2 will be blocking for
VLAN 101.) In effect, this bureaucracy achieves some amount acclimation by amid the two
VLANs to canyon over abstracted uplinks.
9 Suppose Catalyst B is the basis arch for all VLANs. What commands on Catalyst A could
be acclimated to accomplish the aforementioned amount acclimation beyond ports 1/1 and 1/2 as in the previous
question? (VLAN 101 should be transported over 1/1 and VLAN 102 over 1/2.)
10 What Spanning-Tree Agreement affection can be acclimated to abbreviate the initialization adjournment on
the Catalyst A ports area PCs are connected?
11 From Figure 14-1, area should the UplinkFast affection be enabled? Area should
BackboneFast be enabled?
PC-1 PC-2
VLAN 101 VLAN 102
Catalyst A
1/1 1/2
GE
Catalyst B
Catalyst D
Catalyst C
Catalyst E
GE
GE
GE
GE
GE
Non-trunking
access links
All links are
trunk links,
carrying all VLANs
Scenario 14-2 465
12 On Catalyst A, what command can be acclimated to accredit an IP abode of 10.1.101.1
255.255.255.0 to VLAN 101 for Telnet purposes?
13 Catalyst E has an IP abode of 10.1.254.1 255.255.255.0 assigned to its sc0 interface.
However, neither Catalyst C nor Catalyst D can ping Catalyst E successfully. Running the
show cdp acquaintance detail command shows that Catalyst E is absolutely animate and sending
CDP information. As well, Catalyst E is apparent to be application 10.1.254.1 as its IP address.
What are some accessible causes for the ping failure?
14 For this network, which is added adapted for bigger multicast achievement and
handling—IGMP concern or CGMP?
15 Accept that a server is affiliated to Catalyst E anchorage 3/3. What command can be acclimated to
monitor cartage transmitted and accustomed on the server anchorage with a arrangement analyzer
connected to Catalyst E anchorage 3/8?
Scenario 14-2
Refer to the arrangement diagram in Figure 14-2 and complete the afterward tasks. Accept that
each of the Catalysts has a MAC abode formed from its one letter name (Catalyst A = aa-aaaa-
aa-aa-aa, Catalyst B = bb-bb-bb-bb-bb-bb, and so on.)
Figure 14-2 Arrangement Diagram for Scenario 14-2
PC-1
VLAN 101
PC-2
VLAN 102
Catalyst A
2/1 2/2
Catalyst B
2/1 2/2
Catalyst C ATM Billow Catalyst D
Gigabit
EtherChannel
PC-3
VLAN 101
PC-4
VLAN 102
Gigabit
EtherChannel
466 Chapter 14: Scenarios for Final Preparation
1 The articulation amid Catalyst A and Catalyst C should be a Gigabit EtherChannel using
trunking for all accessible VLANs. What agreement is acclimated to accommodate the EtherChannel
link?
2 If Catalyst A has its EtherChannel authentic on ports 2/1 and 2/2 in auto mode, what is
necessary to accompany the articulation into acknowledged EtherChannel operation?
3 Accept that alone two hosts are affiliated to Catalyst A. Host PC-1 (MAC abode 11-11-
11-11-11-11, IP abode 10.1.101.1) communicates alone with Server-1 (a1-a1-a1-a1-a1-
a1, 10.1.101.200). Host PC-2 (22-22-22-22-22-22, 10.1.102.1) alone talks with Server-2
(a2-a2-a2-a2-a2-a2, 10.1.102.200). Is the cartage counterbalanced beyond the links of the
EtherChannel trunk, bold no router is involved?
4 Catalyst C is a Catalyst 5000 with an RSM. What commands are bare on the RSM to
configure an interface for acquisition on VLAN 101, application the arrangement 10.1.101.0 with
subnet affectation 255.255.255.0?
5 What is bare for the RSM in Catalyst C to barter acquisition advice with the RSM
in Catalyst D?
6 Accept that all Catalysts are application VTP to configure VLANs in a distinct domain. VLANs
101 and 102 are the alone admission band VLANs in the arrangement and charge be present on all
switches. Area will LANE apparatus be placed? How abounding of anniversary will be required?
7 Suppose that Catalyst C will action as a LECS. How can Catalyst D admission the LECS
NSAP address? How can you (the arrangement administrator) admission the address?
8 What command on Catalyst B will acquiesce Telnet admission to the about-face alone from hosts on
the 192.168.17.0 255.255.255.0 network?
9 Accept that all switches and avenue processors are application the absence multicast
configurations. Area in the arrangement will multicast cartage basic from PC-1 on
Catalyst A (VLAN 101) be seen?
10 What is bare to absolute multicast cartage to alone those ports that absolutely accompany multicast
groups, application CGMP with PIM close mode? Accept this aforementioned charge on both VLAN 101
and 102.
11 Arrangement administrators appetite to accept bound ascendancy over hosts affective about aural the
network. Catalyst B needs to accept anchorage akin aegis enabled on all 24 ports of its Module
2 band card. Alone one host is affiliated per port, so the absence behavior of shutting the
port bottomward is acceptable. What command would be all-important to do this?
Scenario 14-3 467
Scenario 14-3
Refer to the arrangement diagram in Figure 14-3 and complete the afterward tasks. Accept that
each of the Catalysts has a MAC abode formed from its one letter name (Catalyst A = aa-aaaa-
aa-aa-aa, Catalyst B = bb-bb-bb-bb-bb-bb, and so forth).
Figure 14-3 Arrangement Diagram for Scenario 14-3
1 In what band of the hierarchical campus architecture are Catalysts A and B located? Catalysts
C and D? What blazon of amount is present?
2 Amount acclimation is adorable beyond the two block links from Catalyst A to Catalysts C and
D, and on the two block links from Catalyst B to Catalysts C and D. Given that the Access
Layer functions at Band 2 and the Amount at Band 3 (using MLS), what is the appropriate
way to accomplish amount balancing?
3 Suppose the PCs in VLAN 101 use abode 192.168.101.1 as their absence gateway. The
PCs in VLAN 102 use 192.168.102.1. What commands are all-important to configure HSRP
on the Catalyst C RSM so that it becomes the animate router for VLAN 101 and the standby
router for VLAN 102? If a bootless router interface is restored, ascendancy should be anesthetized back
to it from the HSRP standby router. (You may use IP addresses 192.168.101.2 and
192.168.102.2 if needed.)
PC-1
VLAN 101
PC-2
VLAN 102
Catalyst A Catalyst B
Catalyst C Catalyst D
PC-3
VLAN 201
PC-4
VLAN 202
VLANs
201/202
VLANs
101/102
VLANs
101/102
RSM
VLAN 5
(non-trunk)
RSM
VLANs
201/202
468 Chapter 14: Scenarios for Final Preparation
4 MLS is to be implemented on the network. What about-face commands are bare on Catalyst
C and D to acquiesce MLS operation with the corresponding RSMs?
5 MLS is configured on both RSMs illustrated in Figure 14-3 for all accurate VLANs.
How abounding XTAG entries does Catalyst C have? (This bearings assumes that Catalyst C
has a NFFC bore to action MLS information.)
6 What blazon of admission account should be implemented on an RSM to accomplish the authentic type
of MLS breeze mask:
a. Destination-Source breeze mask
b. Destination breeze mask
c. Full breeze mask
7 Application MLS, some amount of packet clarification is desired. For example, users in the
192.168.191.0 255.255.255.0 arrangement should be accustomed to use alone HTTP (www) traffic
into VLAN 180. What admission account should be acclimated to apparatus this clarify and how should
it be activated on an RSM?
8 What command can be acclimated to appearance the accepted MLS accumulation table, alternating with outbound
switch ports?
9 Suppose PC-1 needs to allocution to PC-3. The aboriginal packet campaign through Catalyst A, C, and on
to B and PC-3. Afresh a acknowledgment is beatific from PC-3 to Catalyst B, D, afresh to A and aback to PC-
1. (The paths declared actuality are academic and ability not be accomplished on an actual
network.) Which Catalysts accept articular applicant MLS entries and which ones have
identified accredit MLS entries?
10 Answer the afterward MLS timer questions:
a. What is the breach acclimated to age out abridged MLS adjustment entries?
b. How continued are normal, complete adjustment entries buried by default?
c. For concise flows (DNS, pings, and so on), what is the absence fast crumbling time?
11 Anchorage akin aegis is adapted on Catalyst B anchorage 3/1, area 24 users are affiliated via an
Ethernet hub. Rather than accept the about-face anchorage shut bottomward aloft a aegis violation,
network administrators appetite alone the hosts in abuse to be rejected. What command can
be acclimated to accomplish this?
Scenario 14-1 Answers 469
Scenarios Answers
Scenario 14-1 Answers
1 All of the Catalysts absence to server mode, for the VTP area “null.”
2 All added Catalysts will apprentice of the changes. Because anniversary server defaults to the domain
“null,” anniversary one will apprentice of the new area “alpha,” accompany it as a server, and create
VLANs 101 and 102.
3 VLAN 1 is consistently acclimated to canyon VTP advice and should not be disabled on a trunk.
VLAN 1 is additionally acclimated for abounding switch-related protocols, including DTP, PAgP, and CDP.
In fact, on Ethernet trunks you cannot abolish VLAN 1 from the account of VLANs to trunk,
unless Catalyst software Release 5.4 or greater is used. In Release 5.4 or greater, VLAN
1 can be removed from a trunk. Alone the user cartage on VLAN 1 is absolutely removed,
while the switch-related protocols still canyon with VLAN 1 tagging.
4 The afterward commands could be acclimated to accomplish this task:
set block 1/1 auto isl
clear block 1/1 2-1005
set block 1/1 101,102
5 Yes, broadcasts will be beatific beyond the block link. Although Catalyst B has no PCs in
VLAN 101, Catalyst B does accept added block links that charge to carriage VLAN 101 (with
all added VLANs). Therefore, Catalyst B informs A via VTP that it has a blade node
requiring VLAN 101.
6 Catalyst A will become the basis for both VLAN 101 and VLAN 102 because it has the
lowest MAC abode and the everyman Arch ID. (Remember that a abstracted Spanning-Tree
Protocol runs for anniversary VLAN—PVST.)
7 The afterward commands acclimatize the arch antecedence to 100, abundant beneath (more desirable)
than the absence 32768 on the added Catalysts:
set spantree antecedence 100 101
set spantree antecedence 100 102
Another another is to use the afterward commands:
set spantree basis 101
set spantree basis 102
8 For this network, alone one best is available: deterministic basis arch placement. The
root arch for VLAN 101 charge be Catalyst B (to account forwarding on A anchorage 1/1), and
the basis arch for VLAN 102 charge be Catalyst C (to account forwarding on A anchorage 1/2). The
following commands can be used:
470 Chapter 14: Scenarios for Final Preparation
Catalyst B:
set spantree basis 101
set spantree accessory 102
Catalyst C:
set spantree basis 102
set spantree accessory 101
9 Because Catalyst B is the basis bridge, all its links are Basis Ports by analogue (each has a
Root Path Amount of 0). Therefore, the articulation from B to A (A’s anchorage 1/1), the articulation from B to D,
and the articulation from B to C will all be in the forwarding state. From A’s perspective, the Root
Path Amount of the articulation from A to B (0+4) is lower than that of the articulation from A to C (0+4+4).
Therefore, anchorage 1/1 on A will become A’s Basis Port. On the articulation from A to C, anchorage 1/2 on
A will become the Designated Anchorage for the aggregate segment, because A has the lowest
BridgeID. C will abode its articulation to A in the blocking state.
Adjusting the anchorage amount for A’s anchorage 1/1 is all-important to accomplish it abominable alone for VLAN
102. The command set spantree portvlancost 1/1 1000 102 will accomplish the Basis Path Cost
of anchorage 1/1 abundant college (0+1000) than that of anchorage 1/2 (0+4+4). Anchorage 1/2 will admission the
forwarding accompaniment for VLAN 102, while anchorage 1/1 will be blocking. (Notice that the anchorage cost
for 1/1 alone needs to be one greater than the anchorage amount for 1/2 to accomplish the aforementioned result.)
10 set spantree portfast module/port enable
11 UplinkFast should alone be enabled on Catalyst A—the blade bulge of the arrangement with
multiple uplinks. BackboneFast, back used, should be enabled on every about-face in the
network.
12 set interface sc0 10.1.101.1 255.255.255.0 101
13 Catalyst E could accept its sc0 interface assigned to the amiss VLAN. Because the diagram
does not accept a router, casual cartage amid VLANs is impossible.
The VLAN assigned to Catalyst E’s sc0 interface ability not be trunked to Catalyst C or
Catalyst D. Because all links amid switches are block links in this network, the VLAN
would accept to be assigned to the trunks for connectivity.
VTP ability not be configured accurately amid the switches, such that added VLANs
are not actuality authentic in common. For example, Catalyst E could accept its sc0 assigned to
VLAN 53, and Catalyst C’s sc0 assigned to VLAN 53. Suppose that Catalyst C is in VTP
transparent approach and Catalyst E is in VTP applicant mode. After any added VTP servers,
Catalyst E will not accomplish VLAN 53 active.
Remember how advantageous the appearance cdp acquaintance command is for troubleshooting. CDP
uses multicasts at Band 2 to barter advice and will assignment auspiciously alike if IP
addresses or subnet masks are misconfigured.
14 With IGMP snooping, a about-face can accept to IGMP action for itself after requiring
router intervention.
Scenario 14-2 Answers 471
CGMP is a abundant added able and scalable technology, abnormally back Band 3
switches are in use. However, CGMP requires a router to action IGMP contest and inform
the switch.
15 set amount 3/3 3/8 both
Scenario 14-2 Answers
1 Anchorage Aggregation Agreement (PAgP)
2 Catalyst C charge accept its EtherChannel in adorable approach to admit an EtherChannel
negotiation with Catalyst A. In addition, all links in the EtherChannel array charge be set
to trunking approach with identical configurations.
3 To actuate which articulation is acclimated aural an EtherChannel bundle, anamnesis that the antecedent and
destination MAC addresses (by default) are exclusive-OR’d. Because this array has twolinks,
only the atomic cogent bit of the XOR is acclimated to basis the EtherChannel link.
For the PC-1 to Server-1 conversation:
11-11-11-11-11-11 XOR a1-a1-a1-a1-a1-a1
Least cogent bit: .....1 XOR .....1 = 0 (first articulation of bundle)
For the PC-2 to Server-2 conversation:
22-22-22-22-22-22 XOR a2-a2-a2-a2-a2-a2
Least cogent bit: .....0 XOR .....0 = 0 (first articulation of bundle)
Therefore, both conversations will use the aforementioned articulation aural the EtherChannel bundle. The
EtherChannel will not be balanced.
4 interface vlan 101
ip abode 10.1.101.1 255.255.255.0
no shutdown
5 An IP acquisition agreement (RIP, IGRP, EIGRP, OSPF, IS-IS, and so forth) is bare on both
RSMs; LANE connectivity amid the RSMs, and a accepted ELAN and LECs defined
on both Catalyst C and Catalyst D.
6 First, anamnesis that Catalyst switches use VLAN 1 to carriage VTP information. By default,
VLAN 1 exists on a Catalyst. However, LANE has no absence ELAN configuration, so
each ELAN charge be defined. To abutment VLAN 1, an ELAN 1 charge be configured to pass
VTP beyond the ATM LANE cloud.
• The LECS can be placed on either Catalyst C or D.
• An LES/BUS brace for ELAN 1 on either C or D.
472 Chapter 14: Scenarios for Final Preparation
• An LES/BUS brace for ELAN 101 on either C or D.
• An LES/BUS brace for ELAN 102 on either C or D.
• An LEC for ELAN 1 on both C and D.
• An LEC for ELAN 101 on both C and D.
• An LEC for ELAN 102 on both C and D.
Grand total: 1 LECS, 3 LES/BUS pairs, and 6 LECs.
7 Catalyst D can use ILMI to appeal the LECS abode from an ATM switch, hardcode the
LECS abode in its configuration, or use the acclaimed LECS NSAP address. ILMI is
the best adjustable and recommended. You may get the LECS NSAP abode from Catalyst
C itself, application the appearance lane absence command.
8 set ip admittance 192.168.17.0 255.255.255.0
9 By default, a about-face charge advanced advertisement and multicast frames out all accessible ports
on a VLAN. Therefore, the multicast cartage will be apparent on all VLAN 101 ports on
Catalyst A. In addition, Catalyst C and Catalyst D will arch the multicast cartage over
ELAN 101 via LANE. Finally, all VLAN 101 ports on Catalyst B will additionally advanced the
multicasts.
10 CGMP agreement is bare on both switches and routers. On a router, the following
commands can be used:
ip multicast-routing
interface vlan 101
ip pim dense-mode
ip cgmp
interface vlan 102
ip pim dense-mode
ip cgmp
On a switch, alone the afterward command is needed:
set cgmp enable
11 set anchorage aegis 2/1-24 enable
Scenario 14-3 Answers
1 A and B are in the Admission Layer, while C and D could be advised to be in the
Distribution Band or a aggregate Distribution/Core Layer. In the closing case, this
scenario would be alleged a Collapsed Core.
Scenario 14-3 Answers 473
2 Spanning Tree is abortive in this arrangement because the Band 2 VLANs abolish at the
Layer 3 avenue processors on Catalysts C and D. In added words, both links from each
Access Band about-face are forwarding for all VLANs. Therefore we charge accomplishment the Layer
3 technology to accretion amount balancing.
To do this, HSRP would be acclimated on the avenue processors in Catalysts C and D. Catalyst
C’s RSM should become the primary absence aperture for VLANs 101 and 201, while
Catalyst D’s RSM becomes the primary absence aperture for VLANs 102 and 202. In this
fashion, VLAN 101 cartage will biking over the A-C link; VLAN 201 cartage over the B-C
link; VLAN 102 over the A-D link; and VLAN 202 over the B-D link. Additionally accumulate in mind
that the RSMs should be configured as advancement or accessory routers for the non-primary
VLANs, should a primary router fail.
3 HSRP amount acclimation can be configured with the afterward RSM commands:
interface vlan 101
ip abode 192.168.101.2 255.255.255.0
standby 101 antecedence 110
standby 101 preempt
standby 101 ip 192.168.101.1
interface vlan 102
standby 102 antecedence 100
standby 102 preempt
standby 102 ip 192.168.102.1
The absence aperture abode aggregate amid the RSMs is configured as 192.168.101.1 for
VLAN 101 and 192.168.102.1 for VLAN 102. In VLAN 101, the basic interface has an
IP abode of 192.168.101.2. Two HSRP groups are defined, one for anniversary VLAN.
Interface VLAN 101 will be the animate router for VLAN 101 due to its college antecedence of
110 (over a absence of 100 on Catalyst D’s RSM). If ascendancy is anesthetized to the standby router,
this router will accept ascendancy afresh through the use of the accroach command. For VLAN
102, the roles are reversed. With its lower antecedence of 100, this router will become the
standby router in accumulation 102. (Catalyst D’s RSM will be configured with antecedence 110 for
VLAN 102 to booty the animate router role.)
4 set mls enable
MLS is enabled by absence on able Catalyst switches. This absence enables the switch
to accept for MLSP letters from an MLS-capable router.
5 Catalyst C will alone accept two XTAG entries—one per MLS router. (Each XTAG entry
contains all the MAC addresses for a distinct router’s interfaces.)
6 a. Standard admission list
b. No admission list
c. Extended admission list
474 Chapter 14: Scenarios for Final Preparation
7 access-list 101 admittance tcp 192.168.191.0 0.0.0.255 any eq www
access-list 101 abjure ip 192.168.191.0 0.0.0.255 any
access-list 101 admittance ip any any
interface vlan 180
ip access-group 101 out
The aboriginal band of the admission account allows HTTP cartage accurately from the 192.168.191.0
network. The additional band denies any added cartage from this network. The third band permits
any added cartage from any added network. The admission account is activated to outbound cartage on
the VLAN 180 interface, so that alone cartage that the admission account permits will be allowed
into VLAN 180.
8 appearance mls entry
9 Applicant MLS packets were articular on Catalyst C, for the packet from PC-1 to PC-3.
Candidates were additionally articular on Catalyst D, for the acknowledgment packet from PC-3 to PC-1.
However, no distinct Catalyst saw both applicant and accredit packets because the path
changed amid the antecedent and acknowledgment packets. Therefore, no Catalyst has identified
enable packets, and no complete MLS entries exist.
10 a. Abridged crumbling time is 5 seconds.
b. Accustomed crumbling time is 256 seconds.
c. Fast crumbling time is broad (set to 0 abnormal by default).
11 set anchorage aegis 3/1 enable
set anchorage aegis 3/1 best 24
set anchorage aegis 3/1 abuse restrict
The aboriginal command band enables anchorage akin aegis on anchorage 3/1. The additional band configures
port aegis to apprentice up to 24 MAC addresses dynamically on that port. The aftermost line
configures the about-face to bind any MAC addresses begin to be in violation. The anchorage will
stay up, acceptance the added users to communicate.