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Telecom Professional Qualification study materials
Telecom Professional Qualification study resources

Telecom Professional Qualification: Network Security and Service Assurance

Telecom Professional Qualification · Work through your exam, one topic at a time.

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Network Security and Service Assurance

This domain pairs protection of the network with proof that it performs. Questions mix cryptographic and protocol facts (what IPsec ESP actually protects, IDS versus IPS) with availability mathematics and assurance-process vocabulary.

Security foundations

  • The CIA triad: confidentiality, integrity, availability. AAA is commonly implemented with RADIUS or Diameter; the latter is native to LTE/5G core signalling.
  • Symmetric ciphers (AES) are fast and used for bulk data; asymmetric algorithms (RSA, ECDSA) handle key exchange and signatures. Hashing (SHA-256) gives integrity, and a keyed MAC authenticates.
  • IPsec: AH provides integrity and authentication only; ESP provides confidentiality plus integrity; IKEv2 negotiates keys; tunnel mode hides the original header, transport mode does not. TLS protects at the transport/application boundary (HTTPS 443).
  • Threat classes: spoofing, man-in-the-middle, DNS cache poisoning, DDoS, SS7/Diameter signalling abuse, SIM swap, GTP misconfiguration, and fraud such as PBX hacking and international revenue share fraud.
  • Controls: stateful firewalls and NGFW, IDS for detection versus IPS for inline blocking, segmentation, zero trust, PKI, patching and least privilege.

Service assurance

  • FCAPS (fault, configuration, accounting, performance, security) frames management; OSS handles operations, BSS handles customers.
  • Monitoring: SNMP polling and traps, NetFlow/IPFIX, syslog, synthetic probes, TWAMP for performance. ITIL processes: incident, problem, change; root cause analysis closes the loop.
  • SLA metrics: availability, MTTR, MTBF, latency, loss; DR objectives are RTO (time to restore) and RPO (tolerable data loss).

Worked example

A node has MTBF of 1,500 hours and MTTR of 6 hours. Availability = 1,500 ÷ (1,500 + 6) = 99.60%. To reach 99.9% with the same repair time: MTBF ÷ (MTBF + 6) ≥ 0.999, so MTBF ≥ 5,994 hours. Either improve reliability roughly fourfold or cut MTTR to about 1.5 hours - the formula shows both levers explicitly.

Traps that cost marks

  • Saying AH encrypts payload; it does not.
  • Confusing IDS (detects and alerts) with IPS (blocks inline).
  • Swapping MTBF and MTTR in the availability formula, or confusing reliability with availability.
  • Mixing RTO (restore time) with RPO (data-loss tolerance).
  • Treating an SLA credit as proof that the root cause was fixed.