00 · Header

T2 · Webex Calling

Dial Plans, PSTN & Routing

Internal dialing is an organization length plus a per-location prefix. Enterprise dial plans are global, one routing choice, and a pattern language with two wildcards that are illegal in the middle. PSTN is chosen per location: Cisco Calling Plan, Cloud Connected PSTN, or premises-based PSTN through a local gateway. Cloud PSTN serves Webex Calling users. Calls that start on the premises do not use it.

Expand all sections

01 · Executive summary

Five lines, then why it matters

• Internal extension length is 2–10 digits, default 4. Routing prefix length is 1–7 and includes the steering digit, so a length of 4 leaves 3 digits for the site. Lengthening extensions does not rewrite speed dials. [cite:1]
• If extensions repeat across locations, turn off extension dialing between locations. The caller then dials the Enterprise Significant Number: routing prefix plus extension. Directory Connector must not already contain the prefix, or Webex adds it again. User extensions should not start with the steering digit or the outbound dial digit. [cite:1]
• An enterprise dial plan is global for all users and has one routing choice, a trunk or a route group. Patterns are ESN/on-net, +E.164, or a SIP URI domain. X is one digit. ! is only at the end of an E.164 pattern, once. 617495X3XX and 1617495X3! are illegal. [cite:2]
• Same route-group priority means random distribution. If the highest-priority trunk is unavailable, a lower priority is tried. The worked example is trunks 1 and 2 at level 1, trunk 3 at level 2. A route group holds 1 to 10 trunks. [cite:2]
• Three PSTN choices can differ by location. Cloud PSTN, Cisco or Cloud Connected, is only for Webex Calling users. Premises-originated calls cannot use it. Unknown extensions of 2–10 digits can be sent to a trunk as premises calls. Standard Behavior is the recommended unknown-number handling once dial plans exist. [cite:1] [cite:2]

02 · Architecture map

From a digit string to a trunk

flowchart LR
  Digits[Digits or URI] --> Plan[Dial plan]
  Plan --> RG[Route group]
  RG --> Trunk
  Trunk --> LGW[Local gateway or PBX]

03 · Core concepts

Three PSTN choices, one pattern language

PSTN choice

Pattern language

Legal (n0xb944)
  +1408555XXXX
  +14085551234
  +496100!
  84969XXX
  84969764
  example.com
  *.example.com

Illegal
  617495X3XX
  1617495X3!

SIP URI
  Host example.com matches example.com
  Host example.com does not match *.example.com
  Host eu.example.com matches *.example.com

04 · Ecosystem & sister technologies

Glossary, map, sisters, edges

Glossary

Internal extension length

Organization setting, 2–10 digits, default 4. Lengthening it does not rewrite existing speed dials to internal extensions. [cite:1]

Routing prefix

Digits in front of an extension so two locations can reuse the same extension. Length 1–7, unique per location. [cite:1]

Steering digit

The first digit of every routing prefix. It counts inside the prefix length. [cite:1]

Enterprise Significant Number

Location routing prefix plus extension. Required for cross-location extension calls when inter-location extension dialing is off. [cite:1]

Outbound dial digit

Optional digit users dial for an outside line. Default None. Use a different digit from the steering digit. E.164 calls ignore this prefix requirement. [cite:1]

Enterprise dial plan

Global. Applies to all users. One routing choice: a trunk or a route group. Patterns are ESN/on-net, +E.164, or SIP URI domains. [cite:2]

Route group

1 to 10 trunks. Same priority is random. An unavailable higher-priority trunk falls through to a lower priority. [cite:2]

Trunk

Webex Calling to the premises, ending on a local gateway or another supported device. [cite:2]

Unknown extension

2–10 digits, or inbound caller ID that matches no dial-plan pattern. Can be routed to a trunk or route group as a premises call. [cite:2]

Standard Behavior

Recommended unknown-number handling once dial plans exist. Path: Services > PSTN & Routing > Services. [cite:2]

Legacy Behavior

Kept for old local-gateway behavior. The article says not to use it once dial plans are configured. [cite:2]

Caller ID format

+E.164 selects the external CLID. ESN selects the internal CLID. [cite:2]

Verify Call Routing

Simulates a call from a cloud user, workspace, virtual line, or premises trunk. Shows permissions, fraud prevention, digit patterns, intercept, and translation. [cite:2]

Emergency Service Address

Mandatory for U.S. and Canada Cisco Calling Plan locations. The same article later expands ESA as Enterprise Service Address in the validation paragraph. Quote the sentence you mean. [cite:2]

Cloud Connected PSTN

Partner cloud PSTN. No local PSTN hardware for that choice. Still only for Webex Calling users. [cite:2]

Cisco Calling Plan

Cisco’s cloud PSTN. Needs a committed outbound calling plan and a supported country. Read the country in the location wizard on the day you order. The supported-country list changes, so a copied list in this room would be wrong the next time Cisco adds a market. [cite:1]

Mind map

mindmap
  root((Dial plan))
    Internal
    Enterprise
    PSTN
    Unknown

Sister-technology matrix

Integration edges

Cross-platform bridges

Future-integration hooks

• The supported-country list for Cisco Calling Plan changes. re-check it in the location wizard rather than typing a country from memory. [cite:1]
• Open the Webex dial-plan pattern in Control Hub and the route pattern on the Unified CM that still owns the call. Closest-match versus Webex wildcards is why no help page freezes a field map.
• Canon planning: add a worked Verify Call Routing capture when a lab tenant exists. That is not a Cisco roadmap.

Ecosystem troubleshooting

05 · Flow

How a short extension leaves the cloud

06 · Config

Click paths

1. Sign in to Control Hub. Calling > Settings > Service. Scroll to Internal Dialing. Set extension length (2–10, default 4), prefix length (1–7), and the steering digit. [cite:1]
2. Leave inter-location extension dialing on only when every extension is unique. Otherwise the caller dials prefix + extension for other sites. The toggle defaults to on. [cite:1]
3. Open the location. Calling > Dialing. Set a unique prefix whose length matches the org recommendation and is still 1–7. Set the outbound dial digit only if users expect an outside-line digit, and do not reuse the steering digit. [cite:1]
4. If an extension equals a national number, the extension wins. The article recommends an outbound dial digit in that case, and it recommends E.164 for PSTN in both directions. [cite:1]
5. Create trunks, then a route group of 1–10 trunks with priorities. Confirm the group. You can jump to locations or to dial plans from that screen. [cite:2]
6. Services > PSTN & Routing > Gateway configurations > Dial Plans > Create Dial Plan. Name it, pick the routing choice, add patterns. Cisco Calling Plan customers may use Services > Calling > Call Routing. [cite:2]
7. Bulk patterns: Actions, Import Dial Patterns CSV or Export Dial Patters CSV. The export label is printed with that spelling. [cite:2]
8. Per location, enable routing unknown extensions to the premises and pick the trunk or route group. [cite:2]
9. Services > PSTN & Routing > Services. Prefer Standard Behavior once dial plans exist. Choose +E.164 or ESN caller ID. Set maximum unknown extension length. If you lengthen extensions and the PSTN is not E.164, incoming PSTN can be treated as local; enforce E.164 before the call reaches Webex Calling. [cite:2]
10. Run Verify Call Routing on the number you care about. For a U.S. or Canada Cisco Calling Plan location, set the Emergency Service Address. A failed validation does not block premise or CCPP setup, and it can delay emergency handling. [cite:2]

Screenshot placeholder. The paths above are the articles.

07 · Limits

Numbers the articles state

08 · Troubleshooting

Ten failures that follow from the articles

09 · Self-question ladder

Twelve rungs

10 · Lab

Pattern desk, no tenant required

• Goal: classify twelve patterns as legal E.164, legal ESN, legal SIP URI, or illegal, using only n0xb944.
• Prereq: this room. A calling lab is optional. Production dial plans are out of scope.
• Step 1. Copy +1408555XXXX, +496100!, 84969XXX, 84969764. Expected: all four are in the article’s example table.
• Step 2. Reject 617495X3XX and 1617495X3!. Expected: the article names both as illegal.
• Step 3. Decide host example.com against example.com and against *.example.com. Expected: the first host matches, the star does not.
• Step 4. Write the route-group example: trunks 1 and 2 at priority 1, trunk 3 at priority 2. Expected: random between 1 and 2, then 3.
• Step 5. If you have a lab, run Verify Call Routing from a cloud user. Expected: the result lists more than the matched digits.
• Evidence: the twelve-line sheet. Do not paste a production CSV.
• Break it: set the same extension in two locations and leave inter-location dialing on. Recovery: turn the toggle off and dial the ESN.
• Reflection: which of your old CUCM patterns used X in the middle, and how you would rewrite them.

The dial-plan translator on the Labs page is a teaching model. The legal and illegal rows above are the article.

11 · Quiz

Twelve questions

12 · Audio

Slots for Studio

13 · Interview

Oral answers

30 seconds. Internal length defaults to 4. A routing prefix of length 4 includes the steering digit, so three digits name the site. Duplicate extensions mean the caller dials prefix plus extension. PSTN is Cisco, Cloud Connected, or a local gateway, per location.

2 minutes. Enterprise dial plans are global and have one routing choice. I can defend +1408555XXXX, +496100!, and 84969XXX, and I will reject X in the middle and X mixed with !. SIP URI matching is the host only, and *.example.com does not match the apex. Route groups hold up to 10 trunks, random at the same priority. Unknown extensions from 2 to 10 digits go to the premises when that location toggle is on. Standard Behavior is the recommendation after dial plans exist.

30 seconds, cloud PSTN. Cisco Calling Plan needs the committed plan and a supported country. Cloud Connected PSTN is the partner path. Neither one takes a call that starts on the premises.

2 minutes, migration habit. I keep abbreviated dialing with the unknown-extension toggle while a site is only partly moved. I keep the prefix out of Active Directory. I enforce E.164 on the PSTN before I lengthen extensions. I run Verify Call Routing before I argue about a trace. I do not describe this as CUCM closest-match.

What you will not say. You will not claim a Teams dial plan is the same table. You will not invent the Cisco Calling Plan country list from memory.

14 · Citations

1. Configure Webex Calling for your organization — help.webex — article njvdjf2 — help.webex.com article njvdjf2 — retrieved 2026-10-14. Internal extension length 2–10, default 4. Routing prefix length 1–7 including the steering digit. ESN when inter-location extension dialing is off. Outbound dial digit default None. Directory Connector must not already hold the prefix. Speed dials are not rewritten. Cisco Calling Plan needs a committed OCP, a supported country, and the article’s note on pre-existing locations.
2. Configure trunks, route groups, and dial plans for Webex Calling — help.webex — article n0xb944 — help.webex.com article n0xb944 — retrieved 2026-10-14. Three PSTN choices. Cloud PSTN only for Webex Calling users. Route group 1–10 trunks, random at equal priority. Dial-plan pattern language, illegal X examples, SIP URI host match, unknown extensions, Standard versus Legacy behavior, Verify Call Routing, ESA for U.S. and Canada. The export action is printed Export Dial Patters CSV.
3. Cisco CallManager System Guide, Release 4.0(1), Partitions and Calling Search Spaces — Cisco — cisco.com CUCM 4.0(1) partitions and CSS — cited only to keep CUCM closest-match in T6-R02. Read closest-match on the Unified CM that still owns the call. That engine is not the Webex pattern language in n0xb944, which is why the two consoles can pick different routes for the same digits.

15 · Re-engineer later

• Open questions: the live country list for Cisco Calling Plan; whether a current tenant still shows the misspelled export label.
• Check the country in the location wizard, the route pattern on the remaining Unified CM, and the Teams normalization rule in its own admin center. Each list changes on its own product’s schedule.
• Assets missing: dial-plan screenshot, audio.
• Ideas for v1.0: a Verify Call Routing capture from a lab tenant, stored as text.
• Next review: re-check n0xb944 if the wildcard rules change.