AstraQom — telecomunicaciones globales para empresas, inicio
AstraQom — telecomunicaciones globales para empresas, inicio

¿Qué es el SIP Trunking? Guía completa para empresas — AstraQom

Guía completa de SIP trunking: cómo funcionan los troncales SIP, ventajas frente al PSTN, ahorro, seguridad, despliegue y cómo elegir un proveedor Tier-1.

What is a SIP trunk?

SIP (Session Initiation Protocol) trunking is a method for delivering voice and unified communications over an IP data connection instead of legacy copper PSTN lines. A SIP trunk connects your on-premise IP PBX — or a hosted/cloud PBX — to the public telephone network through a licensed carrier such as AstraQom, giving you unlimited concurrent calls, direct-inward-dial (DID) numbers in 117 countries, and toll-free reachability with a single global contract.

How SIP trunking works

  1. Your IP PBX registers to the carrier's SBC (Session Border Controller) over TLS/SRTP.
  2. Outbound calls are signaled via SIP INVITE and routed through Tier-1 interconnects.
  3. Inbound calls to your DIDs are delivered to the same trunk in real time.
  4. Media flows peer-to-peer or through the SBC depending on NAT and codec policy.

SIP trunking vs traditional PSTN (PRI / analog)

  • Cost: SIP eliminates per-line rental; concurrent channels scale on demand.
  • Geographic freedom: a number in any of 117 countries without a local circuit.
  • Resilience: automatic failover to backup routes and DR sites.
  • Feature depth: native support for HD voice (G.722, Opus), video, and messaging.

Benefits for enterprises

  • Consolidate global telephony under one contract and one invoice.
  • Reduce long-distance and international termination spend with Tier-1 routes only — no grey routes.
  • Enable remote and hybrid work with softphone and mobile SIP clients.
  • Meet compliance needs (STIR/SHAKEN, GDPR, HIPAA-aware handling).

Security best practices

  • Terminate signaling on TLS 1.2+ and media on SRTP.
  • IP-ACL your SBC and rate-limit REGISTER attempts.
  • Enforce strong SIP credentials and per-trunk call caps to blunt toll fraud.

Deployment checklist

  1. Audit call volumes, concurrent channels, and codec preferences.
  2. Confirm PBX vendor interop (FreePBX, FusionPBX, 3CX, Cisco CUCM, Avaya, Metaswitch).
  3. Port existing DIDs; provision new numbers where needed.
  4. Pilot on a subset of users, then cut over with keep-alive on the legacy trunk.

How to choose a SIP trunk provider

Prioritize carriers with direct Tier-1 interconnects, transparent rate decks, 24/7 human support, and a documented SLA. AstraQom has operated as an independent global carrier since 2008, with points of presence across the Americas, EMEA and APAC.

Talk to an AstraQom SIP specialist to size a trunk for your enterprise.