Cisco UCM Sizing for 5,000-10,000 Users with Medium OVA
Short answer
D one publisher, two TFTP, and four call processing subscribers
Question
Key Takeaways
The question tests knowledge of Cisco's predefined deployment templates; the trap is underestimating the node count required for high availability at the upper end of the medium capacity range.
For Cisco Unified Communications Manager (UCM) deployments supporting 5,000 to 10,000 users using the medium Open Virtual Archive (OVA), the recommended architecture consists of seven nodes. The community consensus and official sizing guidelines confirm that this scale requires a specific high-availability configuration.
Common mistake: Candidates often select option A or C because they assume a simpler topology or confuse the requirements for smaller deployments (under 3,000 users) with those for 5,000+ users, failing to account for the need for redundant call processing pairs.
Expert Analysis
Why the Answer Is Correct
According to Cisco's Collaboration Virtualization Design Guide, a medium-sized deployment handling between 5,000 and 10,000 users requires a robust 7-node cluster structure. This includes one Publisher server, two TFTP servers, and two pairs of Call Processing Subscribers (totaling four CP subscribers) to ensure load balancing and high availability across the specified user range.
Why the Other Options Are Wrong
Option A suggests only two CP subscribers, which is insufficient for the stated user load and lacks the necessary redundancy for the upper limit of the medium template. Option B proposes a single CP subscriber, which is a critical failure point for any enterprise deployment of this size. Option C includes only two CP subscribers total, which aligns more closely with smaller deployments (e.g., up to 2,000-3,000 users) rather than the 5,000-10,000 range.
Community Comment Notes
Comment [3] provides the definitive reference link to the Cisco Collaboration Virtualization Design Guide, confirming the 7-node structure: 1 Publisher, 2 TFTP, and 4 CP subscribers (2 pairs). Comment [2] reinforces this by explicitly stating the breakdown for the 5,000-10,000 user bracket. Comment [1] incorrectly attempts to downscale the requirements but ultimately acknowledges D as the correct choice despite its flawed reasoning about lower thresholds.
Official Reference
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Collaboration/enterprise/14/collbcvd/sizing.html
This link opens the official vendor documentation in a new tab.
Exam Strategy
Memorize the three main Cisco UCM OVA sizes (Small, Medium, Large) and their corresponding node counts and capacities. Specifically, note that 'Medium' scales from ~1,000 up to 10,000 users, requiring increased redundancy (more CP nodes) as you approach the higher limits.
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 3 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 3
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G0y0 👍 1 Answered DA, and C. are incorrect. Although you need here a medium OVA, this deploy would be useful if you have between 2000 or 3000 users. B. is incorrect. Although you need here a medium OVA, this deploy would be useful if you have between 1000 or 2000 users. D. is almost the correct answer. With this medium OVA, it is useful for up to 5000 users. However, between 5,000 and 10,000 users, you must consider to employ a Large Size OVA.
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Lauser 👍 1 Answered DAgree, it is D: Between 5,000 and 10,000 users or devices: 7 nodes 1 Publisher, 2 TFTP, 2 call processing pairs (4 call processing subscribers) https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Collaboration/enterprise/14/collbcvd/sizing.html
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b3532e4 👍 1Answer D Between 5,000 and 10,000 users or devices 7 nodes: 1 Publisher, 2 TFTP, 2 call processing pairs (4 call processing subscribers)
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