Master Guide

this article provides a complete overview of how enterprises can integrate with exotel’s virtual sip trunking (vsip) it includes configuration options (tcp, tls, fqdn), onboarding steps, best practices, and supported use cases 1\ what is virtual sip trunking (vsip)? virtual sip trunking allows enterprise pbx/sbc systems to connect directly with exotel’s voice infrastructure using sip over tcp or tls it supports both inbound and outbound pstn calling through ip connectivity, with optional fqdn based flexibility 2\ supported use cases use case description outbound sip (ip → pstn) calls from customer sip infra routed to exotel → pstn inbound sip (pstn → ip) incoming calls to exophone routed to customer sip server ip–pstn intermix bi directional call routing between ip infra and exotel vns sip bot integration direct sip to bot integration with no agent involvement fqdn based load balanced sip fqdns resolve dynamically to multiple ips for cloud/hybrid setups native sip voicebot integration direct sip call to customer hosted sip native voicebot platform 3\ transport options transport port encryption dns support use case tcp 5070 no yes default, legacy infra tls 443 yes yes encrypted sip + srtp flows fqdn any tcp/tls required cloud, autoscaling, ha sip infra 4\ integration path – high level flow what is supported sip trunking with tcp and tls transport sip trunk routing using static ips or fqdn bi directional call support (ip to pstn and pstn to ip) exophones (virtual numbers) mapped to sip trunks sip to flow integration using connect or ivr — see sip to flow integration guide sip to sip integration for native voicebot routing — see native sip voicebot integration guide note – vsip throttling exotel enforces a default vsip rate limit of 200 calls per minute (cpm) per trunk to safeguard carrier capacity and call quality if your traffic profile requires a higher burst rate, raise a request via your csm or support ticket the capacity planning team will review historical traffic, carrier limits, and qos requirements and can increase the throttling threshold accordingly what is not supported sip over udp (not supported) sip registration based authentication sip traffic without prior account upgrade/kyc supported regional exophones for mum sip setup veeno ka, dl, mum, ap, gj getting started with exotel vsip (veeno accounts) create your exotel account via my in exotel com complete kyc and upgrade the account with help from your exotel account manager link procure exophones by emailing hello\@exotel com (mention region specific need) decide trunking mode tcp or tls, static ip or fqdn collect and share with exotel account sid exophones trunk source ips (for outbound trunking) trunk destination ips/fqdn (for inbound trunking) chosen transport protocol (tcp/tls) once provisioned, your sip traffic will be routed via exotel’s regional edge pop kyc verification based on the setup required convert to full account – exotel team upgrades it share configuration details account sid exophones (required for pstn origination) source ip(s) (for outbound) destination ip(s) or fqdn (for inbound) transport type (tcp/tls) provisioning voip and voip pstn enabled sip trunk created in backend by tech support dial whom uri format configured testing inbound and outbound calls validated sip packets reviewed using tools like sngrep 5\ configuration types a tcp trunking (port 5070) — see exotel virtual sip trunking tcp integration guide uses format sip \<number>@pstn in4 exotel com 5070;transport=tcp requires static ip whitelisting b tls trunking (port 443) — see exotel virtual sip trunking tls integration guide uses format sip \<number>@pstn in4 exotel com 443;transport=tls encrypted sip signaling and srtp media recommended for secure communication c fqdn based trunking — see exotel virtual sip trunking fqdn integration guide no ip whitelisting required uses dns lookup to resolve sip server ip dynamically ideal for cloud or redundant infrastructure 6\ fqdn configuration guidance if you are using a dns resolvable fqdn instead of a static ip for your sip server, please ensure the following your sip server is accessible via a public fqdn (e g , sip customer com) it resolves to an ip address reachable by exotel specify the port (e g , 5070 for tcp or 443 for tls) and transport protocol share the fqdn, port, and transport protocol with your exotel account manager exotel will configure the trunk to use your fqdn this enables dynamic ip handling and is ideal for cloud hosted or ha infrastructures once this is provisioned, you can begin testing map your vn to the sip trunk and initiate a test call use tools like sngrep or tcpdump to validate invite requests and srtp media flow in the dial whom field, use format sip \<number>@\<fqdn> \<port>;transport=tcp|tls confirm the p asserted identity header shows the correct leg1 number (caller identity) 7\ best practices for vsip integration use fqdn if infra is cloud based, ha, or load balanced keep dns ttl between 30–60 seconds for fast recovery avoid sip alg in nat/firewall appliances use pcma (g 711 a law) as primary codec use tls + srtp for security sensitive traffic validate trunk reachability before mapping vns restrict rtp media port range to 10000–20000 (10k ports only) each sip call uses 2 ports exotel media servers support 3000 concurrent calls → 6000 ports a 50% buffer ensures capacity during retries, hold ups, or port conflicts helps avoid nat related media drops and ensures predictable firewall rules 8\ support channels provisioning support contact your exotel csm or email hello\@exotel com technical support visit support exotel com share the following account sid trunk transport type (tcp/tls/fqdn) sample call sids sip trace logs (from sngrep/wireshark)