IT AI Skill

Network Management

Manage network infrastructure including LAN/WAN design, routing, switching, VLANs, SD-WAN, network monitoring, and troubleshooting. Use when designing networks, configuring switches/routers, implementing VLANs, setting up SD-WAN, or troubleshooting network issues. Triggers on phrases like "network management", "LAN", "WAN", "SD-WAN", "VLAN", "routing", "switching", "network design", "network monitoring", "network troubleshooting", "BGP", "OSPF", "STP", "QoS", "firewall rules", "network security", "network segmentation", "access control list", "ACL", "port security".

Network Management

Manage network infrastructure including LAN/WAN design, routing, switching, VLANs, SD-WAN, monitoring, and troubleshooting.

Workflow

1. Network Architecture

NETWORK ARCHITECTURE
═══════════════════════════════════════

Enterprise Network Design:
═══════════════════════════════════════

                    Internet
                      ↓
                 Edge Firewall
                      ↓
              Core Switch (Layer 3)
              ═══════════════════════════
              ↓           ↓           ↓
         Distribution   Distribution  Distribution
         Switch (Floor A) Switch (Floor B) Switch (Remote)
         ↓           ↓           ↓           ↓
     Access       Access      Access      Access
     Switch       Switch      Switch      Switch
     ↓            ↓           ↓           ↓
  Workstations  Servers     WiFi APs    Branch Office

NETWORK SEGMENTS (VLANs):
═══════════════════════════════════════

VLAN ID   Name             Subnet              Purpose          Security
───────────────────────────────────────────────────────────────────────────────
10        Management       10.10.10.0/24       Network devices  Restricted
20        Servers          10.10.20.0/24       Production       Firewall rules
30        Users            10.10.30.0/24       Employee LAN     Standard
40        Guests           10.10.40.0/24        Guest WiFi       Internet only
50        VoIP             10.10.50.0/24       Phone systems    QoS priority
60        IoT              10.10.60.0/24       IoT devices      Isolated
70        DMZ              10.10.70.0/24       Public servers   Firewall DMZ
80         Dev/Test        10.10.80.0/24       Development      Isolated from prod

REDUNDANCY:
═══════════════════════════════════════

  → Core switches: Stacked (VSS/MLX) or HSRP/VRRP
  → ISP: Dual ISP (primary + backup)
  → Uplinks: LACP (EtherChannel) bonded
  → WAN: SD-WAN (multiple links, active-active)
  → Power: Dual PSU, UPS

2. Routing & Switching

ROUTING CONFIGURATION
═══════════════════════════════════════

Dynamic Routing:
═══════════════════════════════════════

  Internal: OSPF (OSPFv2 for IPv4, OSPFv3 for IPv6)
    → Area 0: Backbone (core)
    → Area 1: Floor A
    → Area 2: Floor B
    → Area 3: Remote site

  External: BGP (Multi-homed ISP)
    → AS: 65001 (private)
    → Peers: ISP1 (AS 64500), ISP2 (AS 64501)
    → Default route: Both ISPs (ECMP)
    → Health check: BFD (fast failover)

Switching:
═══════════════════════════════════════

  Spanning Tree:
    → Mode: Rapid PVST+
    → Root bridge: Core switch 1 (primary)
    → Backup root: Core switch 2 (secondary)
    → BPDU guard: Enabled on access ports
    → Portfast: Enabled on access ports

  Link Aggregation:
    → LACP mode: Active
    → Channels: 2x1G or 4x1G
    → Fallback: Single link (graceful degradation)

ACCESS CONTROL LISTS (ACLs):
═══════════════════════════════════════

  → VLAN-to-VLAN: Firewall (not ACL)
  → Server protection: Inbound ACL on server VLAN
  → Guest isolation: No access to internal networks
  → IoT isolation: Only internet + specific servers

3. SD-WAN

SD-WAN IMPLEMENTATION
═══════════════════════════════════════

SD-WAN Architecture:
═══════════════════════════════════════

  Branch Office:
    → SD-WAN edge appliance (hardware/virtual)
    → Links: MPLS + Internet + 4G/5G backup
    → Centralized management (cloud controller)

  Data Center:
    → SD-WAN edge (connect to firewall)
    → Links: Dedicated + Internet

  Cloud:
    → Direct cloud on-ramp (AWS Direct Connect, Azure ExpressRoute)
    → SaaS optimization (Office 365, Salesforce → internet)

LINK PRIORITIZATION:
═══════════════════════════════════════

  Application              Path                     Policy
  ────────────────────────────────────────────────────────────────────────
  VoIP                    MPLS (lowest latency)     QoS priority 1
  ERP (SAP/Oracle)        MPLS                      QoS priority 2
  Email (O365)            Internet (direct)         QoS priority 3
  Web browsing            Internet                  Best available
  Cloud backup            Internet (off-hours)      Best available
  Video conferencing      MPLS or Internet          Adaptive path

SD-WAN FEATURES:
═══════════════════════════════════════

  → Application-aware routing (identify by SSL, deep packet)
  → Forward error correction (FEC) for WAN optimization
  → Compression and deduplication
  → Centralized policy management
  → Zero-touch provisioning (branch deployment)
  → Integrated security (IPS, firewall, CASB)

4. Network Monitoring

NETWORK MONITORING
═══════════════════════════════════════

Monitoring Stack:
═══════════════════════════════════════

  Tool                  Purpose                    Data Source       Alert
  ────────────────────────────────────────────────────────────────────────────────
  PRTG / SolarWinds     Device monitoring          SNMP             Threshold
  Wireshark             Packet analysis            Port mirror      Manual
  NetFlow/sFlow         Traffic analysis           Router/switch    Anomaly
  Nmap                  Port scanning              Active scan      Scheduled
  SmokePing             Latency/jitter monitoring  ICMP/HTTP        Threshold
  UptimeRobot           External availability      HTTP/HTTPS       Downtime

  Monitoring Coverage:
═══════════════════════════════════════

  → All routers, switches, firewalls (SNMP)
  → ISP links (NetFlow, ping)
  → WiFi controllers and APs (SNMP, API)
  → Network utilization (per interface)
  → Error rates (CRC, collisions, drops)
  → CPU/memory utilization (devices)
  → Port status (up/down, speed, duplex)

NETWORK HEALTH DASHBOARD:
═══════════════════════════════════════

  Metric              Target        Current      Status
  ────────────────────────────────────────────────────────────────
  Uptime              ≥ 99.99%      99.995%      ✓ Good
  Latency (internal)  ≤ 5ms         2ms          ✓ Good
  Latency (WAN)       ≤ 50ms        35ms         ✓ Good
  Packet loss         ≤ 0.1%        0.02%        ✓ Good
  Utilization (peak)  ≤ 70%         55%          ✓ Good
  WiFi coverage       ≥ 95%         97%          ✓ Good
  DNS resolution      ≤ 10ms        5ms          ✓ Good

5. Network Troubleshooting

NETWORK TROUBLESHOOTING FRAMEWORK
═══════════════════════════════════════

Layer-by-Layer Approach (OSI Model):
═══════════════════════════════════════

Layer 1 (Physical):
  → Cable test (Fluke, link lights)
  → Port status (show interface)
  → Speed/duplex mismatch
  → SFP module (transceiver test)

Layer 2 (Data Link):
  → MAC address table (show mac address-table)
  → STP status (show spanning-tree)
  → VLAN configuration (show vlan)
  → ARP table (show arp)
  → Duplicate MAC detection

Layer 3 (Network):
  → IP configuration (show ip interface brief)
  → Routing table (show ip route)
  → OSPF neighbors (show ip ospf neighbor)
  → BGP sessions (show ip bgp summary)
  →traceroute / pathping

Layer 4+ (Transport/Application):
  → Port connectivity (telnet, Test-NetConnection)
  → Firewall rules (show access-lists)
  → DNS resolution (nslookup, dig)
  → Application-specific (HTTP, SMTP, etc.)

COMMON ISSUES & RESOLUTIONS:
═══════════════════════════════════════

Issue                     Diagnosis                   Resolution
───────────────────────────────────────────────────────────────────────
Intermittent connectivity Cable/port issue           Replace cable, check port
Slow WiFi                 Channel interference        Change channel, reduce power
DNS failures              DNS server down/unreachable Switch to alternate DNS
High latency              Congestion/route issue      Check utilization, verify route
VLAN not working          VLAN mismatch/tagging       Verify VLAN config end-to-end
DHCP not assigning        DHCP server/pool issue      Check DHCP scope, relay agent

Edge Cases

Multi-site: WAN optimization, latency management
Remote workers: VPN, Zero Trust, SASE
WiFi: Interference, roaming, capacity
IoT: Network segmentation, security
Compliance: Network access control (NAC)

Integration Points

Monitoring: PRTG, SolarWinds, Nagios, Zabbix
Configuration: Ansible, Terraform, Python
SD-WAN: VMware Velocloud, Cisco Viptela, Fortinet
Security: Palo Alto, Fortinet, Check Point, Cisco
WiFi: Cisco Meraki, Aruba, Ubiquiti
NAC: Cisco ISE, Aruba ClearPass

Output

Network Management Status

NETWORK STATUS — Q4 2024
═══════════════════════════════════════

Devices managed: 245 (switches, routers, APs, firewalls)
Uptime: 99.995% (target: ≥99.99%) ✓
VLANs: 8 (all operational)
SD-WAN: 12 sites (active-active, 0 outages)
WiFi coverage: 97% (target: ≥95%) ✓
Open tickets: 2 (minor, resolved <4h)
Last audit: Q4 2024 (compliant)
Next action: Upgrade 3 edge switches (EOL Q2 2025)

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