User, Agent, and Extension: Concepts and Relationships

This document explains the definitions and relationships between three core concepts in the CTICloud contact center platform: User, Agent, and Extension. This guide helps customers understand the mapping logic between the platform's user management system and telephony system.

---

1. Concept Definitions

1.1 User

Definition: A User is a "system user" entity in the CTICloud platform, representing a personnel account that uses the platform. Each User corresponds to an employee identity within an organization, used for logging into the CTICloud platform and accessing related functions.

Typical Roles:

• Business Administrator
• IT Administrator
• Supervisor Agent
• Regular Agent

Key Points:

• User is the top-level logical identity, primarily used for access control, feature permissions, and operation auditing
• Not all Users have contact center agent capabilities
• An Agent entity is created only when the User's role includes contact center agent or supervisor agent roles

---

1.2 Agent

Definition: An Agent is an "agent entity" in contact center operations, designed to handle specific call capabilities and business allocation logic. It represents personnel in the contact center who can receive or initiate calls.

Agent Types:

• Regular Agent: Handles daily inbound/outbound call operations
• Supervisor Agent: Has agent capabilities plus additional management functions like monitoring, quality assurance, call intrusion, and forced disconnection of subordinate agents

User-Agent Relationship:

• Each User can be associated with at most one Agent
• An Agent is created only when the user role includes "Contact Center Agent" or "Contact Center Supervisor Agent"
• Agent lifecycle aligns with User lifecycle, but is active only when agent functionality is enabled

---

1.3 Extension

Definition: An Extension is a physical or logical "extension number" that handles voice call signaling and media channels. Simply put, it is the terminal device identifier where an agent "answers calls."

Functions:

• Extensions operate within the CTICloud telephony system infrastructure
• Provide direct integration with platform features (call recording, monitoring, transfer, conference, etc.)
• Support advanced contact center functions and real-time call control

Extension Types:

• Softphone Extension: Software-based telephony client (WebRTC, desktop applications)
• SIP Device Extension: Physical SIP terminal device (IP phones, hardware endpoints)

---

1.4 External Phone Number Binding

Definition: In addition to Extension binding, agents can also bind to external phone numbers (landlines or mobile phones) outside the contact center system. This is a completely different binding method that routes calls through PSTN to reach agents at their external numbers.

Working Mechanism:

1. Agent Binding: Agent binds to an external phone number (e.g., home landline, personal mobile)
2. Inbound Call Routing: When a customer call is routed to the agent, the system first dials the agent's external number via PSTN
3. Call Bridging: Once the agent answers the external number, the system bridges the customer call with the agent
4. Outbound Calls: For agent-initiated outbound calls, the system similarly uses PSTN to reach the agent's external number first

Use Cases:

• Remote Work: Agents working from home can use their home landline
• Mobile Workforce: Field agents can use their mobile phones while maintaining contact center capabilities
• Business Continuity: During office closures or emergencies, agents can continue operations from any location
• Flexible Scheduling: Part-time agents can work from various locations without requiring office equipment

Technical Requirements:

• External number must be reachable via PSTN
• Network reliability at agent's location for consistent call quality
• Proper caller ID configuration to maintain professional appearance to customers

Key Differences from Extension Binding:

• Technology: Uses PSTN routing instead of IP telephony infrastructure
• Network Reliability: PSTN provides stable connection when IP network is unreliable
• Use Cases:
  • Remote work scenarios where agents work from home or field locations
  • Network backup when IP connectivity is unstable or unavailable
  • Ensuring call quality through traditional telephone networks
• Functionality: Identical contact center features and capabilities as Extension binding

---

2. Relationship Overview

The diagram below illustrates the logical relationships between the entities and two binding methods:

flowchart TD
    A[User<br/>Platform Account<br/>Employee Identity] --> |1:1<br/>Contact Center Roles Only| B[Agent<br/>Call Handling Entity]
    
    B --> |Option 1: IP Network| C[Extension<br/>Internal Telephony<br/>Office Environment]
    B --> |Option 2: PSTN Network| D[External Phone Number<br/>PSTN Routing<br/>Remote/Network Backup]
    
    C -.-> E[Same Platform Features:<br/>• Call Recording<br/>• Monitoring<br/>• Transfer/Conference<br/>• All Contact Center Functions]
    
    D -.-> E
    
    D -.-> F[PSTN Advantages:<br/>• Network Reliability<br/>• Remote Work Support<br/>• Backup Connectivity<br/>• Quality Assurance]
    
    style A fill:#e1f5fe
    style B fill:#f3e5f5
    style C fill:#e8f5e8
    style D fill:#fff3e0
    style E fill:#f1f8e9
    style F fill:#e3f2fd

Binding Logic:

• User: Platform account identity
• Agent: Contact center agent role that can bind to either:
  • Extension: Internal telephony system via IP network (office environment)
  • External Phone Number: External landline/mobile via PSTN (remote work, network backup)

Operational Flow Examples:

Method 1: Extension Binding (IP Network/Office):

1. User logs into the platform
2. If the user has agent permissions, the system activates the corresponding Agent
3. When agent goes online, Agent binds to an available Extension (softphone or SIP device)
4. When inbound calls are allocated to the Agent, the system directly routes calls to the bound Extension via IP network
5. Agent can use all platform features (transfer, conference, monitoring, recording, etc.)
6. When agent goes offline, the system automatically releases the Extension binding

Method 2: External Phone Number Binding (PSTN Network/Remote):

1. User logs into the platform from remote location or when IP network is unreliable
2. If the user has agent permissions, the system activates the corresponding Agent
3. When agent goes online, Agent binds to their external phone number (landline or mobile)
4. When inbound calls are allocated to the Agent:
   • System initiates PSTN call to agent's external number
   • Agent answers their external phone
   • System bridges customer call with agent
5. For outbound calls, system follows similar PSTN routing to agent's external number
6. Agent can use all platform features through PSTN bridging (same functionality as Extension)
7. When agent goes offline, the system releases the external number binding

---

3. Implementation Examples

---

4. CTICloud Multi-Tenant Context

In CTICloud's multi-tier account architecture:

• Organization Level: Enterprise-wide user management
• Division Level: Branch/subsidiary-specific configurations
• Tenant Level: Department-level isolation where User-Agent-Extension relationships operate

Key Points:

• All User, Agent, and Extension entities are isolated by Tenant
• Business identifiers (agent numbers, extension numbers) are unique within each tenant scope
• Cross-tenant operations require appropriate authorization and context switching

---

5. API Integration Considerations

When integrating with CTICloud APIs:

---

This document is part of the CTICloud Contact Center documentation suite. For additional technical details, please refer to the complete API specification and integration guides.