Configure trunks, route groups, and dial plans for Webex Calling

Publisher

Cisco Systems, Inc. (Webex Help Center)

URL

https://help.webex.com/article/n0xb944/Configure-Trunks-Route-Groups-and-Dial-Plans-for-Cisco-Webex-Calling

Published

2026-09-07

Updated

unknown

Accessed

2026-09-16

HTTP status

200

License

Cisco proprietary documentation, all rights reserved; no-redistribution; short excerpts and locators only

Source notes citing this source

• During coexistence, Webex Contact Center calls for work still on Avaya can be sent back with a Flow Designer Blind Transfer to an Avaya VDN number that a Webex Calling dial plan routes to the premises trunk. inferred in context
• Webex Calling dial plans send calls matching defined dial patterns to on-premises destinations through a chosen trunk or route group. in context
• A Webex Calling route group is a group of trunks that lets Webex Calling distribute calls over several trunks or provide redundancy. in context
• A Webex Calling trunk is a connection between Webex Calling and the premises, terminated on the premises by a local gateway or another supported device; trunks can be registration-based or certificate-based. in context
• Only the SBCs shown in the device type list in Control Hub are validated by Cisco's partners as compatible Webex Calling Local Gateways. in context
• Webex Calling dial plans route calls to on-premises destinations through trunks or route groups. in context
• In Webex Calling, a Local Gateway is an on-premises device that interconnects the trunk with on-premises PSTN and/or a PBX. in context
• Webex Calling trunks, route groups and dial plans support migration and coexistence with premises PBXs, including mixed sites with both premises and Webex Calling users. in context
• Webex Calling trunks are either registration-based, where the SBC performs SIP registration, or certificate-based, where Webex trusts the Local Gateway by its FQDN and certificate. in context
• Only SBCs shown in the Control Hub device type list are validated by Cisco's partners as compatible Webex Calling Local Gateways. in context
• If an Avaya contact center stays in service, Webex Calling callers can still reach it by routing the VDN extensions or DIDs that front its vectors over the SBC route group via dial-plan patterns. inferred in context
• Adding a certificate-based trunk requires an FQDN, and the SBC certificate must be signed by a supported CA and carry that FQDN as common name or subject alternative name. in context
• Extensions and DIDs still homed on Avaya can be reached from Webex Calling users by pointing dial-plan patterns, or unknown-extension routing, at a route group whose trunk is the SBC facing the Avaya system. inferred in context
• Dial patterns may be E.164 numbers with + or enterprise significant numbers, may use X for one digit and ! for any sequence, and ! may appear only once at the end of an E.164 pattern. in context
• Webex Calling allows up to 10,000 dial patterns per dial plan, 10,000 dial plans per enterprise and 10,000 patterns per CSV upload. in context
• Webex Calling dial plans route calls matching their dial patterns to on-premises destinations through a trunk or route group. in context
• Trunks used for premises-based PSTN through a Local Gateway can also be used to connect Webex Calling to premises PBXs. in context
• A Webex Calling route group bundles up to 10 trunks for distribution or redundancy, with priority setting failover order and random distribution among equal-priority trunks. in context
• Premises routing in Webex Calling is built in the order trunk, then route group, then dial plan referencing the route group. in context
• A third-party SBC used as a Webex Calling Local Gateway is supported only with a certificate-based trunk. in context
• A location can send calls its users make to an unknown extension of 2 to 10 digits to a selected route group or trunk as premises calls. in context
• Webex Calling supports third-party SBC integration only with certificate-based trunks. in context
• A Webex Calling dial plan routes calls matching enterprise dial patterns (E.164 numbers, extensions or SIP URI domains) to an on-premises destination through a trunk or route group, and applies enterprise-wide. in context
• Webex Calling's Calls to On-Premises Extensions setting routes unknown 2 to 10 digit extensions dialled at a location to a PBX over an existing trunk or route group. in context
• The Webex Calling trunk setting Dual Identity Support decides the From and P-Asserted-Identity headers on outbound INVITEs to the trunk: when enabled the two can differ, and when disabled they are identical. in context
• The Webex Calling trunk option P-Charge-Info Support adds a P-Charge-Info header to outbound PSTN calls. It is disabled by default, and its policy options are the primary or location main number, or a charge number customized on the location page. in context
• Cisco positions P-Charge-Info as letting the PSTN provider identify the chargeable number from one header, without relying on PAI for normal originations and Diversion for redirected calls. in context
• Cisco states that 4 of the 17 Local Gateway trunk error conditions, numbers 2 6 11 and 12, are shown only when all the edge proxy nodes experience an issue. in context
• Control Hub publishes 17 numbered error conditions for a certificate-based Local Gateway trunk with a verification action for each, 8 of them describing a TLS connection to the Local Gateway failing and 6 describing a TLS connection from the Local Gateway to Webex Calling failing, covering DNS resolution, transport, an invalid or expired or revoked certificate, an invalid or expired certificate authority, a missing FQDN in the common name or subject alternative name, and absent or unsuccessful SIP OPTIONS. in context
• Because Webex Calling dial plans are enterprise-wide, per-device or per-line routing differences that Unified CM expresses with different CSSs (for example site-specific gateways) cannot be reproduced through Webex Calling dial plans alone. inferred in context
• Webex Calling dial patterns allow only X (one digit) and ! (any digit sequence, E.164 only, once at the end). X cannot appear in the middle of a number or be combined with !. in context
• Webex Calling dial plans, which route calls to on-premises destinations over trunks or route groups, are configured for the whole enterprise and apply to all users regardless of location. in context
• A Webex Calling route group contains at least one and at most 10 trunks. An enterprise can have up to 10,000 route groups and 10,000 dial plans, each dial plan with up to 10,000 dial patterns. in context
• When a Webex Calling location enables routing of unknown extensions, calls from its users to unknown 2-10 digit extensions go to the selected trunk or route group as premises calls. in context
• Webex Calling dial plan patterns may be +E.164 patterns, enterprise dial patterns without a leading plus, or SIP URI domain patterns; wildcards X and ! are supported but cannot be combined in one pattern. in context
• The Webex Calling 'Calls to On-Premises Extensions' setting is enabled per location and routes calls from that location's users to unknown extensions of 2 to 10 digits to a selected route group or trunk as premises calls. in context
• For unknown-extension handling, Standard Behavior is the default and recommended option for PBX interoperability, while Legacy Behavior exists for backward compatibility and is not recommended when dial plans are configured. in context
• Webex Calling dial plans are configured globally for the enterprise and apply to all users regardless of location; they route matching calls to on-premises destinations over a trunk or route group. in context
• In Webex Calling dial patterns, X matches one digit (0-9). ! matches any digit sequence but only at the end of an E.164 pattern. ! and X cannot be combined in one pattern, and X cannot sit in the middle of a number. in context
• A Webex Calling dial plan is a set of dial patterns (extensions, enterprise/ESN numbers, +E.164 patterns or SIP URI domains) that routes matching calls to on-premises destinations through a single routing choice of trunk or route group. in context
• Within a Webex Calling route group, calls are distributed randomly among trunks of the same priority and fall back to lower-priority trunks only when the higher-priority trunks are unavailable. in context
• Webex Calling allows up to 100 trunks per location, 10 trunks per route group, 10,000 route groups and 10,000 dial plans per enterprise, and 10,000 dial patterns per dial plan. in context
• When premises (unknown) extension routing is enabled on a Webex Calling location, calls from its users to an unknown 2-10 digit extension are sent as premises calls to the selected trunk or route group. in context
• Control Hub has a call routing verification tool that simulates a call from a user, workspace, virtual line or premises trunk and shows the outgoing permissions, digit patterns, call intercept and translation patterns applied. in context
• Control Hub accepts both FQDN and SRV formats for the trunk address, while the Local Gateway's tenant-side configuration toward Webex Calling should use only SRV-based Webex Calling Edge addresses. in context
• For a certificate-based Webex Calling trunk, the Local Gateway must be reachable from the internet on a public IPv4 address that resolves from a DNS A or SRV record in a domain verified in Control Hub. in context
• When a Webex Calling certificate-based trunk uses an SRV address, the SRV service type must have the _sips._tcp prefix. in context
• Each Webex Calling trunk is created with an FQDN or SRV host address that must be unique across the whole organization; no two trunks may share an address. in context
• A Webex Calling dial plan can hold up to 10,000 dial patterns, and the CSV upload also accepts up to 10,000. in context
• Webex Calling premises dial plans accept E.164 patterns, which begin with '+', enterprise patterns for on-premises extensions or ESN numbers, and SIP URI domain patterns. in context
• The Webex Calling premises dial plan accepts From and To headers in E.164 or as extensions, but not a combination of the two. in context
• Webex Calling dial patterns support two wildcards: X for one digit and !, which matches any digit sequence and may appear only once, at the end of an E.164 pattern; X cannot be used mid-number and X and ! cannot be combined in one pattern. in context
• When adding a certificate-based trunk to a location in Control Hub, the administrator enters a maximum number of concurrent calls, which must be set according to the Local Gateway's capacity. in context
• Grouping several registration-based trunks in a route group could in principle raise aggregate concurrency beyond 250 calls, but no Cisco page read for this packet documents route groups as a capacity mechanism or how calls are distributed across member trunks. inferred in context
• Webex Calling allows up to 100 trunks per location. in context
• A Webex Calling route group can contain up to 10 trunks, and an enterprise can have up to 10,000 route groups. in context
• Webex Calling certificate-based trunks can be configured with a DNS SRV address, which provides redundancy and load distribution toward the premises gateway. in context
• A Webex Calling route group must contain at least one and at most 10 trunks, and can mix registration-based and certificate-based trunks. in context
• In a Webex Calling route group, calls are distributed randomly among trunks of the same priority, and if the highest-priority trunk is unavailable the call is tried on a lower-priority trunk. in context
• The Verify call routing result shows the outgoing call permissions, fraud prevention, digit patterns, call intercept and translation patterns applied while routing the call. in context
• Control Hub's Verify call routing tool accepts a premises trunk as the call source, alongside a cloud user, workspace or virtual line. in context
• Every Webex Calling trunk must be assigned to a location in Control Hub before it can be used. in context
• Webex Calling trunks are either registration-based, where the gateway performs SIP registration, or certificate-based, where Webex trusts the gateway by its FQDN and certificate. in context
• Control Hub's Verify Call Routing tool takes a call source (cloud user, workspace, virtual line or premises trunk) and a number or URI, and shows the outgoing call permissions, fraud prevention, digit patterns, call intercept and translation patterns applied to the call. in context
• Each Webex Calling location needs PSTN connectivity set up, chosen from Cisco PSTN, Cloud Connected PSTN or Premises-based PSTN (Local Gateway). in context
• A Webex Calling route group can contain up to 10 trunks. in context
• Within a route group, calls are distributed randomly among trunks of equal priority, and if the highest-priority trunk is unavailable Webex Calling tries a lower-priority trunk. in context
• Control Hub reports Local Gateway trunk status as Online, Offline, Impaired or Unknown, where Impaired means the connection failed with at least one Webex Calling edge proxy. in context
• Local Gateway trunk status in Control Hub updates at roughly three-minute intervals, so a just-repaired trunk may still show its previous state briefly. in context
• Verify call routing takes a call source (a cloud user, workspace, virtual line or premises trunk) and a destination number or URI. in context
• The Control Hub Verify call routing tool simulates a call and shows the outgoing call permissions, fraud prevention, digit patterns, call intercept and translation patterns applied while routing it. in context
• A certificate-based Local Gateway must be reachable from the internet on a public IPv4 address, directly or through static NAT, with firewall rules that allow TLS SIP signaling and UDP SRTP media. in context
• Certificates with only the Server Authentication Extended Key Usage are supported for certificate-based trunks. Webex Calling does not require a Client Authentication EKU. in context
• A certificate-based trunk connects to Webex Calling over mutual TLS and is addressed by an FQDN or SRV address that must be unique within the organization and on a verified or claimed domain. in context
• The trunk errors numbered 2, 6, 11 and 12 in Cisco's table are shown only when all edge proxy nodes have the issue. in context
• The Control Hub trunk error 'TLS Connection to Local Gateway failed due to DNS resolution failure' is resolved by making sure the configured SRV or FQDN resolves in DNS. in context
• The Control Hub trunk error list includes separate errors for an expired gateway certificate, a certificate issued by an expired CA, and expired certificates in the chain. Each is resolved by replacing the expired certificate. in context
• The trunk error 'the FQDN configured for your gateway is missing from CN or SAN' is resolved by making sure the certificate CN or SAN contains the FQDN or SRV configured on the trunk. in context
• When the trunk error says the gateway certificate is signed by an invalid Certificate Authority, or that Webex is unable to trust the CA, the fix is a certificate signed by a CA on Cisco's supported list. in context
• The trunk error 'SIP options sent to the Local Gateway received no response' is resolved by making sure CUBE is configured to receive SIP OPTIONS and respond to them. in context
• The trunk error saying the TLS connection and SIP OPTIONS from the Local Gateway to Webex Calling have failed is resolved by making sure CUBE is configured to send OPTIONS requests. in context
• The trunk error list includes errors for a revoked gateway certificate, in both directions of the TLS connection. The fix is to make sure the Local Gateway certificate is not revoked. in context
• When the SIP OPTIONS response shows a server error or Service Unavailable, the documented fix is to check that the Local Gateway is not in maintenance mode and that call routing is not disabled. in context
• The trunk error 'TLS Connection to Local Gateway failed due to a transport issue' is resolved by checking that the resolved IP addresses and port of the Local Gateway are valid. in context
• An Impaired trunk (failing on some but not all edge proxies) may not show the transport, CN/SAN, OPTIONS-failure or server-error messages, so the absence of those messages does not rule those causes out for one proxy. inferred in context
• The trunk configuration article gives the Control Hub path to trunk status as Services > Calling > Call Routing > Trunk. disputed in context
• On a registration-based trunk, the Local Gateway performs SIP registration and must keep an active registration; the connection to Webex Calling depends on that registration. in context
• A trunk status of Impaired means the connection between at least one Webex Calling edge proxy and the Local Gateway is unsuccessful. It is a partial failure, not a full outage. in context
• A trunk status of Offline means the connection between Webex Calling and the Local Gateway is unsuccessful. in context
• In Control Hub, a Local Gateway trunk status of Online means the connection between all Webex Calling edge proxies and the Local Gateway is successful. in context
• Control Hub updates trunk status every 3 minutes, and the admin can also refresh it manually. in context
• A trunk status of Unknown is shown while the connection to a recently added Local Gateway is still being established. in context
• Cloud PSTN, whether Cisco Calling Plan or Cloud Connected PSTN, provides PSTN access only for Webex Calling users; calls originating from premises users cannot reach the cloud PSTN through that path. in context
• A per-location setting for calls to on-premises extensions lets users keep abbreviated dialling, for example 4 digits, while a site is only partially migrated, by routing unmatched extensions of a configured length between 2 and 10 digits to a chosen route group or trunk. in context
• A certificate-based Local Gateway must be directly reachable from the internet at a public IPv4 address, using 1-to-one static NAT if the gateway itself holds a private address. in context
• A route group may contain a maximum of 10 trunks. in context
• A Webex Calling location may hold a maximum of 100 trunks. in context
• A maximum of 10000 route groups may be configured for 1 enterprise customer. in context
• Webex Calling offers 3 PSTN connectivity options: Cisco Calling Plan, Cloud Connected PSTN from a partner provider, and premises-based PSTN through a Local Gateway. in context
• A route group is a group of trunks that lets Webex Calling distribute calls over multiple trunks or provide redundancy, and it may contain trunks from multiple locations. in context
• A trunk in Webex Calling is a connection between Webex Calling and the premises, terminated on the premises by a supported session border controller acting as a Local Gateway. in context
• Premises-based PSTN through a Local Gateway keeps the current PSTN provider, and the same trunks can also connect to premises PBXs. in context
• A route group is a group of up to 10 trunks that lets Webex Calling distribute calls across trunks or provide redundancy, with priority weights set per trunk. in context
• A trunk is added in Control Hub under Services > Calling > Call Routing > Trunk > Add Trunk by choosing a location, a name of at most 24 characters, and a trunk type of Registration-based or Certificate-based. in context
• Creating a registration-based trunk yields a register domain, trunk group OTG/DTG, line/port, outbound proxy address, username and password; lost credentials must be regenerated from the trunk information screen. in context
• A trunk can be deleted from Services > Calling > Call Routing > Trunk via More Options > Delete Trunk as long as it is not in use. in context
• Control Hub shows trunk status as Online (all Webex Calling edge proxies connected), Impaired (at least one proxy failing), Offline (no connection) or Unknown (connection in progress), refreshed every 3 minutes. in context
• Control Hub shows a Local Gateway trunk as Online, Offline, Impaired (at least one Webex Calling Edge proxy cannot connect) or Unknown (connection in progress for a new gateway). in context
• Local Gateway trunk status in Control Hub updates every 3 minutes. in context
• Webex Calling distributes calls randomly among trunks in a route group that share the same priority. in context
• If the highest-priority trunk in a Webex Calling route group is unavailable, the system attempts to route the call to a trunk with a lower priority. in context
• A Webex Calling route group can contain at most 10 trunks. in context
• Webex Calling trunk status in Control Hub is updated every 3 minutes. in context
• A Webex Calling Local Gateway trunk shows Impaired when the connection between at least one Webex Calling edge proxy and the Local Gateway has failed, and Offline when the connection to Webex Calling is unsuccessful. in context
• If emergency service address validation fails while configuring a premises-based or Cisco Calling Plan PSTN connection, an administrator may close the address screen and continue, and Cisco states that an unvalidated address may delay emergency call handling and may incur additional charges if calls are routed to an emergency relay centre. in context
• A certificate-based trunk's fully qualified domain name or SRV host address must be unique across the whole organisation, and a different port does not make an address unique: a trunk at london.lgw.cisco.com:5062 cannot be created while any other trunk uses the host address london.lgw.cisco.com, in either FQDN or SRV form. in context
• A certificate-based trunk address must resolve from the public internet through a DNS A record or a DNS SRV record; an FQDN must resolve to an A record and not to a CNAME, an SRV service type must carry the prefix _sips._tcp, and Cisco prefers a time to live of 300 seconds or higher on all record types. in context
• A trunk's SRV address, fully qualified domain name or port cannot be edited; changing any of them requires adding a new trunk and deleting the old one, and a trunk can only be deleted while it is not in use. in context
• A single CSV upload can carry a maximum of 10000 dial patterns into a Webex Calling dial plan. in context
• A Webex Calling dial pattern uses 2 wildcards: an exclamation mark matches any sequence of digits and may appear only once, only at the end and only in an E.164 pattern, and an X matches a single digit from 0 to 9; an X may not appear in the middle of a number and the exclamation mark may not be used in a pattern that also uses X. in context
• Cisco states that a Webex Calling dial plan accepts the From and To headers in E.164 form or in extension form and that the pair cannot be a combination of the two. in context
• Webex Calling dial plans are configured globally for an enterprise and apply to all users regardless of location, and a dial plan names exactly 1 routing choice, either a trunk or a route group, for the patterns it holds. in context
• The Dual Identity Support setting on a trunk decides whether Webex Calling may populate different values in the From and P-Asserted-Identity headers of an initial outbound INVITE; with it disabled, P-Asserted-Identity is set identical to From. in context
• In Cisco's 3 worked Dual Identity Support scenarios, disabling the setting changes the P-Asserted-Identity header in 2 of them and changes nothing in the third: a user presenting the location main number moves from a direct line to the location number in P-Asserted-Identity, a call to an on-premises user moves from a direct line to the enterprise significant number, and a user presenting their own number is unaffected because both headers already carry the direct line. in context
• The P-Charge-Info Support policy on a trunk is set to Disabled by default, and when enabled it carries a chargeable number in a P-Charge-Info header on outbound PSTN calls under 1 of 2 policies, the Webex Calling primary or location main number, or a charge number customised on the location page. in context
• Cisco states that the P-Charge-Info header cannot be included when no regular non-toll-free number is available, so the header may be absent even when support is enabled, and that PSTN providers cannot rely solely on it and must still consider the P-Asserted-Identity or Diversion header. in context
• Within a route group, calls are distributed at random among the trunks that share the highest priority level, and a lower priority is used only when every trunk at the higher priority is unavailable. in context
• The trunk troubleshooting table publishes 17 numbered error conditions, and Cisco states that 4 of them, numbers 2, 6, 11 and 12, are shown only when all the edge proxy nodes experience an issue. in context
• A SIP URI dial pattern matches only the host portion to the right of the at sign, and a pattern with a leading asterisk matches sub-domains of the named domain but does not match the domain itself. in context
• Where a certificate-based trunk uses an SRV address, both the SRV record and the A record it derives must appear in the subject alternative name of the Local Gateway certificate, and the certificate's common name or subject alternative name must carry the fully qualified domain name chosen for the trunk in Control Hub. disputed in context
• A Webex Calling trunk name cannot be longer than 24 characters. in context
• If a trunk search returns more than 1000 trunks, the results cannot be sorted and cannot be searched within. in context
• A Webex Calling trunk reports 1 of 4 statuses, where Online means every Webex Calling edge proxy connected, Offline means none did, Impaired means at least 1 edge proxy did not, and Unknown means a connection is in progress for a recently added Local Gateway; the status refreshes every 3 minutes. in context
• The Calls to On-Premises Extensions setting is enabled per location and routes a call to an unknown extension of 2 to 10 digits to a selected trunk or route group as a premises call, where a caller identity that matches no dial plan pattern is what makes an extension unknown; the maximum unknown extension length is configurable over the same 2 to 10 digit range. in context
• Call routing between Webex Calling and premises offers 2 settings for unknown numbers: Standard Behavior, which Cisco gives as the default and the recommended option for interoperability with an on-premises PBX, and Legacy Behavior, which provides backward compatibility with the older local gateway behaviour and which Cisco does not recommend when dial plans are configured. in context
• Control Hub publishes a Verify Call Routing tool that simulates a call from a chosen cloud user, workspace, virtual line or premises trunk to a number or URI and reports the routing decision, including the outgoing call permissions, fraud prevention, digit patterns, call intercept and translation patterns applied. in context

Cite this source record

APA

WarmTransfer. (2026, September 7). Configure trunks, route groups, and dial plans for Webex Calling. WarmTransfer. https://warmtransfer.net/knowledge/sources/cisco-help-n0xb944-trunks-route-groups-dial-plans

BibTeX

@misc{warmtransfer-cisco-help-n0xb944-trunks-route-groups-dial-plans,
  title  = {Configure trunks, route groups, and dial plans for Webex Calling},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/cisco-help-n0xb944-trunks-route-groups-dial-plans},
  note   = {Cisco Systems, Inc. (Webex Help Center), accessed 2026-09-16}
}