EtherChannel practice questions

A network engineer is configuring EtherChannel between two Cisco Catalyst switches. The ports are configured as access ports in VLAN 10. After configuring the port-channel interface and adding the physical ports, the engineer notices that the EtherChannel does not come up. The show etherchannel summary command shows the port-channel in a down state. What is the most likely cause?

Trap 1: The physical ports have different duplex settings.

Incorrect because duplex mismatch would cause issues, but the scenario states the ports are configured identically as access ports, so duplex should match.

Trap 2: The switch is using PAgP and the neighbor is using LACP.

Incorrect because if both sides use different protocols, the channel will not form, but the scenario does not specify protocol mismatch.

Trap 3: The physical ports are in different VLANs.

Incorrect because the scenario says both are in VLAN 10, so VLANs match.

A
The physical ports are configured as access ports in VLAN 10, but the port-channel interface is not configured with the same VLAN.
Correct because the port-channel interface must have the same access VLAN as the physical ports, or the channel will not form.
B
The physical ports have different duplex settings.
Why wrong: Incorrect because duplex mismatch would cause issues, but the scenario states the ports are configured identically as access ports, so duplex should match.
C
The switch is using PAgP and the neighbor is using LACP.
Why wrong: Incorrect because if both sides use different protocols, the channel will not form, but the scenario does not specify protocol mismatch.
D
The physical ports are in different VLANs.
Why wrong: Incorrect because the scenario says both are in VLAN 10, so VLANs match.

Question 2mediummultiple choice

An engineer is troubleshooting an EtherChannel between two switches. The show etherchannel summary output shows that the port-channel is up, but only one physical link is active. The other three links are in a suspended state. The physical ports are all configured identically with the same VLAN allowed. What is the most likely cause?

Trap 1: The port-channel has been configured with the 'channel-group 1 mode…

Incorrect because speed mismatch would cause all ports to be down, not just three.

Trap 2: The port-channel has been configured with the 'port-channel…

Incorrect because min-links specifies the minimum number of links to bring up the channel, not the maximum.

Trap 3: The physical ports are in different VLANs.

Incorrect because the scenario states they are all in the same VLAN.

A
The port-channel has been configured with the 'channel-group 1 mode on' command, but the physical ports are using different speeds.
Why wrong: Incorrect because speed mismatch would cause all ports to be down, not just three.
B
The port-channel has been configured with the 'port-channel min-links 1' command.
Why wrong: Incorrect because min-links specifies the minimum number of links to bring up the channel, not the maximum.
C
The port-channel has been configured with the 'port-channel max-links 1' command.
Correct because max-links limits the number of active ports in the EtherChannel.
D
The physical ports are in different VLANs.
Why wrong: Incorrect because the scenario states they are all in the same VLAN.

Question 3easymultiple choice

A network engineer is configuring an EtherChannel between a Cisco switch and a server that supports LACP. The switch ports are configured as trunk ports allowing multiple VLANs. The engineer wants to ensure the EtherChannel forms automatically without manual intervention. Which configuration should be applied on the switch?

Trap 1: Configure the port-channel with 'channel-group 1 mode passive'.

Incorrect because passive mode waits for the other side to initiate; if the server also uses passive, the channel will not form.

Trap 2: Configure the port-channel with 'channel-group 1 mode desirable'.

Incorrect because desirable is a PAgP mode, not LACP.

Trap 3: Configure the port-channel with 'channel-group 1 mode on'.

Incorrect because 'on' forces the channel without negotiation, which may not be compatible with the server's LACP.

A
Configure the port-channel with 'channel-group 1 mode active'.
Correct because LACP active mode initiates negotiation with the server.
B
Configure the port-channel with 'channel-group 1 mode passive'.
Why wrong: Incorrect because passive mode waits for the other side to initiate; if the server also uses passive, the channel will not form.
C
Configure the port-channel with 'channel-group 1 mode desirable'.
Why wrong: Incorrect because desirable is a PAgP mode, not LACP.
D
Configure the port-channel with 'channel-group 1 mode on'.
Why wrong: Incorrect because 'on' forces the channel without negotiation, which may not be compatible with the server's LACP.

Question 4mediummultiple choice

A network engineer is troubleshooting an EtherChannel between two Cisco switches. The show etherchannel 1 port-channel command shows the port-channel is up, but traffic is not load-balanced evenly. The engineer notices that all traffic is using only one link. The physical ports are all configured identically. What is the most likely cause?

Trap 1: The load-balancing method is set to src-mac, and the traffic is…

Incorrect because src-mac would use multiple links if multiple source MACs are present.

Trap 2: The physical ports have different speeds.

Incorrect because speed mismatch would cause some ports to be down, but the channel is up.

Trap 3: The port-channel is configured with 'lacp fast-switchover'.

Incorrect because fast-switchover affects failover, not load balancing.

A
The load-balancing method is set to src-mac, and the traffic is from multiple MAC addresses.
Why wrong: Incorrect because src-mac would use multiple links if multiple source MACs are present.
B
The load-balancing method is set to src-dst-ip, and all traffic is between the same two IP addresses.
Correct because src-dst-ip hashes on source and destination IP; if they are the same, all traffic goes to the same link.
C
The physical ports have different speeds.
Why wrong: Incorrect because speed mismatch would cause some ports to be down, but the channel is up.
D
The port-channel is configured with 'lacp fast-switchover'.
Why wrong: Incorrect because fast-switchover affects failover, not load balancing.

Question 5easymultiple choice

A network engineer is configuring EtherChannel between two Cisco switches using LACP. The engineer wants to ensure that if fewer than two links are operational, the EtherChannel does not come up. Which command should be configured?

Trap 1: Configure 'lacp min-bundle 2' under the port-channel interface.

Incorrect because the correct command is 'port-channel min-links', not 'lacp min-bundle'.

Trap 2: Configure 'channel-group 1 mode active' on the physical ports.

Incorrect because this sets the LACP mode, not the minimum links requirement.

Trap 3: Configure 'port-channel max-links 2' under the port-channel…

Incorrect because max-links sets the maximum number of active links, not the minimum.

A
Configure 'port-channel min-links 2' under the port-channel interface.
Correct because min-links specifies the minimum number of active links needed for the channel to be up.
B
Configure 'lacp min-bundle 2' under the port-channel interface.
Why wrong: Incorrect because the correct command is 'port-channel min-links', not 'lacp min-bundle'.
C
Configure 'channel-group 1 mode active' on the physical ports.
Why wrong: Incorrect because this sets the LACP mode, not the minimum links requirement.
D
Configure 'port-channel max-links 2' under the port-channel interface.
Why wrong: Incorrect because max-links sets the maximum number of active links, not the minimum.

Question 6easymultiple choice

A network engineer is configuring an EtherChannel between two Cisco switches. The engineer wants to use PAgP and ensure that the channel forms only if the neighboring switch is also configured for PAgP. Which mode should be configured on the local switch?

Trap 1: Configure 'channel-group 1 mode auto' on the physical ports.

Incorrect because auto is a PAgP mode that passively waits for negotiation, but it may not form if the neighbor is also auto.

Trap 2: Configure 'channel-group 1 mode active' on the physical ports.

Incorrect because active is an LACP mode, not PAgP.

Trap 3: Configure 'channel-group 1 mode on' on the physical ports.

Incorrect because 'on' forces the channel without negotiation, so it does not require the neighbor to use PAgP.

A
Configure 'channel-group 1 mode desirable' on the physical ports.
Correct because PAgP desirable mode actively negotiates with the neighbor to form the channel.
B
Configure 'channel-group 1 mode auto' on the physical ports.
Why wrong: Incorrect because auto is a PAgP mode that passively waits for negotiation, but it may not form if the neighbor is also auto.
C
Configure 'channel-group 1 mode active' on the physical ports.
Why wrong: Incorrect because active is an LACP mode, not PAgP.
D
Configure 'channel-group 1 mode on' on the physical ports.
Why wrong: Incorrect because 'on' forces the channel without negotiation, so it does not require the neighbor to use PAgP.

Question 7hardmultiple choice

A network engineer is configuring an EtherChannel between a Cisco switch and a router. The switch ports are configured as trunk ports with allowed VLANs 10, 20, and 30. The router is configured with subinterfaces for each VLAN. After configuring the EtherChannel, the engineer notices that the router can ping devices in VLAN 10 but not in VLAN 20 or 30. What is the most likely cause?

Trap 1: The allowed VLAN list on the switch does not include VLAN 20 and 30.

Incorrect because the scenario says the switch ports are configured with allowed VLANs 10, 20, and 30.

Trap 2: The router subinterfaces are configured with the wrong…

Incorrect because if encapsulation were wrong, none of the VLANs would work.

Trap 3: The EtherChannel is configured with 'lacp system-priority' that is…

Incorrect because system-priority affects LACP negotiation, not VLAN connectivity.

A
The native VLAN is configured as VLAN 1 on the switch but VLAN 10 on the router.
Correct because a native VLAN mismatch can cause connectivity issues for some VLANs, especially if the native VLAN is used for management or control traffic.
B
The allowed VLAN list on the switch does not include VLAN 20 and 30.
Why wrong: Incorrect because the scenario says the switch ports are configured with allowed VLANs 10, 20, and 30.
C
The router subinterfaces are configured with the wrong encapsulation.
Why wrong: Incorrect because if encapsulation were wrong, none of the VLANs would work.
D
The EtherChannel is configured with 'lacp system-priority' that is too high.
Why wrong: Incorrect because system-priority affects LACP negotiation, not VLAN connectivity.

Question 8hardmultiple choice

A network engineer is troubleshooting an EtherChannel between two Cisco switches. The show etherchannel summary command shows the port-channel is up, but the show interfaces trunk command shows that the trunk is not passing traffic for VLAN 100. The allowed VLAN list on the port-channel interface includes VLAN 100. What is the most likely cause?

Trap 1: The native VLAN is configured as VLAN 100 on one side.

Incorrect because native VLAN mismatch would cause issues for all VLANs, not just one.

Trap 2: The port-channel is configured with 'switchport trunk allowed vlan…

Incorrect because if the physical ports exclude VLAN 100, the port-channel would also exclude it.

Trap 3: The VLAN 100 does not exist on the switch.

Incorrect because if the VLAN did not exist, the trunk would not show it in the allowed list.

A
One of the physical ports in the EtherChannel has VLAN 100 removed from its allowed list.
Correct because the allowed VLAN list on physical ports must match; if one port does not allow VLAN 100, the trunk may not pass that VLAN.
B
The native VLAN is configured as VLAN 100 on one side.
Why wrong: Incorrect because native VLAN mismatch would cause issues for all VLANs, not just one.
C
The port-channel is configured with 'switchport trunk allowed vlan add 100' but the physical ports have 'switchport trunk allowed vlan except 100'.
Why wrong: Incorrect because if the physical ports exclude VLAN 100, the port-channel would also exclude it.
D
The VLAN 100 does not exist on the switch.
Why wrong: Incorrect because if the VLAN did not exist, the trunk would not show it in the allowed list.

Question 9hardmultiple choice

A network engineer is configuring an EtherChannel between two Cisco switches. The engineer wants to use LACP and ensure that the local switch is the one that determines which ports are active in the channel. Which configuration should be applied?

Trap 1: Configure 'lacp port-priority 100' on the physical ports of the…

Incorrect because port-priority determines which ports are active within the channel, not which switch controls.

Trap 2: Configure 'channel-group 1 mode active' on the physical ports.

Incorrect because mode active only initiates negotiation, it does not determine control.

Trap 3: Configure 'lacp fast-switchover' on the port-channel interface.

Incorrect because fast-switchover affects failover time, not control.

A
Configure 'lacp system-priority 100' on the local switch.
Correct because a lower system priority value makes the switch more likely to be the controlling switch in LACP.
B
Configure 'lacp port-priority 100' on the physical ports of the local switch.
Why wrong: Incorrect because port-priority determines which ports are active within the channel, not which switch controls.
C
Configure 'channel-group 1 mode active' on the physical ports.
Why wrong: Incorrect because mode active only initiates negotiation, it does not determine control.
D
Configure 'lacp fast-switchover' on the port-channel interface.
Why wrong: Incorrect because fast-switchover affects failover time, not control.

Question 10mediummultiple choice

A network engineer runs the following command on Switch SW1:

SW1# show etherchannel summary

Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use N - not in use, no aggregation f - failed to allocate aggregator

M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port

Number of channel-groups in use: 1 Number of aggregators: 1

Group Port-channel Protocol Ports ------+-------------+-----------+-------------------------------------------- 1 Po1(SU) LACP Gi0/0(P) Gi0/1(P) Gi0/2(s) Gi0/3(D)

Based on this output, what can be concluded?

Trap 1: Port-channel 1 is operating as a Layer 3 interface.

The 'S' flag indicates Layer 2, not Layer 3.

Trap 2: Interface Gi0/3 is in standby mode waiting to join the bundle.

The 'D' flag means the port is down, not standby.

Trap 3: All four interfaces are actively forwarding traffic in the…

Gi0/2 is suspended and Gi0/3 is down, so only two ports are active.

A
Port-channel 1 is operating as a Layer 3 interface.
Why wrong: The 'S' flag indicates Layer 2, not Layer 3.
B
Interface Gi0/2 is suspended due to a configuration mismatch.
The 's' flag means suspended, typically due to mismatched parameters.
C
Interface Gi0/3 is in standby mode waiting to join the bundle.
Why wrong: The 'D' flag means the port is down, not standby.
D
All four interfaces are actively forwarding traffic in the EtherChannel.
Why wrong: Gi0/2 is suspended and Gi0/3 is down, so only two ports are active.

Question 11mediummultiple choice

A network engineer runs the following command on Switch SW2:

SW2# show interfaces port-channel 1 etherchannel

Port-channel1 :

Age of the Port-channel = 0d:00h:10m:32s Logical slot/port = 16/1 Number of ports = 2 HotStandby port = null Port state = Port-channel Ag-Inuse Protocol = LACP

Ports in the Port-channel:

Index Load Port EC state No of bits ------+------+------+----------------+---------- 0 00 Gi0/0 Active 4 1 00 Gi0/1 Active 4

Time since last port bundled: 0d:00h:05m:23s Gi0/1

Based on this output, what can be concluded?

Trap 1: The EtherChannel is not operational because the load is zero.

Zero load indicates no traffic, not a failure.

Trap 2: The port-channel is in 'Ag-Inuse' state, which means it is not yet…

Ag-Inuse means the port-channel is in use and forwarding.

Trap 3: Load balancing is set to source-destination IP, causing the zero…

The load values are based on the hash result; zero could be due to no traffic, not the method.

A
The EtherChannel is not operational because the load is zero.
Why wrong: Zero load indicates no traffic, not a failure.
B
Both member ports are in Active state, meaning they are participating in LACP negotiation.
Active state in LACP means the port is actively trying to form an aggregation.
C
The port-channel is in 'Ag-Inuse' state, which means it is not yet forwarding traffic.
Why wrong: Ag-Inuse means the port-channel is in use and forwarding.
D
Load balancing is set to source-destination IP, causing the zero load values.
Why wrong: The load values are based on the hash result; zero could be due to no traffic, not the method.

Question 12easymultiple choice

A network engineer runs the following command on Switch SW3:

SW3# show etherchannel load-balance

EtherChannel Load-Balancing Configuration: src-dst-ip

EtherChannel Load-Balancing Operational State: src-dst-ip

Based on this output, what can be concluded?

Trap 1: The switch uses source MAC and destination MAC for load balancing.

The output explicitly states 'src-dst-ip', not MAC.

Trap 2: The operational state differs from the configured state, indicating…

Both states match, so there is no mismatch.

Trap 3: The switch is using round-robin to distribute traffic across ports.

Round-robin is not a standard EtherChannel load-balancing method.

A
The switch uses source MAC and destination MAC for load balancing.
Why wrong: The output explicitly states 'src-dst-ip', not MAC.
B
The load-balancing method is based on source and destination IP addresses.
The output confirms 'src-dst-ip' as the method.
C
The operational state differs from the configured state, indicating a problem.
Why wrong: Both states match, so there is no mismatch.
D
The switch is using round-robin to distribute traffic across ports.
Why wrong: Round-robin is not a standard EtherChannel load-balancing method.

Question 13hardmultiple choice

A network engineer runs the following command on Switch SW4:

SW4# show etherchannel 1 detail
Channel-group number: 1

Group state = L2

Ports in the group: -------------------

Port: Gi0/0 --------

Port state = Up, In-Bundle Channel group = 1 Mode = Active/PagNego Gcchange = - Port-channel = Po1 GC = 0x00010001 Pseudo port-channel = Po1

Port index = 0 Load = 0x00

Flags: S - Device is sending Slow LACPDUs F - Device is sending Fast LACPDUs A - Device is in active mode. P - Device is in passive mode.

Local information:

LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/0 SA bndl 32768 0x1 0x1 0x101 0x3D

Partner information:

LACP port Admin Oper Port Port Port Flags State Priority Key Key Number State Gi0/0 SA bndl 32768 0x1 0x1 0x102 0x3D

Age of the port = 0d:00h:15m:20s

Based on this output, what can be concluded?

Trap 1: The port is in passive mode and waiting for the partner to initiate.

Flag 'A' indicates active mode, not passive.

Trap 2: The port is sending fast LACPDUs because the flag is 'F'.

The flag is 'S', meaning slow LACPDUs.

Trap 3: The port is not in use because the load is 0x00.

Load of 0x00 indicates no current traffic, but the port is still bundled and ready.

A
The port is in passive mode and waiting for the partner to initiate.
Why wrong: Flag 'A' indicates active mode, not passive.
B
The port is sending fast LACPDUs because the flag is 'F'.
Why wrong: The flag is 'S', meaning slow LACPDUs.
C
The port is bundled and the LACP state is synchronized.
State 'bndl' and the port state '0x3D' indicate synchronization and bundling.
D
The port is not in use because the load is 0x00.
Why wrong: Load of 0x00 indicates no current traffic, but the port is still bundled and ready.

Question 14mediummultiple choice

A network engineer runs the following command on Switch SW5:

SW5# show running-config | section interface port-channel
interface Port-channel1
 switchport mode trunk
 switchport trunk allowed vlan 1-100,200-300

interface Port-channel2
 switchport mode access
 switchport access vlan 10

SW5# show interfaces trunk

Port Mode Encapsulation Status Native vlan Po1 on 802.1q trunking 1

Port Vlans allowed on trunk Po1 1-100,200-300

Port Vlans allowed and active in management domain Po1 1-100,200-300

Port Vlans in spanning tree forwarding state and not pruned Po1 1-100,200-300

Based on this output, what can be concluded?

Trap 1: Port-channel2 is also trunking but not displayed due to a software…

Port-channel2 is configured as access, so it will not appear in trunk output.

Trap 2: Port-channel1 is trunking and allowed VLANs include VLANs 101-199.

The allowed VLANs are 1-100 and 200-300, so 101-199 are excluded.

Trap 3: The native VLAN on Po1 is VLAN 10.

The native VLAN is shown as 1, not 10.

A
Port-channel2 is also trunking but not displayed due to a software bug.
Why wrong: Port-channel2 is configured as access, so it will not appear in trunk output.
B
Port-channel1 is trunking and allowed VLANs include VLANs 101-199.
Why wrong: The allowed VLANs are 1-100 and 200-300, so 101-199 are excluded.
C
Port-channel1 is operational as a trunk with the configured allowed VLANs.
The trunk output confirms the trunk is up and the allowed VLAN list matches.
D
The native VLAN on Po1 is VLAN 10.
Why wrong: The native VLAN is shown as 1, not 10.

Question 15mediummultiple choice

A network engineer runs the following command on Switch SW6:

SW6# show etherchannel 3 summary

Flags: D - down P - bundled in port-channel I - stand-alone s - suspended H - Hot-standby (LACP only) R - Layer3 S - Layer2 U - in use N - not in use, no aggregation f - failed to allocate aggregator

M - not in use, minimum links not met u - unsuitable for bundling w - waiting to be aggregated d - default port

Number of channel-groups in use: 1 Number of aggregators: 1

Group Port-channel Protocol Ports ------+-------------+-----------+-------------------------------------------- 3 Po3(RU) PAgP Gi0/0(P) Gi0/1(P) Gi0/2(I)

Based on this output, what can be concluded?

Trap 1: Port-channel 3 is a Layer 2 EtherChannel.

The 'R' flag indicates Layer 3, not Layer 2.

Trap 2: All three interfaces are bundled and forwarding traffic.

Gi0/2 is stand-alone, so only two ports are bundled.

Trap 3: The EtherChannel is not in use because the 'U' flag is missing.

The 'U' flag is present in Po3(RU), indicating it is in use.

A
Port-channel 3 is a Layer 2 EtherChannel.
Why wrong: The 'R' flag indicates Layer 3, not Layer 2.
B
Interface Gi0/2 is in stand-alone mode because it is not receiving PAgP packets from the neighbor.
The 'I' flag means stand-alone, typically due to PAgP negotiation failure.
C
All three interfaces are bundled and forwarding traffic.
Why wrong: Gi0/2 is stand-alone, so only two ports are bundled.
D
The EtherChannel is not in use because the 'U' flag is missing.
Why wrong: The 'U' flag is present in Po3(RU), indicating it is in use.

Question 16hardmultiple choice

A network engineer runs the following command on Switch SW7:

SW7# show interfaces port-channel 1

Port-channel1 is up, line protocol is up (connected) Hardware is EtherChannel, address is aaaa.bbbb.cccc (bia aaaa.bbbb.cccc) Description: Link to Core Internet address is 192.168.1.1/30 MTU 1500 bytes, BW 2000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec) Full-duplex, 1000Mb/s, link type is auto, media type is unknown input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters never Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 1000 bits/sec, 2 packets/sec 5 minute output rate 500 bits/sec, 1 packets/sec 12345 packets input, 1234567 bytes, 0 no buffer Received 0 broadcasts (0 IP multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 0 multicast, 0 pause input 0 input packets with dribble condition detected 67890 packets output, 9876543 bytes, 0 underruns 0 output errors, 0 collisions, 2 interface resets 0 unknown protocol drops 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 pause output 0 output buffer failures, 0 output buffers swapped out

Based on this output, what can be concluded?

Trap 1: The port-channel is a Layer 2 interface because it has an IP…

Having an IP address indicates Layer 3, not Layer 2.

Trap 2: The interface is experiencing input errors due to CRC errors.

The output shows 0 input errors and 0 CRC.

Trap 3: The port-channel is operating at half-duplex.

The output shows 'Full-duplex'.

A
The port-channel is a Layer 2 interface because it has an IP address.
Why wrong: Having an IP address indicates Layer 3, not Layer 2.
B
The bandwidth of 2 Gbps suggests that two 1 Gbps links are aggregated.
The bandwidth is 2000000 Kbit/sec, which is 2 Gbps, typical for two 1 Gbps links.
C
The interface is experiencing input errors due to CRC errors.
Why wrong: The output shows 0 input errors and 0 CRC.
D
The port-channel is operating at half-duplex.
Why wrong: The output shows 'Full-duplex'.

Question 17hardmultiple choice

A network engineer runs the following command on Switch SW8:

SW8# show etherchannel 2 detail | include "Port state|Port: Gi|Partner"

Port: Gi0/0 Port state = Up, In-Bundle Port: Gi0/1 Port state = Up, In-Bundle Port: Gi0/2 Port state = Down, Not-In-Bundle Partner information: Gi0/0: Partner state = bndl Gi0/1: Partner state = bndl Gi0/2: Partner state = down

Based on this output, what can be concluded?

Trap 1: All three ports are bundled and forwarding traffic.

Gi0/2 is down and not in-bundle.

Trap 2: The EtherChannel is using PAgP because the partner state shows…

The 'bndl' state is common to both LACP and PAgP; the protocol is not specified here.

Trap 3: Gi0/2 is in standby mode waiting to become active.

The state is 'Down', not standby.

A
All three ports are bundled and forwarding traffic.
Why wrong: Gi0/2 is down and not in-bundle.
B
Gi0/2 is not bundled because the partner is in 'down' state, indicating a physical layer issue.
Both local and partner states are down, suggesting a physical problem.
C
The EtherChannel is using PAgP because the partner state shows 'bndl'.
Why wrong: The 'bndl' state is common to both LACP and PAgP; the protocol is not specified here.
D
Gi0/2 is in standby mode waiting to become active.
Why wrong: The state is 'Down', not standby.

Question 18hardmultiple choice

A network engineer runs the following command on Switch SW9:

SW9# show etherchannel 4 port-channel

Port-channels in the group: ---------------------------

Port-channel: Po4 (Primary Aggregator)

Age of the Port-channel = 0d:00h:20m:10s Logical slot/port = 16/4 Number of ports = 3 HotStandby port = null Port state = Port-channel Ag-Inuse Protocol = LACP

Ports in the Port-channel:

Index Load Port EC state No of bits ------+------+------+----------------+---------- 0 00 Gi0/0 Active 4 1 00 Gi0/1 Active 4 2 00 Gi0/2 Standby 4

Time since last port bundled: 0d:00h:15m:00s Gi0/1

Based on this output, what can be concluded?

Trap 1: All three ports are actively forwarding traffic in the EtherChannel.

Gi0/2 is in standby, not active.

Trap 2: Gi0/2 is in standby mode because it is not receiving LACP packets…

Standby is a normal LACP state, not a failure.

Trap 3: The port-channel is not in use because the load is zero.

The port-channel is in 'Ag-Inuse' state, meaning it is in use.

A
All three ports are actively forwarding traffic in the EtherChannel.
Why wrong: Gi0/2 is in standby, not active.
B
Gi0/2 is in standby mode because it is not receiving LACP packets from the neighbor.
Why wrong: Standby is a normal LACP state, not a failure.
C
The EtherChannel has a maximum bundle size of 2, so Gi0/2 is a hot-standby port.
The standby state indicates that the maximum number of active ports has been reached, and Gi0/2 is ready to replace a failed port.
D
The port-channel is not in use because the load is zero.
Why wrong: The port-channel is in 'Ag-Inuse' state, meaning it is in use.

Question 19mediummultiple choice

Consider the following configuration snippet:

interface Port-channel1
 switchport mode trunk
 switchport trunk allowed vlan 10,20,30

interface GigabitEthernet0/1
 channel-group 1 mode active

interface GigabitEthernet0/2
 channel-group 1 mode passive

What is the effect of this configuration?

Trap 1: The EtherChannel will not form because both sides must use the same…

Incorrect. LACP active/passive is a valid combination; the active side initiates negotiation.

Trap 2: The EtherChannel will form using PAgP because the mode is not…

Incorrect. The 'channel-group 1 mode active' command explicitly uses LACP, not PAgP.

Trap 3: The EtherChannel will form but only VLAN 1 will be allowed on the…

Incorrect. The 'switchport trunk allowed vlan' command restricts the trunk to VLANs 10, 20, and 30.

A
The EtherChannel will form using LACP, and the port-channel will operate as a trunk carrying VLANs 10, 20, and 30.
Correct. LACP active/passive will negotiate, and the port-channel trunk configuration applies to all member ports.
B
The EtherChannel will not form because both sides must use the same LACP mode.
Why wrong: Incorrect. LACP active/passive is a valid combination; the active side initiates negotiation.
C
The EtherChannel will form using PAgP because the mode is not specified as lacp.
Why wrong: Incorrect. The 'channel-group 1 mode active' command explicitly uses LACP, not PAgP.
D
The EtherChannel will form but only VLAN 1 will be allowed on the trunk.
Why wrong: Incorrect. The 'switchport trunk allowed vlan' command restricts the trunk to VLANs 10, 20, and 30.

Question 20mediummultiple choice

Given the following configuration:

interface Port-channel1
 no switchport
 ip address 192.168.1.1 255.255.255.0

interface GigabitEthernet0/1
 no switchport
 channel-group 1 mode on

interface GigabitEthernet0/2
 no switchport
 channel-group 1 mode on

Which statement is true about this EtherChannel?

Trap 1: The EtherChannel will form only if the neighbor also uses LACP…

Incorrect. 'mode on' does not use LACP; it is static.

Trap 2: The EtherChannel will not form because the interfaces are in no…

Incorrect. Layer 3 EtherChannels are supported; 'no switchport' is valid.

Trap 3: The EtherChannel will form but will use PAgP negotiation.

Incorrect. 'mode on' is static and does not use any negotiation protocol.

A
The EtherChannel will form only if the neighbor also uses LACP active mode.
Why wrong: Incorrect. 'mode on' does not use LACP; it is static.
B
The EtherChannel will form and operate as a Layer 3 routed interface.
Correct. 'no switchport' makes it a Layer 3 interface, and 'mode on' creates a static channel without negotiation.
C
The EtherChannel will not form because the interfaces are in no switchport mode.
Why wrong: Incorrect. Layer 3 EtherChannels are supported; 'no switchport' is valid.
D
The EtherChannel will form but will use PAgP negotiation.
Why wrong: Incorrect. 'mode on' is static and does not use any negotiation protocol.