Coexistence Design¶
2.6 Interworking Design (CUCM-Webex Coexistence)¶
2.6.1 Coexistence Architecture Overview¶
During the migration period, CUCM and Webex Calling must coexist and interoperate seamlessly. This section details the architecture for the coexistence phase.
+-----------------------------------------------------------------------------+
| CUCM - WEBEX CALLING COEXISTENCE ARCHITECTURE |
+-----------------------------------------------------------------------------+
| |
| +-----------------+ |
| | WEBEX CLOUD | |
| | (Mumbai + Chennai DCs) | |
| +--------+--------+ |
| | |
| | SIP Trunk |
| | (TLS/SRTP) |
| | |
| +--------v--------+ |
| | CUBE/LGW | |
| | Mumbai (HA) | |
| | | |
| | Routes between: | |
| | * Webex Cloud | |
| | * CUCM Cluster | |
| | * PSTN | |
| +---+---------+---+ |
| | | |
| +-------------------+ +-------------------+ |
| | | |
| v v |
| +-----------------------+ +-----------------------+ |
| | CUCM CLUSTER | | WEBEX CALLING | |
| | (Remaining Users) | | (Migrated Users) | |
| | ----------------- | | ----------------- | |
| | * CC Agents (175) | | * Enterprise users | |
| | * Pending migration | | * Hunt Groups | |
| | * UCCX integration | | * Auto Attendants | |
| | | <-----------------> | | |
| | Extensions: | Inter-cluster | Extensions: | |
| | Remaining batches | calling via | Migrated ranges | |
| | | CUBE trunk | | |
| +-----------------------+ +-----------------------+ |
| |
| COEXISTENCE PERIOD: Migration batches 1-7 (approximately 8-12 weeks) |
| |
| CALL FLOW SUMMARY: |
| =================== |
| Webex -> CUCM: Webex Cloud -> CUBE -> CUCM SIP Trunk -> CUCM User |
| CUCM -> Webex: CUCM -> SIP Trunk -> CUBE -> Webex Cloud -> Webex User |
| Webex -> PSTN: Webex Cloud -> Zone/LGW -> PSTN (India) |
| CUCM -> PSTN: CUCM -> CUBE -> PSTN (existing routing) |
| |
+-----------------------------------------------------------------------------+
2.6.2 Coexistence Dial Plan Integration¶
Routing Logic During Coexistence:
| From | To | Route Path | Dial String |
|---|---|---|---|
| Webex User | CUCM User | Webex -> CUBE -> CUCM | Extension (4-digit) or ESN (8-XX-XXXX) |
| CUCM User | Webex User | CUCM -> CUBE -> Webex | Extension (4-digit) or ESN (8-XX-XXXX) |
| Webex User | PSTN (India) | Webex -> Zone -> LGW -> PSTN | 9 + number |
| CUCM User | PSTN | CUCM -> CUBE -> PSTN | 9 + number |
| External | Webex User | PSTN -> LGW -> Webex | DID |
| External | CUCM User | PSTN -> CUBE -> CUCM | DID |
CUBE Dial Peer Configuration for Coexistence:
! ============================================================
! CUBE Configuration - Coexistence Phase
! Routes calls between CUCM, Webex, and PSTN
! ============================================================
! --- Dial Peer for CUCM to Webex ---
dial-peer voice 300 voip
description CUCM-to-Webex-Coexistence
destination-pattern [1-5]... ! Extensions migrated to Webex
session protocol sipv2
session target dns:webexapis.com
session transport tcp tls
voice-class sip tenant 100
voice-class codec 1
dtmf-relay rtp-nte
srtp
! --- Dial Peer for Webex to CUCM ---
dial-peer voice 400 voip
description Webex-to-CUCM-Coexistence
destination-pattern [1-5]... ! Extensions still on CUCM
session protocol sipv2
session target ipv4:10.1.1.10 ! CUCM Subscriber
voice-class codec 1
dtmf-relay rtp-nte
! --- Inbound from Webex for CUCM destinations ---
dial-peer voice 401 voip
description Webex-Inbound-to-CUCM
incoming uri via Webex
session protocol sipv2
voice-class sip tenant 100
voice-class codec 1
dtmf-relay rtp-nte
srtp
! --- Translation Rules for Extension Routing ---
voice translation-rule 10
rule 1 /^1/ /1/ ! Mumbai extensions - check if Webex or CUCM
rule 2 /^2/ /2/ ! Chennai extensions
rule 3 /^3/ /3/ ! Branch extensions
rule 4 /^4/ /4/ ! EMEA extensions
rule 5 /^5/ /5/ ! Americas extensions
2.6.3 Coexistence Call Flow Diagrams¶
Scenario 1: Webex User Calls CUCM User (Internal)¶
+-----------------------------------------------------------------------------+
| CALL FLOW: Webex User (Ext 1500) -> CUCM User (Ext 1001) |
+-----------------------------------------------------------------------------+
| |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| | Webex | | Webex | | CUBE | | CUCM | | CUCM | |
| | User |--->| Cloud |--->| LGW |--->| Cluster |--->| User | |
| | (1500) | | | | | | | | (1001) | |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| |
| 1. Webex user dials extension 1001 |
| 2. Webex Cloud recognizes 1001 is NOT on Webex (not yet migrated) |
| 3. Webex routes call to CUBE via SIP trunk |
| 4. CUBE receives call, matches dial-peer for CUCM destinations |
| 5. CUBE sends INVITE to CUCM cluster |
| 6. CUCM routes call to extension 1001 |
| 7. CUCM user phone rings |
| 8. Media path: Webex User <-> CUBE <-> CUCM User |
| |
| CODEC NEGOTIATION: G.711 (transcoding at CUBE if needed) |
| |
+-----------------------------------------------------------------------------+
Scenario 2: CUCM User Calls Webex User (Internal)¶
+-----------------------------------------------------------------------------+
| CALL FLOW: CUCM User (Ext 1001) -> Webex User (Ext 2500) |
+-----------------------------------------------------------------------------+
| |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| | CUCM | | CUCM | | CUBE | | Webex | | Webex | |
| | User |--->| Cluster |--->| LGW |--->| Cloud |--->| User | |
| | (1001) | | | | | | | | (2500) | |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| |
| 1. CUCM user dials extension 2500 |
| 2. CUCM routes pattern 2XXX to SIP trunk (CUBE) |
| 3. CUBE receives call, matches dial-peer for Webex destinations |
| 4. CUBE sends INVITE to Webex Cloud (TLS/SRTP) |
| 5. Webex Cloud routes call to extension 2500 |
| 6. Webex user's Webex App/phone rings |
| 7. Media path: CUCM User <-> CUBE <-> Webex User |
| |
+-----------------------------------------------------------------------------+
Scenario 3: External PSTN Call to Webex User (via DID)¶
+-----------------------------------------------------------------------------+
| CALL FLOW: PSTN -> Webex User (DID +91-22-4960-1500) |
+-----------------------------------------------------------------------------+
| |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| | PSTN | | Tata | | CUBE | | Webex | | Webex | |
| | Caller |--->| SIP |--->| LGW |--->| Cloud |--->| User | |
| | | | | | | | | | (1500) | |
| +---------+ +---------+ +---------+ +---------+ +---------+ |
| |
| 1. External caller dials +91-22-4960-1500 |
| 2. Tata SIP trunk delivers call to CUBE |
| 3. CUBE receives INVITE with To: +912249601500 |
| 4. CUBE translates DID to extension 1500 |
| 5. CUBE checks: Is 1500 on Webex? YES (migrated user) |
| 6. CUBE sends INVITE to Webex Cloud |
| 7. Webex routes to user 1500 |
| 8. User's Webex App/phone rings with CLI display |
| |
| KEY: DID-to-Extension translation must be maintained in CUBE |
| during coexistence to route calls to correct platform |
| |
+-----------------------------------------------------------------------------+
2.6.4 Coexistence Testing Procedures¶
Pre-Migration Test Matrix:
| Test Case | From | To | Expected Result | Pass/Fail |
|---|---|---|---|---|
| TC-01 | Webex User | CUCM User (same site) | Call completes, 2-way audio | [ ] |
| TC-02 | CUCM User | Webex User (same site) | Call completes, 2-way audio | [ ] |
| TC-03 | Webex User | CUCM User (different site) | Call completes via ESN | [ ] |
| TC-04 | CUCM User | Webex User (different site) | Call completes via ESN | [ ] |
| TC-05 | Webex User | PSTN (India) | Call completes via Zone/LGW | [ ] |
| TC-06 | CUCM User | PSTN (India) | Call completes via CUBE | [ ] |
| TC-07 | PSTN | Webex User (via DID) | Call completes, CLI displayed | [ ] |
| TC-08 | PSTN | CUCM User (via DID) | Call completes, CLI displayed | [ ] |
| TC-09 | Webex User | Hunt Group (CUCM) | Call reaches HG, cycles agents | [ ] |
| TC-10 | CUCM User | Hunt Group (Webex) | Call reaches HG, cycles agents | [ ] |
| TC-11 | Webex User | Auto Attendant (Webex) | Menu prompts, transfers work | [ ] |
| TC-12 | Webex User | CUCM User (transfer) | Transfer completes | [ ] |
| TC-13 | CUCM User | Webex User (transfer) | Transfer completes | [ ] |
| TC-14 | Webex User | Conference (3-party) | All parties hear each other | [ ] |
| TC-15 | Webex User | Voicemail (Unity) | VM deposit and retrieval works | [ ] |
2.6.5 Coexistence Troubleshooting Guide¶
+-----------------------------------------------------------------------------+
| COEXISTENCE TROUBLESHOOTING DECISION TREE |
+-----------------------------------------------------------------------------+
| |
| SYMPTOM: Webex user cannot call CUCM user |
| =========================================== |
| |
| Step 1: Check if CUCM user extension is in CUBE dial plan |
| -> Run: show dial-peer voice summary |
| -> Verify destination-pattern matches CUCM extensions |
| |
| Step 2: Check SIP trunk status to CUCM |
| -> Run: show sip-ua status |
| -> Verify TCP connection to CUCM is active |
| |
| Step 3: Check for 4xx/5xx errors in CUBE |
| -> Run: debug ccsip messages |
| -> Common issues: |
| - 404 Not Found: Extension not registered on CUCM |
| - 503 Service Unavailable: CUCM overloaded |
| - 488 Not Acceptable: Codec mismatch |
| |
| Step 4: Check Webex-to-CUBE connectivity |
| -> Control Hub -> Calling -> Trunk -> Status |
| -> Verify trunk shows "Active" |
| |
+-----------------------------------------------------------------------------+
| |
| SYMPTOM: CUCM user cannot call Webex user |
| =========================================== |
| |
| Step 1: Verify SIP trunk to CUBE in CUCM |
| -> CUCM Admin -> Device -> Trunk -> Status |
| -> Should show "Full Service" |
| |
| Step 2: Check route pattern in CUCM |
| -> Route patterns for migrated extensions should point to CUBE |
| -> If extension range not routed, add route pattern |
| |
| Step 3: Check CUBE tenant configuration for Webex |
| -> Verify credentials are correct |
| -> Check TLS certificate validity |
| |
+-----------------------------------------------------------------------------+
| |
| SYMPTOM: One-way audio between platforms |
| ======================================== |
| |
| Step 1: Check media binding in CUBE |
| -> Verify "bind media source-interface" is correct |
| -> Media interface must be reachable from both CUCM and Webex |
| |
| Step 2: Check NAT/firewall traversal |
| -> Webex media uses UDP 19560-65535 |
| -> CUCM media uses UDP 16384-32767 |
| -> Both must be allowed through firewall |
| |
| Step 3: Verify SRTP settings match |
| -> Webex requires SRTP (encrypted) |
| -> If CUCM side is RTP, CUBE must encrypt/decrypt |
| |
+-----------------------------------------------------------------------------+
2.6.6 Coexistence Limitations¶
| Limitation | Impact | Workaround |
|---|---|---|
| No direct SIP signaling Webex<->CUCM | All calls traverse CUBE | Ensure CUBE capacity |
| Codec transcoding required | CPU overhead on CUBE | Size CUBE appropriately |
| Hunt Group split not supported | HG members must be on same platform | Migrate entire HG together |
| Shared Line across platforms not supported | Virtual Line users must be on Webex | Migrate all VL users together |
| CUCM Barge/Monitor to Webex users not supported | Supervisor functions limited | Wait for Phase 2 (CC migration) |
| Extension mobility across platforms not supported | Users must use assigned platform | Plan user assignments carefully |