Cisco CCNP Enterprise (350-401 ENCOR) — All Questions

In OSPF, what must match on both routers for a neighbor adjacency to form on a broadcast segment?

• a.Router IDs must be identical
• b.Interface bandwidth values must be identical
• c.Process IDs must be identical
• d.Area ID, subnet/mask, hello and dead timers, and authentication must match✓

For OSPF neighbors to reach full adjacency, the interfaces must share the same area, be on the same subnet, agree on hello and dead intervals, and pass any authentication. Router IDs must be unique, not identical, the process ID is locally significant, and interface bandwidth affects cost but not adjacency formation.

Which attribute does BGP evaluate first (after next-hop reachability) when selecting the best path, and in which direction does a higher value win?

• a.Weight, where the highest weight is preferred (Cisco-proprietary, local to the router)✓
• b.MED, where the highest value is preferred
• c.AS-path length, where the longest path is preferred
• d.Local preference, where the lowest value is preferred

On Cisco routers the first tie-breaker in BGP best-path selection is Weight, which is local to the router and prefers the highest value. Local preference (higher preferred) comes next and is exchanged within the AS, while a shorter AS-path is preferred and a lower MED is preferred later in the process.

Which protocol provides first-hop gateway redundancy and is a Cisco-proprietary option where one router is Active and another is Standby for a shared virtual IP?

• a.VRRP
• b.HSRP✓
• c.GLBP
• d.STP

HSRP (Hot Standby Router Protocol) is Cisco-proprietary and elects an Active router and a Standby router that share a virtual IP and MAC to provide gateway redundancy. VRRP is the open-standard equivalent, and GLBP additionally load-balances across gateways. STP is a Layer 2 loop-prevention protocol, not a gateway redundancy protocol.

On a Layer 2 switch running Rapid PVST+, what is the role of a port that is elected to forward traffic away from the root bridge on a segment?

• a.Root port
• b.Blocking port
• c.Designated port✓
• d.Alternate port

The designated port is the single forwarding port elected for each segment, sending traffic away from the root bridge. The root port is the switch's best path toward the root, an alternate port is a backup to the root port, and a blocking (discarding) port is not forwarding. Each non-root switch has one root port; each segment has one designated port.

Two switches are connected by several links bundled with LACP into one logical link. What benefit does this EtherChannel provide?

• a.Increased aggregate bandwidth and redundancy without spanning-tree blocking the redundant links✓
• b.Automatic routing between VLANs without a Layer 3 device
• c.Encryption of all frames on the bundle
• d.Elimination of the need for a default gateway

An EtherChannel bundles multiple physical links into one logical link, increasing aggregate bandwidth and providing redundancy, and because STP treats the bundle as a single link the member links are not individually blocked. It does not perform inter-VLAN routing, encryption, or remove the need for a gateway.

A switch port should connect to another switch and carry traffic for multiple VLANs. How should the port be configured?

• a.As an access port assigned to one VLAN
• b.As a routed port with an IP address
• c.In administratively shutdown state
• d.As a trunk port using 802.1Q tagging✓

A trunk port uses 802.1Q tagging to carry traffic for multiple VLANs across a single link between switches, preserving VLAN identity with tags (except the native VLAN). An access port belongs to a single VLAN and carries untagged traffic, and a routed port terminates Layer 3, so neither carries multiple VLANs as a trunk does.

Which statement about a VXLAN overlay used in modern campus and data-center fabrics is correct?

• a.VXLAN provides only 4094 total segments, like classic VLANs
• b.VXLAN encapsulates Layer 2 frames in UDP and uses a 24-bit VNID, allowing about 16 million segments✓
• c.VXLAN operates purely at Layer 1 with no encapsulation
• d.VXLAN replaces IP routing entirely in the underlay

VXLAN encapsulates Ethernet frames inside UDP/IP (MAC-in-UDP) and uses a 24-bit VXLAN Network Identifier, providing roughly 16 million segments, far beyond the 4094 of 802.1Q VLANs. It rides on top of a routed IP underlay rather than replacing it, enabling scalable Layer 2 overlays across a Layer 3 network.