BYOC-P or BYOP-P call processing

Publisher

Zoom Communications

URL

https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0079205

Published

unknown

Updated

unknown

Accessed

2026-09-24

HTTP status

200

License

Zoom proprietary; all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• Route groups enabled for BYOC-P are for third-party PSTN interoperability and do not support a private numbering plan. in context
• If no interoperability with a legacy PBX is required, only BYOC-P needs to be enabled at the SBC and route group level. in context
• BYOP-P calls may use localized or E.164 numbers up to 24 digits, whereas BYOC-P calls use E.164 in the Request-URI user part. in context
• On outbound calls Zoom populates calling name and number in the Contact and P-Asserted-Identity headers and does not use Remote-Party-ID; on inbound calls it accepts calling identity in RPID as well as PAI and From. in context
• Zoom supports up to 47 bytes for caller names in SIP fields on BYOC-P/BYOP-P calls. in context
• If Unified CM sends delayed-offer INVITEs toward the SBC, the SBC (or an MTP in Unified CM) must convert them to early offer before they reach Zoom. inferred in context
• Zoom requires the SBC to send INVITEs with an SDP offer (early offer), and Zoom's own outbound INVITEs also carry the SDP offer. in context
• Zoom sends a call to a backup SBC when the primary is marked down by OPTIONS keepalive failure or answers Zoom's INVITE with 403, 408, 480, 488, 500, 502, 503, 504 or 606; when a route group is exhausted it moves to SBCs in the backup region or data centre. in context
• For a hybrid deployment with a legacy PBX, Zoom says to enable the SBC for both BYOC-P and BYOP-P, and to point Zoom external contacts and routing rules at a SIP Group containing BYOP-P-enabled route groups so the private dial plan extends to Zoom. in context
• On calls into Zoom, Zoom supports PRACK for early media but does not use SIP preconditions or the Replaces header. in context
• Zoom marks an SBC failed after four consecutive OPTIONS keepalive failures, which takes 90 to 120 seconds in total to detect. in context
• Provider Exchange by itself does not give Unified CM extension-dialling interop with Zoom Phone; that needs a premises SBC with BYOP-P. inferred in context
• Zoom's BYOC-P/BYOP-P call processing article states that on outbound calls from Zoom, Zoom supports PRACK for reliable 1xx responses but does not use REFER or SUBSCRIBE/NOTIFY. disputed in context
• URI dialling is not supported on BYOC-P/BYOP-P trunks; calls into Zoom must carry E.164 SIP URIs, or digit strings for BYOP-P. in context
• Zoom supports caller names up to 47 bytes on BYOC-P calls which is 47 ASCII characters but fewer accented or CJK characters. in context
• Zoom's preferred codec order for BYOC-P and BYOP-P calls is Opus first then G.722 then G.711 A-law or u-law then G.729. in context
• Zoom reroutes a BYOC-P call when the SBC is down or answers with SIP 403 408 480 488 500 502 503 504 or 606. in context
• BYOC-P failover tries alternate SBCs in the same route group first then backup route groups then alternate Zoom data centers. in context
• For a hybrid environment Zoom requires both BYOC-P and BYOP-P to be enabled at the SBC level whereas a cloud-only deployment needs only BYOC-P. in context
• For inbound BYOC calls the user part of the Request-URI sent to Zoom should contain the E.164 number while BYOP calls may use private extension dialing. in context
• Zoom BYOC-P accepts only SIP URIs; Tel URIs and secure SIP (SIPS) URIs are not supported. in context
• Zoom sends SIP OPTIONS to a BYOC-P SBC every 30 seconds and marks it down after 4 consecutive failures which takes 90 to 120 seconds. in context
• A BYOC-P SBC marked down returns to service after three consecutive successful OPTIONS exchanges which typically takes 60 to 90 seconds. in context
• On calls from Zoom to the SBC the Request-URI is E.164 for BYOC-P while BYOP-P allows localized or E.164 format up to 24 digits. in context
• Zoom uses a 30-minute session expiration timer on BYOC-P calls and accepts a minimum session expiration of 90 seconds. in context
• Zoom premises peering prefers codecs in the order Opus, G.722, G.711 A-law/mu-law, then G.729. in context
• 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. in context
• For incoming calls, Zoom can take caller identity from Remote-Party-ID in addition to P-Asserted-Identity and From. in context
• Inbound INVITEs from the SBC to Zoom must carry an SDP offer (early offer); otherwise Zoom answers 488 Not Acceptable Here. in context
• 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. in context
• 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. in context
• On calls from Zoom, calling name and number are populated in both the Contact and P-Asserted-Identity headers. in context
• 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. in context
• 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 in context
• On BYOC-P/BYOP-P trunks Zoom supports PRACK for reliable 1xx responses but does not use REFER or SUBSCRIBE/NOTIFY. in context
• Zoom lists OPUS, G.722, G.711 A-law/mu-law and G.729 as preferred codecs for BYOC-P/BYOP-P SBCs. in context
• For BYOC-P route groups, calling and called numbers must be in E.164 format; BYOP-P allows localized or E.164 numbers up to 24 digits. in context
• Inbound calls from the SBC to Zoom on BYOC-P/BYOP-P must send an INVITE containing the SDP offer (early offer). in context
• Zoom sends SIP OPTIONS keepalives to a BYOC-P SBC every 30 seconds and marks the trunk down after four consecutive failed responses, within 90-120 seconds. in context
• Zoom reroutes a BYOC-P call to a backup SBC when the SBC returns 403, 408, 480, 488, 500, 502, 503, 504 or 606. in context
• Because BYOC-P is TLS-only and health is judged by OPTIONS responses, an SBC TLS or certificate failure would likely surface as failed keepalives and a trunk marked down rather than as a distinct error. inferred in context

Cite this source record

APA

WarmTransfer. (2026, September 24). BYOC-P or BYOP-P call processing. WarmTransfer. https://warmtransfer.net/knowledge/sources/zoom-kb0079205-byoc-p-call-processing

BibTeX

@misc{warmtransfer-zoom-kb0079205-byoc-p-call-processing,
  title  = {BYOC-P or BYOP-P call processing},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/zoom-kb0079205-byoc-p-call-processing},
  note   = {Zoom Communications, accessed 2026-09-24}
}