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Cisco DCIT 300-615 practice questions

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Question 1Troubleshooting Cisco Data Center Infrastructure

On a Cisco Nexus switch, which command displays the FCoE VLAN-to-VSAN mapping and the associated interface state for FCoE traffic?

  1. show vlan fcoe
  2. show vsan fcoe-map
  3. show interface fcoe
  4. show fcoe Correct answer.

Explanation

The show fcoe command lists the FCoE VLANs, the VSAN each maps to, and the interfaces where FCoE is enabled, making it the primary verification tool for FCoE binding. The other commands are not valid Nexus CLI syntax for this purpose.

Question 2Troubleshooting Cisco Data Center Infrastructure

A vPC domain fails to form and the secondary peer reports that the peer-link is down. Which condition on the peer-link interfaces must be verified first?

  1. The interfaces are trunk ports carrying the vPC VLANs and are members of the same port channel Correct answer.
  2. The interfaces are administratively shut down on the primary peer only
  3. The interfaces are configured as routed ports with an IP address
  4. The interfaces are configured as FEX fabric ports

Explanation

The vPC peer-link must be a Layer 2 port channel whose member ports are trunking and allow the vPC VLANs; otherwise the peer-link stays down and vPC consistency checks fail. Routed ports or FEX fabric ports cannot serve as a peer-link.

Question 3Troubleshooting Cisco Data Center Infrastructure

After a zoning change, a host can no longer see its target. Which command on a Cisco MDS switch shows the active zone set and whether the changed zoneset has been activated?

  1. show flogi database
  2. show running-config zone
  3. show zoneset active vsan 10 Correct answer.
  4. show zone active

Explanation

show zoneset active vsan <id> displays the currently activated zone set and its members, confirming whether the edited configuration was actually activated. The running-config view only shows the intended configuration, not what is enforced by the fabric.

Question 4Troubleshooting Cisco Data Center Infrastructure

Which command verifies that a VSAN is operational and shows its configured and operational state on a Nexus switch?

  1. show vsan Correct answer.
  2. show fcalias
  3. show vsan active
  4. show vsan membership

Explanation

show vsan reports each VSAN's state, membership count, and interface assignment, which is the baseline check for VSAN operational status. Membership and alias commands address narrower objects rather than overall VSAN state.

Question 5Troubleshooting Cisco Data Center Infrastructure

A Nexus switch cannot establish an OTV overlay adjacency with its remote peer. Which command confirms whether the overlay interface is up and whether the site VLAN and VLAN translation are correct?

  1. show otv route
  2. show otv overlay Correct answer.
  3. show otv isis database
  4. show otv arp-nd cache

Explanation

show otv overlay summarizes the overlay interface state and the configured site VLAN, VLAN translation, and join-interface information used for adjacency formation. The other commands examine routing or adjacency databases rather than overlay configuration state.

Question 6Troubleshooting Cisco Data Center Infrastructure

Which command on a Nexus 9000 verifies VXLAN VNI-to-VLAN mapping and the associated VRF for a tenant?

  1. show nve peers
  2. show bgp l2vpn evpn
  3. show nve vni Correct answer.
  4. show vxlan vni

Explanation

show nve vni lists each configured VNI, its mapped VLAN, VRF, and state, which is the direct check for VXLAN encapsulation mappings. Peer and BGP views verify control-plane reachability rather than local VNI mappings.

Question 7Troubleshooting Cisco Data Center Infrastructure

A server team reports that LACP is not bundling a port channel toward a Nexus switch. Which command shows whether LACP protocol data units are being received on the member interface?

  1. show lacp counters
  2. show port-channel summary
  3. show lacp neighbor Correct answer.
  4. show interface brief

Explanation

show lacp neighbor displays the partner system ID and port information learned from received LACPDUs, so an empty output indicates PDUs are not arriving. Counter and summary commands show aggregate state but not the neighbor identity required to confirm PDU exchange.

Question 8Troubleshooting Cisco Data Center Infrastructure

Which command verifies fabric login entries and the associated FC IDs on a Cisco MDS switch when troubleshooting a host that cannot access storage?

  1. show fcsie
  2. show flogi database Correct answer.
  3. show fcns database
  4. show interface fc1/1

Explanation

show flogi database lists all devices that completed fabric login, including their FC IDs and the interfaces they logged in on, which confirms whether the host reached the fabric. The name server database only shows registered name entries and can be empty even when login succeeded.

Question 9Troubleshooting Cisco Data Center Infrastructure

A vPC consistency check reports a type-1 mismatch between peers. What is the operational consequence of a type-1 parameter mismatch?

  1. The peer-link is automatically shut down and vPC is disabled
  2. Only the affected VLAN is placed in a blocked state on both peers
  3. Traffic continues but the mismatch is logged as informational only
  4. The vPC member ports on the secondary peer are suspended to protect the network Correct answer.

Explanation

Type-1 parameters are strictly required to match; when they differ, vPC member ports on the secondary switch are suspended to prevent forwarding loops and inconsistent behavior. Type-2 mismatches are informational and do not suspend ports.

Question 10Troubleshooting Cisco Data Center Infrastructure

An administrator wants to verify that FCoE traffic is actually being forwarded on a Nexus switch after enabling FCoE on the interfaces. Which two checks together confirm the data path is operational?

  1. show lldp neighbors and show cdp neighbors
  2. show run interface and show version
  3. show vlan and show spanning-tree
  4. show fcoe and show interface fc Correct answer.

Explanation

show fcoe confirms the VLAN-to-VSAN binding and interface enablement, while the Fibre Channel interface view confirms the virtual FC interface is up and passing frames. Configuration and neighbor views do not prove the forwarding path is active.

Question 11Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch shows the port in an isolated state after a zoning change. Which action most directly resolves an isolated port caused by a zoning conflict?

  1. Reset the port by shutting and no shutting the interface
  2. Disable the VSAN and re-enable it
  3. Re-activate the zone set after correcting conflicting zone members Correct answer.
  4. Change the port to an F port

Explanation

Ports become isolated when zoning conflicts exist, such as a device being a member of conflicting zones; correcting the zone membership and re-activating the zone set clears the isolation. A shut/no shut does not resolve a policy conflict and may re-isolate the port.

Question 12Troubleshooting Cisco Data Center Infrastructure

A Nexus switch is configured for vPC, and the primary peer fails. What is the expected behavior of the secondary peer's vPC member ports when the peer-link is also down?

  1. The member ports are converted to routed ports automatically
  2. The member ports forward only traffic destined to the local VTEP
  3. The member ports remain up and forwarding continues until the peer-link recovers
  4. The member ports are suspended because the peer-link is down and the peer is not reachable Correct answer.

Explanation

If the peer-link fails and the vPC peer cannot be reached, the secondary peer suspends its vPC member ports to prevent split-brain forwarding and loops. This behavior is controlled by the auto-recovery and graceful consistency mechanisms.

Question 13Troubleshooting Cisco Data Center Infrastructure

An OTV edge device is not advertising MAC routes to the overlay. Which command verifies whether the MAC address is present in the local OTV MAC table?

  1. show otv route Correct answer.
  2. show otv isis adjacency
  3. show mac address-table
  4. show otv arp-nd cache

Explanation

show otv route displays the OTV MAC routing table, including local and remote MAC entries and their overlay state. The standard MAC table shows bridging entries but not OTV route advertisement status.

Question 14Troubleshooting Cisco Data Center Infrastructure

A VXLAN fabric uses BGP EVPN. A host on one leaf cannot reach a host on another leaf, but both hosts appear in the local MAC tables. Which command best verifies that the remote MAC is learned through EVPN?

  1. show nve peers
  2. show bgp l2vpn evpn Correct answer.
  3. show ip route vrf all
  4. show mac address-table

Explanation

show bgp l2vpn evpn displays EVPN type-2 MAC/IP routes learned from remote VTEPs, confirming whether the remote MAC was advertised and accepted. Local MAC and NVE peer views do not show the EVPN route entries.

Question 15Troubleshooting Cisco Data Center Infrastructure

After a fabric merge, an MDS switch reports a domain ID conflict. Which command identifies the current principal switch and domain assignments?

  1. show fspf domain
  2. show fcdomain
  3. show fcns database
  4. show fcdomain domain-list vsan 10 Correct answer.

Explanation

show fcdomain domain-list vsan <id> lists the principal switch and all domain IDs in the VSAN, which is the direct way to identify a conflict. The name server and FSPF views do not report domain assignments.

Question 16Troubleshooting Cisco Data Center Infrastructure

A Nexus switch reports that a port channel is in a suspended state after a vPC configuration change. Which command verifies whether the port channel is a vPC member and its consistency status?

  1. show port-channel summary
  2. show vpc brief Correct answer.
  3. show running-config vpc
  4. show vpc consistency-parameters

Explanation

show vpc brief lists each vPC, its member port channels, and their status, which confirms whether the port channel is a vPC member and if it is suspended. Consistency-parameter output details specific mismatches rather than overall membership status.

Question 17Troubleshooting Cisco Data Center Infrastructure

A storage array is logged into the fabric but is not visible to a host. Which command on the MDS switch verifies the name server registration and the associated FC ID for the array?

  1. show flogi database
  2. show interface fc1/1
  3. show fcns database Correct answer.
  4. show zone active

Explanation

show fcns database lists devices registered with the name server, including their FC IDs and symbolic names, confirming whether the array is registered and visible. Fabric login output confirms login but not name server registration.

Question 18Troubleshooting Cisco Data Center Infrastructure

An administrator troubleshoots a Nexus 7000 OTV deployment and needs to confirm that the join interface is up and has a valid IP address. Which command provides this information?

  1. show otv isis adjacency
  2. show interface
  3. show otv overlay Correct answer.
  4. show otv route

Explanation

show otv overlay reports the overlay interface state along with the join-interface configuration used for encapsulation. Interface output shows link state but not the OTV join-interface binding.

Question 19Troubleshooting Cisco Data Center Infrastructure

A Nexus switch is configured for VXLAN and the underlay uses OSPF. A VTEP cannot reach a remote VTEP. Which command sequence best isolates whether the issue is underlay reachability or NVE configuration?

  1. show mac address-table and show arp
  2. show bgp l2vpn evpn and show vrf
  3. show nve vni and show vxlan vni
  4. show ip route and show nve peers Correct answer.

Explanation

Checking the routing table confirms underlay reachability to the remote VTEP loopback, while show nve peers confirms whether the NVE peering formed. Together they separate routing failures from NVE configuration problems.

Question 20Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch shows a high number of CRC errors on an ISL. Which action is the most appropriate first step?

  1. Change the VSAN on the ISL
  2. Increase the buffer credits on the port
  3. Replace the SFP or cable and re-check the error counters Correct answer.
  4. Disable the port and leave it disabled

Explanation

CRC errors on an ISL typically indicate a physical layer problem such as a faulty SFP, cable, or connector, so replacing the optics or cable and re-checking counters is the correct first step. Buffer and VSAN changes do not address physical corruption.

Question 21Troubleshooting Cisco Data Center Infrastructure

A vPC domain uses a peer-keepalive link over a routed path. The peer-keepalive is down while the peer-link is up. What is the effect on vPC operation?

  1. The secondary peer suspends all vPC member ports immediately
  2. The vPC domain is removed and must be reconfigured
  3. vPC continues to operate normally because the peer-link is the primary control path Correct answer.
  4. The primary peer shuts down its vPC member ports

Explanation

The peer-keepalive link is used to detect peer liveness, but vPC operation continues as long as the peer-link is up; the keepalive failure is a warning condition. Member ports are not suspended solely because keepalive is lost while the peer-link remains up.

Question 22Troubleshooting Cisco Data Center Infrastructure

An OTV deployment experiences a site VLAN mismatch between edge devices. What symptom is most likely observed?

  1. The IS-IS metric is set to maximum
  2. The overlay adjacency fails to form and MAC routes are not exchanged Correct answer.
  3. The site VLAN is automatically translated to VLAN 1
  4. The join interface is administratively down

Explanation

OTV edge devices must agree on the site VLAN for the overlay adjacency to form; a mismatch prevents adjacency establishment and MAC route exchange. The join interface state and IS-IS metrics are independent of the site VLAN value.

Question 23Troubleshooting Cisco Data Center Infrastructure

A Nexus 9000 leaf is configured for EVPN multihoming. A server is dual-homed to two leaves, and traffic is not load-sharing. Which command verifies the Ethernet segment state and the designated forwarder election?

  1. show evpn ethernet-segment Correct answer.
  2. show bgp l2vpn evpn
  3. show evpn multisite
  4. show nve peers

Explanation

show evpn ethernet-segment reports the Ethernet segment identifier, its member interfaces, and the designated forwarder state used for multihoming. BGP and NVE views show route and peer information but not the segment's forwarding election.

Question 24Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch in a VSAN uses inter-VSAN routing. A host in VSAN 10 cannot reach a target in VSAN 20 even though the IVR zone is configured. Which command verifies that IVR is enabled and the correct IVR topology is active?

  1. show ivr zoneset
  2. show ivr service-group
  3. show ivr Correct answer.
  4. show zone active vsan 10

Explanation

show ivr displays the global IVR state, including whether IVR is enabled and the active IVR topology, which is the prerequisite for IVR zones to take effect. Zone views show membership but not the IVR service state.

Question 25Troubleshooting Cisco Data Center Infrastructure

A Nexus switch reports a vPC type-2 consistency mismatch for a spanning-tree parameter. What is the expected operational impact?

  1. The secondary peer suspends all vPC member ports
  2. The peer-link is disabled until the mismatch is corrected
  3. The primary peer reloads to re-synchronize the configuration
  4. The mismatch is logged but vPC member ports remain forwarding Correct answer.

Explanation

Type-2 parameters are not strictly required to match; a mismatch is logged as a warning while vPC member ports continue forwarding. Only type-1 mismatches cause member port suspension on the secondary peer.

Question 26Troubleshooting Cisco Data Center Infrastructure

On a Cisco Nexus 9000 running VXLAN with a BGP EVPN control plane, which command displays the tunnel endpoints learned for a remote VTEP along with the VNI and next-hop information?

  1. show nve peers Correct answer.
  2. show bgp l2vpn evpn
  3. show nve vni
  4. show interface nve1

Explanation

The show nve peers command lists remote VTEP IP addresses that the local NVE has learned and indicates the peer state, which is the fastest way to confirm whether a remote tunnel endpoint is known. show nve vni shows local VNI state and counters but not the remote peer list, and it does not itself prove reachability to the remote VTEP.

Question 27Troubleshooting Cisco Data Center Infrastructure

An engineer suspects that a Nexus 9000 leaf is not programming a MAC address learned locally into the EVPN control plane. Which command best shows whether the MAC is present in the local MAC table with the expected VLAN and interface?

  1. show l2route evpn mac all
  2. show mac address-table address <mac> Correct answer.
  3. show system internal l2fwder mac
  4. show ip arp vrf <vrf>

Explanation

The show mac address-table address command filters the Layer 2 forwarding table for a specific MAC and reports the VLAN and port where it was learned, confirming local learning before EVPN advertisement. EVPN-level tables are only useful once local learning has been verified.

Question 28Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch shows an ISL port in a down state with the reason 'Isolation' after a zoning change. Which condition most directly produces this port state?

  1. The port is receiving frames that violate the configured VSAN or trunking parameters. Correct answer.
  2. The port has negotiated an incorrect speed with the peer switch.
  3. The port is administratively shut down by the administrator.
  4. The port is licensed but not assigned to any VSAN.

Explanation

An isolated state on an MDS ISL typically indicates that the link is being disabled because of a protocol or configuration violation detected on the port, such as a VSAN mismatch or trunking parameter conflict. The switch isolates the port to protect the fabric from inconsistent traffic.

Question 29Troubleshooting Cisco Data Center Infrastructure

Which command on a Cisco MDS switch displays the status of the FC domain, including the principal switch and the local domain ID?

  1. show zone active vsan <id>
  2. show fspf internal route vsan <id>
  3. show flogi database vsan <id>
  4. show fcdomain domain-list vsan <id> Correct answer.

Explanation

The show fcdomain domain-list command reports the domain IDs assigned in the VSAN and identifies the principal switch, which is essential when diagnosing domain ID conflicts after a fabric merge. It directly reflects FC domain manager state.

Question 30Troubleshooting Cisco Data Center Infrastructure

An administrator needs to confirm which VSANs are allowed on a specific trunking ISL between two MDS switches. Which command provides this information?

  1. show interface fc1/1 brief
  2. show interface fc1/1 trunk vsan Correct answer.
  3. show trunk protocol
  4. show vsan membership

Explanation

The show interface trunk vsan command displays the VSANs that are allowed and operational on a trunking ISL, which is the direct way to verify trunk configuration on a specific port. VSAN membership commands describe local configuration rather than per-port trunk state.

Question 31Troubleshooting Cisco Data Center Infrastructure

Which command verifies the operational state of a vPC peer-link and shows whether the peer-link is up and trunking the expected VLANs?

  1. show vpc peer-keepalive
  2. show vpc role
  3. show port-channel summary
  4. show vpc brief Correct answer.

Explanation

The show vpc brief command reports vPC domain status, including peer-link state and the VLANs carried, making it the standard check for peer-link health. It also shows peer status and vPC consistency information in one view.

Question 32Troubleshooting Cisco Data Center Infrastructure

After enabling FCoE on a Nexus switch, an engineer wants to confirm that the FCoE VLAN is correctly mapped to the VSAN and that the interface is carrying FCoE frames. Which command provides the VLAN-to-VSAN mapping?

  1. show interface fcoe
  2. show fcoe
  3. show vlan fcoe Correct answer.
  4. show fcoe database

Explanation

The show vlan fcoe command displays the mapping between FCoE VLANs and VSANs and indicates the operational state of that mapping. This is the direct check that the FCoE VLAN is bound to the intended VSAN.

Question 33Troubleshooting Cisco Data Center Infrastructure

A Nexus 7000 OTV edge device is not forming an overlay adjacency with its remote peer. Which command verifies that the join interface has an IP address and is operational?

  1. show interface <join-interface> Correct answer.
  2. show interface overlay1
  3. show otv
  4. show otv adjacency

Explanation

The join interface carries the underlay connectivity used to build OTV tunnels, so verifying its link state and IP address is the first step. The show interface command for that physical or logical interface reports both.

Question 34Troubleshooting Cisco Data Center Infrastructure

A Nexus switch reports a vPC type-2 consistency mismatch involving a spanning-tree parameter between peers. What is the expected operational behavior?

  1. The vPC domain is suspended and all vPC ports are shut down.
  2. The vPC remains up but the mismatched parameter can cause forwarding inconsistency. Correct answer.
  3. The secondary peer takes over the primary role automatically.
  4. The peer-link is disabled until the parameters match.

Explanation

Type-2 mismatches are configuration inconsistencies that do not prevent the vPC from coming up, but they can produce inconsistent forwarding or spanning-tree behavior across the pair. Only type-1 mismatches cause the vPC to be suspended.

Question 35Troubleshooting Cisco Data Center Infrastructure

A host connected to a Cisco MDS switch is logged in but cannot access a target. Which command verifies the name server entries and shows the FC IDs registered in the VSAN?

  1. show zone active vsan <id>
  2. show flogi database vsan <id>
  3. show fcns database vsan <id> Correct answer.
  4. show fspf database vsan <id>

Explanation

The name server database contains the devices registered in the VSAN with their FC IDs and symbolic names, which confirms whether both host and target are visible to the fabric name server. Zoning must still permit communication, but name server visibility is the prerequisite.

Question 36Troubleshooting Cisco Data Center Infrastructure

An engineer observes that a Nexus 9000 VTEP cannot reach a remote VTEP over an OSPF underlay. Which command sequence best isolates whether the problem is routing or forwarding?

  1. show ip route <remote-vtep> followed by show ip arp <remote-vtep> Correct answer.
  2. show nve peers followed by show vxlan interface
  3. show interface loopback0 followed by show vrf
  4. show bgp l2vpn evpn followed by show l2route evpn mac all

Explanation

Checking the routing table for the remote VTEP address confirms whether a route exists, and checking ARP confirms whether the next hop is resolved and reachable at Layer 2. Together they separate a routing failure from an adjacency or forwarding problem.

Question 37Troubleshooting Cisco Data Center Infrastructure

A vPC domain uses a peer-keepalive link over a routed path. The peer-keepalive is down while the peer-link remains up. What is the most likely consequence?

  1. Both peers immediately suspend all vPC member ports.
  2. The primary peer takes over all traffic and the secondary reboots.
  3. The secondary peer shuts down its vPC member ports to avoid split-brain. Correct answer.
  4. The vPC domain continues to operate normally with no impact.

Explanation

When the peer-keepalive fails while the peer-link is still up, the secondary peer disables its vPC member ports to prevent a dual-active scenario. The primary keeps forwarding, so traffic continues but redundancy is reduced.

Question 38Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS ISL reports a steadily increasing CRC error counter. Which action is the most appropriate first step?

  1. Reconfigure the VSAN trunk allowed list on the ISL.
  2. Replace the SFP and clean or replace the fiber optic cabling. Correct answer.
  3. Reset the port with the shutdown and no shutdown commands.
  4. Increase the buffer-to-buffer credit allocation on the port.

Explanation

CRC errors on an ISL indicate physical-layer corruption, so the first step is to inspect and clean or replace the optics and cabling. Configuration changes will not correct errors caused by a dirty connector or failing transceiver.

Question 39Troubleshooting Cisco Data Center Infrastructure

An OTV deployment shows that edge devices at two sites have different site VLAN configurations. Which symptom is most likely observed?

  1. The site VLAN is automatically synchronized between edge devices.
  2. The overlay interface stays up but MAC routes are not exchanged between sites. Correct answer.
  3. The join interface fails to obtain an IP address.
  4. The internal interface is placed in an error-disabled state.

Explanation

A site VLAN mismatch prevents the OTV edge devices from correctly identifying their local site, which blocks proper MAC route advertisement over the overlay even though the overlay interface may remain up. Consistent site VLAN configuration is required for correct OTV operation.

Question 40Troubleshooting Cisco Data Center Infrastructure

A Nexus 9000 leaf is configured for EVPN multihoming, and a server dual-homed to two leaves is not load-sharing traffic. Which command verifies the Ethernet segment state and its member interfaces?

  1. show vpc brief
  2. show evpn ethernet-segment Correct answer.
  3. show nve peers
  4. show bgp l2vpn evpn route-type 4

Explanation

The show evpn ethernet-segment command reports the Ethernet segment identifier, its state, and the interfaces that belong to it, which confirms whether the segment is up and correctly associated. EVPN type-4 routes advertise the segment, but the local segment state is the operational check.

Question 41Troubleshooting Cisco Data Center Infrastructure

A host in VSAN 10 cannot reach a target in VSAN 20 despite inter-VSAN routing being enabled. Which command verifies that the IVR zone set is active and contains the required zones?

  1. show ivr virtual-fcdomain
  2. show ivr zoneset active Correct answer.
  3. show ivr service-group active
  4. show zone active vsan 10

Explanation

The show ivr zoneset active command displays the active IVR zone set, which defines the cross-VSAN pairs permitted to communicate. If the required zone is missing, traffic is blocked even when IVR is enabled globally.

Question 42Troubleshooting Cisco Data Center Infrastructure

An engineer needs to verify that a vPC member port is forwarding and that its bundle is not suspended. Which command provides per-port vPC status?

  1. show vpc brief
  2. show port-channel summary Correct answer.
  3. show spanning-tree interface port-channel <id>
  4. show vpc consistency-parameters global

Explanation

The show port-channel summary command reports each member port's status and flags bundles that are suspended, which directly answers whether the member is forwarding. It also shows the protocol used for the bundle.

Question 43Troubleshooting Cisco Data Center Infrastructure

A Nexus 9000 switch is configured with a VXLAN VNI mapped to a VLAN, and an engineer needs to confirm the mapping and the associated VRF for the tenant. Which command provides this?

  1. show vxlan vni
  2. show bgp l2vpn evpn summary
  3. show nve vni Correct answer.
  4. show nve interface

Explanation

The show nve vni command lists configured VNIs along with their mapped VLANs and the associated VRF, which confirms tenant mapping on the VTEP. It also shows whether each VNI is up and whether it is in L2 or L3 mode.

Question 44Troubleshooting Cisco Data Center Infrastructure

An OTV edge device is not advertising MAC routes to the overlay. Which command verifies whether the MAC address is present in the OTV MAC table?

  1. show otv route
  2. show otv arp-nd-cache
  3. show otv mac Correct answer.
  4. show otv isis database

Explanation

The show otv mac command displays the OTV MAC address table, which shows locally learned MACs and whether they have been advertised to remote sites. It is the direct check for MAC route presence.

Question 45Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch shows a high volume of credit-loss errors on an ISL. What does this typically indicate?

  1. The ISL is using an unsupported SFP type.
  2. The ISL is configured with the wrong VSAN trunk allowed list.
  3. The ISL has a physical cabling defect that corrupts frames.
  4. The ISL is receiving frames faster than the peer can process them, causing buffer credit depletion. Correct answer.

Explanation

Credit-loss errors occur when the transmitter sends frames without sufficient buffer-to-buffer credits, usually because the peer is slow to return credits or the link is oversubscribed. Increasing credits or addressing the congestion source is the appropriate response.

Question 46Troubleshooting Cisco Data Center Infrastructure

A Nexus 9000 leaf is not learning a remote host's MAC address through EVPN, although the remote leaf has the host in its local MAC table. Which command on the local leaf verifies that the EVPN MAC route was received from the remote VTEP?

  1. show nve peers
  2. show ip route vrf <vrf>
  3. show bgp l2vpn evpn route-type 2 Correct answer.
  4. show mac address-table

Explanation

Type-2 EVPN routes carry MAC and IP advertisements, so inspecting them confirms whether the remote leaf advertised the host and whether the local leaf received it. If the route is present but not installed, the problem shifts to import or forwarding programming.

Question 47Troubleshooting Cisco Data Center Infrastructure

A vPC peer-link fails while the peer-keepalive remains up. What is the expected behavior of the vPC domain?

  1. The secondary peer disables its vPC member ports and the primary continues forwarding. Correct answer.
  2. The vPC domain remains fully operational with both peers forwarding.
  3. The primary peer shuts down and the secondary takes over all vPC ports.
  4. Both peers suspend all vPC member ports permanently.

Explanation

When the peer-link fails but the keepalive is still up, the secondary peer detects that the primary is alive and disables its vPC member ports to prevent loops and duplicate forwarding. The primary remains active, so service continues with reduced redundancy.

Question 48Troubleshooting Cisco Data Center Infrastructure

An engineer must confirm that a Cisco MDS switch is the principal switch in a VSAN before resolving a domain ID conflict. Which command output identifies the principal switch?

  1. show interface fc1/1 brief
  2. show fcdomain domain-list vsan <id> Correct answer.
  3. show flogi database vsan <id>
  4. show vsan <id>

Explanation

The domain-list output marks the principal switch for the VSAN and lists assigned domain IDs, which is exactly what is needed to resolve a domain ID conflict. The principal switch arbitrates domain ID assignment during a fabric merge.

Question 49Troubleshooting Cisco Data Center Infrastructure

An EVPN multihoming deployment uses all-active mode. A server dual-homed to two leaves reports that return traffic arrives on only one link. Which design or configuration factor most likely explains this?

  1. The underlay is using OSPF instead of IS-IS.
  2. The Ethernet segment is configured in single-active mode instead of all-active. Correct answer.
  3. The peer-link between the leaves is down.
  4. The server is using a static MAC address.

Explanation

In all-active multihoming, both leaves advertise the Ethernet segment and traffic is load-shared toward the server. If the segment is actually configured for single-active mode, only one leaf forwards at a time, which matches the observed behavior.

Question 50Troubleshooting Cisco Data Center Infrastructure

A Cisco MDS switch in a VSAN shows that a port is isolated after a zoning change. Which action most directly resolves an isolated port caused by a zone configuration inconsistency?

  1. Increase the buffer credits on the isolated port.
  2. Replace the SFP on the isolated port.
  3. Correct the conflicting zone or VSAN configuration and re-enable the port. Correct answer.
  4. Disable and re-enable the trunking protocol globally.

Explanation

Isolation caused by configuration inconsistency is resolved by correcting the underlying mismatch, such as a zone or VSAN conflict, and then bringing the port back into service. Hardware or credit changes do not address a configuration-driven isolation.