VoIP Platforms

Understanding VoIP platforms, analysing SIP flows and mastering IP telephony architectures

VoIP platforms and their challenges

IP telephony relies on open protocols (SIP, RTP, SRTP) that traverse enterprise and Internet IP networks. Understanding how these platforms work, analysing SIP flows and diagnosing interoperability issues are essential skills to guarantee the reliability and quality of communications.

SIP Security MechanismsTLS/SRTPINVITE sip:user@domainVia: SIP/2.0/TLSSIP/2.0 401 UnauthWWW-Authenticate: DigestREGISTER sip:proxyAuthorization: Digest...Encrypted SIPTLS 1.3 / Port 5061Encrypted MediaSRTP / AES-128Security ControlsDigest Authentication (RFC 3261)SIP over TLS (SIPS URI scheme)SRTP Media Encryption (RFC 3711)Protection AgainstEavesdropping / Packet SniffingMan-in-the-Middle AttacksRegistration Hijacking

Risks and threats

Toll fraud

Unauthorized use of telephony resources, international call hijacking, overbilling. Unprotected VoIP systems are prime targets for large-scale fraud.

Eavesdropping

Unencrypted SIP and RTP flows can be captured on the network. Without TLS for signaling and SRTP for media, any conversation can be intercepted.

Denial of service

SIP servers exposed to the Internet are vulnerable to DoS and DDoS attacks. An abnormal volume of INVITE, REGISTER or OPTIONS requests can saturate the infrastructure and disrupt phone service.

Identity spoofing

The SIP protocol does not natively provide strong authentication. Without controls, an attacker can forge caller identities and compromise trust in communications.

Key SBC functions

SIP session control

The SBC controls the establishment, maintenance and release of SIP sessions. It authenticates devices, limits concurrent sessions and enforces routing policies.

Protocol normalization

The SBC ensures interoperability between equipment from different vendors by normalizing SIP variants, adapting codecs and transforming signaling.

Topology hiding

Concealment of the internal voice network structure. The SBC rewrites SIP headers and SDP information to reveal nothing about the internal infrastructure.

Interconnection protection

At interconnection points with carriers and partners, the SBC filters flows, detects anomalies, enforces rate limits and protects the infrastructure against abuse and attacks.

The Bill-IT approach

We analyse your existing VoIP platforms, study SIP flows and design SBC configurations tailored to your constraints. Our approach covers the entire chain: from SIP signaling analysis to interoperability diagnostics, from SBC configuration to architecture optimization.

VoIP Security ThreatsCommon attack vectors targeting VoIP infrastructureVoIPInfrastructure!Toll FraudUnauthorized internationalcalls via compromisedSIP accounts!EavesdroppingInterception of voicestreams and signalingvia packet capture!DoS / DDoSSIP flood attacks,INVITE/REGISTER stormscausing service outage!Caller ID SpoofingForged SIP headersmanipulating From/PAIfor social engineering!SRTP DowngradeForcing fallback tounencrypted RTP viaSDP manipulationCritical RiskHigh RiskSBC mitigates all listed threats through policy enforcement
VoIP Platform Analysis & SIP Security | Bill-IT