Zoom Phone routing and PSTN connectivity

See also

Sources

1. 1
   BYOC-C lets a business connect one or more carriers to Zoom Phone data centers through cloud peering without any on-premises hardware.

   Bring Your Own Carrier - Cloud Peering (BYOC-C) | Zoom Technical Library · Bring Your Own Carrier - Cloud Peering (BYOC-C), Overview · Checked 2026-09-24
2. 2
   BYOC-C customers pick an approved provider from Zoom's Provider Exchange and contract and pay that provider separately, in addition to their Zoom Phone bill.

   Bring Your Own Carrier - Cloud Peering (BYOC-C) | Zoom Technical Library · Provider Exchange section; billing statement · Checked 2026-09-24
3. 3
   A cloud peering provider can be combined with the Zoom Phone Native model to reach PSTN services that Native alone does not offer.

   Bring Your Own Carrier - Cloud Peering (BYOC-C) | Zoom Technical Library · International coverage section · Checked 2026-09-24
4. 4
   BYOC-P SBCs, route groups, SIP groups and routing rules are managed in the Zoom admin portal under Product configuration > Numbers > BYOC Configuration.

   BYOC-P or BYOP-P configuration guide · Add a Session Border Controller (SBC), navigation step · Checked 2026-09-24
5. 5
   BYOC-P configuration proceeds in order: add the SBC, create route groups containing SBCs, link route groups to SIP groups, assign SIP groups to phone numbers, then add routing rules where custom digit routing is needed.

   BYOC-P or BYOP-P configuration guide · Sections Add a Session Border Controller; How to manage Route Groups; SIP Groups; Add a Routing Rule · Checked 2026-09-24
6. 6
   International and special-destination calling on BYOC must be enabled at account billing level (Countries/Regions, BYOC tab), requires an enterprise account, and users additionally need it allowed via the International Calling policy.

   Enabling international and special destination calls for BYOC · Prerequisites; How to enable (Plans and Billing / Account Management); user-level policy section · Checked 2026-09-24
7. 7
   Zoom Phone endpoints always initiate connectivity into Zoom data centers, but BYOC-P SBCs require bi-directional connectivity with Zoom.

   Bring Your Own Carrier - Premises Peering (BYOC-P) | Zoom Technical Library · Bring Your Own Carrier - Premises Peering (BYOC-P), Note · Checked 2026-09-24
8. 8
   BYOC-P customers must provide and maintain their own supported SBC to peer with Zoom Phone data centers.

   Bring Your Own Carrier - Premises Peering (BYOC-P) | Zoom Technical Library · Bring Your Own Carrier - Premises Peering (BYOC-P), Overview · Checked 2026-09-24
9. 9
   In BYOC-P a business connects its own on-premises SBC, itself connected to a carrier, to Zoom Phone's cloud PBX, while keeping cloud PBX features such as call queues, auto receptionists and number assignment.

   Bring Your Own Carrier - Premises Peering (BYOC-P) | Zoom Technical Library · Bring Your Own Carrier - Premises Peering (BYOC-P), Overview · Checked 2026-09-24
10. 10
    With internet (OTT) BYOC-P connectivity, calls automatically reroute to an alternate Zoom data center within the region when necessary.

    BYOC-P or BYOP-P deployment and connectivity options · Connectivity options > Internet (OTT) · Checked 2026-09-24
11. 11
    When BYOC-P peering runs over the internet (OTT), TLS 1.2 and SRTP secure the communication between the customer SBC and Zoom.

    BYOC-P or BYOP-P deployment and connectivity options · Connectivity options > Internet (OTT) · Checked 2026-09-24
12. 12
    BYOC-P over private circuits uses dedicated SIP trunks to one or more Zoom data centers in a region and requires BGP peering with public ASNs and public IP addresses, with the customer procuring the circuits from a carrier.

    BYOC-P or BYOP-P deployment and connectivity options · Connectivity options > Private Circuits · Checked 2026-09-24
13. 13
    BYOC-P and BYOP-P establish SIP trunks from Zoom to customer SBCs within chosen regions, and multiple regional connections with distinct IPs are supported.

    BYOC-P or BYOP-P deployment and connectivity options · Deployment options section · Checked 2026-09-24
14. 14
    For BYOC-P, service areas are determined by the customer's chosen telephony service provider rather than by Zoom's native service territories.

    Bring Your Own Carrier - Premises Peering (BYOC-P) | Zoom Technical Library · Bring Your Own Carrier - Premises Peering (BYOC-P), highlighted statement on service areas · Checked 2026-09-24
15. 15
    Porting existing BYOC numbers to Zoom native service needs a hand-signed Letter of Agency, a completed BYOC Porting Sheet, a toll-free LOA for toll-free numbers and a telephone bill from the last three months, submitted through Zoom Support.

    Requesting a BYOC number port · Prerequisites; required documents; How to request a BYOC number port · Checked 2026-09-24
16. 16
    Numbers provisioned through a Provider Exchange carrier appear under Number Management > Phone Numbers on the Cloud Peering tab, where they can be assigned to users.

    Setting up Phone provider exchange · Viewing provisioned phone numbers · Checked 2026-09-24
17. 17
    Zoom premises peering prefers codecs in the order Opus, G.722, G.711 A-law/mu-law, then G.729.

    BYOC-P or BYOP-P call processing · Audio codecs · Checked 2026-09-24
18. 18
    Zoom implements the E.164 numbering plan for its global dial plan, and all BYOC-P SIP trunks must send and receive E.164 dialing strings.

    Managing dial plan functionality · Numbering standards / E.164 · Checked 2026-09-24
19. 19
    Zoom's dial plan checks account-level external contacts first, then routing rules with site-specific rules before account-wide rules, and stops at the first match.

    Managing dial plan functionality · Dial plan order of operations · Checked 2026-09-24
20. 20
    For BYOC numbers, an admin can choose which carrier (Zoom or the BYOC carrier) handles emergency calls, and when the BYOC carrier is used the address given to the PSAP comes from the BYOC carrier's records.

    Routing emergency calls · BYOC carrier routing section · Checked 2026-09-24
21. 21
    When emergency calls go to an internal safety response team call queue, that queue's business hours must be 24 hours, 7 days a week and its overflow must be Disconnect or Forward to Call Queue.

    Routing emergency calls · Internal Safety Response Team; call queue requirements · Checked 2026-09-24
22. 22
    External contacts whose routing path is set to a SIP group are treated as BYOP calls, so BYOC-only deployments should use PSTN routing or leave that field blank.

    Managing dial plan functionality · External contacts configuration / routing path · Checked 2026-09-24
23. 23
    Zoom fails over to an alternate SBC when the primary is down on OPTIONS keepalive or answers an INVITE with 403, 408, 480, 488, 500, 502, 503, 504 or 606.

    BYOC-P or BYOP-P call processing · Failover routing · Checked 2026-09-24
24. 24
    BYOC-P signalling uses TCP/5061 and media uses UDP/10000-64000, a range that differs from standard Zoom client port ranges.

    BYOC-P or BYOP-P infrastructure requirements · Firewall requirements · Checked 2026-09-24
25. 25
    For incoming calls, Zoom can take caller identity from Remote-Party-ID in addition to P-Asserted-Identity and From.

    BYOC-P or BYOP-P call processing · Incoming calls to Zoom, caller identity paragraph · Checked 2026-09-24
26. 26
    Inbound INVITEs from the SBC to Zoom must carry an SDP offer (early offer); otherwise Zoom answers 488 Not Acceptable Here.

    BYOC-P or BYOP-P call processing · Incoming calls to Zoom · Checked 2026-09-24
27. 27
    The Zoom Technical Library states that Zoom Phone Native offers service within 48 countries through 17 global data centers.disputed

    Zoom Phone Native | Zoom Technical Library · Zoom Phone Native, coverage heading 'Zoom Phone Native offers service within 48 countries through 17 global data centers' · Checked 2026-09-24
28. 28
    Zoom's Phone global-coverage product page states local telephony service across 50+ countries, with toll-free and other service numbers in up to 56 countries.disputed

    VoIP International Calls: Coverage In 45+ Countries | Zoom · Page body, coverage summary paragraph · Checked 2026-09-24
29. 29
    Because ZPLS sends survivability PSTN calls through the customer SBC and requires a BYOC ELIN, a site served only by Zoom Phone Native numbers is unlikely to have PSTN egress during a survivability event without adding BYOC-P.inferred

    PSTN Integration Considerations | Zoom Technical Library · PSTN Routing Considerations; ELIN Considerations · Checked 2026-09-24
30. 30
    Zoom Phone Native uses Zoom's cloud and underlying carriers for PSTN delivery and needs no on-premises SBC or SIP trunk; an internet connection, a Zoom app or device and a supported license suffice.

    Zoom Phone Native | Zoom Technical Library · Zoom Phone Native, opening section · Checked 2026-09-24
31. 31
    URI dialing is not supported on BYOC-P/BYOP-P trunks, and for incoming calls Zoom accepts only SIP URIs with E.164 numbers or digit strings; Tel URIs and secure SIP URIs are not supported.

    BYOC-P or BYOP-P call processing · Outbound calls from Zoom; Incoming calls to Zoom · Checked 2026-09-24
32. 32
    Outbound PSTN routing follows the calling number's type: Zoom Native numbers route through Zoom's PSTN service and BYOC-P numbers route through the premises SIP trunk.

    Managing dial plan functionality · Call routing by number type · Checked 2026-09-24
33. 33
    Zoom sends a SIP OPTIONS request to each configured SBC every 30 seconds and declares the trunk down after four consecutive failed keepalives, which takes 90 to 120 seconds.

    BYOC-P or BYOP-P call processing · Options Keepalive · Checked 2026-09-24
34. 34
    On calls from Zoom, calling name and number are populated in both the Contact and P-Asserted-Identity headers.

    BYOC-P or BYOP-P call processing · Outbound calls from Zoom, caller identity paragraph · Checked 2026-09-24
35. 35
    On calls from Zoom to the SBC, the Request-URI carries the destination in E.164 for BYOC-P, while BYOP-P calls may be localized or E.164 with a maximum of 24 digits.

    BYOC-P or BYOP-P call processing · Outbound calls from Zoom · Checked 2026-09-24
36. 36
    In June 2022 Zoom announced Provider Exchange as an enhancement to its BYOC Cloud Peering partner program, available in over 70 countries.

    Zoom Phone Provider Exchange Now Available in Over 70 Countries · Blog post body, opening paragraphs · Checked 2026-09-24
37. 37
    The Zoom Technical Library states the Provider Exchange network collectively covers over 90 countries with PSTN connectivity.

    Bring Your Own Carrier - Cloud Peering (BYOC-C) | Zoom Technical Library · Provider Exchange Network section · Checked 2026-09-24
38. 38
    An account owner or admin connects a Provider Exchange carrier from Number Management > Provider Exchange by clicking Connect and signing an authorization with the Zoom account name, or via the provider's marketplace listing and portal.

    Setting up Phone provider exchange · How to connect to a provider (web portal and marketplace methods) · Checked 2026-09-24
39. 39
    Read together, Zoom's KB articles indicate Zoom does not originate REFER toward a BYOC-P SBC but can accept REFER from an SBC when the per-SBC REFER option is enabled, so transfers are not handed off to the carrier by Zoom-initiated REFER.inferred

    BYOC-P or BYOP-P call processing · Outbound calls from Zoom; read with KB0083637 Add a Session Border Controller (SBC) · Checked 2026-09-24
40. 40
    Zoom's BYOC-P infrastructure article organises peering IPs by regional clusters including US01, UK01, EU01/EU02, CA01 and SA01.

    BYOC-P or BYOP-P infrastructure requirements · Network infrastructure / IP address tables · Checked 2026-09-24
41. 41
    Creating a BYOC route group may take up to 48 hours to complete.

    BYOC-P or BYOP-P configuration guide · How to manage Route Groups · Checked 2026-09-24
42. 42
    When a route group is set to BYOC-P, both calling and called numbers must be formatted in E.164.

    BYOC-P or BYOP-P configuration guide · Add a Route Group · Checked 2026-09-24
43. 43
    Zoom routing rules are admin-defined regular expressions that route digits or digit strings to specific destinations and can modify the called number.

    BYOC-P or BYOP-P configuration guide · Add a Routing Rule · Checked 2026-09-24
44. 44
    Zoom routing rules can translate the called number before the route is selected, and Zoom describes them as the most flexible routing method.

    Managing dial plan functionality · Routing Rules · Checked 2026-09-24
45. 45
    The BYOC-P SBC certificate must carry the SBC FQDN in the CN or SAN, come from an approved CA with Server Authentication key usage, and be presented with its full chain including intermediates.

    BYOC-P or BYOP-P infrastructure requirements · Certificates section · Checked 2026-09-24
46. 46
    Zoom maintains a list of certified SBC vendors and models that have undergone interoperability testing for BYOC-P/BYOP-P.

    BYOC-P or BYOP-P infrastructure requirements · SBC certification paragraph · Checked 2026-09-24
47. 47
    Zoom requires BYOC-P SBCs to support SIP (RFC 3261), DTMF per RFC 2833, topology hiding (RFC 5853) and SIP Early Offer on INVITEs sent to Zoom.

    BYOC-P or BYOP-P infrastructure requirements · General SBC Requirements · Checked 2026-09-24
48. 48
    The BYOC SBC settings include an 'Allow REFER support to transfer calls' option (Zoom Phone only) that makes Zoom accept SIP REFER messages from that SBC.

    BYOC-P or BYOP-P configuration guide · Add a Session Border Controller (SBC), 'Allow REFER support to transfer calls' option · Checked 2026-09-24
49. 49
    Zoom's BYOC-P infrastructure requirements list Opus, G.722, G.711 mu-law, G.711 A-law and G.729 as required SBC codecs.

    BYOC-P or BYOP-P infrastructure requirements · General SBC Requirements, codecs · Checked 2026-09-24
50. 50
    The SBC record has an optional Survivability IP Address field that applies only to customers with Zoom Phone Local Survivability enabled.

    BYOC-P or BYOP-P configuration guide · Add a Session Border Controller (SBC), 'Survivability IP Address (Optional)' · Checked 2026-09-24
51. 51
    A per-SBC BYOC setting (Zoom Phone only) enables negotiation of T.38 for fax calls.

    BYOC-P or BYOP-P configuration guide · Add a Session Border Controller (SBC), 'Use T.38 protocol for faxing' · Checked 2026-09-24
52. 52
    When adding a BYOC-P SBC in Zoom, the signalling protocol is TLS only and cannot be modified.

    BYOC-P or BYOP-P configuration guide · Add a Session Border Controller (SBC), Protocol field · Checked 2026-09-24
53. 53
    Routing rules that direct calls to another site's internal extension must prepend that site's site code to the extension.

    Managing dial plan functionality · Site codes / internal routing · Checked 2026-09-24
54. 54
    Zoom describes Zoom Phone PSTN connectivity as three primary service offerings: Zoom Phone Native, BYOC Cloud Peering (BYOC-C) and BYOC Premises Peering (BYOC-P).

    Overview | Zoom Technical Library · Overview (Zoom Phone Bluepaper), service offerings paragraph · Checked 2026-09-24
55. 55
    Zoom's BYOC-P infrastructure presents DigiCert-issued certificates.

    BYOC-P or BYOP-P infrastructure requirements · Certificates section · Checked 2026-09-24
56. 56
    On BYOC-P/BYOP-P trunks Zoom supports PRACK for reliable 1xx responses but does not use REFER or SUBSCRIBE/NOTIFY.

    BYOC-P or BYOP-P call processing · Outbound calls from Zoom · Checked 2026-09-24
57. 57
    During survivability, emergency calls present a single site-level ELIN, which must be a BYOC number terminating on the failover SBC's PSTN trunk, and ZPLS routes emergency callbacks to the original caller for up to 2 hours.

    PSTN Integration Considerations | Zoom Technical Library · ELIN Considerations · Checked 2026-09-24
58. 58
    During a survivability event, outbound calls from the ZPLS module go to the SBC and its PSTN SIP trunk and present the user's BYOC number as calling party.

    PSTN Integration Considerations | Zoom Technical Library · PSTN Routing Considerations · Checked 2026-09-24
59. 59
    Any SBC certified for Zoom Phone BYOC can be used with the Zoom Phone Local Survivability module, and existing BYOC customers do not need a separate SBC for survivability.

    PSTN Integration Considerations | Zoom Technical Library · SBC Integration Considerations · Checked 2026-09-24
60. 60
    With ZPLS, the customer SBC must route inbound PSTN calls to the primary and secondary Zoom data center SIP zones first, with the ZPLS module as the tertiary choice used only during survivability events.

    PSTN Integration Considerations | Zoom Technical Library · SBC Integration Considerations · Checked 2026-09-24

Documents

Cite this page

WarmTransfer. (2026, September 24). Zoom Phone routing and PSTN connectivity. WarmTransfer. https://warmtransfer.net/knowledge/zoom-phone-routing

@misc{warmtransfer-zoom-phone-routing,
  title  = {Zoom Phone routing and PSTN connectivity},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/zoom-phone-routing},
  note   = {Verified 2026-09-24}
}