58 questions · Etherchannel topic · All types, answers revealed
What is the maximum number of active member links supported in a single EtherChannel on Cisco Catalyst switches?
Correct. Up to 8 active links are supported in a single EtherChannel.
Why this answer
Cisco Catalyst switches support up to 8 active member links in a single EtherChannel. Some platforms also support up to 16 links with 8 active and 8 standby using LACP, but the maximum active links is 8.
What is the default load-balancing method used by Cisco switches for EtherChannel?
Correct. The default is src-mac on most Cisco switches.
Why this answer
Cisco switches default to source MAC address-based load balancing for EtherChannel. This method distributes traffic based on the source MAC address of the frame, which can lead to uneven distribution if traffic patterns are not diverse.
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?
Correct because PAgP desirable mode actively negotiates with the neighbor to form the channel.
Why this answer
The correct answer is 'desirable' because it actively negotiates with the neighbor. The wrong answers either use LACP or force the channel without negotiation.
Drag and drop each PAgP port mode on the left to its matching negotiation behavior on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Sends PAgP packets and responds to PAgP packets
Responds to PAgP packets but does not initiate
Both sides send PAgP, forms channel
One side initiates, other responds, forms channel
Neither side initiates, no channel formed
Why these pairings
Desirable initiates negotiation; auto waits. At least one side must be desirable to form channel.
Drag and drop each EtherChannel port state on the left to its matching description on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Port is part of the channel and forwards traffic
Port is not part of the channel, operates as normal switchport
Port is disabled due to incompatible parameters
Port is in process of negotiation (LACP/PAgP)
Port has been added to the port-channel interface
Why these pairings
Bundled ports actively forward traffic; stand-alone ports operate individually; suspended ports are disabled due to misconfiguration.
Which two statements about PAgP (Port Aggregation Protocol) are true? (Choose two.)
Correct because PAgP uses the Cisco-proprietary multicast address 0100.0CCC.CCCC.
Why this answer
PAgP is a Cisco proprietary protocol for dynamic EtherChannel formation. It uses multicast address 01-00-0C-CC-CC-CC, supports modes 'auto' and 'desirable', and uses a learning method to detect misconfigurations. PAgP cannot interoperate with LACP and does not support standby links.
Which two statements about EtherChannel configuration and verification are true? (Choose two.)
Correct because when the first physical port is added with a mode that enables LACP, the port-channel interface is dynamically created.
Why this answer
EtherChannel interfaces can be configured as Layer 2 (switchport) or Layer 3 (no switchport). The 'channel-group' command assigns a physical port to a port-channel. The 'show etherchannel summary' command displays the state and bundle information.
On NX-OS, the 'channel-group' command uses the 'force' option to override mismatched parameters.
Which three statements about PAgP (Port Aggregation Protocol) are true? (Choose three.)
Correct because PAgP uses the Cisco proprietary multicast address 01-00-0c-cc-cc-cc.
Why this answer
PAgP is a Cisco proprietary protocol for EtherChannel negotiation. It uses modes 'auto', 'desirable', and 'on'. PAgP packets are sent using Cisco's proprietary multicast address 01-00-0c-cc-cc-cc.
PAgP supports up to 8 ports per channel and does not support standby ports. PAgP can detect misconfigurations.
Drag and drop each EtherChannel load-balance method on the left to its matching hashing input on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Source and destination IP addresses
Source and destination MAC addresses
Source and destination Layer 4 ports
Source IP address only
Destination IP address only
Which three statements about LACP (Link Aggregation Control Protocol) are true? (Choose three.)
Correct because LACP uses the Slow Protocols multicast address 0180.c200.0002.
Why this answer
LACP is an IEEE standard (802.3ad) that allows dynamic formation of EtherChannels. It uses LACPDUs to negotiate parameters, supports up to 16 links (8 active, 8 standby), and can detect mismatched parameters like speed or duplex. The 'active' mode initiates negotiation, while 'passive' waits.
Drag and drop the steps of EtherChannel troubleshooting and verification into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Troubleshooting begins with checking physical layer, then verifying protocol negotiation, inspecting bundle state, checking load balancing, and finally reviewing logs.
Drag and drop each EtherChannel port state on the left to its matching description on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Port is actively forwarding traffic in the EtherChannel
Port is active but not part of any EtherChannel
Port is administratively down or error-disabled in the channel
Why these pairings
Bundled ports actively forward traffic, stand-alone ports are active but not in channel, suspended ports are error-disabled.
Drag and drop the steps of PAgP EtherChannel negotiation into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Drag and drop the steps of EtherChannel load-balancing hash configuration into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Configuration begins with selecting hash algorithm, then applying it globally, verifying on interfaces, checking load distribution, and finally adjusting if needed.
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?
Correct because LACP active mode initiates negotiation with the server.
Why this answer
The correct answer is LACP active mode, which initiates negotiation. The wrong answers either use passive mode (which waits for the other side) or static mode (which does not negotiate).
Examine the following configuration: interface Port-channel1 switchport mode trunk ! interface GigabitEthernet0/1 switchport mode trunk channel-group 1 mode active spanning-tree portfast ! interface GigabitEthernet0/2 switchport mode trunk channel-group 1 mode active spanning-tree portfast What is the effect of the 'spanning-tree portfast' command on the member interfaces of this EtherChannel?
Correct. When interfaces are bundled into an EtherChannel, STP is handled at the port-channel level, and per-interface PortFast is overridden.
Why this answer
PortFast is used on access ports to immediately transition to forwarding state, bypassing STP listening/learning. However, on trunk ports, PortFast can cause loops if used incorrectly. In this case, the member interfaces are part of an EtherChannel, and PortFast is applied at the interface level.
But the port-channel interface itself does not have PortFast. The PortFast on member interfaces is ignored because the channel is a trunk; the port-channel interface controls STP. The correct practice is to apply PortFast on the port-channel interface, not on individual members.
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?
Why this answer
The output shows that Port-channel1 is configured as a trunk with allowed VLANs 1-100 and 200-300. The 'show interfaces trunk' output confirms that Po1 is trunking and the allowed VLAN list matches. Port-channel2 is not shown in the trunk output, which is expected because it is an access port.
The correct answer is that Port-channel1 is operational as a trunk.
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?
Correct because src-dst-ip hashes on source and destination IP; if they are the same, all traffic goes to the same link.
Why this answer
The correct answer is that the load-balancing method is set to src-dst-ip, but the traffic is from a single source to a single destination IP. The wrong answers involve issues that would prevent the channel from being up or affect all links.
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?
State 'bndl' and the port state '0x3D' indicate synchronization and bundling.
Why this answer
The output shows detailed LACP information for port Gi0/0. The local and partner states are both 'bndl', meaning the port is bundled. The flags 'SA' indicate the port is in active mode and sending slow LACPDUs.
The port state '0x3D' is a hexadecimal representation of the LACP state, which includes bits for activity, aggregation, synchronization, collecting, distributing, and defaulted. The correct answer is that the port is actively participating in LACP and is bundled.
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?
Active state in LACP means the port is actively trying to form an aggregation.
Why this answer
The output shows that the port-channel is in 'Ag-Inuse' state, meaning the aggregation is active. Both Gi0/0 and Gi0/1 are in 'Active' state, which is correct for LACP. The load field shows '00' for both, indicating that load balancing is not distributing traffic evenly; this could be because there is no traffic or the load-balancing method is not effective.
The correct answer is that the EtherChannel is operational with two active member ports.
Drag and drop each EtherChannel protocol on the left to its matching vendor on the right.
Drag a concept onto its matching description — or click a concept then click the description.
IEEE standard, supported by multiple vendors
Cisco proprietary
Standard for LACP
Vendor that developed PAgP
Describes LACP
Drag and drop each EtherChannel load-balance method on the left to its matching hashing input on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Source MAC address
Destination MAC address
Source and destination IP addresses
Source and destination Layer 4 ports
Source and destination MAC addresses
Why these pairings
Methods use different combinations of source/destination MAC, IP, or port to compute hash for link selection.
Drag and drop each LACP port mode on the left to its matching negotiation behavior on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Sends LACP packets to negotiate
Responds only to received LACP packets
Why these pairings
Active initiates negotiation, passive waits for partner.
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?
Correct because max-links limits the number of active ports in the EtherChannel.
Why this answer
The correct answer is that the maximum number of active ports in the port-channel has been configured to 1. The wrong answers involve misconfigurations that would affect all ports or prevent the channel from forming.
Which three statements about EtherChannel configuration and verification are true? (Choose three.)
Correct because mismatched speed or duplex will prevent the channel from being established.
Why this answer
EtherChannel configuration requires consistent settings across member ports (speed, duplex, VLAN, trunking). The 'show etherchannel summary' command displays the state (SU for Layer 2 in use, P for bundled). The 'on' mode forces the channel without negotiation.
Misconfigurations can cause the channel to not form or to flap.
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?
The output confirms 'src-dst-ip' as the method.
Why this answer
The output shows that both the configured and operational load-balancing method is 'src-dst-ip', which means the switch uses source and destination IP addresses to determine which member port to use for each flow. This is a common and valid method. The correct answer is that the load-balancing method uses both source and destination IP addresses.
Drag and drop the steps of EtherChannel troubleshooting and verification steps into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Troubleshooting begins with checking physical port status, then verifying EtherChannel bundle state, inspecting protocol details, checking load-balancing, and finally testing connectivity.
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?
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.
Why this answer
The correct answer is that the native VLAN mismatch is causing issues. The wrong answers involve misconfigurations that would affect all VLANs or are unrelated.
Drag and drop each PAgP port mode on the left to its matching negotiation behavior on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Sends PAgP packets to negotiate
Responds only to received PAgP packets
Why these pairings
Desirable initiates negotiation, auto waits for partner.
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?
Correct because a lower system priority value makes the switch more likely to be the controlling switch in LACP.
Why this answer
The correct answer is to set the LACP system priority lower on the local switch. The wrong answers involve other LACP parameters that do not determine which switch controls active port selection.
Drag and drop the steps of Layer 3 EtherChannel (routed port-channel) setup into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Layer 3 EtherChannel setup requires creating port-channel interface, assigning IP, adding member ports with no switchport, configuring channel-group, and finally verifying routing.
Which two statements about EtherChannel load balancing are true? (Choose two.)
Correct because the 'port-channel load-balance' command is applied globally, but some platforms allow per-interface override.
Why this answer
EtherChannel load balancing can use source/destination MAC, IP, or TCP/UDP port information. The default method varies by platform but is often src-dst-mac. The hash is computed per frame, and all frames in a flow use the same link to avoid reordering.
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?
The 'I' flag means stand-alone, typically due to PAgP negotiation failure.
Why this answer
The output shows that Port-channel3 is a Layer 3 (R) port-channel in use (U) using PAgP. Two ports (Gi0/0 and Gi0/1) are bundled (P), while Gi0/2 is in stand-alone mode (I). Stand-alone mode in PAgP means the port is not part of the channel, typically because the neighbor is not configured for PAgP or there is a mismatch.
The correct answer is that Gi0/2 is not bundled and is operating as a regular interface.
Drag and drop the steps of troubleshooting a failed EtherChannel bundle into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
First, verify that the port-channel interface exists. Then check that physical ports are in the same VLAN and have matching configurations. Next, confirm that the channel-group mode is compatible on all ports.
After that, inspect LACP or PAgP counters for errors. Finally, check for hardware or cabling issues if all else fails. This systematic approach isolates configuration errors before hardware faults.
Which LACP mode must be configured on at least one side of an EtherChannel for the channel to establish?
Correct. Active mode initiates LACP negotiation.
Why this answer
LACP requires at least one side to be in active mode to initiate negotiation. If both sides are passive, the channel will not form because neither side sends LACP packets.
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?
Correct because min-links specifies the minimum number of active links needed for the channel to be up.
Why this answer
The correct answer is 'port-channel min-links 2', which sets the minimum number of active links required. The wrong answers either set maximum links or are unrelated.
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?
Correct. 'no switchport' makes it a Layer 3 interface, and 'mode on' creates a static channel without negotiation.
Why this answer
The 'mode on' command forces the interface into an EtherChannel without any negotiation protocol (no LACP or PAgP). Both sides must be configured with 'mode on' for the channel to come up. The port-channel is a routed interface (no switchport) with an IP address.
Drag and drop each EtherChannel protocol on the left to its matching vendor on the right.
Drag a concept onto its matching description — or click a concept then click the description.
IEEE standard (multi-vendor)
Cisco proprietary
Consider this configuration: interface Port-channel1 switchport mode trunk switchport trunk native vlan 999 ! interface GigabitEthernet0/1 switchport mode trunk switchport trunk native vlan 999 channel-group 1 mode active ! interface GigabitEthernet0/2 switchport mode trunk switchport trunk native vlan 999 channel-group 1 mode active What is the effect of the 'switchport trunk native vlan 999' command on the EtherChannel?
Correct. The native VLAN is set to 999, so untagged frames are placed in that VLAN.
Why this answer
The native VLAN is used for untagged traffic on a trunk. Setting it to 999 (an unused VLAN) helps prevent VLAN hopping attacks and ensures that any untagged frames are dropped. The configuration is consistent across all member interfaces and the port-channel, so the channel will form.
Drag and drop the steps of LACP active/passive mode negotiation into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Drag and drop the steps of PAgP EtherChannel negotiation steps into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Given the configuration: interface Port-channel1 switchport mode trunk switchport trunk allowed vlan 10-20 ! interface GigabitEthernet0/1 switchport mode trunk channel-group 1 mode passive ! interface GigabitEthernet0/2 switchport mode trunk channel-group 1 mode passive What is missing for this EtherChannel to form with a neighbor that uses LACP active?
Correct. The configuration is complete and consistent.
Why this answer
The configuration uses LACP passive on both member interfaces. For LACP to negotiate, one side must be active. The neighbor is active, so that is fine.
However, the port-channel interface does not have the 'switchport trunk allowed vlan' command applied; it is only on the port-channel. That is actually correct—the port-channel configuration applies to the channel. But the question asks what is missing; the answer is that the port-channel interface itself must have the allowed VLAN list, which it does.
Actually, the configuration is complete. The trick is that the port-channel interface already has the allowed VLAN list. So nothing is missing.
But the options might include a common mistake. Let's re-evaluate: The configuration shows the port-channel with allowed VLANs, and the member ports without. That is correct.
So the answer is that nothing is missing. However, a common issue is that the member ports must also have the same allowed VLAN list if configured individually, but here they are not configured, so they inherit from the port-channel. This is fine.
So the correct answer is that the configuration is valid.
Which two statements about EtherChannel load balancing are true? (Choose two.)
Correct because many Cisco switches default to src-mac for Layer 2 EtherChannels.
Why this answer
EtherChannel load balancing can use source and/or destination MAC or IP addresses to determine which physical link to use for a given frame. The default method varies by platform but often uses source MAC. The hash is computed per frame, not per packet, and the algorithm is deterministic for a given flow to prevent reordering.
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?
The bandwidth is 2000000 Kbit/sec, which is 2 Gbps, typical for two 1 Gbps links.
Why this answer
The output shows that Port-channel1 is up with an IP address (192.168.1.1/30), indicating it is a Layer 3 interface. The bandwidth is 2 Gbps (2000000 Kbit/sec), which suggests that two 1 Gbps links are aggregated. The interface has no errors and low utilization.
The correct answer is that the port-channel is a Layer 3 interface with an aggregated bandwidth of 2 Gbps.
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?
Correct. LACP active/passive will negotiate, and the port-channel trunk configuration applies to all member ports.
Why this answer
The configuration creates an EtherChannel using LACP with one side in active mode and the other in passive mode. The active side initiates negotiation, so the channel will form. The port-channel interface is configured as a trunk, so the channel will carry VLANs 10, 20, and 30.
Drag and drop the steps of Layer 3 EtherChannel (routed port-channel) setup into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Layer 3 EtherChannel setup requires creating the port-channel interface, assigning an IP address, adding member ports as L3 ports, enabling the interface, and verifying routing.
Drag and drop the steps of LACP EtherChannel negotiation and bundle formation into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
LACP first exchanges system priority to determine which side is active, then exchanges port priorities to select which ports bundle, next negotiates the operational key, then forms the bundle by synchronizing parameters, and finally the port channel interface becomes operational. This order follows the LACP state machine as defined in IEEE 802.3ad.
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?
The standby state indicates that the maximum number of active ports has been reached, and Gi0/2 is ready to replace a failed port.
Why this answer
The output shows that Gi0/0 and Gi0/1 are in 'Active' state, while Gi0/2 is in 'Standby' state. In LACP, a standby port is a hot-standby port that becomes active if an active port fails. This is configured using the 'lacp max-bundle' command or when the number of ports exceeds the maximum allowed.
The correct answer is that Gi0/2 is a hot-standby port ready to take over if an active port fails.
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?
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.
Why this answer
The correct answer is that the VLAN is not allowed on one of the physical ports. The wrong answers involve issues that would affect all VLANs or are unrelated.
Drag and drop the steps of LACP active/passive mode negotiation into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Drag and drop each LACP port mode on the left to its matching negotiation behavior on the right.
Drag a concept onto its matching description — or click a concept then click the description.
Sends LACP packets and responds to LACP packets
Responds to LACP packets but does not initiate
Both sides send LACP packets, forms channel
One side initiates, other responds, forms channel
Neither side initiates, no channel formed
Why these pairings
Active initiates negotiation; passive waits for partner. Both must have at least one active side to form EtherChannel.
Drag and drop the steps of EtherChannel load-balancing hash configuration into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
Configuration starts with selecting the global load-balancing method, applying it, verifying with show commands, then optionally overriding per-interface, and finally testing with traffic.
Drag and drop the steps of configuring a Layer 2 EtherChannel using PAgP into the correct order, from first to last.
Drag steps to the numbered slots on the right, or tap a step then tap a slot.
Why this order
First, create the port-channel interface globally. Then set the channel-group mode to desirable on the first interface. Next, set the same mode on the second interface.
After that, verify the bundle forms using show commands. Finally, assign the port-channel to a VLAN to enable data forwarding. This sequence ensures PAgP negotiation completes before the bundle is used.
Examine the following configuration: interface Port-channel1 switchport mode trunk ! interface GigabitEthernet0/1 switchport mode trunk channel-group 1 mode desirable ! interface GigabitEthernet0/2 switchport mode access channel-group 1 mode desirable What is the problem with this configuration?
Correct. All member ports must have the same switchport mode.
Why this answer
EtherChannel requires all member interfaces to have the same switchport mode (all trunk or all access). Here, Gi0/1 is configured as trunk, but Gi0/2 is configured as access. This mismatch will prevent the channel from forming.
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?
Both local and partner states are down, suggesting a physical problem.
Why this answer
The filtered output shows that Gi0/0 and Gi0/1 are up and in-bundle, with their partners also in 'bndl' state. Gi0/2 is down and not in-bundle, with its partner also down. This indicates that the physical link on Gi0/2 is down, possibly due to a cable issue or the neighbor port being down.
The correct answer is that Gi0/2 is not part of the EtherChannel because the link is down.
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?
The 's' flag means suspended, typically due to mismatched parameters.
Why this answer
The output shows that port-channel 1 is in use (U) and Layer2 (S). Gi0/0 and Gi0/1 are bundled (P), Gi0/2 is suspended (s), and Gi0/3 is down (D). A suspended port in LACP indicates a misconfiguration, such as mismatched port parameters (speed, duplex, VLAN, or trunk mode).
The correct answer is that Gi0/2 has a configuration mismatch.
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?
Correct because the port-channel interface must have the same access VLAN as the physical ports, or the channel will not form.
Why this answer
The correct answer is that the physical ports must be configured identically, including the allowed VLAN list. For access ports, the VLAN must match. The wrong answers involve issues that would not prevent the channel from forming if the VLANs match.
Which three statements about LACP (Link Aggregation Control Protocol) are true? (Choose three.)
Correct because LACP uses the IEEE 802.3 Slow Protocols multicast address 01-80-c2-00-00-02.
Why this answer
LACP is an IEEE standard (802.3ad) that allows dynamic EtherChannel formation. It uses system priority and port priority to determine which side controls the aggregation. LACP supports up to 16 links per group (8 active, 8 standby).
It can operate in active or passive modes.
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