SIP Trunking

Communications & CX / Unified Communications

SIP Trunking

SIP-based voice trunking — the modern equivalent of PRI lines. Connects your PBX or UC platform to the public phone network over IP. Cheaper than PRI, scales by the channel, and supports advanced routing, failover, and global numbering.

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68
providers vetted

Global
number coverage available

3–4
shortlist candidates

$0
cost for our guidance

When should you be evaluating SIP Trunking?

Rubber Duck has worked extensively with our SIP Trunking providers to understand where they have seen the most success and the biggest ROI for clients adopting the solution. Here is what the data reflects.

  • You have an existing PBX (on-prem or cloud) and need PSTN connectivity for outbound and inbound calls
  • You’re replacing PRI/T1 lines with cheaper, more flexible SIP
  • You need numbers in multiple countries served from a single platform
  • You want carrier diversity — multiple SIP providers for failover
  • You’re powering Microsoft Teams Direct Routing or another UCaaS that requires bring-your-own-trunk

Providers delivering SIP trunking

Every provider below has been vetted for call quality, interoperability, and post-sale accountability. Want the 3–4 best fits for your environment? That’s one conversation.

Browse the full directory → · Or get matched in 10 minutes →

Products & platforms

Deep-dives on the specific platforms our partners deliver in this category.

Product deep-dives for this category are on their way. In the meantime, we keep current datasheets and comparison matrices on file — ask an advisor.

Proof in the field

Shortlist the right SIP trunking provider in one conversation

68 vetted options, a shortlist of 3–4 that fit, zero cost for the guidance. Bring your questions.

Start a Communications Assessment Schedule a Consultation

The Process

How your SIP Trunking engagement runs

The same disciplined path every time — so you always know what happens next and who is accountable for it.

1

Day 1

Assess

We map your environment, contracts, and goals. No pitch — an honest read on where you stand and what it should cost.

2

Week 1

Shortlist

You get 3–4 fits from 475 vetted providers, with the reasoning attached — capabilities, pricing leverage, trade-offs.

3

Weeks 2–3

Evaluate

We run the demos, reference checks, and side-by-side pricing benchmarks so your team doesn't have to.

4

Weeks 3–4

Negotiate

Terms, SLAs, and pricing negotiated with portfolio-level leverage — anchored to real market rates, not list price.

5

Ongoing

Manage

We oversee implementation and stay your escalation point for the life of the service, through every renewal.

Typical timeline for mid-market engagements. Complex builds — colocation, dark fiber, custom AI deployments — carry longer evaluation and delivery windows, and we set that expectation on day one.

The Economics

Why source SIP Trunking through Rubber Duck

No retainers, no hourly billing, no markup on your contract. Here is how that works:

Same or better pricing

Your contract is signed directly with the provider at rates we benchmark against comparable deals — you pay the same or less than going direct.

$0 advisory fee

Providers fund our advisory through their partner programs, and every provider compensates us the same way — so recommendations are based on fit, never commission.

One escalation point

After go-live we stay accountable: implementation oversight, billing disputes, outage escalations, and renewal strategy all route through your advisor.

Common Questions

What buyers ask before their first call

Does the guidance really cost nothing?

Yes. Our advisory is supplier-funded: providers pay us through the same partner programs they fund for all technology advisors, and every provider compensates us the same way. You pay the provider directly, at rates we benchmark — the same or less than going direct.

How are you different from a reseller or an MSP?

We don't carry inventory, quotas, or a house brand to protect. A reseller earns more when you buy what they stock; we earn the same regardless of which vetted provider you choose — so the recommendation is driven by fit. Where a managed service is the right answer, we source and oversee it rather than sell you our own.

Do we keep a direct relationship with the provider?

Yes. Your contract, billing, and SLAs sit directly with the provider you select. We sit on your side of that relationship — running the evaluation and negotiation up front, then acting as your escalation point after go-live.

What if we're already under contract?

That's the most common starting point. We benchmark your current rates now, flag billing errors worth disputing immediately, and build the renegotiation plan around your renewal window — including co-terming services so future decisions happen on your schedule, not the vendors'.

How fast do we get to a shortlist?

For most categories you'll have a reasoned shortlist of three or four providers within a week of the first assessment call. Complex infrastructure — colocation, dark fiber, large contact-center builds — takes longer, and we tell you that up front.