# Session border controller selection and certification Canonical: https://warmtransfer.net/knowledge/sbc-selection Last verified: 2026-10-14 Webex Calling lists third-party session border controllers (SBCs) only for certificate-based Local Gateway trunks[^48]. Microsoft supports Phone System with Direct Routing only on certified SBC devices[^29], and Zoom states that Zoom Phone supports a limited set of SBCs from named manufacturers[^50]. ## Webex Calling Local Gateway A Webex Calling registration-based [Local Gateway](https://warmtransfer.net/knowledge/webex-calling-local-gateway) trunk supports only Cisco Unified Border Element (CUBE)[^44][^55]. Certificate-based trunks also support several third-party SBCs[^55]. Webex Calling lists its supported third-party SBCs only in the certificate-based trunk table (Table 4), so third-party SBCs can be used only on certificate-based Local Gateway trunks[^48]. A registration-based trunk supports up to 250 concurrent calls per trunk, and a certificate-based trunk supports more than 250[^43]. Cisco lists the Cisco Secure Routers C8231-G2, C8231-E-G2, C8235-G2, C8235-E-G2, C8355-G2 and C8375-E-G2 as Local Gateway platforms for both the registration-based and the certificate-based trunking model, with a minimum of Cisco IOS XE 26.2.1[^56]. For CUBE setup, see [Cisco Unified Border Element configuration and licensing](https://warmtransfer.net/knowledge/cube-configuration). The certificate-based Local Gateway table publishes a minimum version for each of its 11 third-party rows[^58]. | Third-party SBC | Minimum version | Claim | |---|---|---| | Oracle AP series, Oracle VME, Oracle SBC on Public Cloud | 9.3.0 |[^42] | | AudioCodes Mediant CE and VE, Mediant Appliances | 7.40A.250.440 |[^35] | | Ribbon SBC 5000 Series, SBC 7000, SBC SWe | 10.1 |[^46] | | Ribbon SBC SWe Edge | 11.0.2 |[^47] | | Ribbon SBC 1000, SBC 2000 | 11.0.1 |[^45] | | Ribbon 8000 with SBC SWe Edge | 25.0 |[^58] | | anynode SBC | 4.10 |[^34] | | Italtel NetMatch-S SBC | NetMatch-S-CI 5.8.0-20240111 |[^41] | 5 of the third-party rows in the certificate-based table carry a documented ICE interoperability limitation[^57]. Those rows are AudioCodes Mediant CE and VE, AudioCodes Mediant Appliances, Ribbon SBC 5000 Series and SBC 7000 and SBC SWe, Ribbon SBC SWe Edge, and Ribbon SBC 1000 and SBC 2000[^57]. Webex for Government supports only certificate-based trunking on CUBE[^54]. Registration-based trunking is not available for Webex for Government, and no third-party SBCs are supported[^54]. Every third-party SBC in the certificate-based table is marked 'Not supported' for Webex for Government[^40]. When a Webex Calling deployment uses a third-party SBC, Cisco states that it supports Webex Calling up to the edge deployment and the Webex Calling registered Cisco IP phones[^59]. Cisco states that it does not support the SBC itself and is not responsible for support cases between the customer and the SBC vendor[^37][^59]. ## Microsoft Teams Direct Routing Microsoft describes [Direct Routing](https://warmtransfer.net/knowledge/teams-direct-routing) as connecting a supported customer-provided SBC to Teams Phone[^14]. This is disputed: Microsoft's Direct Routing infrastructure requirements list a Microsoft-certified SBC as required[^26]. Microsoft supports Phone System with Direct Routing only when it is used with certified SBC devices[^29]. Microsoft reserves the right to reject support cases in which a non-certified device is connected to Phone System through Direct Routing[^22]. Microsoft certifies Direct Routing SBCs by having them tested in a third-party lab, and only devices that pass are certified[^9]. Microsoft states that it is not accepting new nominations for Direct Routing SBC certification until further notice[^20]. Certification is granted to specific SBC firmware versions[^8]. Higher firmware versions are supported as long as the major.minor version matches the documented one[^8]. In Microsoft's Direct Routing deployment overview, selecting a Microsoft-certified SBC is step 2[^25]. It comes after reviewing infrastructure and licensing requirements and before configuring networking, DNS, certificates and connectivity[^25]. For Direct Routing issues, the customer must contact the SBC vendor's support first[^31]. The SBC vendor escalates to Microsoft through internal channels if needed[^31]. To escalate an SBC-related issue to Microsoft support, the customer must present an SBC vendor investigation report that contains the vendor's ticket reference number[^32]. For diagnosis steps, see [Troubleshooting Teams Direct Routing](https://warmtransfer.net/knowledge/teams-direct-routing-troubleshooting). ### SBC requirements The SBC certificate must meet these requirements[^10]: - It must have the SBC FQDN in the CN or SAN[^10]. - It must be signed by a CA in the Microsoft Trusted Root Program[^10]. - It must include the Server Authentication EKU[^10]. Wildcard certificates that comply with RFC 2818 are supported[^10]. The SBC FQDN must belong to a verified Microsoft 365 domain in the tenant, and the default *.onmicrosoft.com domain cannot be used[^15]. Direct Routing supports SILK, G.711, G.722, G.729 and AMR-WB between Teams and the SBC, with AMR-WB in non-bypass mode only[^30]. Direct Routing does not support media re-targeting[^19]. If the SBC signals a new media IP mid-call, Teams Direct Routing never sends media to the new address[^19]. ### Certified list versions | Listed product | Versions shown | Claim | |---|---|---| | AudioCodes Mediant 500, 800, 2600, 4000, 1000B, 9000, 3100, Virtual Edition, Cloud Edition (most rows) | Supported 7.40A.600 (Recommended 7.40A.500) |[^6] | | Ribbon SBC 5400, SBC 7000, all SBC SWe variants including hosted offers | Available versions of 11.1 and later, 10.1, 9.2 and 7.2 |[^27] | | Ribbon SBC 1000, SBC 2000, SBC SWe Edge (formerly SWe Lite) | Available versions of 12.x and later, 11.x or 9.x |[^28] | | Oracle AP 1100, AP 3900, AP 4600, AP 6350, AP 3950, AP 4900, VME | 9.x and 10.x |[^23] | | Oracle AP 6300 | 9.x only |[^23] | | Oracle AP 6400 | 10.x only |[^23] | | Oracle Cloud Native SBC | 1.26.0.1.0 or higher |[^24] | | TE-SYSTEMS anynode | Supported 3.20 (Recommended 4.0) |[^5] | | Italtel NetMatch-S CI | Supported 5.8 (Recommended latest version) |[^16] | | Cisco CUBE on ISR 1000, ISR 4000, ASR 1000, CSR 1000V | From IOS XE Amsterdam 17.2.1r |[^12] | | Avaya ASBCE | 8.1.1 or higher |[^7] | ### Media bypass, ELIN and emergency calling Microsoft lists the following products as certified with media bypass[^27][^5][^16]: - The Ribbon SBC 5400, SBC 7000 and SBC SWe entries[^27]. - TE-SYSTEMS anynode[^5]. - Italtel NetMatch-S CI[^16]. Avaya ASBCE requires 8.1.2 or higher for media bypass and 10.2.0.2 for ELIN[^7]. Microsoft marks Ribbon SBC 1000, SBC 2000 and SBC SWe Edge as ELIN capable[^28]. None of the Cisco CUBE rows is marked ELIN capable, although all of them are marked 911 Service Provider Capable[^13]. Microsoft lists the Oracle Cloud Native SBC as non-media-bypass only, with 911 provider and ELIN capability shown as TBC[^24]. Several products on Microsoft's certified list have no media bypass mark[^21]. These include Thinktel Think 365 SBC, Oracle Cloud Native SBC, Ericsson vSBC, Cataleya Orchid Link, Patton SmartNode eSBC, Mediatrix Sentinel, Frafos ABC SBC, Vodia PBX and Brekeke PBX[^21]. Microsoft certifies and supports 3 emergency services providers for Direct Routing: Bandwidth Dynamic Location Routing, Intrado Emergency Routing Service and Inteliquent[^11]. Microsoft may reject support cases if a non-certified provider is used[^11]. Microsoft lists TE-SYSTEMS anynode as supporting Direct Routing Local Media Optimization at version 4.0.1 or later[^17]. It lists the Italtel NetMatch-S CI as supporting Local Media Optimization at version 5.7 or higher[^18]. ## Zoom Phone Zoom states that Zoom Phone supports a limited set of SBCs from these manufacturers: AudioCodes, Avaya, Cisco, Mitel, NextGen, Oracle, Ribbon and TE-Systems[^50]. To integrate with Zoom Phone, an SBC must support TLS 1.2, SRTP and mutual TLS[^53]. Zoom Phone also requires the SBC to use SIP Early Offer (marked mandatory), RFC 2833 DTMF and RFC 5853 topology hiding[^52]. Zoom Phone's SBC requirements list Opus, G.711 mu-law, G.711 A-law and/or G.729 as the codecs[^51]. Zoom's [BYOC-P](https://warmtransfer.net/knowledge/zoom-phone-byoc) prerequisites include the following[^49]: - The ability to administer the customer's own SBC[^49]. - A public IP address for SIP trunk connectivity[^49]. - Pre-existing PSTN connections with a carrier[^49]. Ribbon states that its SBC SWe, SBC SWe Edge, SBC 1000, SBC 2000, SBC 5400, SBC 7000 and EdgeMarc portfolio are all certified for Zoom Phone[^33]. For Ribbon platform details, see [Ribbon SBC Edge and SBC SWe](https://warmtransfer.net/knowledge/ribbon-sbc). ## Genesys Cloud BYOC This is disputed: Genesys states that an SBC is not required between Genesys Cloud BYOC and Microsoft Teams, and that customers may include one or connect directly to Teams[^4]. Genesys also notes that BYOC Cloud customers may, in certain scenarios, need an SBC so that their premises equipment can communicate with the Genesys Cloud Media Tier[^3]. ## Choosing one SBC for more than one platform [anynode](https://warmtransfer.net/knowledge/anynode-sbc) shows Supported 3.20 on Microsoft's Direct Routing list[^5] and a minimum of 4.10 for Webex Calling certificate-based Local Gateway[^34]. WarmTransfer's reading of the sources is that an anynode release between 3.20 and 4.09 meets Microsoft's Direct Routing supported minimum but falls below the Webex Calling certificate-based minimum of 4.10[^1]. We infer that an AudioCodes Mediant SBC at 7.40A.600 or later appears to meet both the Microsoft Direct Routing supported version and the Webex Calling certificate-based minimum of 7.40A.250.440[^2]. The [AudioCodes Mediant](https://warmtransfer.net/knowledge/audiocodes-mediant-sbc) rows in the Webex Calling certificate-based table carry the documented ICE interoperability limitation[^57]. ## Applicability Applies to: Cisco Webex Calling, Microsoft Teams Phone, AudioCodes Mediant SBC, Ribbon Communications SBC Core, Ribbon Communications SBC Edge, Oracle Acme Packet SBC, Oracle Cloud Native SBC, TE-SYSTEMS anynode, Italtel NetMatch-S CI, Cisco Unified Border Element, Avaya Session Border Controller for Enterprise, Oracle Communications Session Border Controller, Ribbon Communications SBC SWe Edge, Zoom Phone, Ribbon Communications SBC portfolio, and Genesys Cloud. Deployments: cloud, byoc-premises, certificate-based-trunk, direct-routing, premises-based-pstn, and registration-based-trunk. Sources checked 2026-10-14. Microsoft grants Direct Routing certification to specific firmware versions and accepts higher versions only within the same major.minor version[^8]. For Webex for Government, only certificate-based trunking on CUBE is supported[^54][^40]. Cisco Secure Router G2 models require at least Cisco IOS XE 26.2.1 as Local Gateway platforms[^56]. ## What remains uncertain - **Zoom Phone models and versions.** The specific Zoom Phone certified SBC models and firmware versions across all manufacturers are not covered by the sources below. - **Ribbon's statement about Zoom.** Whether Zoom requires a Zoom-certified SBC, as attributed to Ribbon, is not covered by the sources below. - **The AudioCodes ICE limitation.** The specific content of the ICE limitation described in section 2.4.2 of AudioCodes' Webex Calling configuration note is not covered by the sources below. - **Oracle known issues.** Known issues for Oracle SBCs on a Webex Calling certificate-based trunk are not covered by the sources below. - **Cisco capacity table.** The alignment of the capacity column in Cisco's Local Gateway capacity table is not covered by the sources below. - **AudioCodes version ordering on Microsoft's list.** The reason Microsoft prints a recommended AudioCodes version lower than the supported version is not covered by the sources below. - **Genesys SBC policy.** Genesys's policy on supported or tested SBCs for Genesys Cloud BYOC is not covered by the sources below. - **Cisco Secure Router G2 minimum.** This item is documented rather than uncertain. The Cisco Secure Router G2 models are listed as Local Gateway platforms at a minimum of Cisco IOS XE 26.2.1[^56]. ## Sources [^1]: An anynode release between 3.20 and 4.09 meets Microsoft's Direct Routing supported minimum but falls below the Webex Calling certificate-based minimum of 4.10 (inferred). Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 anynode row, compared with ms-learn-direct-routing-certified-sbcs Certified SBC vendors table, TE-SYSTEMS row. Checked 2026-10-14. [^2]: An AudioCodes Mediant SBC at 7.40A.600 or later appears to meet both the Microsoft Direct Routing supported version and the Webex Calling certificate-based minimum of 7.40A.250.440 (inferred). Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table AudioCodes rows, compared with cisco-help-t9xctu-get-started-local-gateway Table 4 AudioCodes rows. Checked 2026-10-14. [^3]: Genesys notes that BYOC Cloud customers may in certain scenarios need an SBC so that their premises equipment can communicate with the Genesys Cloud Media Tier. Source: [Telephony connection options overview](https://help.genesys.cloud/articles/telephony-connection-options/), Footnote (asterisk) under comparison table, BYOC Cloud 'Equipment required'. Checked 2026-10-14. [^4]: Genesys states that an SBC is not required between Genesys Cloud BYOC and Microsoft Teams, and that customers may include one or connect directly to Teams (disputed). Source: [Is Session Border Controller (SBC) required between Genesys Cloud BYOC and Microsoft Teams?](https://help.mypurecloud.com/?p=322213), FAQ answer, first sentence. Checked 2026-10-14. [^5]: Microsoft lists TE-SYSTEMS anynode as Direct Routing certified with media bypass, at Supported 3.20 (Recommended 4.0). Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, TE-SYSTEMS anynode row. Checked 2026-10-14. [^6]: In Microsoft's Direct Routing certified list most AudioCodes Mediant SBC rows (500, 800, 2600, 4000, 1000B, 9000, 3100, Virtual Edition and Cloud Edition) show 'Supported 7.40A.600 (Recommended 7.40A.500)'. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, AudioCodes rows, Software version column. Checked 2026-10-14. [^7]: Microsoft lists Avaya ASBCE as Direct Routing certified at release 8.1.1 or higher, 8.1.2 or higher for media bypass, and 10.2.0.2 for ELIN. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Avaya row. Checked 2026-10-14. [^8]: Direct Routing certification is granted to specific SBC firmware versions, and higher firmware versions are supported as long as the major.minor version is the same as the documented one. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory Note, final paragraph and example block (6.10.258 example). Checked 2026-10-14. [^9]: Microsoft certifies Direct Routing SBCs by having them tested in a third-party lab, and only devices that pass are certified. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory bullet list 'Microsoft works with each vendor to'. Checked 2026-10-14. [^10]: The Direct Routing SBC certificate must have the SBC FQDN in the CN or SAN, must be signed by a CA in the Microsoft Trusted Root Program, and must include the Server Authentication EKU. Wildcard certificates compliant with RFC 2818 are supported. Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), 'Public trusted certificate for the SBC' section. Checked 2026-10-14. [^11]: Microsoft certifies and supports three emergency services providers for Direct Routing: Bandwidth Dynamic Location Routing, Intrado Emergency Routing Service and Inteliquent. It may reject support cases if a non-certified provider is used. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), '911 service providers' footnote below Certified SBC vendors table. Checked 2026-10-14. [^12]: Microsoft lists Cisco CUBE on ISR 1000, ISR 4000, ASR 1000 and CSR 1000V as Direct Routing certified from IOS XE Amsterdam 17.2.1r. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Cisco rows. Checked 2026-10-14. [^13]: In Microsoft's Direct Routing certified list none of the Cisco CUBE rows is marked ELIN capable, although all of them are marked 911 Service Provider Capable. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Cisco rows, ELIN capable column (blank). Checked 2026-10-14. [^14]: Microsoft describes Direct Routing as connecting a supported customer-provided SBC to Teams Phone. Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), Opening paragraph. Checked 2026-10-14. [^15]: The Direct Routing SBC FQDN must belong to a verified Microsoft 365 domain in the tenant, and the default *.onmicrosoft.com domain cannot be used. Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), 'SBC domain names' section. Checked 2026-10-14. [^16]: Microsoft lists the Italtel NetMatch-S CI as Direct Routing certified with media bypass, at Supported 5.8 (Recommended latest version). Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Italtel row. Checked 2026-10-14. [^17]: Microsoft lists TE-SYSTEMS anynode as supporting Direct Routing Local Media Optimization at version 4.0.1 or later. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), 'Support for Local Media Optimization' table, TE-SYSTEMS row. Checked 2026-10-14. [^18]: Microsoft lists the Italtel NetMatch-S CI as supporting Direct Routing Local Media Optimization at version 5.7 or higher. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), 'Support for Local Media Optimization' table, Italtel row. Checked 2026-10-14. [^19]: Direct Routing does not support media re-targeting: if the SBC signals a new media IP mid-call, Teams Direct Routing never sends media to the new address. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Final Note at end of article. Checked 2026-10-14. [^20]: Microsoft states it is not accepting new nominations for Direct Routing SBC certification until further notice. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Paragraph immediately before 'Certified SBC vendors' heading. Checked 2026-10-14. [^21]: Several products on Microsoft's certified list have no media bypass mark, including Thinktel Think 365 SBC, Oracle Cloud Native SBC, Ericsson vSBC, Cataleya Orchid Link, Patton SmartNode eSBC, Mediatrix Sentinel, Frafos ABC SBC, Vodia PBX and Brekeke PBX. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Media bypass column. Checked 2026-10-14. [^22]: Microsoft reserves the right to reject support cases in which a non-certified device is connected to Phone System through Direct Routing. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory Note above 'Certified SBC vendors', third paragraph. Checked 2026-10-14. [^23]: Microsoft lists Oracle AP 1100, AP 3900, AP 4600, AP 6350, AP 3950, AP 4900 and VME as Direct Routing certified on 9.x and 10.x, AP 6300 on 9.x only, and AP 6400 on 10.x only. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Oracle rows. Checked 2026-10-14. [^24]: Microsoft lists the Oracle Cloud Native SBC for Direct Routing as non-media-bypass only, at 1.26.0.1.0 or higher, with 911 provider and ELIN capability shown as TBC. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Oracle Cloud Native SBC row. Checked 2026-10-14. [^25]: In Microsoft's Direct Routing deployment overview, selecting a Microsoft-certified SBC is step 2. It comes after reviewing infrastructure and licensing requirements and before configuring networking, DNS, certificates and connectivity. Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), 'Deployment overview' table, steps 1-3. Checked 2026-10-14. [^26]: Microsoft's Direct Routing infrastructure requirements list a Microsoft-certified SBC as required (disputed). Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), 'Infrastructure requirements' table, Session Border Controller (SBC) row. Checked 2026-10-14. [^27]: Microsoft lists Ribbon SBC 5400, SBC 7000 and all SBC SWe variants (including hosted offers) as Direct Routing certified on available versions of 11.1 and later, 10.1, 9.2 and 7.2, with media bypass. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Ribbon Communications rows SBC 5400 / SBC 7000 / All SBC SWe variants. Checked 2026-10-14. [^28]: Microsoft lists Ribbon SBC 1000, SBC 2000 and SBC SWe Edge (formerly SWe Lite) as Direct Routing certified on available versions of 12.x and later, 11.x or 9.x, and marks them ELIN capable. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Certified SBC vendors table, Ribbon rows SBC 1000 / SBC 2000 / SBC SWe Edge. Checked 2026-10-14. [^29]: Microsoft supports Phone System with Direct Routing only when it is used with certified SBC devices. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory Note above 'Certified SBC vendors'. Checked 2026-10-14. [^30]: Direct Routing supports SILK, G.711, G.722, G.729 and AMR-WB between Teams and the SBC, with AMR-WB in non-bypass mode only. Source: [Plan Direct Routing](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-plan), 'Supported codecs' section. Checked 2026-10-14. [^31]: For Direct Routing issues the customer must contact the SBC vendor's support first, and the SBC vendor escalates to Microsoft through internal channels if needed. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory Note above 'Certified SBC vendors'. Checked 2026-10-14. [^32]: To escalate an SBC-related Direct Routing issue to Microsoft support, the customer must present an SBC vendor investigation report that contains the vendor's ticket reference number. Source: [Session Border Controllers certified for Direct Routing - Microsoft Teams](https://learn.microsoft.com/en-us/microsoftteams/direct-routing-border-controllers), Introductory Note above 'Certified SBC vendors', second paragraph. Checked 2026-10-14. [^33]: Ribbon states that its SBC SWe, SBC SWe Edge, SBC 1000, SBC 2000, SBC 5400, SBC 7000 and EdgeMarc portfolio are all certified for Zoom Phone. Source: [Zoom Phone | Ribbon Communications](https://ribboncommunications.com/solutions/enterprise-solutions/securing-communications-sip-trunks/zoom-phone), Page body, certified products sentence. Checked 2026-10-14. [^34]: For Webex Calling certificate-based Local Gateway, the minimum version for anynode SBC is 4.10. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', row 'anynode—SBC'. Checked 2026-10-14. [^35]: For Webex Calling certificate-based Local Gateway, the minimum version for AudioCodes Mediant CE and VE and for Mediant appliances is 7.40A.250.440. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', AudioCodes rows. Checked 2026-10-14. [^36]: Webex's per-Local-Gateway capacity guidelines pair about 2000-6500 concurrent calls (about 65000 users) with certificate-based Interconnect, and about 250-2000 concurrent calls (about 20000 users) with certificate-based OTT. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 5 'Calling capacity guidelines (per local gateway)'. Checked 2026-10-14. [^37]: Cisco supports deployments that use a validated third-party SBC with Webex Calling, but it does not support the SBC itself and is not responsible for support cases between the customer and the SBC vendor. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Support responsibilities text near 'Supported session border controllers'. Checked 2026-10-14. [^38]: The minimum IOS XE release for CUBE as a Webex Calling Local Gateway is Cupertino 17.9.1a for certificate-based trunks and Bengaluru 17.6.1a for registration-based trunks. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Supported CUBE platforms and minimum versions table. Checked 2026-10-14. [^39]: Webex Calling does not require a Client Authentication EKU during the Local Gateway TLS handshake and accepts Server-Authentication-only certificates. Some third-party SBCs enforce strict EKU validation and may reject such certificates. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Certificate EKU note in the certificate-based trunk requirements. Checked 2026-10-14. [^40]: CUBE is the only SBC that currently supports Webex for Government, and every third-party SBC in the certificate-based table is marked 'Not supported' for Webex for Government. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), 'Supported session border controllers' section text and Table 4 Webex for Government column. Checked 2026-10-14. [^41]: For Webex Calling certificate-based Local Gateway, the minimum version for the Italtel NetMatch-S SBC is NetMatch-S-CI 5.8.0-20240111. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', row 'Italtel NetMatch-S SBC'. Checked 2026-10-14. [^42]: For Webex Calling certificate-based Local Gateway, the minimum version for the Oracle AP series, Oracle VME and Oracle SBC on Public Cloud is 9.3.0. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', Oracle rows, Minimum version column. Checked 2026-10-14. [^43]: A Webex Calling registration-based trunk supports up to 250 concurrent calls per trunk, and a certificate-based trunk supports more than 250. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 2 (trunk type comparison), concurrent calls row. Checked 2026-10-14. [^44]: A Webex Calling registration-based Local Gateway trunk supports only Cisco Unified Border Element (CUBE). Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 2 (trunk type comparison), registration-based column. Checked 2026-10-14. [^45]: For Webex Calling certificate-based Local Gateway, the minimum version for the Ribbon SBC 1000 and SBC 2000 is 11.0.1. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', row 'Ribbon—SBC 1000, SBC 2000'. Checked 2026-10-14. [^46]: For Webex Calling certificate-based Local Gateway, the minimum version for the Ribbon SBC 5000 Series, SBC 7000 and SBC SWe is 10.1. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', row 'Ribbon—SBC 5000 Series, SBC 7000, and SBC SWe'. Checked 2026-10-14. [^47]: For Webex Calling certificate-based Local Gateway, the minimum version for the Ribbon SBC SWe Edge is 11.0.2. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 'Certificate-based', row 'Ribbon—SBC SWe Edge'. Checked 2026-10-14. [^48]: Webex Calling lists its supported third-party SBCs only in the certificate-based trunk table (Table 4), so third-party SBCs are usable only on certificate-based Local Gateway trunks. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), 'Supported session border controllers' section, Table 4 'Certificate-based'. Checked 2026-10-14. [^49]: Zoom's BYOC-P prerequisites include the ability to administer the customer's own SBC, a public IP address for SIP trunk connectivity, and pre-existing PSTN connections with a carrier. Source: [BYOC-P or BYOP-P deployment and connectivity options](https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0079213), Prerequisites list. Checked 2026-10-14. [^50]: Zoom states that Zoom Phone supports a limited set of SBCs from these manufacturers: AudioCodes, Avaya, Cisco, Mitel, NextGen, Oracle, Ribbon and TE-Systems. Source: [Overview | Zoom Technical Library](https://library.zoom.com/zoom-workplace/zoom-phone/zoom-phone-bluepaper/overview), Supported Platforms, Devices, and Hardware > Supported Session Border Controller (SBC) Manufacturers. Checked 2026-10-14. [^51]: Zoom Phone's SBC requirements list Opus, G.711 mu-law, G.711 A-law and/or G.729 as the codecs. Source: [Overview | Zoom Technical Library](https://library.zoom.com/zoom-workplace/zoom-phone/zoom-phone-bluepaper/overview), Supported Platforms, Devices, and Hardware > SBC Requirements, codec bullet. Checked 2026-10-14. [^52]: Zoom Phone requires the SBC to use SIP Early Offer (marked mandatory), RFC 2833 DTMF and RFC 5853 topology hiding. Source: [Overview | Zoom Technical Library](https://library.zoom.com/zoom-workplace/zoom-phone/zoom-phone-bluepaper/overview), Supported Platforms, Devices, and Hardware > SBC Requirements, bullets 4-6. Checked 2026-10-14. [^53]: To integrate with Zoom Phone, an SBC must support TLS 1.2, SRTP and mutual TLS. Source: [Overview | Zoom Technical Library](https://library.zoom.com/zoom-workplace/zoom-phone/zoom-phone-bluepaper/overview), Supported Platforms, Devices, and Hardware > SBC Requirements, bullets 1-2. Checked 2026-10-14. [^54]: For Webex for Government only certificate-based trunking on CUBE is supported: registration-based trunking is unavailable and no third-party session border controllers are supported. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Webex for Government note. Checked 2026-09-04. [^55]: Registration-based trunks support only Cisco Unified Border Element, whereas certificate-based trunks additionally support several third-party session border controllers. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Registration versus certificate comparison table. Checked 2026-09-04. [^56]: Cisco Secure Routers C8231-G2, C8231-E-G2, C8235-G2, C8235-E-G2, C8355-G2 and C8375-E-G2 are listed as Local Gateway platforms for both the registration-based and the certificate-based trunking model, at a minimum of Cisco IOS XE 26.2.1. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 3 Registration-based SBC and Table 4 Certificate-based SBC, Cisco Secure Routers rows. Checked 2026-09-15. [^57]: 5 of the third-party session border controller rows in the certificate-based Local Gateway table carry a documented ICE interoperability limitation: AudioCodes Mediant CE and VE, AudioCodes Mediant Appliances, Ribbon SBC 5000 Series and SBC 7000 and SBC SWe, Ribbon SBC SWe Edge, and Ribbon SBC 1000 and SBC 2000. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 Certificate-based SBC, Open caveats column. Checked 2026-09-15. [^58]: The certificate-based Local Gateway table publishes a minimum version for each of its 11 third-party rows: Oracle AP series and VME and Oracle SBC on Public Cloud at 9.3.0; AudioCodes Mediant CE and VE and Mediant Appliances at 7.40A.250.440; Ribbon SBC 5000 Series and SBC 7000 and SBC SWe at 10.1; Ribbon SBC SWe Edge at 11.0.2; Ribbon SBC 1000 and SBC 2000 at 11.0.1; Ribbon 8000 with SBC SWe Edge at 25.0; anynode SBC at 4.10; and Italtel NetMatch-S SBC at NetMatch-S-CI 5.8.0-20240111. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Table 4 Certificate-based SBC, Minimum version column, read as table cells. Checked 2026-09-15. [^59]: For a Webex Calling deployment on a third-party session border controller, Cisco states that it supports Webex Calling up to the edge deployment and the Webex Calling registered Cisco IP phones, is not responsible for providing assistance for the session border controller itself, and is not responsible for support cases between the customer and the session border controller vendor. Source: [Get started with Local Gateway](https://help.webex.com/en-us/article/t9xctu/Get-started-with-Local-Gateway), Support for Third-party Local Gateway, Webex Calling support and Vendor support bullets. Checked 2026-09-15.