On a shared port route, your calls use capacity from a pool that the seller's other customers also use; on a dedicated port route, a fixed number of channels (and often CPS) is reserved for you alone. Choosing between dedicated vs shared ports is a trade off: shared ports are cheaper and flexible, dedicated ports cost more but guarantee capacity and keep your quality separate from other people's traffic.
What "port" means here
In wholesale voice, a port is one channel: one call in progress. A route with 100 ports can carry 100 calls at the same time. The term comes from TDM, where each call used a physical timeslot, but it is still used for SIP routes. See channels and CPS for how to calculate what you need.
The two models compared
| Aspect | Shared ports | Dedicated ports |
|---|---|---|
| Capacity | Pool shared with other customers, not guaranteed at peak | Fixed number reserved for you |
| Pricing | Per minute only | Per minute plus a monthly fee per port, or a minimum commitment |
| Quality isolation | Other customers' traffic can affect the route | Your traffic runs on its own capacity, and often its own path |
| Flexibility | Scale up and down freely | Changes need notice; unused ports are still paid |
| Common for | Most wholesale routes, A-Z decks | Call centers, dialers, high volume destinations, Local CLI routes |
Why shared routes can degrade
A shared route is only as good as the traffic of everyone on it. If another customer starts sending a large dialer campaign, the pool can fill, and the destination operator may see a spike of short calls from the route. The result for you can be rejected calls at peak, lower ASR, or in the worst case the route being blocked or downgraded. This is one reason carriers ask every customer for their traffic type.
When dedicated ports make sense
- Your traffic is steady and large enough to fill the ports most of the day, so the monthly fee is spread over many minutes.
- You run a call center where agents sit idle if calls cannot be placed.
- Your traffic is dialer traffic and the seller only accepts it on separate capacity.
- You need a CLI setup specific to you, such as your own numbers on a Local CLI route.
Questions to ask the seller
- Is the route shared, and how much capacity is in the pool?
- For dedicated ports: how many channels and how many CPS, and are they billed monthly or by commitment?
- Is the dedicated route on its own path to the operator, or the same path with a reserved quota?
- How much notice to add or remove ports?
- What happens to calls above your dedicated capacity: rejected, or sent to shared capacity?
Calculating the cost
Compare the cost per minute including the port fee. If a dedicated port costs a fixed monthly amount and each port carries 5,000 minutes a month, divide the fee by 5,000 and add it to the per minute rate. If your ports are busy only a few hours a day, the effective rate goes up quickly. Check your usage with CDR monitoring before committing.
Request capacity that fits
Tell us your peak channels, CPS and whether you need dedicated capacity, and VoIPMatcher sources a VoIP termination route that fits. Request a voice route.
Frequently asked questions
What happens when all channels on a SIP trunk are busy?
Extra calls are rejected by the seller's switch, often with a SIP 503 Service Unavailable or a similar code. Your switch may then fail over to another route, which adds post-dial delay, or the call fails. On a shared route this can happen at peak even below your usual volume, because other customers use the same pool.
How many concurrent calls can a SIP trunk handle?
As many as the channels agreed with the seller. There is no fixed number per trunk: a wholesale SIP trunk can carry from a few channels to thousands, limited by the carrier's capacity, your bandwidth and the CPS limit. On shared routes the real limit can vary at peak; dedicated ports fix it for you.
Can I mix dedicated and shared capacity?
Yes. A common setup reserves dedicated ports for your steady base load and lets calls above it overflow to shared capacity or to another route. Ask the seller what happens to calls above your dedicated ports, whether they are rejected or sent to the shared pool, and at which rate they are billed.
Is a dedicated port the same as a dedicated route?
Not always. A dedicated port reserves capacity for you, but your calls may still travel the same path to the operator as everyone else's traffic, with a reserved quota. A dedicated route also has its own path. Ask which one you are buying, since only a separate path fully isolates your quality from other traffic.
Need a route?
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