00 · Header

T6 · Migrations

CUCM to Webex Calling

Color-coded sequence: Source PBX → Plan → Cutover → Webex. A packet moves along the arrows. Reduced motion keeps every step visible.

The documented path is Unified CM to multi-tenant Webex Calling. It is a PPDIO project, not a lift-and-shift. Phased moves split users across both platforms, and every group changes dial plans on Unified CM, Webex Calling, and the Local Gateway.

Room T6-R02 Version v0.1 last-verified: TODO Difficulty L2 Est. time 90–110 min Prereq T2-R02 Reading 17 min

01 · Executive summary

Five lines, then why it matters

The introduction says not to lift-and-shift Unified CM. Redefine requirements. The method is PPDIO: Prepare, Plan, Design, Implement, Optimize. [cite:1]
Choose flash-cut or phased. Flash-cut moves everyone at once. The guides spend their detail on phased, because groups of users sit on both platforms during the move. [cite:1] [cite:3]
Each time a group moves, dial plans and call routing must be updated on Unified CM, Webex Calling, and the Local Gateway. [cite:3]
Cisco recommends migrating a physical site or department together, unless feature dependencies force smaller batches (shared hunt pilot, call queue, shared line, pickup, call park). [cite:4]
BroadWorks and BroadCloud have a separate Control Hub migration. They are not this Unified CM path. [cite:9]

Why it matters. Cutover week fails when the dial plan is updated on only one of the three systems, or when a hunt group is split across the move. The lab on the Labs page is a study model of +E.164 normalization, not a CUCM engine.

02 · Architecture map

Two platforms, one gateway, during the phase

Mermaid source (not rendered)

flowchart LR
  UCM[Unified CM] --- LGW[Local Gateway]
  LGW --- WXC[Webex Calling]

03 · Core concepts

Decisions the introduction forces

PPDIO

Prepare, Plan, Design, Implement, Optimize. The introduction uses that sequence for Unified CM to Webex Calling and says the current deployment should not be lifted as-is. [cite:1]

Flash-cut versus phased

Flash-cut moves users and devices at once and is the fastest. Phased moves groups over time. While that happens, enterprise users are split across Unified CM and Webex Calling. [cite:1] [cite:3]

Reasons to consider staying

The introduction lists unsupported phone models; complex on-premises integrations that are hard to replicate; a complex dial plan, highly granular classes of service, or both; restrictive or unreliable internet; stringent data-privacy policies; compliance that needs on-premises or in-country recording; third-party integrations without a Webex alternative; and contact-center integrations where the contact center is not moving to the cloud yet. The last bullet is clipped on the page at the word “inter.” [cite:1]

+E.164

The Webex Calling configuration workflow says the Unified CM dial plan normalizes numbers as +E.164. Webex Calling sends unmatched calls, including PSTN numbers and Unified CM extensions it cannot see, to the Local Gateway. [cite:8]

CSS order, from the System Guide

The migration articles still only say to map the dial plan. The evaluation rule is in the Cisco CallManager System Guide, Release 4.0(1), chapter “Partitions and Calling Search Spaces,” and the 12.5(1) Troubleshooting Guide restates it. Digit analysis looks through every partition in the calling search space for the best match. Partition order breaks ties when two patterns match equally. The null partition is searched last. A line CSS and a device CSS are concatenated, line first. The Labs walker now follows that rule. It is not a live CUCM. [cite:10] [cite:11]

04 · Ecosystem

What has to move with the users

Mini map of the neighbors named on this room’s sequence. Orientation sketch, not a new product claim.

PPDIO: Prepare, Plan, Design, Implement, Optimize. The migration introduction’s process. [cite:1]
Flash-cut: Move all users and devices at once. Fastest, and the introduction contrasts it with a phased approach. [cite:1]
Phased migration: Groups move over time. Users are split across Unified CM and Webex Calling until phase 2. [cite:3]
Local Gateway: For a phased move the introduction names ISR 1100 and 4000, Catalyst 8200 and 8300, Catalyst 8000V, and certified third-party SBCs. [cite:1]
Unmatched call: A destination Webex Calling does not own. The configuration workflow sends those calls, including unseen Unified CM extensions, to the Local Gateway. [cite:8]
+E.164: The form the configuration workflow attributes to Unified CM normalization. [cite:8]
Main number: Set for each location. It can belong to a user or to a feature such as an auto attendant. [cite:4]
Migration Insights: Control Hub path Services → Upgrades & Migrations → Migration Insights. Unified CM data can be uploaded as a .tar. [cite:5]
Migrate features from UCM: Control Hub card under Services → Updates & Migrations. Maps auto attendant, devices, lines, layout, virtual line, call queue, hunt group, call park, and user calling data. [cite:6]
UserBasedUCMFeatureMigration: Python script that processes Unified CM CDR for migration tasks. Read what the feature-migration article says the script does, then run the published tool. The article does not print the Python internals, and they change when Cisco ships a new script. [cite:6]
Enterprise to MPP: 7800 and 8800 phones can be moved with Control Hub’s “Migrate your phone to Webex Calling” tool. 8821 and 8831 are not eligible for MPP. [cite:4] [cite:7]
BroadWorks migration: A different Control Hub tool. PBX type BroadWorks or BroadCloud. The do_not_move_phone flag is BroadWorks-only. [cite:9]

Mind map

Sister matrix

Piece	What the guides say	Why it bites at cutover	Where	Failure	Cite
Users	Users must be provisioned in Webex even for a phased migration.	A phone with no Webex user has nowhere to land.	Prepare article.	Waiting until move night to create users.	[cite:2]
Desk phones	Webex Calling desk phones in the prepare article: 6800, 7800, 8800, and 9800 series only.	Other Cisco IP phone families are outside that list.	Prepare.	Promising a 79xx fleet will register as-is.	[cite:2]
7800 / 8800 firmware	Control Hub tool “Migrate your phone to Webex Calling” moves 7800 and 8800 from Enterprise firmware to MPP.	MPP is a firmware change, not a setting.	Implement article.	Shipping phones that are still on Enterprise firmware.	[cite:4]
Ineligible 8800 models	8821 and 8831 are not eligible to migrate to MPP. 8832NR can migrate; some features may not be supported. V15 and later hardware needs minimum 11.3.3 MPP and cannot downgrade.	A model number is not “an 8800.”	Firmware article. The tool’s steps also apply to Dedicated Instance. Phones migrated with the tool must use Webex Calling.	Putting an 8821 in the MPP job.	[cite:7]
Jabber	Single step moves the client and the calling service together, typically for a small user count. Dual step is recommended for larger customers: Webex App registers to Unified CM first, then calling moves.	A big site that changes client and PBX the same morning doubles the variables.	Plan article.	Forcing single-step on a large Jabber estate.	[cite:3]
Locations	Set the main number for each location, on a user or on a feature such as an auto attendant.	Calling locations without a main number are incomplete for the move.	Implement.	Leaving the main number blank.	[cite:4]
Features that share users	Move voicemail, auto attendants, call queues, and hunt groups to Webex Calling equivalents. Dependencies include BLF monitoring, the same hunt pilot or call queue, shared lines, call pickup, the same call-park numbers, intercom, and executive/admin.	Splitting a hunt pilot across platforms strands the pilot.	Implement. Cisco prefers a site or department together.	Migrating one member of a hunt group.	[cite:4]
Feature import	Mapped objects include auto attendant, devices, configured lines, device layout, virtual line, call queue, hunt group, call park, and user calling data.	The CSV is not the whole Unified CM database.	Services → Updates & Migrations → Migrate features from UCM.	Assuming every CUCM feature has a row.	[cite:6]
CDR script	UserBasedUCMFeatureMigration processes CDR collected on a server or Unified CM. Compressed files upload in Control Hub.	The article does not document the script’s source.	Same feature-migration article.	Editing the script from memory. Follow the feature-migration article’s steps instead of editing the script. The internals are not published, and a local edit drifts from the next Cisco build.	[cite:6]
Dial plan	Each group transition needs dial-plan and call-routing updates on Unified CM, Webex Calling, and the Local Gateways. Unified CM normalizes to +E.164. A CSS field crosswalk is not published.	One-sided routing black-holes the split estate.	Plan article and the configuration workflow.	Updating only Webex Calling.	[cite:3] [cite:8]
PSTN during coexistence	Webex Calling sends unmatched calls to the Local Gateway, including PSTN numbers and Unified CM extensions it cannot see. The gateway routes between Webex Calling and Unified CM.	Extensions that have not moved are invisible to Webex Calling until the gateway knows them.	Configuration workflow, on-premises IP PBX section.	Expecting Webex Calling to dial a Unified CM extension with no gateway route.	[cite:8]
Other PBX migrations	BroadWorks and BroadCloud use their own Control Hub migration, including an optional BroadWorks-only `do_not_move_phone` flag.	A Unified CM BAT file is the wrong input for that tool.	Article n1ku0vfb.	Telling a BroadWorks partner to follow this room’s BAT steps.	[cite:9]

Integration edges

From	To	What crosses	Proof	Cite
Unified CM BAT / .tar	Migration Insights	User and device export	Upload the .tar. Step 3 is Migrate to Webex Calling → Start New Task. A downloaded zip leads to a CSV you upload on Unified CM. Cloud-Connected UC can take device migration if it is enabled.	[cite:5]
Unified CM features	Migrate features from UCM	The mapped feature list	admin.webex.com → Services → Updates & Migrations → that card → Get Started	[cite:6]
CDR files	UserBasedUCMFeatureMigration	Records the script knows how to read	The article names the script and CDR input. It does not paste the code.	[cite:6]
7800 / 8800 Enterprise firmware	MPP on Webex Calling	The phone-migration tool	Phones migrated with the firmware tool must use Webex Calling	[cite:4] [cite:7]
Jabber	Webex App on Unified CM, then Webex Calling	Dual-step client move	Step 1: Webex App registers to Unified CM. Step 2: calling, numbers, and registration move.	[cite:3]
Webex Calling	Local Gateway	Unmatched PSTN and unseen Unified CM extensions	Configuration workflow	[cite:8]
Local Gateway	Unified CM	Calls from Webex Calling, and the reverse	The gateway routes both directions in that section	[cite:8]
Group move	Three dial plans	Routing updates	Unified CM, Webex Calling, and the Local Gateways, each time a group moves	[cite:3]

Bridges

This path	Legacy habit	Not this path	Cite
Unified CM to multi-tenant Webex Calling	CSS, partitions, and route patterns still exist on the Unified CM that has not been decommissioned. Open the Webex Calling dial plan in Control Hub and the CSS, partitions, and route patterns on the Unified CM that is still in service. The migration article does not print a field-by-field map, because closest-match and Webex patterns are different engines.	No parity matrix is published on help.webex.com for Microsoft, Amazon Connect, or Genesys. [cite:9]	[cite:1]
Directory Connector or the Entra path named in the wider identity rooms	CUCM LDAP sync is a different product. Open Directory Connector in Control Hub and the LDAP filter on the Unified CM that still syncs. The two products do not share a filter language, so the migration guides say “map” without printing a crosswalk.	Teams admin center is not Control Hub.	[cite:1]
BroadWorks / BroadCloud tool	Do not feed it a Unified CM BAT and expect the same three steps.	`do_not_move_phone` is documented as BroadWorks only.	[cite:9]

Future hooks

A partition and CSS crosswalk stays open until a help article prints one.
Survivability Gateway is named in the introduction’s architecture discussion. Its outage behavior stays in T2 until this migration set restates it.
Contact-center moves are a reason the introduction gives for staying on premises when that contact center is not moving. They are not this room’s procedure.

Ecosystem troubleshooting

Symptom	Mix-up	Check	Move	Cite
Half a hunt group rings, half does not	The group was split across platforms	Same hunt pilot or call queue in the dependency list	Move the dependent users together	[cite:4]
Webex users cannot dial remaining extensions	The Local Gateway was not updated for that group	Three-system routing update	Change Unified CM, Webex Calling, and the gateway	[cite:3] [cite:8]
An 8821 is in the MPP job	Model family treated as eligible	8821 and 8831 are not eligible	Leave those devices off the tool	[cite:7]
A BroadWorks estate is run through the Unified CM .tar task	Two migrations were merged	Article title is BroadWorks and BroadCloud	Use that tool, not this room’s BAT steps	[cite:9]

05 · Flow

Order of the move

Prepare: decide whether the requirements say to stay. Unsupported phones, a complex dial plan or highly granular classes of service, and a contact center that is not moving are on that list. [cite:1]
Provision users in Webex even if the cut is phased. Confirm desk phones are in the 6800, 7800, 8800, or 9800 series. [cite:2]
Plan Jabber: small populations can move client and calling together. Larger populations should move the soft client first, with Webex App still registered to Unified CM, and move calling in a second step. [cite:3]
Choose groups. Prefer a physical site or department. Shrink the batch only for feature dependencies. [cite:4]
For each group, update dial plans and call routing on Unified CM, Webex Calling, and the Local Gateways. [cite:3]
Set each location’s main number. Move voicemail, auto attendants, call queues, and hunt groups with the users who depend on them. [cite:4]
Import Unified CM data via Migration Insights (.tar, then Step 3, Start New Task). Import mapped features from the Updates & Migrations card. Use the CDR script only as that article describes it. [cite:5] [cite:6]
Migrate eligible 7800 and 8800 phones to MPP with the Control Hub tool. Exclude 8821 and 8831. Phones the firmware tool migrates must use Webex Calling. [cite:7]
After the last group (the plan article’s phase 2), on-premises UC can be removed. Not before. [cite:3]

06 · Config

Control Hub paths that are printed

Task	Path in the article	Stop
Insights	Control Hub → Services → Upgrades & Migrations → Migration Insights. Import the Unified CM .tar. Step 3: Migrate to Webex Calling → Start New Task.	Do not invent extra wizard steps.
Device handoff	Download the zip, upload the device CSV on Unified CM. If Cloud-Connected UC is enabled, it takes up device migration.	The article does not say every MAC is in that CSV. Do not add columns from memory.
Features	admin.webex.com → Services → Updates & Migrations → Migrate features from UCM → Get Started.	Read the mapped feature list under Services → Updates & Migrations → Migrate features from UCM. That list is what the tool moves, and it changes when Cisco adds a feature to the article.
Phones	Migrate your phone to Webex Calling, for 7800 and 8800 Enterprise-to-MPP.	8821 and 8831 are out. V15 hardware needs at least 11.3.3 MPP and cannot downgrade.
Locations	Set the main number. It can be a user or a feature such as an auto attendant.	Voicemail still needs the pilot the implement article tells you to transition. Open voicemail management for the pilot the implement article tells you to transition, and open each other feature’s own page in Control Hub. Portal-number screens differ by feature, which is why this room stays on voicemail.

07 · Limits

Bounds the articles actually print

Bound	What is printed	Source
Desk phone families	6800, 7800, 8800, 9800 series for Webex Calling desk phones in the prepare article	[cite:2]
Not eligible for MPP	8821 and 8831	[cite:7]
8832NR	Can migrate; some features may not be supported	[cite:7]
8800 V15 and later	Minimum 11.3.3 MPP after conversion; cannot downgrade to earlier MPP	[cite:7]
Firmware tool outcome	Phones migrated with the tool must use Webex Calling. Steps also apply to Dedicated Instance.	[cite:7]
LGW platforms named for phased migration	ISR 1100 and 4000, Catalyst 8200/8300, Catalyst 8000V, certified third-party SBCs	[cite:1]
CSS evaluation order	Best match across every partition in the CSS. Order is only the tie-break. Null partition last. Line CSS is concatenated in front of the device CSS.	[cite:10] [cite:11]
LDAP or CSS field crosswalk	Open LDAP and CSS on the Unified CM admin page and the user in Control Hub. The guides say “map” and do not print the table, because the field names differ by UC version.	Guides say “map,” and do not print the table

08 · Troubleshooting

Cutover failures

Symptom	Likely cause	Evidence	Next move	Cite
Moved users cannot reach people still on Unified CM	Gateway or dial plan not updated for the group	Webex Calling cannot see those extensions	Update all three routing planes	[cite:3] [cite:8]
Only some members of a queue moved	Batch ignored the dependency list	Same call queue or hunt pilot	Put the dependent users back into one batch	[cite:4]
Phone will not take MPP	8821, 8831, or a V15 unit below 11.3.3	Eligibility paragraph	Remove the model or meet the firmware floor	[cite:7]
Location has no main number	The implement step was skipped	Main number can be a user or an auto attendant	Set it before calling the location done	[cite:4]
Users were never created in Webex	Phased was misread as “create them later”	Prepare: users must be provisioned even for a phased migration	Create them before the group moves	[cite:2]
Jabber and calling changed the same hour on a large site	Single-step used where dual-step is recommended	Plan article: dual step for larger customers	Split client move from calling move	[cite:3]
On-prem UC was powered off while a group remained	Phase 2 started early	Decommission after all users, soft clients, and devices have moved	Restore the path until the last group is on Webex Calling	[cite:3]
A CSS spreadsheet was treated as Cisco’s mapping	No crosswalk exists in these articles	Complex dial plan is a reason to stay, not a converted table	Do not treat a spreadsheet as Cisco’s mapping. Test the calls.	[cite:1]

09 · Self-question ladder

L1What does the introduction forbid as a method?

A lift-and-shift of the current Unified CM deployment. Redefine requirements. [cite:1]

L1What does PPDIO stand for in this guide?

Prepare, Plan, Design, Implement, Optimize. [cite:1]

L2When are users split across both platforms?

During a phased move, until everyone has transitioned. [cite:3]

L2Which three places need dial-plan updates for each group?

Unified CM, Webex Calling, and the Local Gateways. [cite:3]

L2What does Webex Calling do with a Unified CM extension it cannot see?

It sends the call to the Local Gateway, along with other unmatched destinations such as PSTN numbers. [cite:8]

L2How does the configuration workflow describe Unified CM numbering?

The Unified CM dial plan normalizes numbers as +E.164. [cite:8]

L3Who should use dual-step Jabber migration?

Larger customers. Step 1 moves Jabber to the Webex App while the app still registers to Unified CM. Step 2 moves calling. Single-step is the small-population option. [cite:3]

L3What batching does Cisco recommend, and what overrides it?

Physical sites or departments together. Feature dependencies such as a shared hunt pilot, call queue, shared line, pickup, or call park can force a tighter batch. [cite:4]

L3Which 8800 models are not eligible for MPP?

8821 and 8831. 8832NR can migrate with a feature caveat. V15 and later need at least 11.3.3 MPP and cannot downgrade. [cite:7]

L3Where do you import a Unified CM .tar?

Control Hub → Services → Upgrades & Migrations → Migration Insights, then Step 3 Migrate to Webex Calling → Start New Task. [cite:5]

L4Name two reasons the introduction gives for considering staying on premises.

Any two from the printed list. A complex dial plan or highly granular classes of service is one. A contact center that is not moving yet is another. [cite:1]

L4What will you not claim about CSS order?

An evaluation algorithm. It is not in these articles. The labs explorer is a teaching model. Read closest-match on the Unified CM that still routes the call. The labs explorer is a teaching model, and it is not the order that cluster uses. [cite:1]

10 · Lab

Paper cutover for one department

Use a lab org if you have one. The pass condition is a written batch, not a production cut.

List one department and the shared features that would force them into one batch: hunt, queue, shared line, pickup, park.
Write the three routing updates you would make for that batch: Unified CM, Webex Calling, Local Gateway.
Mark each desk phone 6800, 7800, 8800, 9800, or out of the prepare list. Flag 8821 and 8831 as not eligible for MPP.
Choose single-step or dual-step for any Jabber users and write why.
Name the location’s main number as a user or an auto attendant.
Open the dial-plan lab and normalize one on-prem national number to +E.164. Label it a study model.
Write “do not decommission” until the plan article’s phase 2.
Reflection: which dependency would have split the batch if you had migrated by last name instead of by site?

11 · Quiz

Twelve checks

0 revealed

Q1MCQ

The introduction’s instruction about the current Unified CM design is:

Lift it unchanged
Do not lift-and-shift; redefine requirements
Copy every CSS into a Webex location
Start by decommissioning Unified CM

Reveal

B. [cite:1]

Q2MCQ

Each group transition requires routing updates on:

Webex Calling only
Unified CM only
Unified CM, Webex Calling, and the Local Gateways
The phone keypad

Reveal

C. [cite:3]

Q3Scenario

A 200-person site still on Jabber wants the smallest blast radius. Which option does the plan article recommend for larger customers?

Reveal

Dual step. Webex App registers to Unified CM first. Calling moves in step 2. Single step is described for a small number of users. [cite:3]

Q4MCQ

8821 and 8831 are:

The preferred MPP targets
Not eligible to migrate to MPP
V15-only
BroadWorks phones

Reveal

B. [cite:7]

Q5MCQ

Webex Calling’s treatment of a Unified CM extension it cannot see is:

Drop
Send to the Local Gateway
Send to Partner Hub
Normalize it to an extension and stop

Reveal

B. [cite:8]

Q6Scenario

You want to migrate people alphabetically and a hunt pilot has members in three letters. What does the implement article push you toward?

Reveal

Keep users who share the hunt pilot together. Sites or departments are the recommended unit when dependencies allow. [cite:4]

Q7MCQ

Migration Insights import of Unified CM data uses:

A .tar, then Start New Task
A Genesys export
Only a screenshot
The BroadWorks do_not_move_phone flag

Reveal

A. [cite:5]

Q8MCQ

do_not_move_phone is documented as:

A Unified CM BAT column
BroadWorks only
Required for every 8800
An E911 setting

Reveal

B. [cite:9]

Q9Draw it

Draw Unified CM, the Local Gateway, and Webex Calling. Mark unmatched calls moving toward the gateway.

Reveal

That is the configuration-workflow picture: unmatched PSTN numbers and unseen Unified CM extensions go to the gateway, and the gateway routes between the two. [cite:8]

Q10MCQ

A complex dial plan or highly granular class of service is:

Automatically converted by Migration Insights
A printed reason to consider keeping call control on premises
Forbidden
A Partner Hub role

Reveal

B. [cite:1]

Q11Scenario

Phase 2 has not finished and someone wants the Unified CM publisher powered off tonight. What does the plan article say?

Reveal

On-premises UC comes out after all users, soft clients, and devices have moved. [cite:3]

Q12MCQ

The main number of a location can be assigned to:

Only a gateway
A user or a feature such as an auto attendant
Only a hunt pilot MAC
Only Partner Hub

Reveal

B. [cite:4]

12 · Audio

90 seconds. PPDIO, no lift-and-shift, three places to update, sites together unless a shared feature forces the batch.

No mp3 shipped.

45 seconds. The mistake is updating Webex Calling and leaving Unified CM and the gateway stale.

13 · Interview

“I treat Unified CM to Webex Calling as PPDIO, not a copy of the old dial plan. If we phase it, every group is a routing change on Unified CM, Webex Calling, and the Local Gateway, because Webex Calling sends extensions it cannot see to that gateway. I move a site or a department together, and I only shrink the batch when people share a hunt pilot, queue, line, pickup, or park. Jabber on a large site moves to the Webex App while it still registers to Unified CM, and calling moves second. 8821 and 8831 do not go through the MPP tool. I will not pretend a CSS crosswalk exists, and I will not decommission Unified CM until the last user is gone. BroadWorks is a different article.”

14 · Citations

Introduction, migrate Unified CM to Webex Calling — help.webex — article nbedetf — help.webex.com article nbedetf — retrieved 2026-10-14. PPDIO. Do not lift-and-shift. Flash-cut versus phased. Stay-on-premises list. LGW platforms for a phased approach: ISR 1100 and 4000, Catalyst 8200/8300, Catalyst 8000V, certified third-party SBCs.
Prepare to migrate from Unified CM to Webex Calling — help.webex — article 4yz2zd — help.webex.com article 4yz2zd. Users must be provisioned in Webex even for a phased migration. Desk phones: 6800, 7800, 8800, and 9800 series.
Plan to migrate from Unified CM to Webex Calling — help.webex — article nw9po3o — help.webex.com article nw9po3o. Single-step versus dual-step Jabber. Dial-plan and routing updates on Unified CM, Webex Calling, and the Local Gateways for each group. Decommission after phase 2.
Implement the migration from Unified CM to Webex Calling — help.webex — article q0pgpb — help.webex.com article q0pgpb. Sites or departments together. Feature dependencies. Main number. “Migrate your phone to Webex Calling” for 7800 and 8800 Enterprise to MPP. Voicemail, auto attendant, call queue, hunt group.
Migrate Unified CM data to Webex Calling — help.webex — article x974bd — help.webex.com article x974bd. Migration Insights. .tar import. Step 3 Start New Task. CSV back to Unified CM. Cloud-Connected UC can take device migration.
Migrate devices and features from Unified CM to Webex Calling — help.webex — article d2lemv — help.webex.com article d2lemv. Services → Updates & Migrations → Migrate features from UCM. Mapped feature list. Python script UserBasedUCMFeatureMigration processes CDR.
Migrate enterprise phone to Webex Calling phone firmware — help.webex — article n19c71 — help.webex.com article n19c71. 8821 and 8831 not eligible. 8832NR caveat. V15 minimum 11.3.3 MPP, no downgrade. Tool requires Webex Calling. Steps apply to Dedicated Instance.
Webex Calling configuration workflow — help.webex — article 32gfts — help.webex.com article 32gfts. Unmatched calls go to the Local Gateway, including PSTN numbers and Unified CM extensions Webex Calling cannot see. Unified CM normalizes numbers as +E.164.
Migration from BroadWorks and BroadCloud to Webex Calling — help.webex — article n1ku0vfb — help.webex.com article n1ku0vfb. Separate tool. do_not_move_phone is BroadWorks only.
Cisco CallManager System Guide, Release 4.0(1), chapter Partitions and Calling Search Spaces — Cisco — cisco.com CUCM System Guide 4.0(1), partitions and calling search spaces — retrieved 2026-10-14. Digit analysis looks through every partition for the best match. Order breaks equal matches. Null partition is last. Line CSS is placed in front of the device CSS. Combined CSS clause limit 1024 characters.
Troubleshooting Guide for Cisco Unified Communications Manager, Release 12.5(1), chapter Dial Plans and Routing Issues — Cisco — cisco.com CUCM 12.5(1) troubleshooting, dial plans — retrieved 2026-10-14. From each listed partition, take the best pattern, then choose the best among those. Equal matches go to the partition listed first. Null partition is searched last. Line and device calling search spaces are combined.

15 · Re-engineer later

CSS evaluation order is cited from the System Guide. The combined CSS clause length of 1024 characters, including separators, is in that same chapter. [cite:10]
Compare the LDAP filter and CSS on Unified CM admin with the user in Control Hub. Those screens change with the cluster version, and these articles do not print the crosswalk.
Run the tool the feature-migration article names and read that article for what it processes. The Python internals are not published and change with the script Cisco ships.
Features that are not in d2lemv’s mapped list.
The contact-center stay bullet is clipped on nbedetf (“contact center inter”). Do not invent the missing letters.

Sources and go deeper

Checked links were opened this month. A confirm row has no address because that page was not opened.

Wikipedia Webex (Wikipedia) last checked 2026-10
Vendor doc Webex Help Center last checked 2026-10
DevDocs Webex developer documentation last checked 2026-10
DevDocs Webex developer getting started last checked 2026-10
Community Webex community last checked 2026-10
SRND Cisco Collaboration design zone last checked 2026-10
RFC RFC 3261 SIP: Session Initiation Protocol last checked 2026-10
Port table IANA service name and port number registry last checked 2026-10
Port table Port reference for Webex Calling last checked 2026-10
RFC RFC 3263 Locating SIP Servers last checked 2026-10
RFC RFC 3264 An Offer/Answer Model with SDP last checked 2026-10
Wikipedia Session Initiation Protocol (Wikipedia) last checked 2026-10
RFC RFC 3550 RTP last checked 2026-10
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