1.2 Technical Requirements Analysis¶
1.2.1 Core Technical Requirements¶
| Requirement ID | Category | Requirement Description | Priority |
|---|---|---|---|
| NET-001 | Segmentation | Implement micro-segmentation across all sites | Critical |
| NET-002 | Automation | Zero-touch provisioning for new switches | High |
| NET-003 | Policy | Centralized policy management across regions | Critical |
| NET-004 | Visibility | End-to-end path visibility and analytics | High |
| NET-005 | Security | 802.1X authentication for all endpoints | Critical |
| NET-006 | Mobility | Seamless roaming within and across buildings | Medium |
| NET-007 | Scale | Support 15,000+ concurrent endpoints | Critical |
| NET-008 | Availability | 99.99% uptime for critical services | Critical |
| NET-009 | Compliance | Meet PCI-DSS, SOC2, GDPR requirements | Critical |
| NET-010 | Integration | Integrate with existing ServiceNow, Splunk | High |
1.2.2 SD-Access Fabric Requirements¶
| Component | Requirement | Sizing |
|---|---|---|
| Fabric Sites | Autonomous fabric per region | 6 primary fabrics |
| Virtual Networks (VN) | Separate overlay for business units | 4-6 VNs |
| Scalable Groups (SGT) | Micro-segmentation policies | 15-20 SGTs |
| Anycast Gateway | Distributed gateway per VN | Per Edge Node |
| Host Pools | IP address pools per site | /22 to /20 per site |
| Control Plane HA | Redundant CP nodes per fabric | 2 CP nodes per site |
| Border Node HA | Redundant border for WAN/DC | 2 Border nodes per hub |
1.2.3 DNAC Controller Requirements¶
Cluster Sizing Calculation:
┌─────────────────────────────────────────────────────────────────────────────┐
│ DNA CENTER SIZING CALCULATION │
├─────────────────────────────────────────────────────────────────────────────┤
│ │
│ Total Network Devices: │
│ ────────────────────── │
│ Core Switches: 24 devices │
│ Distribution Switches: 44 devices │
│ Access Switches: 300 devices │
│ WAN Routers: 24 devices │
│ Wireless Controllers: 12 devices │
│ Access Points: 450 devices │
│ ───────────────────────────────────── │
│ TOTAL MANAGED DEVICES: 854 devices │
│ │
│ DNAC Appliance Selection: │
│ ───────────────────────── │
│ DN2-HW-APL-XL (Extra Large Cluster) │
│ │
│ Capacity: │
│ - Up to 8,000 network devices │
│ - Up to 200,000 endpoints │
│ - 3-node cluster for HA │
│ │
│ Deployment: Single DNAC Cluster (Primary: New Jersey, DR: London) │
│ │
└─────────────────────────────────────────────────────────────────────────────┘
1.2.4 ISE Deployment Requirements¶
ISE Node Sizing:
┌─────────────────────────────────────────────────────────────────────────────┐
│ ISE DEPLOYMENT SIZING │
├─────────────────────────────────────────────────────────────────────────────┤
│ │
│ Endpoint Population: │
│ ──────────────────── │
│ Employees (Corporate Devices): 12,000 endpoints │
│ BYOD Devices: 3,000 endpoints │
│ IoT/OT Devices: 2,500 endpoints │
│ Guest Devices (Peak): 1,500 endpoints │
│ ───────────────────────────────────────────────── │
│ TOTAL CONCURRENT ENDPOINTS: 19,000 endpoints │
│ │
│ ISE Deployment Model: Distributed │
│ ───────────────────────────────────── │
│ │
│ Primary Administration Node (PAN): │
│ Location: New Jersey (Primary) │
│ Appliance: SNS-3695-K9 (Large) │
│ │
│ Secondary Administration Node (PAN): │
│ Location: London (Secondary) │
│ Appliance: SNS-3695-K9 (Large) │
│ │
│ Policy Service Nodes (PSN) - Regional: │
│ APAC: Mumbai, Chennai (2 × SNS-3655-K9) │
│ EMEA: London, Frankfurt (2 × SNS-3655-K9) │
│ Americas: New Jersey, Dallas (2 × SNS-3655-K9) │
│ │
│ Monitoring & Troubleshooting Node (MnT): │
│ Location: New Jersey (Co-located with PAN) │
│ Location: London (Co-located with Secondary PAN) │
│ │
│ pxGrid Nodes: │
│ Integrated with PAN nodes for SD-Access integration │
│ │
│ PSN Capacity Formula: │
│ ───────────────────── │
│ Authentications per second = Endpoints × Auth Rate × Peak Factor │
│ 19,000 × 0.001 × 2.5 = 47.5 auth/sec per PSN pair │
│ │
│ SNS-3655 supports up to 40,000 concurrent sessions │
│ Total PSN capacity: 6 nodes × 40,000 = 240,000 (sufficient headroom) │
│ │
└─────────────────────────────────────────────────────────────────────────────┘