Chapter 2: Webex Calling Design¶
Document Reference: ABV-COLLAB-MIG-2026 | Chapter 2 FICTIONAL NUMBER DISCLAIMER -- All telephone numbers, DID ranges, toll-free numbers, and ITN numbers in this document are fictional and used for illustrative purposes only. Ranges used: India
+91-XX-4960-XXXX, India Toll-Free1800-266-10XX, UK Freephone+44-800-096-XXXX, Germany Freephone+49-800-096-XXXX. Do not dial these numbers.Cross-References: Chapter 1 (Discovery), Chapter 4 (Compliance), Chapter 5 (DNS/Network) Related Projects: ABV-SDWAN-2024 (SD-WAN), ABV-DNAC-2024 (DNA Center)
2.1 Webex Calling Architecture Overview¶
2.1.1 Multi-Tenant Platform Selection¶
Abhavtech.com will deploy Webex Calling Multi-Tenant (MT) platform, the standard cloud calling solution for enterprise deployments.
WEBEX CALLING PLATFORM COMPARISON
WEBEX CALLING MT DEDICATED INSTANCE
(Multi-Tenant) (Single-Tenant)
Cloud-native Isolated instance
Shared infrastructure Dedicated resources
Automatic updates Custom configuration
Regional data centers SLA guarantees
Standard features Large enterprise
Best for: 100-50K users Best for: 50K+ users
ABHAVTECH SELECTION
SELECTION RATIONALE:
4,200 users (within MT scale limits)
Multi-region deployment (APAC/UK/EU/US)
Standard feature requirements
Cloud-native management via Control Hub
Cost-effective licensing model
Webex Calling MT Scale Limits (per Organization):
| Component | Maximum | Abhavtech Requirement | Utilization |
|---|---|---|---|
| Users & Workspaces | 150,000 | 4,200 | 2.8% |
| Locations | 15,000 | 14 | 0.1% |
| Virtual Lines | 250,000 | 45 | <0.1% |
| Call Queues (per location) | 1,000 | 15 | 1.5% |
| Hunt Groups (per location) | 1,000 | 13 | 1.3% |
| Auto Attendants (per location) | 1,000 | 8 | 0.8% |
| Trunks (per location) | 100 | 6 | 6% |
2.1.2 Calling Region Strategy¶
Webex Calling requires strategic region selection based on regulatory requirements, data residency needs, and geographic proximity to users.
ABHAVTECH CALLING REGION ASSIGNMENT
WEBEX CONTROL HUB
(admin.webex.com)
APAC REGION UK REGION EU REGION
Home Region Separate Separate
Post-Brexit GDPR
Mumbai HQ London Frankfurt
Chennai
Bangalore Users: 520 Users: 280
Delhi
Noida
Pune
Hyderabad
US REGION
Users: 2,400
(India) Americas
New Jersey
Dallas
Users: 750
CRITICAL: Home region (APAC) is set during first location creation
and CANNOT be changed. All signaling routes to home region.
Calling Region Assignment Matrix:
| Location | Country | Calling Region | Data Center | Rationale |
|---|---|---|---|---|
| Mumbai HQ | India | India | Mumbai + Chennai | Home region, DoT compliance |
| Chennai | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| Bangalore | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| Delhi | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| Noida | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| Pune | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| Hyderabad | India | India | Mumbai + Chennai | DoT toll bypass compliance |
| London | UK | UK | London + Manchester | Post-Brexit separate region |
| Frankfurt | Germany | EU | Frankfurt + Amsterdam | GDPR, BSI C5 compliance |
| New Jersey | USA | US | US Data Centers | Americas operations |
| Dallas | USA | US | US Data Centers | Americas operations |
| Remote/WFH India | India | India | Mumbai + Chennai | ITN numbers for WFH |
| Remote/WFH EMEA | UK/EU | UK/EU | Regional | Follow office location |
| Remote/WFH Americas | USA | US | US | Follow office location |
2.1.3 Data Residency by Region¶
WEBEX CALLING DATA RESIDENCY ARCHITECTURE
DATA TYPE STORAGE LOCATION
* * * * * * * * * * * * * * * * * * * * * * * * *
Signaling Data - Home Region Data Center (Mumbai + Chennai DCs)
Call setup/teardown All control plane signaling
Presence User provisioning data
Configuration Organization settings
Media Data - Regional Media POPs
Voice RTP streams Mumbai + Chennai DCs (India calls)
Audio packets London (UK calls)
Frankfurt (EU calls)
US POPs (Americas calls)
CDR/Analytics - Regional Processing
Call detail records GDPR: EU-processed for EU users
Quality metrics UK: UK-processed for UK users
Usage reports India: Mumbai DC-processed
Voicemail - Webex Cloud (Regional)
Message storage 100MB per user standard
Transcriptions Regional storage compliance
COMPLIANCE MAPPING:
India Mumbai + Chennai DCs (APAC) DoT/TRAI compliant
UK London/Manchester DC UK GDPR, Cyber Essentials
Germany Frankfurt/Amsterdam DC EU GDPR, BSI C5, Cloud CoC L3
Americas US Data Centers SOC2, ISO27001
2.1.4 Media POPs & Edge Locations¶
Webex Calling optimizes media quality using regional Points of Presence (POPs) for media relay while maintaining signaling through the home region.
WEBEX MEDIA POP ARCHITECTURE - ABHAVTECH
WEBEX CLOUD CORE
Mumbai + Chennai DCs (Home)
User provisioning
Call signaling
Configuration
APAC POPs EMEA POPs US POPs
Mumbai + Chennai London Ashburn
Mumbai Frankfurt Dallas
Chennai Amsterdam San Jose
Hong Kong Manchester Chicago
India Sites EMEA Sites Americas Sites
Mumbai HQ London New Jersey
Chennai Frankfurt Dallas
Bangalore
Delhi/Noida
Pune/Hyderabad
MEDIA OPTIMIZATION:
Signaling: Always via Mumbai + Chennai DCs (home region)
Media: Via nearest regional POP
ICE negotiation selects optimal media path
SRTP encryption end-to-end
Expected Latency by Location:
| Location | Nearest Media POP | Expected Latency | Quality Impact |
|---|---|---|---|
| Mumbai | Mumbai DC | 20-40ms | Excellent |
| Chennai | Chennai DC | 25-45ms | Excellent |
| Bangalore | Mumbai + Chennai | 30-50ms | Excellent |
| Delhi/Noida | Mumbai + Chennai | 40-60ms | Good |
| London | London | 10-30ms | Excellent |
| Frankfurt | Frankfurt | 15-35ms | Excellent |
| New Jersey | Ashburn | 10-25ms | Excellent |
| Dallas | Dallas | 10-25ms | Excellent |
2.2 Location Design¶
2.2.1 Location Hierarchy Overview¶
ABHAVTECH WEBEX CALLING LOCATION HIERARCHY
ORGANIZATION
Abhavtech.com
Home: APAC
INDIA (APAC) EMEA AMERICAS
7 Locations 2 Locations 2 Locations
2,400 Users 800 Users 750 Users
Mumbai Branch London Frank- New Dallas
HQ Sites furt Jersey
1,200 1,200 520 280 480 270
Note: Branch Sites include Chennai (450), Bangalore (180), Delhi (150),
Noida (120), Pune (100), Hyderabad (200). WFH users: 250 separate.
2.2.2 India Locations Configuration¶
Mumbai HQ (ABV-IN-MUM)¶
LOCATION: MUMBAI HQ (ABV-IN-MUM)
GENERAL SETTINGS
* * * * * * * * * * * * * * * *
Location Name: ABV-Mumbai-HQ
Site Code: 81
Address: Bandra Kurla Complex, Mumbai 400051, India
Timezone: Asia/Kolkata (GMT+5:30)
Language: English (India)
Announcement Language: en_IN
USER ALLOCATION
* * * * * * * * * * * * * * *
Total Users: 1,200
Enterprise Users: 1,080
Contact Center Agents: 120 (Phase 2 - remain on UCCX until migration)
Phone Devices: 850
Soft Client Only: 350
EXTENSION RANGE
* * * * * * * * * * * * * * *
Extension Length: 4 digits
Extension Range: 1000-1999
Steering Digit: 8 (for ESN dialing)
Outside Access Code: 9
PSTN CONFIGURATION
* * * * * * * * * * * * * * * * * *
PSTN Type: Premises-based (Local Gateway)
LGW Address: lgw-mumbai-01.abhavtech.com
LGW HA Pair: lgw-mumbai-02.abhavtech.com
Trunk Type: Certificate-based registration
Route Group: RG-Mumbai-LGW
INDIA COMPLIANCE
* * * * * * * * * * * * * * * *
Zone: Zone-Mumbai-Circle
Trusted Network Edge: Mumbai-Edge (103.15.XX.XXX/24)
Telecom Circle: Mumbai
PSTN Provider: Tata Communications
DID INVENTORY
* * * * * * * * * * * * *
Main Number: +91-22-4960-0000
DID Range: +91-22-4960-0001 to +91-22-4960-1999
Backup DIDs: +91-22-4961-0000 to +91-22-4961-0499 (Airtel)
Toll-Free: 1800-266-1000, 1800-266-1001 (shared)
Total DIDs: 2,500
FEATURES
* * * * * * * *
Main Auto Attendant: AA-Mumbai-Main
Hunt Groups: 4 (Reception, IT, HR, Finance)
Call Queues: 3 (Support, Sales, General)
Call Park Extensions: 10 (#7810-#7819)
Pickup Groups: 8 (department-based)
EMERGENCY SERVICES
* * * * * * * * * * * * * * * * * *
Emergency Number: 100 (Police), 101 (Fire), 102 (Ambulance)
Callback Number: +91-22-4960-0000
Address Validation: Manual (E-CNAM not available in India)
India Branch Sites Summary¶
| Site Code | Location | Users | Phones | Extension Range | Telecom Circle | Zone | LGW |
|---|---|---|---|---|---|---|---|
| 81 | Mumbai HQ | 1,200 | 850 | 1000-2199 | Mumbai | Zone-Mumbai | lgw-mumbai-01/02 |
| 82 | Chennai | 450 | 320 | 2200-2649 | Tamil Nadu | Zone-TamilNadu | lgw-chennai-01/02 |
| 83 | Bangalore | 180 | 120 | 2650-2829 | Karnataka | Zone-Karnataka | lgw-bangalore-01 |
| 84 | Delhi | 150 | 100 | 2830-2979 | Delhi | Zone-Delhi | lgw-delhi-01 |
| 85 | Noida | 120 | 80 | 2980-3099 | UP West | Zone-UPWest | lgw-noida-01 |
| 86 | Pune | 100 | 60 | 3100-3199 | Mumbai* | Zone-Mumbai | lgw-mumbai-01/02 |
| 87 | Hyderabad | 200 | 140 | 3200-3399 | AP/Telangana | Zone-APTelangana | lgw-hyderabad-01 |
Note: Pune is in Maharashtra circle, shares Zone and LGW with Mumbai
India Location - Network Details¶
| Location | Site Code | Trusted Edge IP | Internal Subnet | MPLS Circuit | Internet Bandwidth |
|---|---|---|---|---|---|
| Mumbai HQ | 81 | 103.15.XX.XXX/24 | 10.1.0.0/16 | 500 Mbps | 1 Gbps DIA (redundant) |
| Chennai | 82 | 103.25.XX.XXX/24 | 10.2.0.0/16 | 200 Mbps | 500 Mbps DIA (redundant) |
| Bangalore | 83 | 103.20.XX.XXX/24 | 10.3.0.0/20 | - | 200 Mbps DIA (+ LTE) |
| Delhi | 84 | 103.30.XX.XXX/24 | 10.4.0.0/20 | - | 200 Mbps DIA (+ LTE) |
| Noida | 85 | 103.35.XX.XXX/24 | 10.5.0.0/20 | - | 100 Mbps DIA (+ LTE) |
| Pune | 86 | 103.15.XX.XXX/24* | 10.6.0.0/20 | 50 Mbps | 100 Mbps DIA |
| Hyderabad | 87 | 103.40.XX.XXX/24 | 10.7.0.0/20 | - | 200 Mbps DIA (+ LTE) |
Pune shares Mumbai's Trusted Edge through MPLS backhaul
2.2.3 EMEA Locations Configuration¶
London (ABV-UK-LON)¶
LOCATION: LONDON (ABV-UK-LON)
GENERAL SETTINGS
* * * * * * * * * * * * * * * *
Location Name: ABV-London
Site Code: 91
Address: Canary Wharf, London E14, United Kingdom
Timezone: Europe/London (GMT/BST)
Language: English (UK)
Announcement Language: en_GB
USER ALLOCATION
* * * * * * * * * * * * * * *
Total Users: 520
Phone Devices: 380
Soft Client Only: 140
EXTENSION RANGE
* * * * * * * * * * * * * * *
Extension Length: 4 digits
Extension Range: 4000-4519
Steering Digit: 8 (for ESN dialing)
Outside Access Code: 9
PSTN CONFIGURATION
* * * * * * * * * * * * * * * * * *
PSTN Type: Cloud Connected PSTN (CCPP)
CCPP Provider: IntelePeer UK
Route Group: RG-UK-CCPP
UK COMPLIANCE
* * * * * * * * * * * * *
Calling Region: UK (separate from EU post-Brexit)
Data Center: London + Manchester (HA pair)
Ofcom Registration: Handled by CCPP provider
UK GDPR: Data processed in UK DCs only
DID INVENTORY
* * * * * * * * * * * * *
Main Number: +44-20-4960-0000
DID Range: +44-20-4960-0001 to +44-20-4960-0799
Toll-Free: +44-800-096-1000
Total DIDs: 800
FEATURES
* * * * * * * *
Main Auto Attendant: AA-London-Main
Hunt Groups: 2 (Reception, Sales)
Call Queues: 1 (UK Support)
Call Park Extensions: 5 (#7910-#7914)
EMERGENCY SERVICES
* * * * * * * * * * * * * * * * * *
Emergency Number: 999 / 112
Callback Number: +44-20-4960-0000
Address Validation: Automatic (UK E-CNAM)
CRITICAL: UK is a SEPARATE Webex Calling region from EU
London users MUST be assigned to UK region, not EU
Frankfurt (ABV-EU-FRA)¶
LOCATION: FRANKFURT (ABV-EU-FRA)
GENERAL SETTINGS
* * * * * * * * * * * * * * * *
Location Name: ABV-Frankfurt
Site Code: 92
Address: Westend, Frankfurt 60325, Germany
Timezone: Europe/Berlin (CET/CEST)
Language: German
Announcement Language: de_DE
USER ALLOCATION
* * * * * * * * * * * * * * *
Total Users: 280
Phone Devices: 200
Soft Client Only: 80
EXTENSION RANGE
* * * * * * * * * * * * * * *
Extension Length: 4 digits
Extension Range: 4520-4799
Steering Digit: 8 (for ESN dialing)
Outside Access Code: 0 (German standard)
PSTN CONFIGURATION
* * * * * * * * * * * * * * * * * *
PSTN Type: Cloud Connected PSTN (CCPP)
CCPP Provider: IntelePeer EU
Route Group: RG-EU-CCPP
GERMANY/EU COMPLIANCE
* * * * * * * * * * * * * * * * * * * * *
Calling Region: EU
Data Center: Frankfurt + Amsterdam (HA pair)
BSI C5: Webex certified (17 domains, 114 requirements)
EU Cloud CoC: Level 3 compliance
GDPR: Full compliance, EU data processing only
BaFin: Not applicable (Abhavtech not financial sector)
DID INVENTORY
* * * * * * * * * * * * *
Main Number: +49-69-4960-0000
DID Range: +49-69-4960-0001 to +49-69-4960-0499
Toll-Free: +49-800-096-1000 (German)
Total DIDs: 500
FEATURES
* * * * * * * *
Main Auto Attendant: AA-Frankfurt-Main (German prompts)
Hunt Groups: 2 (Reception, Support)
Call Queues: 1 (EU Support)
Call Park Extensions: 5 (#7920-#7924)
EMERGENCY SERVICES
* * * * * * * * * * * * * * * * * *
Emergency Number: 112 (EU standard)
Callback Number: +49-69-4960-0000
Address Validation: Automatic (German E-CNAM)
2.2.4 Americas Locations Configuration¶
| Setting | New Jersey (ABV-US-NJ) | Dallas (ABV-US-DAL) |
|---|---|---|
| Site Code | 93 | 94 |
| Address | Newark, NJ 07102 | Dallas, TX 75201 |
| Timezone | America/New_York | America/Chicago |
| Users | 480 | 270 |
| Phones | 350 | 180 |
| Extension Range | 5000-5479 | 5480-5749 |
| OAC | 9 | 9 |
| PSTN Type | CCPP | CCPP |
| CCPP Provider | IntelePeer US | IntelePeer US |
| Main Number | +1-201-496-0000 | +1-214-496-0000 |
| DIDs | 800 | 500 |
| Toll-Free | +1-800-096-1000 (shared) | Shared with NJ |
| Emergency | 911 (E911 enabled) | 911 (E911 enabled) |
| Hunt Groups | 2 | 1 |
| Call Queues | 1 | 1 |
2.2.5 Remote/WFH Users Configuration¶
REMOTE/WFH USERS - WEBEX CALLING DESIGN
TOTAL WFH USERS: 250 (globally distributed)
Region Users PSTN Solution Rationale
India WFH 150 ITN (9XXXXXXXXX) Toll bypass exempt
EMEA WFH 60 Standard (CCPP) No toll bypass rules
Americas WFH 40 Standard (CCPP) No toll bypass rules
INDIA WFH USERS (ITN Solution)
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Why ITN for India WFH?
DoT regulations require PSTN calls to egress from user's telecom circle
WFH users may work from ANY location in India
Traditional Zone/Edge enforcement would BLOCK their PSTN calls
ITN (Internet Telephony Numbers) are EXEMPT from toll bypass rules
ITN Configuration:
Number Format: 9XXXXXXXXX (10-digit, starts with 9)
Provider: Tata Communications
Assignment: Per-user ITN (no shared numbers)
Range: +91-9XXXXXXXXX (150 numbers)
Restrictions: Cannot call when outside India
ITN Assignment Matrix:
User Location ITN Range Notes
Mumbai WFH 9XX-1000-XX Primary allocation
Other India WFH 9XX-1100-XX Secondary allocation
EMEA/AMERICAS WFH
* * * * * * * * * * * * * * * *
No special PSTN restrictions
Assigned to parent office location
Uses standard CCPP numbers
Full Webex Calling features
DEVICE STRATEGY FOR WFH
* * * * * * * * * * * * * * * * * * * * * * * *
Primary: Webex App (desktop/mobile)
Secondary: Cisco MPP phone (optional, shipped to home)
Headset: Cisco 730 or Jabra Evolve2 (provided)
2.3 PSTN Design¶
2.3.1 Global PSTN Strategy Overview¶
ABHAVTECH GLOBAL PSTN STRATEGY
PSTN CONNECTIVITY OPTIONS
LOCAL GATEWAY CCPP ITN (India)
(Premises PSTN) (Cloud PSTN) (Non-Geographic)
Customer SBC Provider SBC Cloud-native
Existing PSTN Port numbers 9XXXXXXXXX
Zone/Edge No hardware No Zone/Edge
(India only) Zone/Edge India WFH
(India only)
INDIA OFFICES EMEA & AMERICAS INDIA WFH
Mumbai London (CCPP) 150 users
Chennai Frankfurt Toll bypass
Bangalore New Jersey exempt
Delhi/Noida Dallas
Pune/Hyd
STRATEGIC RATIONALE:
* * * * * * * * * * * * * * * * * * * *
India (LGW): Leverage existing Tata/Airtel contracts
Maintain CUBE investment
DoT toll bypass compliance via Zone/Edge
EMEA/Americas (CCPP): No local compliance restrictions
Simplified management
Provider handles regulatory
India WFH (ITN): Exempt from toll bypass
Works from any India location
Tata Communications provider
2.3.2 India: Local Gateway Architecture¶
2.3.2.1 Per-Circle LGW Requirements¶
INDIA LOCAL GATEWAY ARCHITECTURE
WEBEX CALLING
(Mumbai + Chennai DCs)
Zone: Zone: Zone:
Mumbai Karnataka Tamil Nadu
Circle Circle Circle
Trusted Edge: Trusted Edge: Trusted Edge:
103.15.50.x/24 103.20.70.x/24 103.25.60.x/24
10.1.x.x/16 10.3.x.x/20 10.2.x.x/16
LGW: CUBE LGW: CUBE LGW: CUBE
Mumbai (HA) Bangalore Chennai (HA)
ISR 4451-X ISR 4331 ISR 4351
IOS-XE 17.12 IOS-XE 17.12 IOS-XE 17.12
PSTN: Tata PSTN: Tata PSTN: Tata
Mumbai SIP Bangalore Chennai SIP
+91-22-XXXX +91-80-XXXX +91-44-XXXX
Zone: Zone: Zone:
Delhi UP West AP/Telangana
Circle Circle Circle
Trusted Edge: Trusted Edge: Trusted Edge:
103.30.80.x/24 103.35.90.x/24 103.40.100.x
LGW: CUBE LGW: CUBE LGW: CUBE
Delhi Noida Hyderabad
ISR 4331 ISR 4331 ISR 4331
PSTN: Tata PSTN: Tata PSTN: Tata
Delhi SIP Noida SIP Hyderabad
+91-11-XXXX +91-120-XXX +91-40-XXXX
TOLL BYPASS ENFORCEMENT:
* * * * * * * * * * * * * * * * * * * * * * * *
Webex checks user IP against Trusted Network Edge definitions
Routes PSTN calls ONLY through user's assigned Zone LGW
Roaming users (different zone) PSTN call BLOCKED
LGW Specifications by Circle:
| LGW | Platform | IOS-XE | Capacity | HA | PSTN Circuits | Locations Served |
|---|---|---|---|---|---|---|
| lgw-mumbai-01/02 | ISR 4451-X | 17.12.2 | 1000 calls | Yes | 30 SIP channels | Mumbai, Pune |
| lgw-chennai-01/02 | ISR 4351 | 17.12.2 | 500 calls | Yes | 15 SIP channels | Chennai |
| lgw-bangalore-01 | ISR 4331 | 17.12.2 | 350 calls | No | 10 SIP channels | Bangalore |
| lgw-delhi-01 | ISR 4331 | 17.12.2 | 250 calls | No | 8 SIP channels | Delhi |
| lgw-noida-01 | ISR 4331 | 17.12.2 | 200 calls | No | 6 SIP channels | Noida |
| lgw-hyderabad-01 | ISR 4331 | 17.12.2 | 80 calls | No | 3 SIP channels | Hyderabad |
2.3.2.2 Zone & Trusted Network Edge Configuration¶
Step-by-Step: Creating Zones in Control Hub
- Navigate to Control Hub > Calling > Service Settings > Zones
- Click Create Zone
- Configure zone settings per circle
Abhavtech Zone Configuration:
| Zone Name | Telecom Circle | Locations | LGW | Trusted Edge IPs (Public) | Internal Subnets |
|---|---|---|---|---|---|
| Zone-Mumbai-Circle | Mumbai | Mumbai HQ, Pune | lgw-mumbai-01/02 | 103.15.XX.XXX/24 | 10.1.0.0/16, 10.6.0.0/20 |
| Zone-TamilNadu-Circle | Tamil Nadu | Chennai | lgw-chennai-01/02 | 103.25.XX.XXX/24 | 10.2.0.0/16 |
| Zone-Karnataka-Circle | Karnataka | Bangalore | lgw-bangalore-01 | 103.20.XX.XXX/24 | 10.3.0.0/20 |
| Zone-Delhi-Circle | Delhi | Delhi | lgw-delhi-01 | 103.30.XX.XXX/24 | 10.4.0.0/20 |
| Zone-UPWest-Circle | UP West | Noida | lgw-noida-01 | 103.35.XX.XXX/24 | 10.5.0.0/20 |
| Zone-APTelangana-Circle | AP/Telangana | Hyderabad | lgw-hyderabad-01 | 103.40.XX.XXX/24 | 10.7.0.0/20 |
Step-by-Step: Adding Trusted Network Edge
- Navigate to Control Hub > Calling > Service Settings > Trusted Network Edge
- Click Add Trusted Edge
- Configure IP ranges
# Control Hub - Trusted Network Edge Configuration
trusted_network_edges:
- name: "Mumbai-Edge"
description: "Mumbai office public IP range"
ip_addresses:
- "103.15.XX.XXX/24"
internal_subnets:
- "10.1.0.0/16"
- "10.6.0.0/20" # Pune backhauls through Mumbai
- name: "Chennai-Edge"
description: "Chennai office public IP range"
ip_addresses:
- "103.25.XX.XXX/24"
internal_subnets:
- "10.2.0.0/16"
- name: "Bangalore-Edge"
description: "Bangalore office public IP range"
ip_addresses:
- "103.20.XX.XXX/24"
internal_subnets:
- "10.3.0.0/20"
- name: "Delhi-Edge"
description: "Delhi office public IP range"
ip_addresses:
- "103.30.XX.XXX/24"
internal_subnets:
- "10.4.0.0/20"
- name: "Noida-Edge"
description: "Noida office public IP range"
ip_addresses:
- "103.35.XX.XXX/24"
internal_subnets:
- "10.5.0.0/20"
- name: "Hyderabad-Edge"
description: "Hyderabad office public IP range"
ip_addresses:
- "103.40.XX.XXX/24"
internal_subnets:
- "10.7.0.0/20"
2.3.2.3 Toll Bypass Enforcement Scenarios¶
TOLL BYPASS ENFORCEMENT - CALL FLOW SCENARIOS
SCENARIO 1: COMPLIANT - Mumbai User calling from Mumbai Office
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1. User at Mumbai HQ dials +91-80-12345678 (Bangalore external number)
2. Webex detects user source IP: 10.1.50.25
3. IP matches Trusted Edge: Mumbai-Edge (10.1.0.0/16)
4. Zone lookup: Zone-Mumbai-Circle
5. Route Group: RG-Mumbai-LGW
6. Call routes to lgw-mumbai-01
7. LGW sends call to Tata SIP trunk (Mumbai)
8. CALL COMPLETES - Toll charged at Mumbai egress point
User - Webex - Zone - Mumbai - Tata
Mumbai Cloud Lookup LGW Mumbai
10.1.x.x Match PSTN
SCENARIO 2: BLOCKED - Mumbai User Roaming to Bangalore Office
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1. Mumbai user visits Bangalore office, uses office WiFi
2. User dials +91-11-12345678 (Delhi external number)
3. Webex detects user source IP: 10.3.50.100
4. IP matches Trusted Edge: Bangalore-Edge (10.3.0.0/20)
5. User's assigned Zone: Zone-Mumbai-Circle
6. MISMATCH: User in Bangalore but assigned to Mumbai zone
7. PSTN CALL BLOCKED - Toll bypass prevention
8. User receives "PSTN calling not available" message
Mumbai - Webex - Zone - CALL
User Cloud Lookup BLOCKED
@B'lore Mismatch
10.3.x.x
WORKAROUND OPTIONS:
Use Webex-to-Webex calling (always works)
VPN back to Mumbai network
Mobile cellular (outside Webex)
SCENARIO 3: WFH USER WITH ITN - Working from Home in Tier-2 City
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
1. WFH user assigned ITN number: +91-9XX-1000-XX
2. User dials +91-22-12345678 (Mumbai external number)
3. ITN numbers are EXEMPT from toll bypass rules
4. No Zone/Edge check required
5. Call routes directly to Tata cloud
6. CALL COMPLETES
WFH - Webex - ITN - Tata
User Cloud Exempt Cloud
Home Pass PSTN
2.3.2.4 LGW CUBE Configuration Template¶
! ============================================================
! CUBE Local Gateway Configuration Template - Mumbai
! Abhavtech.com - ABV-COLLAB-MIG-2026
! IOS-XE Version: 17.12.2 or later (REQUIRED)
! Platform: ISR 4451-X
! ============================================================
! --- Global SIP Settings ---
voice service voip
ip address trusted list
ipv4 52.114.148.0 255.255.252.0 ! Webex Calling signaling
ipv4 52.114.152.0 255.255.252.0
ipv4 52.114.156.0 255.255.252.0
mode border-element
media disable-detailed-stats
allow-connections sip to sip
no supplementary-service sip refer
stun
stun flowdata agent-id 1 boot-count 4
stun flowdata shared-secret 0 <secret>
sip
session refresh
early-offer forced
asymmetric payload full
! --- Codec Class ---
voice class codec 1
codec preference 1 opus
codec preference 2 g711ulaw
codec preference 3 g711alaw
codec preference 4 g729r8
! --- SIP Profile for Webex ---
voice class sip-profiles 100
rule 10 request ANY sip-header SIP-Req-URI modify "sips:" "sip:"
rule 20 request ANY sip-header To modify "<sips:" "<sip:"
rule 30 request ANY sip-header From modify "<sips:" "<sip:"
rule 40 request ANY sip-header Contact modify "<sips:" "<sip:"
rule 50 response ANY sip-header To modify "<sips:" "<sip:"
rule 60 response ANY sip-header From modify "<sips:" "<sip:"
rule 70 response ANY sip-header Contact modify "<sips:" "<sip:"
! --- Tenant for Webex Calling ---
voice class tenant 100
registrar dns:webexapis.com scheme sips expires 3600
credentials number +91226XXX0000 username <LGW-USERNAME> password 0 <PASSWORD> realm webex.com
authentication username <LGW-USERNAME> password 0 <PASSWORD> realm webex.com
sip-server dns:webexapis.com
srtp-crypto 1 AES_CM_128_HMAC_SHA1_80
session transport tcp tls
url sips
error-passthru
bind control source-interface GigabitEthernet0/0/0
bind media source-interface GigabitEthernet0/0/0
! --- Dial Peer to Webex Calling ---
dial-peer voice 100 voip
description Webex-Calling-Outbound
preference 1
destination-pattern .T
session protocol sipv2
session target dns:webexapis.com
session transport tcp tls
voice-class sip tenant 100
voice-class sip profiles 100
voice-class codec 1
dtmf-relay rtp-nte
srtp
no vad
! --- Dial Peer to PSTN (Tata Mumbai) ---
dial-peer voice 200 voip
description PSTN-Tata-Mumbai-Outbound
preference 1
destination-pattern 9[0-9].T
session protocol sipv2
session target ipv4:203.130.X.X ! Tata SIP SBC IP
voice-class codec 1
dtmf-relay rtp-nte
! --- Inbound from PSTN ---
dial-peer voice 201 voip
description PSTN-Tata-Mumbai-Inbound
incoming called-number .
session protocol sipv2
voice-class codec 1
dtmf-relay rtp-nte
! --- Inbound from Webex ---
dial-peer voice 101 voip
description Webex-Calling-Inbound
incoming uri via Webex
session protocol sipv2
voice-class sip tenant 100
voice-class codec 1
dtmf-relay rtp-nte
srtp
! --- URI Class ---
voice class uri Webex sip
host webexapis.com
! --- Certificate Configuration ---
crypto pki trustpoint WEBEX-TRUSTPOINT
enrollment terminal
revocation-check none
! --- TLS Profile ---
voice class tls-profile 1
trustpoint WEBEX-TRUSTPOINT
cipher suites tls13-aes128-gcm-sha256
cn-san-validate server
sni send webexapis.com
2.3.3 EMEA: Cloud Connected PSTN¶
2.3.3.1 UK CCPP Configuration¶
| Configuration Item | Value |
|---|---|
| CCPP Provider | IntelePeer UK |
| Service Type | Cloud Connected PSTN |
| Route Group | RG-UK-CCPP |
| Numbers to Port | +44-20-4960-0001 to +44-20-4960-0799 |
| Main Number | +44-20-4960-0000 |
| Toll-Free | +44-800-096-1000 |
| Emergency | 999 / 112 (auto-configured by CCPP) |
| Zone/Edge Required | NO (UK has no toll bypass regulations) |
| Data Residency | UK Data Centers (London/Manchester) |
Number Porting Process (UK): 1. Submit Letter of Authorization (LOA) to IntelePeer 2. IntelePeer coordinates with existing provider (BT) 3. Typical porting window: 10 business days 4. Port validation test conducted 24 hours before cutover 5. Numbers active on Webex Calling after port complete
2.3.3.2 EU CCPP Configuration (Frankfurt)¶
| Configuration Item | Value |
|---|---|
| CCPP Provider | IntelePeer EU |
| Service Type | Cloud Connected PSTN |
| Route Group | RG-EU-CCPP |
| Numbers to Port | +49-69-4960-0001 to +49-69-4960-0499 |
| Main Number | +49-69-4960-0000 |
| Toll-Free | +49-800-096-1000 (German) |
| Emergency | 112 (EU standard, auto-configured) |
| Zone/Edge Required | NO |
| Data Residency | EU Data Centers (Frankfurt/Amsterdam) |
| BSI C5 Compliance | Webex certified |
| EU Cloud CoC | Level 3 |
2.3.4 Americas: Cloud Connected PSTN¶
| Configuration Item | New Jersey | Dallas |
|---|---|---|
| CCPP Provider | IntelePeer US | IntelePeer US |
| Route Group | RG-US-CCPP | RG-US-CCPP |
| Numbers to Port | +1-201-496-0001 to 0799 (800) | +1-214-496-0001 to 0499 (500) |
| Main Number | +1-201-496-0000 | +1-214-496-0000 |
| Toll-Free | +1-800-096-1000 (shared) | Shared with NJ |
| Emergency | 911 (E911 enabled) | 911 (E911 enabled) |
| E911 Address | Validated per user | Validated per user |
2.3.5 DID Number Mapping¶
Working Document -- Not Yet Finalised
The DID number mapping table (per-site DID ranges, provider assignments, port/retain decisions, and migration timeline) is maintained as a separate working document and will be reintroduced here once the number ranges are confirmed and approved.
Contact the Abhavtech project lead to obtain the current DID mapping workbook.
2.4 Dial Plan Design¶
2.4.1 Extension Numbering¶
ABHAVTECH EXTENSION NUMBERING PLAN
EXTENSION FORMAT: 4 Digits
* * * * * * * * * * * * * * * * * * * * * * * * * *
Site Code Location Extension Range Users Capacity
81 Mumbai HQ 1000-2199 1,200 extensions
82 Chennai 2200-2649 450 extensions
83 Bangalore 2650-2829 180 extensions
84 Delhi 2830-2979 150 extensions
85 Noida 2980-3099 120 extensions
86 Pune 3100-3199 100 extensions
87 Hyderabad 3200-3399 200 extensions
91 London 4000-4519 520 extensions
92 Frankfurt 4520-4799 280 extensions
93 New Jersey 5000-5479 480 extensions
94 Dallas 5480-5749 270 extensions
RESERVED RANGES:
* * * * * * * * * * * * * * * *
0XXX - Reserved for future
6XXX - Reserved for system features
7XXX - Auto Attendants and Call Park
8XXX - Hunt Groups and Queues
9XXX - Reserved (avoid OAC conflict)
CONFLICT AVOIDANCE:
* * * * * * * * * * * * * * * * * *
First digit of extensions (1-5) Steering digit (8) OAC (9)
No extension starts with 8 or 9
2.4.2 ESN (Enterprise Significant Number) Format¶
ESN DIAL PLAN - INTER-SITE DIALING
ESN FORMAT: 8 - XX - XXXX
Extension (4 digits)
Site Code (2 digits)
Steering Digit
EXAMPLES:
* * * * * * * * *
Mumbai user calling Chennai extension 2100:
Dial: 8-82-2100 Routes to Chennai ext 2100
London user calling Mumbai extension 1500:
Dial: 8-81-1500 Routes to Mumbai ext 1500
Dallas user calling Frankfurt extension 4600:
Dial: 8-92-4600 Routes to Frankfurt ext 4600
ESN ROUTING TABLE:
* * * * * * * * * * * * * * * * * *
ESN Prefix Location Route
881XXXX Mumbai HQ ABV-Mumbai-HQ
882XXXX Chennai ABV-Chennai
883XXXX Bangalore ABV-Bangalore
884XXXX Delhi ABV-Delhi
885XXXX Noida ABV-Noida
886XXXX Pune ABV-Pune
887XXXX Hyderabad ABV-Hyderabad
891XXXX London ABV-London
892XXXX Frankfurt ABV-Frankfurt
893XXXX New Jersey ABV-NewJersey
894XXXX Dallas ABV-Dallas
CONFIGURATION:
Control Hub Calling Dial Plan Location Routing Prefix
2.4.3 PSTN Routing by Region¶
India PSTN Dial Plan:
| Pattern | Description | Route |
|---|---|---|
| 9[2-9]XXXXXXXXX | India local/STD | Zone LGW |
| 9011[1-9]X. | International | Zone LGW |
| 100 | Police | Emergency |
| 101 | Fire | Emergency |
| 102 | Ambulance | Emergency |
| 1800XXXXXXX | Toll-Free | Zone LGW |
UK PSTN Dial Plan:
| Pattern | Description | Route |
|---|---|---|
| 901[0-9]XXXXXXXX | UK geographic | CCPP |
| 90800XXXXXXX | UK toll-free | CCPP |
| 9+[1-9]X. | International | CCPP |
| 999 | Emergency | Emergency |
| 112 | EU Emergency | Emergency |
Germany PSTN Dial Plan:
| Pattern | Description | Route |
|---|---|---|
| 0[1-9]X. | German national | CCPP |
| 00[1-9]X. | International | CCPP |
| 112 | EU Emergency | Emergency |
US PSTN Dial Plan:
| Pattern | Description | Route |
|---|---|---|
| 91[2-9]XXXXXXXXX | US domestic | CCPP |
| 9011[1-9]X. | International | CCPP |
| 911 | Emergency | E911 |
| 91800XXXXXXX | Toll-Free | CCPP |
2.4.4 Emergency Calling Configuration¶
EMERGENCY CALLING CONFIGURATION BY REGION
INDIA:
* * * * * *
Emergency Numbers: 100 (Police), 101 (Fire), 102 (Ambulance), 112
Callback Number: Per-location main number
Address Format: Manual entry (no automated E-CNAM in India)
Routing: Via Local Gateway to local PSTN
UK:
* * *
Emergency Numbers: 999, 112
Callback Number: User's DID
Address Format: BT Openreach validated
Routing: Via CCPP
GERMANY (EU):
* * * * * * * * * * * * *
Emergency Number: 112 (EU standard)
Callback Number: User's DID
Address Format: German address format (Stra e, PLZ, Stadt)
Routing: Via CCPP
USA:
* * * *
Emergency Number: 911
Service Type: E911 (Enhanced 911)
Callback Number: User's DID
ELIN: Assigned per location
Address: Validated dispatchable address per user
Routing: Via CCPP with E911 lookup
REMOTE/WFH USERS:
* * * * * * * * * * * * * * * * *
Users prompted to update emergency address in Webex App
Nomadic E911: Address follows user, not device
India WFH: 112 routes to Webex-provided emergency service
US WFH: E911 with user-declared address
2.5 Feature Design¶
2.5.1 Hunt Groups¶
Hunt Group Migration from CUCM:
| Hunt Group | Pilot Number | Pattern | Members | Migration Strategy |
|---|---|---|---|---|
| HG-Mumbai-Reception | +91-22-4960-0000 | Circular | 8 | Migrate batch 2 |
| HG-Mumbai-IT | +91-22-4960-0001 | Top Down | 12 | Migrate batch 1 (Pilot) |
| HG-Mumbai-HR | +91-22-4960-0002 | Circular | 6 | Migrate batch 2 |
| HG-Mumbai-Finance | +91-22-4960-0003 | Longest Idle | 8 | Migrate batch 3 |
| HG-Chennai-Reception | +91-44-4960-0000 | Circular | 4 | Migrate batch 4 |
| HG-Bangalore-Reception | +91-80-4960-0000 | Circular | 3 | Migrate batch 4 |
| HG-Delhi-Reception | +91-11-4960-0000 | Circular | 3 | Migrate batch 4 |
| HG-London-Reception | +44-20-4960-0000 | Circular | 4 | Migrate batch 5 |
| HG-London-Sales | +44-20-4960-0001 | Longest Idle | 10 | Migrate batch 5 |
| HG-NJ-Reception | +1-201-496-0000 | Circular | 4 | Migrate batch 6 |
| HG-NJ-Sales | +1-201-496-0001 | Longest Idle | 8 | Migrate batch 6 |
| HG-Dallas-Reception | +1-214-496-0000 | Circular | 3 | Migrate batch 6 |
Webex Calling Hunt Group Configuration:
# Hunt Group Template - Mumbai Reception
hunt_group:
name: "HG-Mumbai-Reception"
location: "ABV-Mumbai-HQ"
phone_number: "+91-22-4960-0000"
extension: "8001"
language: "en_IN"
time_zone: "Asia/Kolkata"
call_policies:
policy: "CIRCULAR" # Options: CIRCULAR, REGULAR (Top-Down), SIMULTANEOUS, UNIFORM (Longest Idle)
ring_pattern: "NORMAL"
forward_enabled: true
forward_destination: "+91-22-4960-0001" # Forward to IT Support if no answer
forward_after_rings: 6
wait_for_answer: true
no_answer_number_of_rings: 4
distinctive_ring: true
agents:
- extension: "1001"
weight: null # Not applicable for CIRCULAR
- extension: "1002"
- extension: "1003"
- extension: "1004"
Critical: Hunt Group Migration Batching Rule
MIGRATION RULE: Hunt Group members MUST migrate together
All agents in a hunt group must move to Webex Calling in the same batch.
Split migration (some agents on CUCM, some on Webex) will break routing.
Pre-migration checklist:
- Identify all hunt group members
- Assign all members to same migration batch
- Validate all member phones are MPP-capable
- Configure hunt group in Webex before member cutover
2.5.2 Auto Attendants¶
Auto Attendant Design:
| Auto Attendant | Location | Main Number | Hours | Language |
|---|---|---|---|---|
| AA-Mumbai-Main | Mumbai HQ | +91-22-4960-0000 | 24/7 | English/Hindi |
| AA-Chennai | Chennai | +91-44-4960-0000 | Business | English/Tamil |
| AA-London-Main | London | +44-20-4960-0000 | Business | English |
| AA-Frankfurt-Main | Frankfurt | +49-69-4960-0000 | Business | German/English |
| AA-NewJersey | New Jersey | +1-201-496-0000 | Business | English |
| AA-TollFree-India | Mumbai | 1800-266-1000 | 24/7 | English/Hindi |
| AA-TollFree-UK | London | +44-800-096-1000 | Business | English |
| AA-TollFree-US | New Jersey | +1-800-096-1000 | Business | English |
Sample Auto Attendant Menu (Mumbai Main):
AA-MUMBAI-MAIN - IVR MENU STRUCTURE
GREETING: "Welcome to Abhavtech. Your call may be recorded for quality."
BUSINESS HOURS (9 AM - 6 PM IST):
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
"Press 1 for Sales" Transfer to HG-Mumbai-Sales
"Press 2 for Customer Support" Transfer to Call Queue (Phase 2)
"Press 3 for Human Resources" Transfer to HG-Mumbai-HR
"Press 4 for Finance" Transfer to HG-Mumbai-Finance
"Press 5 for IT Support" Transfer to HG-Mumbai-IT
"Press 0 for Reception" Transfer to HG-Mumbai-Reception
"To dial by extension, press 9" Extension dialing enabled
No input timeout (10 sec) Transfer to Reception
AFTER HOURS (6 PM - 9 AM IST):
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
"Thank you for calling Abhavtech. Our office is currently closed.
Office hours are Monday to Friday, 9 AM to 6 PM India Standard Time.
Please leave a message after the tone, or call back during business
hours. For emergencies, press 1 to reach our on-call support."
Press 1 After-hours mobile (rotational)
No input Voicemail (general mailbox)
HOLIDAY SCHEDULE:
* * * * * * * * * * * * * * * * *
Indian national holidays After-hours greeting
Configured in Control Hub schedules
2.5.3 Virtual Lines (Shared Line Migration)¶
Shared Line to Virtual Line Migration:
Webex Calling uses Virtual Lines to replace CUCM shared lines. Virtual Lines are independently licensed line appearances that can be shared across multiple devices.
| CUCM Shared Line | Users | Virtual Line Name | Extension | DID |
|---|---|---|---|---|
| Reception Mumbai | 4 | VL-Mumbai-Reception | 8900 | +91-22-4960-8900 |
| Reception Chennai | 2 | VL-Chennai-Reception | 8901 | +91-44-4960-8901 |
| Finance Hotline | 3 | VL-Finance-Hotline | 8902 | +91-22-4960-8902 |
| Executive Admin | 2 | VL-Exec-Admin | 8903 | +91-22-4960-8903 |
| CEO Assistant | 2 | VL-CEO-Assistant | 8904 | Internal only |
Virtual Line Configuration:
# Virtual Line Template
virtual_line:
name: "VL-Mumbai-Reception"
location: "ABV-Mumbai-HQ"
extension: "8900"
phone_number: "+91-22-4960-8900"
calling_line_id:
first_name: "Reception"
last_name: "Mumbai"
announcement_language: "en_IN"
devices:
- type: "MPP"
model: "Cisco 8865"
mac: "AA:BB:CC:DD:EE:01"
line_key_position: 2
- type: "MPP"
model: "Cisco 8865"
mac: "AA:BB:CC:DD:EE:02"
line_key_position: 2
- type: "MPP"
model: "Cisco 8845"
mac: "AA:BB:CC:DD:EE:03"
line_key_position: 2
- type: "MPP"
model: "Cisco 8845"
mac: "AA:BB:CC:DD:EE:04"
line_key_position: 2
2.5.4 Call Park & Pickup¶
Call Park Configuration:
| Location | Park Extensions | Range | Timeout | Recall Destination |
|---|---|---|---|---|
| Mumbai HQ | 10 | #7810 - #7819 | 60 sec | Original parker |
| Chennai | 5 | #7820 - #7824 | 60 sec | Original parker |
| Bangalore | 5 | #7825 - #7829 | 60 sec | Original parker |
| London | 5 | #7910 - #7914 | 60 sec | Original parker |
| Frankfurt | 5 | #7920 - #7924 | 60 sec | Original parker |
| New Jersey | 5 | #7930 - #7934 | 60 sec | Original parker |
| Dallas | 3 | #7935 - #7937 | 60 sec | Original parker |
Call Pickup Groups:
| Location | Pickup Group | Extensions | Pickup Code |
|---|---|---|---|
| Mumbai - IT | CPG-Mumbai-IT | 1100-1120 | *98 |
| Mumbai - HR | CPG-Mumbai-HR | 1200-1220 | *98 |
| Mumbai - Finance | CPG-Mumbai-Fin | 1300-1330 | *98 |
| Mumbai - Sales | CPG-Mumbai-Sales | 1400-1450 | *98 |
| Chennai - All | CPG-Chennai | 2000-2300 | *98 |
| London - All | CPG-London | 4000-4400 | *98 |
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)
CUBE/LGW
Mumbai (HA)
Routes between:
Webex Cloud
CUCM Cluster
PSTN
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 |
Chapter 2 Summary¶
Key Design Decisions¶
| Decision Area | Selection | Rationale |
|---|---|---|
| Platform | Webex Calling Multi-Tenant | Scale fits, cost-effective, cloud-native |
| Home Region | APAC (Mumbai + Chennai DCs) | Majority users in India |
| India PSTN | Local Gateway per circle | DoT compliance, existing contracts |
| EMEA PSTN | CCPP (IntelePeer) | No toll bypass, simplified management |
| Americas PSTN | CCPP (IntelePeer) | Simplified management, E911 support |
| India WFH | ITN Numbers | Toll bypass exempt, location-flexible |
| Extension Length | 4 digits | Matches existing CUCM |
| ESN Format | 8-XX-XXXX | Location routing prefix |
| Coexistence | CUBE trunk | Bidirectional CUCM->Webex routing |
Cross-Reference Matrix¶
| This Chapter Section | Related Chapter | Related Section |
|---|---|---|
| 2.1.3 Data Residency | Chapter 4 | 4.3 India Compliance, 4.4 EMEA Compliance |
| 2.2.2 India Locations | Chapter 1 | 1.1 Site Inventory |
| 2.3.2 Local Gateway | Chapter 5 | 5.5 Firewall Requirements |
| 2.3.2 Zone/Edge | Chapter 4 | 4.3.2 Toll Bypass Prevention |
| 2.4.4 Emergency Calling | Chapter 4 | 4.5 Americas Compliance |
| 2.6 Coexistence | Chapter 7 | 7.2 Migration Procedures |
Chapter 2 Appendix¶
Template 2.A: Location Configuration Checklist¶
| Item | Configured | Verified | Notes |
|---|---|---|---|
| Location name | [ ] | [ ] | |
| Site code | [ ] | [ ] | |
| Street address | [ ] | [ ] | |
| Timezone | [ ] | [ ] | |
| Language | [ ] | [ ] | |
| Extension range | [ ] | [ ] | |
| OAC | [ ] | [ ] | |
| PSTN type (LGW/CCPP) | [ ] | [ ] | |
| Zone assignment (India) | [ ] | [ ] | |
| Main number | [ ] | [ ] | |
| Emergency callback | [ ] | [ ] | |
| Hunt groups | [ ] | [ ] | |
| Auto attendant | [ ] | [ ] | |
| Call park range | [ ] | [ ] |
Template 2.B: LGW Deployment Checklist¶
| Item | Mumbai | Chennai | Bangalore | Delhi | Noida | Hyderabad |
|---|---|---|---|---|---|---|
| Platform verified | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| IOS-XE 17.12+ | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| Webex certificate installed | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| TLS profile configured | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| Tenant registered | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| PSTN trunk active | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| Test call Webex->PSTN | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
| Test call PSTN->Webex | [ ] | [ ] | [ ] | [ ] | [ ] | [ ] |
End of Chapter 2: Webex Calling Design