The TCO delta widens further when you factor in DNA licensing: Catalyst switches running DNA Advantage already include ISE-style telemetry that competes with ClearPass's profiling data, so organizations standardized on DNA Advantage often find ISE a no-cost incremental step versus paying ClearPass list price on top.
Vendor neutrality favors ClearPass; ecosystem depth favors ISE.
ClearPass is vendor-neutral by design - it speaks RADIUS, TACACS+, 802.1X, and REST APIs to any switch, access point, or firewall that ships those standards. Enterprises running mixed vendors (Aruba APs + Cisco switches, Juniper EX, Arista, HPE ProCurve) typically pick ClearPass because the policy engine is the same regardless of the access layer vendor.
Cisco ISE is optimized for the Cisco ecosystem - pxGrid integration with Cisco SecureX, Talos threat intelligence, Cisco Secure Endpoint posture, DNA Center telemetry, and Cisco Duo for SSO - and is the default choice for organizations that have standardized on Catalyst Center, DNA Advantage, and Cisco security stack (Cisco ISE Docs, September 2026). The trade-off is that ISE is technically supported on third-party switches but lacks the deep policy and telemetry integrations that drive operational value in Cisco environments.
Posture, profiling, and guest services compared.
ClearPass OnGuard and Cisco ISE Posture both check endpoint health in 2026 - OS version, AV status, disk encryption, hotfix levels - but the integration depth differs. ClearPass OnGuard ships built-in posture profiles for Windows 10/11, macOS 13/14/15, Ubuntu 22.04/24.04, and iOS/Android 14+; integration with third-party MDM (Intune, Jamf, Kandji) is supported but requires custom configuration.
Cisco ISE Posture ships tighter integration with Microsoft Intune, Jamf, and Cisco Secure Endpoint, plus the AnyConnect posture module that runs on the endpoint agent. ISE's posture typically reduces policy-violation incidents by 20-30% in Cisco-centric environments; ClearPass's posture is more flexible in mixed-OS estates where every device is not Cisco-managed (ClearPass, ISE Posture Docs, September 2026).
ClearPass Profiler and ISE Profiling both do device fingerprinting by analyzing DHCP, HTTP, and CDP/LLDP traffic to identify IoT, BYOD, and rogue devices. ClearPass ships roughly 3,500 device profiles out of the box; ISE ships roughly 4,200 profiles with more granular IoT classification (medical, industrial, building automation). For healthcare and manufacturing estates with thousands of IoT devices, ISE's larger profile library often wins.
TACACS+ for network admin AAA.
Both ClearPass and ISE ship TACACS+ for network administrator authentication, authorization, and accounting - critical for SOX, PCI-DSS, and FedRAMP environments. ClearPass bundles TACACS+ in the base ClearPass Access license with no per-command pricing; Cisco ISE bundles TACACS+ in all tiers (Essentials, Advantage, Premier).
The biggest differentiator is policy granularity: ClearPass allows per-command TACACS+ authorization rules per device group (e.g., 'only network admins in group X can issue 'reload' on core switches'); ISE supports the same but adds Cisco-specific command sets and integration with Cisco DNA Center for intent-based policy (Aruba, Cisco ISE, September 2026).
Deployment timeline and migration cost.
A typical ClearPass deployment for 5,000 endpoints runs 6-10 weeks with 0.5-1 FTE of network engineering plus $30,000-$80,000 in professional services; an equivalent Cisco ISE deployment runs 8-16 weeks with 1-1.5 FTE of network engineering plus $50,000-$150,000 in professional services because of the deeper Catalyst integration.
Migrating from ISE to ClearPass (or vice versa) typically takes 3-6 months because of the policy translation work; most enterprises budget $50,000-$200,000 for the migration plus 0.5-1 FTE of dedicated engineering time. The most common 2026 migration pattern is to leave ISE on existing Catalyst sites and deploy ClearPass for new sites and contractor access, then converge on a single platform after 12-18 months.
Bottom line for 2026 buyers.
Aruba ClearPass is the right choice for vendor-neutral networks, mixed-OS estates, and enterprises that want 30-50% lower 5-year TCO at 1,000-10,000 endpoints; Cisco ISE is the right choice for Catalyst-centric DNA Advantage environments, organizations with deep pxGrid/Talos integration, and enterprises that want threat-centric NAC features bundled into Premier licensing. Both platforms ship mature 802.1X, TACACS+, and posture - the deciding factors are vendor stack and per-endpoint cost.
Alternatives to consider
If neither contender in this comparison fits, these adjacent options are worth a look:
- Premium tier (when both candidates are mid-tier and you want the flagship experience).
- Budget tier (when you'd use the cheapest viable alternative anyway).
- Niche alternative (when one specific dimension — battery, ecosystem, weight — dominates your decision).
FAQs
Does ClearPass support FIPS mode?
Yes - ClearPass Policy Manager 6.10+ ships FIPS 140-2 mode for federal and DoD customers in 2026, with RADIUS and TACACS+ traffic validated against NIST CMVP module #3889. Cisco ISE 3.x ships FIPS 140-2 validated modules for hardware appliances and supports FIPS-mode operation on the SNS-3700 series; both platforms are accepted by US federal agencies and DoD contractors (NIST CMVP, September 2026).
Which NAC platform has better IoT device fingerprinting?
Cisco ISE ships a larger built-in device profile library (4,200+ profiles) with more granular IoT classification (medical, industrial, building automation). ClearPass ships 3,500+ profiles and a more flexible custom-profile creation workflow. For healthcare and manufacturing IoT estates above 5,000 devices ISE is the smoother fit; for office IT and small IoT estates ClearPass is sufficient.
Can ClearPass integrate with Cisco DNA Center?
Yes - ClearPass integrates with Cisco DNA Center via the pxGrid 2.0 API and the DNA Center Assurance API in 2026, pulling switch port telemetry and pushing policy updates to switches. The integration is supported but not as deep as ISE's native integration; enterprises that want full DNA Center-driven policy typically choose ISE.
Does ISE work on non-Cisco switches?
Yes - Cisco ISE supports RADIUS, TACACS+, and 802.1X on Aruba, Juniper EX, Arista, HPE ProCurve, and other vendors' switches in 2026. The integration is functional but lacks the policy and telemetry depth of ISE on Catalyst switches; enterprises with non-Cisco access layers typically prefer ClearPass for operational reasons.
What is pxGrid in Cisco ISE?
pxGrid (Platform Exchange Grid) is Cisco's API for sharing contextual data between ISE and other security tools - SecureX, Secure Endpoint, Talos, Stealthwatch, Duo, and third-party SIEM/SOAR platforms. It is included in ISE Advantage and Premier tiers and is the single biggest reason Cisco-centric enterprises choose ISE over ClearPass. ClearPass supports similar integrations via its own REST API but lacks the pxGrid ecosystem depth.
Is there a free or open-source NAC alternative?
PacketFence is the most-deployed open-source NAC in 2026, with RADIUS, 802.1X, guest onboarding, and posture capabilities comparable to ClearPass Access. PacketFence is free and self-hosted but lacks the mature commercial support, profiling, and ecosystem integrations of ClearPass and ISE; it is most common in education, government, and small-business deployments. Most enterprises above 1,000 endpoints prefer ClearPass or ISE for support reasons.
Fazlur Rahman
