Network Engineer

Roles and Responsibilities:

Core Networking & Switching:

Strong understanding of STP (Spanning Tree Protocol), BPDU, loop prevention, PortFast

Switch loop detection mechanisms

VLANs, trunking, and VTP operations (including switch replacement scenarios)

EtherChannel / Port-Channel concepts and design considerations

vPC (Virtual Port Channel) – concepts and advantages

Switch stacking – advantages and use cases

DHCP & Layer 2 Security:

DHCP deep dive (DORA process) and packet flow

IP allocation process via DHCP

DHCP Relay (same & inter-VLAN scenarios)

DHCP Snooping and security implementation

Wireless & Access Layer:

Access Point troubleshooting steps

CAPWAP protocol and relevant commands

Routing & L3 Concepts:

OSPF fundamentals

BGP fundamentals, neighbor establishment and troubleshooting

BGP soft reset vs hard reset

Route selection behavior (eBGP vs iBGP)

Route redistribution (OSPF ↔ BGP) and multi-domain connectivity

High Availability & Design:

HSRP concepts and gateway redundancy

Primary/secondary core switch design

Uplink design and failover behavior

Troubleshooting & Validation:

Service/port validation (e.g., verifying port 22 reachability from L3 devices)

Real-time troubleshooting approach

Transport Layer:

Deep understanding of TCP vs UDP