​Cisco C9300LM-48UX-4Y-A vs C9300LM-48U-4Y-A: The Extension Power Showdown

Jul 21 , 2025 5

Cisco C9300LM-48UX-4Y-A vs C9300LM-48U-4Y-A: The Extension Power Showdown

When choosing access layer switches, model suffixes like -UX (UXF expandable) and -U (basic) often signal a key divide: expandability. Today, we’ll dissect these “sibling models” across performance, features, design, usability, cost, and real-world use cases.

1. Performance: Same Core, Different Scalability

Both models share the same UADK architecture (dual-core ARM Cortex-A72, 8GB DDR4 RAM, 256MB flash), so base performance (packet forwarding, per-port bandwidth) is identical. However, the -UX’s “UXF expandable” design unlocks superior scalability:

• Stack Module Support:

• -UX: Supports UXF stack modules via 4×10G SFP+ ports, enabling up to 8 devices in a stack (384 total ports, 40Gbps stacking bandwidth).

• -U: Limited to FlexStack+ stacking (2×10G SFP+ ports), supporting up to 4 devices (192 total ports, 20Gbps stacking bandwidth).

• Interface Flexibility:

• -UX: 48×10/100/1000BASE-T ports + 4×10G SFP+ (replaceable with SFP modules for short/long-range fiber).

• -U: Fixed 4×10G SFP+ ports (no module replacement).

• Power Redundancy:

• -UX: Higher-efficiency 80Plus Silver-certified power supply, maintaining lower temperatures under full PoE++ load (60W/port).

Verdict: -U is a “basic all-rounder”; -UX is an “expandable powerhouse.”

2. Feature Set: Scalability Drives Differentiation

Core features (VLANs, QoS) are consistent, but -UX’s expandability enables advanced capabilities:

Real-World Example: A hotel chain uses -UX for headquarters (connecting 8 branch access switches); individual branches use -U (2 stacked units cover 100 rooms).

3. Design & Aesthetics: Physical Manifestation of Scalability

Design differences directly reflect expandability:

• Size & Weight:

• -UX: 1U (440mm×44.5mm×310mm, 4.8kg) with space for UXF modules.

• -U: 1U (440mm×44.5mm×290mm, 4.2kg), more compact for space-constrained racks.

• Interface Layout:

• -UX: Front-panel split (24+24 ports) with 2 hot-swappable UXF slots (status lights for module health).

• -U: 48 ports in a single block, with 2 fixed 10G SFP+ ports (simpler labeling).

User Feedback: IT managers praise -UX’s “plug-and-play” module design—troubleshooting is easier than -U’s cable-heavy stacking.

4. Cost-Effectiveness: The Long-Term Scalability Equation

Pricing (China market, new):

• C9300LM-48UX-4Y-A: ~¥18,000

• C9300LM-48U-4Y-A: ~¥14,000

But total cost depends on future expansion needs:

• -U’s hidden costs: Scaling to 300 endpoints in 3 years requires 2 additional switches + stack modules (~¥33,000 total, exceeding -UX’s ¥18,000).

• -UX’s long-term savings: One-time investment covers 8 stacked units (384 ports), avoiding future device purchases.

Bottom Line: -U saves money upfront; -UX saves money long-term.

5. System Upgrades: Common Pitfalls with UX Modules

IOS XE upgrades are similar, but -UX’s UXF modules introduce compatibility risks:

Issue 1: Module Firmware Mismatch

• Symptom: Post-upgrade, UXF modules run old firmware, causing unstable stacking (packet loss).

• Cause: UXF modules require separate firmware updates, matching the main switch’s version.

• Fix: Use Cisco’s “bundle firmware package” (main device + modules) and upgrade via archive tar /xtract.

Issue 2: Stack Link Negotiation Failure

• Symptom: Stacking fails with “Stack link negotiation failed” after upgrade.

• Cause: Incompatible transceiver types (e.g., 10G SR vs. LR modules) with the new firmware.

• Fix: Use compatible transceivers or verify compatibility via show stack compatibility.

Issue 3: Configuration Loss

• Symptom: Lost configurations after power failure during upgrade.

• Cause: Failing to save main device/module configurations.

• Fix: Run write memory (main device) and module ux-firmware save (modules) before upgrading.

Pro Tip: Test upgrades in a lab first (1 main device + 1 UXF module) to validate compatibility.

6. Use Cases: Where They Shine

• C9300LM-48UX-4Y-A: Medium enterprise campuses (300-500 endpoints), regional corporate offices (branch traffic aggregation), university labs (high-bandwidth experiment setups). Strengths: Flexible scaling, high-bandwidth stacking, advanced encryption.

• C9300LM-48U-4Y-A: Small businesses (≤100 endpoints), community centers (50 endpoints + IP phones), school teacher offices (40 computers). Strengths: Compact size, low cost, simple deployment.

Shared Advantage: Both support Cisco DNA Center (automated AP/IP phone provisioning), IPv6 routing, and SD-WAN—future-proof for evolving networks.

From “can I add another module?” to “will my network scale with growth?”, the C9300LM series’ -UX and -U models deliver clarity—choose based on your need for expandability, and avoid the pitfalls of under- or over-provisioning.