What is Zentrunk?
Zentrunk is Plivo’s cloud-based SIP trunking service that connects IP PBX systems to PSTN and mobile networks.What SIP methods does Zentrunk support?
Supported: ACK, BYE, CANCEL, INVITE, OPTIONS, UPDATE Not supported: INFO, MESSAGE, NOTIFY, PRACK, PUBLISH, REFER, REGISTER, SUBSCRIBEWhat codecs and encryption are supported?
- Codecs: PCMA, PCMU
- Encryption: TLS for signaling, SRTP for media
- DTMF: RFC-2833 format
Are call recording and T.38 fax supported?
No. Call recording and T.38 fax are not supported features.Where are Zentrunk’s data centers located?
| Region | Location |
|---|---|
| North America | North California, Virginia |
| Europe | Frankfurt |
| South America | São Paulo |
| Asia Pacific | Singapore, Sydney, Mumbai |
What are the default CPS limits?
| Level | Default | Description |
|---|---|---|
| Account-level | 2 CPS | Total calls per second across all trunks |
| Trunk-level | Configurable | Allocated per trunk from account pool |
Can CPS limits be increased?
Yes. Contact Plivo Sales to increase your CPS allocation.How does call queuing work with CPS?
- Calls exceeding trunk CPS fail immediately
- Calls exceeding account CPS queue for processing
What IP addresses must be whitelisted?
| Region | CIDR Blocks |
|---|---|
| North California | 13.52.9.0/25, 216.120.187.128/26 |
| Virginia | 18.214.109.128/25, 18.215.142.0/26, 204.89.148.128/26 |
| Frankfurt | 3.120.121.128/26 |
| São Paulo | 18.228.70.64/26 |
| Sydney | 13.238.202.192/26 |
| Singapore/Mumbai | Check Zentrunk documentation |
What authentication methods are available?
- IP Access Control Lists
- Username/password credentials
- Both combined
What are the resource limits?
| Resource | Limit |
|---|---|
| Trunks per account | 100 (recommended) |
| IP ACLs per account | Unlimited |
| Concurrent calls | Unlimited (elastic scaling) |
How do SIP OPTIONS pings work?
- Send pings to the outbound trunk URI only
- Maximum frequency: 1 ping per 10-15 seconds
- Higher frequency may trigger blocking
Why must I use Plivo numbers as caller ID?
Plivo numbers are required as caller ID for all outbound calls. Using non-Plivo numbers results in anunknown_caller_id hangup.
Options:
- Rent numbers through the Plivo console
- Port existing numbers to Plivo
- Contact Plivo Support for special cases
Which countries guarantee domestic caller ID?
Plivo guarantees domestic CLI in: US, Canada, UK, Australia, Italy, Peru, and France (beta).Why are premium numbers blocked?
Zentrunk blocks calls to premium-rate numbers to prevent toll fraud (IRSF - International Revenue Share Fraud).How can I call premium numbers?
- Contact Plivo Support
- Provide use case details
- Wait for validation (48+ hours)
How does Zentrunk pricing work?
Call rates vary by originating country, not just destination. For example, calls to Germany from Europe cost less than from outside Europe. Check Zentrunk Pricing for current rates.What are abandoned and short duration call charges?
| Type | Threshold | Surcharge |
|---|---|---|
| Abandoned calls (0 seconds) | > 20% monthly | $0.005 per excess call |
| Short calls (≤6 seconds) | > 20% monthly | $0.0025 per excess call |
How do I access call detail records?
- Navigate to Zentrunk > Logs in the console
- Filter CDRs as needed
- Click Export to download
What debug information is available?
- Call details (basic info)
- Call stats (origination, termination, trunk info)
- SIP logs (PCAP, last response, codec)
What does unknown_caller_id hangup mean?
A non-Plivo number was used as caller ID. Use a Plivo number or port your number.
What does destination_country_barred mean?
Geo permissions are not enabled for that country. Enable the destination country in your console.
What CLI prefixes are blocked in Australia?
Per ACMA regulations:+6113, +611300, +611800, +611900
What traffic is prohibited in China?
- Gambling, financial services, cryptocurrency
- Marketing/spam calls
- Fraudulent calls
- Politically sensitive content
What are China’s outbound calling requirements?
- Cannot use Chinese caller IDs
- Maintain average call duration over 3 minutes
- Avoid high unanswered rates
- Don’t use toll-free numbers
What are China’s inbound calling requirements?
Chinese numbers can only receive calls from within China.What systems work with Zentrunk?
- IP PBX: FreeSWITCH, Asterisk, FreePBX, 3CX, FusionPBX
- Session Border Controllers
- Softphones: Zoiper, X-Lite/Bria
How do I set up a softphone with Zentrunk?
- Create an account in your softphone
- Uncheck “register with domain and receive calls”
- Configure with your Zentrunk SIP URI
How do I map numbers to inbound trunks via API?
Use the Account Phone Number API with theinbound trunk_id parameter.