1. A switch has eight ports: Gi0/1–Gi0/4 in VLAN 10 and Gi0/5–Gi0/8 in VLAN 20. A host on Gi0/1 sends a broadcast. How many ports does the frame leave by? Three Four Seven Eight
Check answer 2. Frames for one quiet server in VLAN 10 are being delivered to every VLAN 10 port rather than just the server's. What is happening, and is it a fault? A broadcast storm has begun; break the loop immediately The server's MAC aged out, so its traffic is an unknown unicast and is flooded — normal behaviour that ends when the server transmits The VLAN has been misconfigured and is bridging into another VLAN The switch has run out of MAC table space and is failing open
Check answer 3. Untagged traffic is landing in the wrong VLAN across a trunk while every tagged VLAN works. Which two outputs confirm the cause? show vlan brief on both ends, and show mac address-table The Native vlan column of show interfaces trunk on both ends, and the CDP native-VLAN-mismatch log show etherchannel summary, and show spanning-tree show interfaces status, and the allowed-VLAN block of show interfaces trunk
Check answer 4. A single VLAN cannot cross a trunk. Every other VLAN is fine and there is no CDP log. Which fault is it, and what distinguishes it? A native mismatch — the missing CDP log confirms it An allowed-list omission — one VLAN affected and no CDP log, unlike a native mismatch which logs A DTP negotiation failure — the trunk never formed An EtherChannel consistency mismatch on the trunk members
Check answer 5. A phone port carries VLAN 10 for the PC and VLAN 110 for the phone. Why is this not a trunk, and what would a trunk have risked? It is a trunk; the terminology is just different for phones Only the phone tags, so exactly one extra VLAN is granted — a trunk could carry or negotiate arbitrary VLANs Trunks cannot carry voice traffic because of QoS marking A trunk would require the PC to tag its own frames
Check answer 6. Two 1 Gbps trunks join SW1 and SW2. Before EtherChannel, show spanning-tree lists two interfaces with one discarding. After bundling them with LACP, what does it list, and how much bandwidth forwards? Still two interfaces, both forwarding — 2 Gbps One Po1 interface forwarding — 2 Gbps One Po1 interface forwarding — 1 Gbps Two interfaces with one still discarding — 1 Gbps
Check answer 7. Why does running a separate spanning tree per VLAN let you use redundant links that a single tree would leave idle? Each VLAN gets its own physical cable Different VLANs can elect different roots and therefore block different ports Per-VLAN trees disable blocking entirely The extended system ID doubles the available path cost
Check answer 8. A two-member LACP bundle is up but only one member forwards, and that member shows (s). Which Week 3 setting is the most likely culprit? The two members have different STP port costs The suspended member has a different trunk allowed-VLAN list from its peer The suspended member is the root port for VLAN 10 CDP is disabled on the suspended member
Check answer 9. Week 3 contains three versions of the same rule about negotiation. Which set is correct? trunk/trunk, active/active, desirable/desirable never form dynamic auto + dynamic auto, LACP passive + passive, PAgP auto + auto never form nonegotiate + nonegotiate, on + on, active + passive never form dynamic desirable + dynamic auto, LACP active + passive never form
Check answer 10. After adding a switch, VLAN 10 traffic takes an unexpected path and an uplink sits idle. show spanning-tree vlan 10 shows the new switch is root. What happened and what is the fix? The new switch has the highest priority; lower it with root secondary Every priority is still the default 32768, so the lowest MAC won — set the intended core with spanning-tree vlan 10 root primary The new switch has a faster uplink, so it won on path cost EtherChannel formed automatically and moved the root
Check answer 11. SW1's Gi0/24 faces an ISP router you do not control. Should CDP stay enabled there, and why? Yes — CDP is needed for the link to pass traffic Yes — it is the only way to detect a native-VLAN mismatch on that link No — discovery advertises device name, platform, software version and management address to a party outside your control No — CDP is incompatible with non-Cisco routers and will err-disable the port
Check answer 12. In show cdp neighbors, SW2 appears with Local Intrfce Gig 0/1 and Port ID Gig 0/3. Which cable end is which? Your port is Gig 0/3; SW2's port is Gig 0/1 Your port is Gig 0/1; SW2's port is Gig 0/3 Both refer to SW2's ports on either side of the bundle Local Intrfce is the management interface, not a data port
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