Skyetel SIP Trunking: endpoint groups, registration and failover research

Choose the identity and routing object first

Skyetel documents IP authentication and credential registration as separate connection modes. IP authentication identifies outbound traffic by a configured public source address; an IP group then contains one or more public IP endpoints used for inbound routing. Registration creates a provider-generated username and password, and a number must be routed to that credential set for inbound delivery. Do not configure an IP group merely because a registered PBX also has a public address.

The provider recommends IP authentication and says registration does not receive the same SLA treatment. That is service-specific guidance, not proof that an allowlisted address prevents abuse or that a registered trunk is unusable. Preserve the selected mode, exact agreement and ownership of each IP group, endpoint, credential set and number as separate evidence.

Preserve the registration lane exactly

The current registration guide exposes reg.skyetel.com as an SRV target and two regional hosts for systems without SRV. It specifies UDP port 5060 only, one PBX per credential set, a minimum 100-second refresh and a 300-second automatic expiry. A 429 response after overly frequent registration is a policy signal, not evidence that the credentials are wrong.

The same guide caps each region at 100 concurrent outbound calls and 1 call per second, giving a documented maximum of 200 outbound channels and 2 CPS per credential across two regions. Channel occupancy and call-start rate remain different measures, and those registration limits do not become purchased or observed capacity. Inbound calls routed to credentials are distributed across the two registration regions; registration success remains separate from authorization, number assignment, routing and an answered call.

Separate IP-group routing from failure handling

An IP group can contain multiple endpoint addresses with priorities or round-robin routing. A custom endpoint port controls inbound delivery to that endpoint, while the provider says outbound IP-authenticated SIP must be sent to port 5060. A saved portal change, source-address authorization, endpoint reachability, correct number route and completed call are therefore separate states.

Number-level failover forwarding, endpoint priorities and the action taken after all available routes fail are different controls. The failover article distinguishes partial from total endpoint outages and warns that retrying through other regions can create extra lookup and relay charges, including double-billed usage for a relayed successful call. A retry policy does not preserve an established call, prove real-time regional health or remove the need to test the customer's intended failure boundary.

Keep call setup, media and fax evidence separate

Skyetel’s troubleshooting guidance says its signaling network is not necessarily in the audio path. IP-health indicators, a successful REGISTER transaction or an answered SIP dialog therefore do not prove bidirectional RTP, decoded audio or the far endpoint's experience. Capture the direction, PBX leg and provider destination before changing NAT, firewall or media policy.

The T.38 documentation distinguishes inbound behavior from a dedicated outbound fax route and sets expectations for heavy or critical fax use. Preserve ordinary voice, T.38 negotiation, image transfer, completion and retry as separate results. A provider-documented fax path does not guarantee that a particular document, destination or gateway combination succeeds.

Bind emergency identity and commercial evidence

The E911 guide requires service to be enabled on the number and the outbound caller ID to match that enabled 11-digit number exactly. It documents 933 as the automated test path and says E911 is not supported through the Short Duration prefix or High Cost servers. A portal toggle, stored address, caller-ID header, 933 response and live emergency-call outcome remain different evidence; follow the provider's current authorized test procedure and local policy rather than placing an unnecessary live emergency call.

The public platform lists numbers, messaging and APIs, but it does not establish inventory, port eligibility, codec policy, encryption outside the registration lane, current rates or a customer's entitlement. Obtain the applicable rate deck, agreement and escalation path before committing a migration date. No account, IP group, endpoint, credential, number route, registration, call, media path, fax, emergency record, price, availability or support response was tested for this review.

Treat Skyetel's 429 phrase as a documented provider interface rule

Skyetel documents 429 - Too Many Requests when REGISTER occurs more frequently than its 100-second minimum. The 429 conflict diagnostic preserves that local rule without replacing SIP 429's registered Provide Referrer Identity meaning or conflating registration cadence with CPS and channels.