VoIP Routes Explained: Wholesale Route Types, Quality Metrics and How to Choose
VoIP routes are the paths a wholesale provider uses to carry your calls over IP to the network that serves each number dialled, priced per minute by destination. Buying wholesale routes is not like buying a phone line — you are buying network-level capacity, and wholesale routes differ in what they carry, what they drop, and how honestly they report on themselves.
By Vedant Vhanyalkar
What are wholesale VoIP routes?
A wholesale VoIP route is a bulk voice termination pathway that carries traffic from one carrier network to another over IP, ending at the network that serves the number being dialled. Wholesale VoIP routes are infrastructure sold in bulk minutes, priced per destination, and bought by carriers, ITSPs, and high-volume voice operations originating the traffic rather than by end users making individual calls.
Wholesale vs retail VoIP routing
Retail VoIP is a product end users consume: a number, an app, a desk phone, a monthly seat with features like voicemail and call forwarding. A wholesale VoIP route is network infrastructure underneath retail products. The distinction matters because the two are bought on completely different criteria and serve different buyers. A retail VoIP buyer evaluates features, user experience, and per-seat pricing. A wholesale route buyer evaluates answer rates, post-dial delay, CLI delivery consistency, and per-minute pricing across destination prefixes.
Wholesale VoIP routing operates at carrier scale: routes are provisioned for thousands of concurrent calls, rated per minute per destination prefix, and purchased by organizations that need to terminate voice traffic at the network layer rather than provision individual user accounts. See MCC Wholesale Voice for carrier-grade termination services.
If you are evaluating a business phone system rather than wholesale carrier capacity, see UCaaS vs VoIP instead — this page is about the wholesale layer.
Who buys routes
Four groups, with different requirements. Carriers and ITSPs buying termination capacity for destinations they do not serve directly. Contact centres and outbound dialer operations sending concentrated volume to specific countries. Resellers building voice products on someone else's infrastructure. And platforms — CPaaS, CRM, dialer software — that need voice underneath a product they sell as something else.
How they are priced
Per minute, per destination prefix, quoted on a rate deck that is reissued frequently because the underlying costs move. Anyone quoting you a single figure for "VoIP routes" is quoting an average of things that are not comparable: fixed-line differs from mobile, one mobile operator differs from another in the same country, and a direct path differs from a transited one.
Ask for the deck against the destinations you actually send, with the billing increment stated. On dialer traffic with short average duration, 60/60 billing versus per-second billing changes the effective cost more than a difference in the headline rate does.
CLI, Non-CLI and CC routes — the three types
CLI routes
A CLI route delivers the calling number to the terminating network so it can be presented to the called party. That single property drives most of the price difference in wholesale voice, because it drives answer rate: a handset showing a number gets answered far more often than one showing "unknown" or nothing at all.
CLI is effectively mandatory for anything customer-facing. Outbound sales, contact centre callbacks, appointment reminders, verification calls, and anything in a regulated sector where the called party must be able to identify or return the call. It is also the precondition for call authentication frameworks — a call with no calling number gives STIR/SHAKEN nothing to sign, so authenticated delivery into markets that use it is not available on Non-CLI traffic.
Route type is only half of it. Whether your CLI actually arrives depends on every interconnect the call crosses. CLI vs NCLI routes covers the three separate reasons a number can go missing and how to diagnose which one you have.
Non-CLI routes
A Non-CLI route completes the call without presenting a calling number. It costs less, and there are legitimate reasons to use it: capacity and failover testing, transit between your own platforms, automated notifications where no return call is expected, and destinations where the terminating network will not accept foreign-origin CLI under any arrangement.
Where it goes wrong is when Non-CLI is bought as a cheaper substitute for CLI on customer-facing traffic. It is not a discount on the same product — it is a different product with materially lower answer rates and no return-call path. If the campaign depends on someone picking up, Non-CLI is usually more expensive per outcome despite the lower rate.
CC routes
CC routes are provisioned for call-centre and outbound dialer traffic. The distinguishing factor is the traffic profile rather than the signalling: very high call attempts per second, short average duration, heavy concentration on a small set of destinations, and a dialer rather than a human initiating each attempt.
That pattern stresses a network differently from general business voice, which is why it is quoted and provisioned separately. Sending dialer volume down a route built for business calling tends to produce congestion, and sometimes a suspended account. See CC Routes for how MCC handles this traffic type.
These three are not interchangeable. A provider quoting one rate for "routes" without asking about your traffic profile has not yet gathered enough information to quote.
Quality metrics every route buyer must track
The thresholds below are the ones commonly used in wholesale voice operations. They are working rules of thumb, not standards — the right number for your traffic depends on destination, route type and campaign, and should be established from your own baseline rather than adopted from any guide including this one.
ASR — Answer Seizure Ratio
The share of call attempts that connect. It is the headline metric and the easiest to distort, because several mechanisms raise it without producing a conversation. Sustained very low ASR usually indicates a genuinely broken path rather than a campaign problem; unusually high ASR on a cheap route is worth investigating rather than celebrating.
ACD — Average Call Duration
The average length of answered calls. Read it beside ASR, always. High ASR combined with very short ACD is the standard signature of calls being answered by something that is not a person, or of calls dropping immediately after connection. Either way the minutes bill and the outcome does not arrive.
PDD — Post-Dial Delay
The silence between dialling and ringing. Long PDD generally means the call is traversing more hops than the route description implies. It also destroys answer rate directly, because callers hang up during silence — so PDD both diagnoses a problem and causes one.
FAS — False Answer Supervision
FAS is a carrier signalling that a call was answered when it was not, so billing starts before anybody picked up. It is the reason ACD and ASR must be read together: FAS inflates ASR and depresses ACD simultaneously.
Providers frequently describe routes as FAS-free. Treat that as a claim to verify, not a specification. Compare answer timestamps in your own CDRs against billed duration, and look for clusters of very short billed calls that never produced a conversation. A provider willing to discuss how they detect and act on FAS is more useful than one asserting it never occurs.
Read them as a set
None of these four means anything alone, and every one of them can be presented favourably in isolation. Compute all four per destination from your own CDRs. Supplier reporting describes the supplier's leg of the call, which is a different question from the one you are asking.
How wholesale VoIP call termination works
1. Origination
Traffic leaves your platform — a softswitch, dialer, PBX or application — as SIP. Your session border controller authenticates the session and passes it to the provider's ingress. What you send here determines what is available downstream: the calling number, the codec offer, and the headers the next network will read. Anything omitted at this point cannot be recovered later.
2. Route selection and wholesale routing optimization
The wholesale provider's switch decides which upstream carrier receives the call, matching the dialled prefix against available paths. Wholesale routing optimization uses multiple selection strategies: least-cost routing (LCR) selects the cheapest option meeting a configured quality floor, ASR-weighted routing prioritizes paths with higher answer rates even at higher per-minute cost, and hybrid approaches balance cost against quality metrics computed in real-time from CDR data.
Wholesale route optimization is dynamic and continuous — the actual carrier chain under a stable contracted retail rate can change several times per month based on upstream route performance without any customer notification. Advanced wholesale platforms implement automatic failover when a primary route's ASR drops below threshold, real-time rerouting around detected carrier outages, and time-of-day routing to avoid congestion during peak hours on high-volume destinations.
For wholesale VoIP operations at scale, routing optimization extends beyond simple LCR: prefix-level quality tracking allows granular per-destination route selection, A/B testing of alternative carriers measures comparative performance before committing volume, and statistical analysis of CDR patterns identifies routes exhibiting degradation before wholesale customer complaints arrive. See MCC Wholesale Voice for wholesale routing optimized across these criteria.
3. Quality enforcement
Before and during the call, the platform applies whatever controls exist: capacity limits, codec negotiation, and monitoring that can withdraw a path performing below threshold. How much of this actually happens varies enormously between providers, and it is worth asking specifically rather than assuming — the difference between monitoring a route and acting on the monitoring is the difference between knowing about a problem and not having one.
4. Termination
The final carrier in the chain hands the call to the network serving the dialled number, which rings the handset. Everything the called party experiences — whether a number displays, how long the silence lasted, whether the call connects at all — was determined by decisions made at the previous three steps.
5. Billing and reconciliation
Minutes are rated per destination against the applicable deck and increment, then invoiced, usually with a settlement cycle short enough to limit credit exposure. Reconcile against your own CDRs every cycle rather than periodically. Discrepancies in wholesale voice are common, frequently explicable, and almost never surfaced by the party they favour.
How MCC provisions routes
MCC provisions wholesale voice by traffic profile rather than selling a single undifferentiated product. CLI and Non-CLI presentation are both available, with availability varying by destination — which is a property of the interconnect rather than a preference, so it is confirmed per destination rather than promised in general.
Call-centre and outbound dialer traffic is handled separately through CC Routes, provisioned against dialer type, CPS requirement and destination mix. General outbound voice at network scale runs through Wholesale Voice.
What is worth asking any provider, including this one: which destinations are direct and which are transited, what the CLI delivery rate is for your specific destinations, and what happens operationally when a route degrades. Those three answers tell you more than a rate deck does.
How to choose a route provider
- Get the FAS position in writing. Not the marketing claim — what they measure, how they detect it, and what remedy applies when your CDRs disagree with their invoice.
- Ask for an ASR floor with a defined consequence. An SLA quoting a number without stating what happens when it is missed is a target, not a commitment.
- Confirm authentication support per destination. Where STIR/SHAKEN or an equivalent framework applies, ask which attestation level your traffic will receive, on which destinations. "We support it" is not an answer to that question.
- Require rate deck transparency. Full prefix-level deck, billing increment stated, and notification terms for repricing. A deck that arrives as a summary is hiding granularity you will pay for.
- Establish what they own versus resell. Not because reselling is disqualifying — most coverage is assembled — but because it tells you how many hops sit between you and the terminating network, and therefore how much they can actually see when you report a fault.
- Test the NOC before you need it. Open a ticket during onboarding and time the response. Route quality is a support question as much as a network one, and the answer you get while you are still a prospect is the best case.
Frequently asked questions
Related reading: CLI vs NCLI routes, Wholesale voice termination, CC Routes.
Discuss route requirements for your traffic.
Routes are quoted against dialer type, CPS requirement, destination mix and CLI or Non-CLI presentation. Confirm coverage for your destinations.