VLAN (Virtual Local Area Network)

A Virtual LAN is a logical Layer-2 network segment overlaid on a physical switched network, defined by IEEE 802.1Q. VLANs let operators isolate traffic, management, voice, guest, IoT, over shared infrastructure. VLAN-hopping attacks (double tagging, switch spoofing) are mitigated by disabling DTP, pruning trunks, and not using VLAN 1 for production traffic.

Categories: Threats and AttacksEncryption and CryptographyIoT

VLAN in context

Telecom threats range from opportunistic SMS phishing and SIM swap to nation-state grade location tracking and lawful-interception abuse. The common thread is that most attacks exploit the inherited trust model of legacy signaling. SS7 and Diameter were designed for a closed operator community that no longer exists.

Cryptography in telecom spans air-interface ciphers (A5/1, A5/3, ZUC, SNOW, NEA/NIA), transport (IPsec, TLS), and identity (AKA, 5G-AKA, EAP-AKA'). Weak or downgradeable ciphers remain a live risk on 2G/3G fallback, and post-quantum migration is now on the roadmap for interconnect and roaming keys.

To place VLAN in the wider telecom-security picture, review Network Slicing, Botnet, WPA2, A5/2, IVR and Private 5G.

Related terms

Related topic hubs

  • Diameter Security 4G/LTE Diameter threats across IPX/roaming and DEA defenses.
  • Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.
  • Silent SMS Type-0 SMS location tracking and detection.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.