Competencies: Networking > Switching
Switching
Body of Knowledge
| Topic | Description | Relevance | Career Tracks |
|---|---|---|---|
Ethernet Fundamentals |
MAC addressing, frame formats, half/full duplex, auto-negotiation, jumbo frames, error detection (CRC). Foundation of all LAN technology. |
Critical |
Network Engineer, Systems Administrator |
VLAN Architecture |
802.1Q tagged VLANs, trunk configuration, native VLAN security, VLAN pruning, inter-VLAN routing, DHCP relay across VLANs. |
Critical |
Network Engineer, Security Engineer |
Spanning Tree Protocol (STP) |
STP/RSTP/MST fundamentals, root bridge election, port roles and states, BPDU guard, root guard, loop guard. Loop prevention. |
Critical |
Network Engineer, Data Center Engineer |
EtherChannel / Link Aggregation |
LACP (802.3ad), static channel groups, load balancing algorithms, member port requirements, troubleshooting bundle issues. |
High |
Network Engineer, Data Center Engineer |
Port Security |
MAC-based port security, sticky MACs, violation modes (protect, restrict, shutdown), aging. Defense against MAC flooding attacks. |
High |
Network Engineer, Security Engineer |
Storm Control |
Broadcast/multicast/unknown unicast storm suppression, threshold configuration, action modes. Prevents network instability from traffic floods. |
Medium |
Network Engineer, Data Center Engineer |
Private VLANs |
Primary and secondary VLANs, isolated and community ports, promiscuous ports. Micro-segmentation within a VLAN for multi-tenant environments. |
Medium |
Network Engineer, Security Engineer |
VXLAN Fundamentals |
Virtual extensible LAN for overlay networks, VTEP, VNI, encapsulation, multicast vs unicast replication. Data center network virtualization. |
High |
Data Center Engineer, Cloud Network Architect |
EVPN-VXLAN |
BGP EVPN control plane for VXLAN, route types 1-5, MAC mobility, ARP suppression, multi-homing. Modern data center fabric. |
Medium |
Data Center Engineer, Cloud Network Architect |
Cisco Fabric (ACI) |
Application Centric Infrastructure, EPG/contract model, spine-leaf topology, policy-driven networking. Cisco software-defined DC networking. |
Medium |
Data Center Engineer, Network Architect |
Network Virtualization (VCS/VSS) |
Virtual switching systems, StackWise, chassis virtualization, multi-chassis EtherChannel, cross-stack resilience. |
Medium |
Network Engineer, Data Center Engineer |
Layer 2 Security Features |
DHCP snooping, dynamic ARP inspection, IP source guard. Defense against L2 attacks (DHCP starvation, ARP spoofing, IP spoofing). |
Critical |
Network Engineer, Security Engineer |
Personal Status
| Topic | Level | Evidence | Active Projects | Gaps |
|---|---|---|---|---|
VLAN Architecture |
Advanced |
CHLA campus segmentation across Catalyst stacks; home lab VyOS multi-VLAN topology with tagged trunks, inter-VLAN routing, and DHCP relay |
No fabric/VXLAN experience at scale |
|
Switching Fundamentals |
Advanced |
Catalyst 9300/9200 management — STP tuning, EtherChannel, port security, storm control; CHLA switch stack deployments and IOS-XE upgrades |
No Nexus/NX-OS, no data center switching fabric |