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010-151 DCTECH study materials
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010-151 DCTECH: Data Center Networking and Virtualization

010-151 DCTECH · Work through your exam, one topic at a time.

All guide sections

Data Center Networking and Virtualization

This domain covers how Nexus and Fabric Interconnect switching, Layer 2 features, and hypervisor networking fit together: VLANs, trunks, port channels, vPC, NPV/NPIV, VSANs, and virtual switches. Expect questions that ask which requirement is missing from a design or why a vPC member is suspended.

Switching fundamentals

  • Access ports carry one VLAN; trunk ports carry many with 802.1Q tags; the native VLAN is untagged and must match on both ends.
  • STP prevents loops; use PortFast/Edge and BPDU Guard on host ports.
  • Port channels bundle links; LACP negotiates, while static on mode does not.
  • vPC pairs two Nexus switches into one logical switch. Requirements: same vPC domain ID, peer-link on both, peer-keepalive reachable over a separate Layer 3 path, matching port-channel configuration on both peers, and member ports split across peers.
  • vPC gives active/active dual-homing without STP blocking; loop avoidance is handled by the peer-link.

SAN and virtualization

  • NPIV lets an N-port log in through an F-port with multiple WWPNs; NPV makes the switch a proxy and reduces domain count.
  • VSANs isolate SAN fabrics; zoning controls which WWPNs can communicate.
  • Hypervisor: standard vSwitch or distributed switch; VM NICs map to port groups and VLANs; VMFS datastores run over FC, iSCSI, or NFS; vMotion needs compatible networking and shared storage.
  • Fabric Interconnect end-host mode presents server uplinks as host ports; switch mode behaves like a traditional switch.

Worked example

Two Nexus 93180YC-EX switches form a vPC pair; a server has two 10G NICs, one to each switch, in a single LACP port channel. Both sides must use the same port-channel number and identical allowed VLAN lists. Peer-keepalive must run over a separate management path, not the peer-link. Why: the peer-link carries vPC data and orphan traffic; if keepalive fails while the peer-link stays up, the secondary vPC is suspended to avoid a split-brain.

Traps

  • Putting peer-keepalive on the peer-link.
  • Mismatched VLAN lists causing vPC inconsistency.
  • Assuming a static port channel negotiates with the peer.
  • Missing a native VLAN mismatch, which is untagged and silent.
  • Confusing a VSAN with a VLAN.