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Chapter 2: Design Documentation

Overview

This chapter contains the comprehensive design documentation for the Avaya to Webex Contact Center migration project. It covers architectural decisions, technical specifications, capacity planning, and implementation guidelines across all contact center components.

Document Structure

Core Design Documents (7 files)

  1. README.md - This file, navigation guide for Chapter 2
  2. component-mapping.md - Avaya to Webex component mapping
  3. target-architecture-diagram.md - High-level architecture diagrams
  4. telephony-architecture.md - PSTN connectivity and voice architecture
  5. omnichannel-design.md - Voice, chat, email, and digital channels
  6. integrations.md - CRM, WFM, and third-party integrations
  7. security-and-compliance.md - Security architecture and compliance

New Design Documents (6 files) - Added November 2025

  1. design-principles.md
  2. Core design tenets (scalability, resiliency, security-by-design)
  3. Naming conventions (agents, queues, entry points)
  4. Documentation standards and quality gates

  5. Change management governance

  6. assumptions-and-dependencies.md

  7. Network infrastructure prerequisites
  8. Firewall rules and security requirements
  9. PSTN carrier coordination
  10. Licensing and cloud setup dependencies

  11. Pre-migration checklist

  12. network-architecture.md

    • Network topology and connectivity models
    • QoS (Quality of Service) design and DSCP marking
    • Security architecture (firewalls, NAT, VLANs)
    • Internet circuit redundancy (dual ISP, BGP)
    • Home agent network considerations

  13. cube-and-sbc-design.md

    • On-premises CUBE vs Cloud-connected PSTN decision matrix
    • Critical DID impact analysis (keep existing DIDs vs porting)
    • CUBE session capacity planning (encryption impact, sizing formulas)
    • Session sizing for 1,000-agent deployment (detailed calculations)
    • Reusing existing CUBE capacity (decision matrix and examples)
    • SIP trunk configuration (carrier and Webex)
    • TLS/SRTP encryption setup
    • High availability (HSRP active-standby)
    • Call flow examples and troubleshooting

  14. agent-endpoints.md

    • Desktop client options (Webex App, browser-based, IP phones)
    • SSO integration with Azure AD/Okta
    • Multi-factor authentication (MFA)
    • CUCM vs Webex Calling registration
    • Headset standards and audio configuration
    • Supervisor desktop and monitoring
    • Home agent requirements and security

  15. dr-and-resiliency.md

    • Recovery objectives (RTO/RPO targets)
    • CUBE/SBC failover procedures
    • Network redundancy and failover
    • Agent re-login and recovery procedures
    • Disaster recovery testing schedule
    • Incident response and escalation

Future Design Documents (3 files) - Planned Q4 2025-Q1 2026

  1. capacity-and-sizing.md 📋 PLANNED (23 KB)

    • Consolidation document with references to existing capacity planning
    • NEW: AI/automation capacity (virtual agents, ASR, NLU, API rate limits, cost: $282K/month)
    • NEW: Storage capacity (call recordings 105 TB, transcripts, logs, backups)
    • NEW: IVR capacity (port sizing, speech recognition sessions)
    • Quick summaries of CUBE (→ cube-and-sbc-design.md Section 4), network (→ network-architecture.md Section 11)

  2. license-mapping.md 📋 PLANNED (6.8 KB)

    • Avaya to Webex license mapping table
    • Official Cisco SKUs and part numbers
    • License types (Premium $120/user, Standard, Supervisor $90/user, add-ons)
    • Cost analysis and volume discounts
    • Procurement process and timeline

  3. ai-and-automation-design.md 📋 PLANNED (11 KB)

    • AI strategy and vision (maturity model, use cases, ROI)
    • Virtual agent design (Dialogflow CX, bot intents, conversational AI)
    • AI-powered routing (predictive behavioral routing, sentiment-based)
    • Real-time agent assist (knowledge base, next-best-action, transcription)
    • Post-call analytics (sentiment analysis, quality scoring automation)
    • RPA and process automation workflows

Subfolders

acd-routing/ (5 files)

Detailed ACD (Automatic Call Distribution) routing design:

ivr-flows/ (3 files)

IVR (Interactive Voice Response) flow design:

Quick Navigation by Role

For Architects

Start with these documents to understand strategic decisions: 1. design-principles.md - Design philosophy 2. target-architecture-diagram.md - High-level view 3. cube-and-sbc-design.md - Telephony architecture 4. network-architecture.md - Network design

For Engineers (Implementation)

Focus on technical specifications: 1. assumptions-and-dependencies.md - Prerequisites 2. cube-and-sbc-design.md - CUBE configuration 3. network-architecture.md - QoS, firewall rules 4. agent-endpoints.md - Desktop setup 5. acd-routing/ - Routing implementation

For Project Managers

Understand scope and dependencies: 1. component-mapping.md - What's changing 2. assumptions-and-dependencies.md - Prerequisites 3. dr-and-resiliency.md - Risk mitigation

For Business Stakeholders

Key business impact documents: 1. cube-and-sbc-design.md - Section 3: DID implications 2. omnichannel-design.md - Customer experience 3. dr-and-resiliency.md - Business continuity

Key Design Decisions Documented

1. SBC Deployment Strategy

Decision: On-premises CUBE (not cloud-connected PSTN)
Rationale: Keep existing DIDs, avoid business disruption
Document: cube-and-sbc-design.md - Section 2

2. CUBE Session Capacity

Requirement: 6,000-6,500 sessions for 1,000 agents
Hardware: 2× Cisco ASR 1002-HX (3,500 sessions each)
Document: cube-and-sbc-design.md - Section 4

3. Agent Desktop Strategy

Primary: Webex App (desktop + mobile)
Secondary: Browser-based Agent Desktop
Rationale: Best user experience, hybrid-ready
Document: agent-endpoints.md - Section 2

4. Authentication Method

Approach: Single Sign-On (SSO) with Azure AD + MFA
Document: agent-endpoints.md - Section 5

5. Network Design

Internet connectivity: Dual ISP with BGP failover
QoS marking: DSCP EF for voice, AF41 for video
Document: network-architecture.md

6. Disaster Recovery

RTO: 15 minutes for core contact center services
RPO: 15 minutes for transactional data
Document: dr-and-resiliency.md - Section 3