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Cisco DCCOR (350-601) practice questions

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Question 1Network

In a Cisco Nexus data center, which protocol provides a loop-free Layer 2 multipath topology by replacing STP with a fabric-wide control plane?

  1. FabricPath Correct answer.
  2. MST
  3. Rapid PVST+
  4. PVST+

Explanation

FabricPath is a Cisco technology on Nexus platforms that builds a loop-free, multipath Layer 2 fabric using IS-IS as its control plane instead of spanning tree. It allows all links to forward traffic through equal-cost multipathing while keeping a single logical topology.

Question 2Network

Which Cisco Nexus feature allows a single physical switch to appear as multiple independent logical switches, each with its own configuration and management?

  1. VDC Correct answer.
  2. vPC
  3. VXLAN
  4. FEX

Explanation

A Virtual Device Context (VDC) partitions a physical Nexus switch into multiple logical switches, each with separate configuration, management, and fault domains. VDCs are commonly used to separate tenants or administrative roles on the same hardware.

Question 3Network

Which two Nexus switches are required to configure a vPC domain, and what is the minimum number of links in the vPC peer-link?

  1. Two switches with a single physical peer-link link
  2. Two switches with a peer-link that is itself a port channel of one or more links Correct answer.
  3. Two switches with no peer-link, only a keepalive
  4. Three switches with a full mesh of links

Explanation

A vPC domain consists of exactly two Nexus switches connected by a peer-link, which is configured as a port channel. The peer-link carries control traffic and, during failures, data traffic, so Cisco recommends it be a port channel with sufficient bandwidth rather than a single link.

Question 4Network

Which Cisco Nexus feature provides first-hop redundancy with an Active/Active forwarding model across two switches?

  1. VRRP
  2. GLBP
  3. vPC with HSRP Correct answer.
  4. HSRP

Explanation

Combining vPC with HSRP allows both vPC peers to forward traffic for the shared gateway, because the vPC domain presents a single logical view to the downstream devices. HSRP alone is Active/Standby, so the Active/Active behavior comes from the vPC integration.

Question 5Network

Which command verifies the operational status of a vPC domain, including the peer-link and keepalive state, on a Nexus switch?

  1. show vpc role
  2. show spanning-tree
  3. show port-channel summary
  4. show vpc Correct answer.

Explanation

The 'show vpc' command displays the vPC domain status, peer-link state, keepalive status, and per-vPC port state. It is the primary verification command for troubleshooting vPC operation.

Question 6Network

A Nexus switch is configured with a vPC domain and you observe that the peer-link is down but the keepalive is up. Which behavior should you expect?

  1. The primary peer suspends its vPC member ports
  2. The secondary peer suspends its vPC member ports to prevent split-brain forwarding Correct answer.
  3. Both vPC peers continue forwarding on all vPC member ports
  4. The vPC domain automatically converts to a port channel without vPC

Explanation

When the peer-link fails but the keepalive remains up, the vPC secondary peer detects the split and suspends its vPC member ports. This prevents duplicate forwarding and split-brain conditions while preserving the primary peer's forwarding.

Question 7Network

Which routing protocol is used by FabricPath to build its Layer 2 multipath topology?

  1. OSPF
  2. BGP
  3. IS-IS Correct answer.
  4. EIGRP

Explanation

FabricPath uses IS-IS as its control plane to compute loop-free multipath topologies across the fabric. IS-IS was chosen for its scalability and its ability to support multipath forwarding at Layer 2.

Question 8Network

Which Nexus feature allows a parent switch to manage remote line cards over a single logical management point while extending ports to top-of-rack locations?

  1. vPC
  2. FEX Correct answer.
  3. OTV
  4. VDC

Explanation

A Fabric Extender (FEX) acts as a remote line card for a parent Nexus switch, extending ports to top-of-rack positions while being managed through the parent. This simplifies cabling and management in a data center access layer.

Question 9Network

Which encapsulation does VXLAN use to transport Layer 2 frames over a Layer 3 underlay?

  1. MPLS
  2. MAC-in-UDP Correct answer.
  3. IP-in-IP
  4. GRE

Explanation

VXLAN encapsulates original Layer 2 frames inside a UDP packet, adding a VXLAN header with a 24-bit VNI. This MAC-in-UDP encapsulation allows Layer 2 segments to be stretched over a routed Layer 3 underlay.

Question 10Network

In a VXLAN EVPN fabric, which protocol distributes MAC and IP reachability information between VTEPs?

  1. PIM
  2. OSPF
  3. BGP EVPN Correct answer.
  4. IS-IS

Explanation

BGP EVPN is the control plane that advertises MAC and IP address reachability between VTEPs in a VXLAN fabric. It replaces flood-and-learn behavior with a scalable, policy-capable control plane.

Question 11Network

Which VXLAN component maps a VLAN to a VNI on a Nexus switch?

  1. The OTV adjacency configuration
  2. The FabricPath IS-IS configuration
  3. The vPC domain configuration
  4. VLAN-to-VNI mapping under the VXLAN configuration Correct answer.

Explanation

VXLAN requires a mapping between the local VLAN and the VNI so that frames from that VLAN are encapsulated with the correct VXLAN segment identifier. On Nexus, this is configured with the VLAN-to-VNI mapping commands under the VXLAN feature.

Question 12Network

Which underlay routing design is commonly recommended for a VXLAN EVPN fabric on Nexus switches?

  1. A Layer 3 routed underlay using OSPF or IS-IS with ECMP Correct answer.
  2. A hub-and-spoke EIGRP design
  3. A full mesh of OSPF areas
  4. A Layer 2 switched underlay using STP

Explanation

A VXLAN EVPN fabric typically uses a Layer 3 routed underlay with OSPF or IS-IS and ECMP so that every VTEP can reach every other VTEP over multiple equal-cost paths. This provides scalability, fast convergence, and loop-free multipathing.

Question 13Network

Which technology extends a Layer 2 domain between two data centers across a Layer 3 WAN while containing STP and unknown unicast flooding?

  1. vPC
  2. OTV Correct answer.
  3. VXLAN EVPN
  4. FabricPath

Explanation

OTV (Overlay Transport Virtualization) extends Layer 2 segments between data centers over a Layer 3 transport while using IS-IS for MAC reachability and containing STP and flooding. It is designed for site-to-site Layer 2 extension without stretching STP domains.

Question 14Network

Which command displays the OTV overlay adjacency and MAC reachability information on a Nexus switch?

  1. show otv adjacency Correct answer.
  2. show fabricpath isis adjacency
  3. show bgp l2vpn evpn
  4. show vpc

Explanation

The 'show otv adjacency' command displays OTV overlay adjacencies, and related OTV show commands display MAC reachability and overlay state. These verify that the OTV overlay is operational between sites.

Question 15Network

Which Cisco Nexus feature is used to configure an Anycast Gateway for a VXLAN EVPN fabric?

  1. Distributed Anycast Gateway Correct answer.
  2. VRRP with vPC
  3. HSRP with vPC
  4. GLBP

Explanation

Distributed Anycast Gateway assigns the same gateway IP and MAC to every leaf switch, so hosts can use their local leaf as the default gateway. This optimizes forwarding in a VXLAN EVPN fabric and avoids traffic tromboning.

Question 16Network

Which Nexus feature allows a switch to be managed through a single IP address while its physical ports are distributed across multiple line cards and fabric extenders?

  1. VXLAN
  2. vPC
  3. FEX with a parent switch Correct answer.
  4. VDC

Explanation

A parent Nexus switch manages its Fabric Extenders through a single management IP, treating the FEX ports as remote line card ports. This provides a single point of management for distributed access ports.

Question 17Network

Which command verifies VXLAN VNI-to-VLAN mappings and the VXLAN interface status on a Nexus switch?

  1. show fabricpath route
  2. show nve vni Correct answer.
  3. show otv
  4. show vpc

Explanation

The 'show nve vni' command displays the VNI mappings and their status on the NVE interface, confirming that VXLAN segments are operational. Related 'show nve' commands display the NVE interface and peer information.

Question 18Network

Which statement describes the role of the vPC keepalive link?

  1. It replaces the peer-link for control plane synchronization
  2. It is a heartbeat path used to detect peer liveness when the peer-link fails Correct answer.
  3. It carries user data traffic between vPC peers during normal operation
  4. It provides Layer 2 connectivity to downstream devices

Explanation

The vPC keepalive link is a heartbeat connection, typically over a management or routed path, used to detect whether the peer is alive when the peer-link fails. It does not carry user data or replace the peer-link for synchronization.

Question 19Network

Which Cisco Nexus feature provides a loop-free Layer 2 multipath fabric by using a switch ID and a fabric-wide topology?

  1. FabricPath Correct answer.
  2. VXLAN
  3. OTV
  4. vPC

Explanation

FabricPath assigns switch IDs and builds a fabric-wide topology using IS-IS, enabling loop-free multipath forwarding at Layer 2. It replaces STP in the data center core and aggregation layers.

Question 20Network

Which two protocols are commonly used as the underlay for a VXLAN EVPN fabric on Nexus switches?

  1. OSPF and IS-IS Correct answer.
  2. EIGRP and RIP
  3. BGP and OSPF
  4. PIM and IGMP

Explanation

OSPF and IS-IS are the common Layer 3 underlay routing protocols used to provide ECMP reachability between VTEPs in a VXLAN EVPN fabric. BGP EVPN runs as the overlay control plane on top of that underlay.

Question 21Network

Which behavior occurs on a vPC peer when the peer-link fails and the keepalive link also fails?

  1. Both peers continue forwarding on all vPC ports Correct answer.
  2. The vPC domain automatically disables all member ports on both peers
  3. The secondary peer suspends its vPC ports
  4. The primary peer suspends its vPC ports

Explanation

If both the peer-link and the keepalive link fail, each peer cannot determine the other's state, so both continue forwarding to avoid a complete outage. This is a split-brain condition that requires careful design to mitigate.

Question 22Network

Which VXLAN component is responsible for encapsulating and decapsulating frames at the edge of the fabric?

  1. VTEP Correct answer.
  2. Underlay router
  3. Anycast gateway
  4. VNI

Explanation

A VTEP (VXLAN Tunnel Endpoint) encapsulates original frames into VXLAN packets and decapsulates them on ingress to the fabric. VTEPs are typically located on the leaf switches in a VXLAN EVPN fabric.

Question 23Network

Which command displays the VXLAN NVE interface and its peer VTEPs on a Nexus switch?

  1. show otv route
  2. show fabricpath isis database
  3. show vpc peer-keepalive
  4. show nve peers Correct answer.

Explanation

The 'show nve peers' command displays the NVE interface's peer VTEPs and their state, confirming VXLAN tunnel establishment. Related 'show nve' commands display VNI mappings and interface details.

Question 24Network

Which statement describes how OTV handles unknown unicast traffic across the overlay?

  1. It drops unknown unicast at the edge device by default unless configured otherwise Correct answer.
  2. It floods unknown unicast across the overlay to all sites
  3. It converts unknown unicast to multicast across the underlay
  4. It forwards unknown unicast only over the join interface

Explanation

OTV edge devices do not flood unknown unicast across the overlay by default; unknown unicast is dropped at the edge unless the behavior is explicitly configured. This containment is a key benefit of OTV for Layer 2 extension.

Question 25Network

Which Cisco Nexus feature allows multiple physical switches to be managed as a single logical switch using a unified control plane?

  1. Cisco Fabric Services Correct answer.
  2. Cisco Nexus vPC
  3. Cisco Nexus VDC
  4. Cisco Nexus Fabric Extender

Explanation

Cisco Fabric Services (CFS) provides a unified control plane for distributing configuration and state across devices in a fabric, enabling coordinated management. It is used by features such as vPC and FabricPath to synchronize information.

Question 26Network

On a Cisco Nexus switch, which command displays the vPC role, peer status, and the vPC member ports along with their consistency status?

  1. show running-config vpc
  2. show vpc consistency-parameters global
  3. show vpc brief Correct answer.
  4. show vpc peer-keepalive

Explanation

The show vpc brief command summarizes the vPC domain ID, local and peer roles, peer-link and keepalive status, and lists each vPC with its port state and consistency result. It is the first command used to confirm whether a vPC is operational and consistent.

Question 27Network

A network engineer must confirm that a vPC member port is configured identically on both peers. Which command output shows whether the Type-2 consistency check passed for that port channel?

  1. show port-channel summary
  2. show vpc consistency-parameters interface port-channel 10 Correct answer.
  3. show vpc brief
  4. show lacp neighbor

Explanation

The per-interface form of show vpc consistency-parameters reports each Type-1 and Type-2 parameter with the local and peer values, so mismatches are visible directly. Type-2 mismatches suspend only the affected vPC, unlike Type-1 mismatches that suspend all vPCs.

Question 28Network

Which statement describes how a Cisco Nexus switch running vPC forwards traffic destined to the vPC peer's router MAC address when the peer-link is operational?

  1. It routes the traffic locally and never uses the peer-link for routed flows.
  2. It drops the traffic because the peer MAC is not in the local MAC table.
  3. It redirects the traffic to the vPC keepalive link for forwarding.
  4. It forwards the traffic across the peer-link so the peer can route it. Correct answer.

Explanation

With a working peer-link, a vPC peer that receives traffic destined to the peer's router MAC forwards it over the peer-link, and the peer performs the routing. This behavior is why the peer-link must carry both control and data traffic and why it is recommended to be a port channel of at least 10 Gbps.

Question 29Network

Which Cisco Nexus feature lets a pair of switches appear as a single Layer 2 and Layer 3 node to attached servers and switches without requiring the attached devices to support multichassis bundling?

  1. FabricPath
  2. vPC Correct answer.
  3. Cisco Fabric Services
  4. VXLAN EVPN

Explanation

vPC presents a pair of Nexus switches as one logical endpoint, allowing attached devices to use a standard port channel or even a single link while both peers forward traffic. FabricPath and VXLAN EVPN change the fabric forwarding model but do not by themselves create the dual-homed logical endpoint for attached servers.

Question 30Network

An engineer needs to verify which VLANs are allowed on the vPC peer-link and confirm that both peers agree. Which command best provides this information?

  1. show vpc consistency-parameters global Correct answer.
  2. show spanning-tree vlan 10
  3. show interface port-channel 1 trunk
  4. show vpc role

Explanation

The global consistency-parameters output includes parameters such as the peer-link VLAN list and STP settings, showing the local and peer values side by side. This confirms whether both peers permit the same VLANs across the peer-link.

Question 31Network

Which protocol does a Cisco Nexus switch use by default to synchronize MAC addresses learned on vPC member ports between the two peers?

  1. LACP over the peer-keepalive link
  2. Cisco Fabric Services over the management network
  3. EVPN route type 2 advertisements
  4. The vPC peer-link using a proprietary synchronization protocol Correct answer.

Explanation

vPC peers synchronize MAC and IGMP state across the peer-link using a Cisco proprietary control protocol carried in the vPC header. This keeps the two peers' Layer 2 tables aligned so either peer can forward traffic for a vPC-attached host.

Question 32Network

A vPC domain uses a peer-keepalive link over the management network. What is the recommended design for that link?

  1. A direct point-to-point link or a dedicated path that is separate from the peer-link and the vPC VLANs Correct answer.
  2. A VLAN carried across the peer-link itself
  3. A loopback-to-loopback path over the VXLAN underlay
  4. A routed path that shares the same physical links as the peer-link

Explanation

The keepalive must remain reachable when the peer-link fails, so it should use a separate path such as a direct link or a dedicated out-of-band segment. Sharing the peer-link or its physical links defeats the purpose of detecting peer unreachability.

Question 33Network

Which spanning-tree enhancement is recommended on a vPC domain to prevent a vPC peer from taking over as root for a VLAN when the primary peer is still active?

  1. Root Guard Correct answer.
  2. Loop Guard
  3. Bridge Assurance
  4. BPDU Guard

Explanation

Root Guard on the vPC interfaces and peer-link prevents a connected device or a misbehaving peer from becoming the spanning-tree root on those ports. This preserves the intended root placement in a vPC topology.

Question 34Network

Which command displays the operational status of the vPC peer-keepalive link, including the source and destination addresses and message statistics?

  1. show vpc statistics peer-keepalive
  2. show vpc consistency-parameters global
  3. show vpc peer-keepalive Correct answer.
  4. show vpc brief

Explanation

The show vpc peer-keepalive command reports the keepalive source and destination, the VRF used, and whether the link is alive. It also shows sent and received message counters used to confirm the heartbeat is flowing.

Question 35Network

Which two components are required to form a vPC domain between two Nexus switches?

  1. A FabricPath spine layer and a switch ID
  2. A cluster management IP and a control VLAN
  3. A peer-link port channel and a peer-keepalive link Correct answer.
  4. A VXLAN tunnel and an EVPN session

Explanation

A vPC domain requires a peer-link port channel that carries control and data traffic and a separate peer-keepalive link used for heartbeat messages. Both must be operational for the domain to form and stay stable.

Question 36Network

On a Cisco Nexus switch, which command shows the vPC domain ID, the local role, and the operational role of the peer?

  1. show vpc role Correct answer.
  2. show running-config vpc
  3. show vpc brief
  4. show vpc statistics

Explanation

The show vpc role command reports the vPC domain ID, the local role priority, the operational role of the local device, and the operational role of the peer. It is used to verify which peer is primary and whether role election completed.

Question 37Network

A vPC member port is suspended and the consistency report shows a mismatch in the allowed VLAN list. What is the most likely result?

  1. Only the affected vPC is suspended while other vPCs remain active. Correct answer.
  2. The domain converts to a single primary peer and all vPCs stay up.
  3. All vPCs in the domain are suspended.
  4. The peer-link is shut down automatically.

Explanation

Allowed VLAN list is a Type-2 parameter, so a mismatch suspends only the affected vPC while other vPCs continue forwarding. Type-1 mismatches, such as differing MTU or STP settings, suspend all vPCs in the domain.

Question 38Network

Which statement correctly describes the vPC role election outcome when both peers are configured with the same role priority and the same system MAC address is not present?

  1. Both switches become primary.
  2. The switch with the higher system MAC address becomes primary.
  3. Role election fails and the domain does not form.
  4. The switch with the lower system MAC address becomes primary. Correct answer.

Explanation

When role priorities are equal, the peer with the lower system MAC address wins the primary role. The primary peer is responsible for running protocols that require a single active instance, such as IGMP snooping querier behavior.

Question 39Network

Which feature allows a vPC peer to keep forwarding traffic for a vPC VLAN after the peer-link fails, provided the peer is still reachable over the keepalive link?

  1. vPC orphan-port suspend
  2. vPC auto-recovery Correct answer.
  3. vPC graceful consistency check
  4. vPC peer-gateway

Explanation

vPC auto-recovery allows a peer to bring up vPC member ports after a peer-link failure if the keepalive link is still alive, using the saved configuration. This avoids a complete outage when the peer-link fails but the peer device remains reachable.

Question 40Network

Which protocol does Cisco FabricPath use to build its loop-free Layer 2 multipath topology?

  1. IS-IS Correct answer.
  2. OSPF
  3. BGP
  4. EIGRP

Explanation

FabricPath uses an IS-IS-based control protocol to advertise switch IDs and compute a loop-free multipath topology across the fabric. The resulting topology supports equal-cost multipathing at Layer 2 without relying on spanning tree.

Question 41Network

In a FabricPath network, which value uniquely identifies each switch in the fabric and is used for topology computation and forwarding?

  1. The vPC domain ID
  2. The VNI
  3. The router MAC address
  4. The switch ID Correct answer.

Explanation

Each FabricPath switch is assigned a switch ID that identifies it in the fabric topology and in the forwarding headers. The switch ID is used by the IS-IS-based control plane to compute paths and by data-plane forwarding decisions.

Question 42Network

Which command displays the FabricPath topology and the switch IDs of the nodes in the fabric on a Nexus switch?

  1. show fabricpath route
  2. show fabricpath isis topology summary Correct answer.
  3. show fabricpath topology
  4. show fabricpath switch-id

Explanation

The show fabricpath isis topology summary command lists the IS-IS topology levels and the switch IDs of the nodes participating in the FabricPath fabric. It is used to confirm fabric membership and topology computation.

Question 43Network

Which statement describes how a FabricPath edge switch handles a frame received from a classic Ethernet access port?

  1. It floods the frame to all FabricPath core ports and relies on spanning tree to prevent loops.
  2. It converts the frame to a VXLAN encapsulated packet before forwarding.
  3. It encapsulates the frame with a FabricPath header and forwards it based on the destination switch ID. Correct answer.
  4. It forwards the frame only to the vPC peer over the peer-link.

Explanation

An edge switch assigns the frame a FabricPath header containing the destination switch ID derived from the destination MAC address and forwards it along the computed topology. This allows multipathing without spanning tree in the core.

Question 44Network

Which Cisco Nexus feature allows a parent switch to manage remote line cards over a single logical management point while extending the backplane over a Layer 2 link?

  1. Cisco Fabric Services
  2. VXLAN EVPN
  3. vPC
  4. Cisco Nexus Fabric Extender Correct answer.

Explanation

A Cisco Nexus Fabric Extender acts as a remote line card of a parent switch, extending the parent's management and data plane over a Layer 2 link. It provides a single management point for many access ports.

Question 45Network

Which command verifies the association between a parent Nexus switch and its attached Fabric Extenders?

  1. show vpc brief
  2. show fex Correct answer.
  3. show module
  4. show interface brief

Explanation

The show fex command lists each Fabric Extender, its FEX number, state, model, and the interfaces used to connect it to the parent. It confirms whether the FEX is online and correctly associated.

Question 46Network

Which component in a VXLAN EVPN fabric is responsible for encapsulating and decapsulating frames at the edge of the fabric?

  1. The route reflector
  2. The VTEP Correct answer.
  3. The anycast gateway
  4. The spine switch

Explanation

A VTEP is the edge device that maps frames into VXLAN segments and performs encapsulation and decapsulation. It maintains the mapping between local VLANs and VNIs and the remote VTEP reachability information.

Question 47Network

Which protocol distributes MAC and IP reachability information between VTEPs in a VXLAN EVPN fabric?

  1. OSPF
  2. LACP
  3. BGP EVPN Correct answer.
  4. PIM-SM

Explanation

BGP EVPN carries MAC and IP reachability information in route types such as type 2 and type 5, allowing VTEPs to learn remote endpoints. This control plane replaces flood-and-learn for MAC address distribution.

Question 48Network

Which command displays the VXLAN NVE interface, its source interface, and the peer VTEPs learned on a Nexus switch?

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

Explanation

The show nve peers command lists the remote VTEP peers known to the local NVE interface along with their state and VNI associations. The show nve interface command shows the local NVE configuration and status but not the peer list.

Question 49Network

Which underlay routing design is commonly recommended for a VXLAN EVPN fabric on Nexus switches to provide loopback-to-loopback reachability for VTEPs?

  1. A Layer 2 spanning-tree core with VLAN extension
  2. A hub-and-spoke topology using static routes
  3. A ring topology using REP
  4. A Layer 3 routed spine-leaf fabric using OSPF or IS-IS Correct answer.

Explanation

A Layer 3 routed spine-leaf underlay using OSPF or IS-IS provides equal-cost multipathing and loopback-to-loopback reachability between VTEPs. This underlay supports the overlay by ensuring VTEP source and destination addresses are reachable.

Question 50Network

An engineer is configuring a vPC domain between two Cisco Nexus switches and needs the peer-keepalive heartbeat to traverse a dedicated point-to-point link between the two switches' management interfaces rather than the production data network. Which command sequence correctly places the peer-keepalive messages on that dedicated path?

  1. vpc domain 10, then peer-keepalive destination 192.0.2.2 source 192.0.2.1 vrf default
  2. vpc domain 10, then peer-keepalive destination 192.0.2.2 source 192.0.2.1 vrf management Correct answer.
  3. vpc domain 10, then peer-gateway, then peer-keepalive destination 192.0.2.2
  4. vpc domain 10, then peer-link port-channel 100, then peer-keepalive enable

Explanation

The peer-keepalive link is an out-of-band heartbeat carried over a routed path, and it is configured inside vPC domain configuration mode with the peer-keepalive destination and source commands. Because the requirement is to keep the heartbeat off the data plane, the management VRF is specified with the vrf management keyword so the packets use the management interface. The peer-link itself carries vPC control and data traffic, not the keepalive heartbeat, so it must not be used for this purpose.