Technical Specifications:

• Part Number: C3850-NM-4-1G= (equals sign indicates spare/replacement part)
• Product Type: Network Expansion Module
• Compatible Platform: Cisco Catalyst 3850 Series Switches
• Form Factor: Field-replaceable network module

Port Configuration:

• Total Ports: 4 x Gigabit Ethernet SFP ports
• Port Type: SFP (Small Form-Factor Pluggable) slots for 1GbE fiber optic transceivers
• Port Naming Convention: GigabitEthernet1/1/1 through GigabitEthernet1/1/4
• Native Speed: 1 Gbps (Gigabit Ethernet)
• Supported Transceivers: Any combination of standard Cisco 1GbE SFP modules
  • 1000BASE-SX (multimode fiber, 850nm, up to 550m)
  • 1000BASE-LX/LH (single-mode fiber, 1310nm, up to 10km)
  • 1000BASE-ZX (single-mode fiber, 1550nm, up to 70km)
  • 1000BASE-T (copper SFP, RJ-45, up to 100m)
  • Third-party compatible SFP modules (where supported)

Performance Characteristics:

• Data Transfer Rate: 1 Gbps per port (4 Gbps aggregate)
• Forwarding Performance: Wire-speed forwarding with no blocking
• Latency: Ultra-low latency switching
• Full-Duplex Operation: All ports support simultaneous send/receive at 1 Gbps

Compatibility:

Compatible Cisco Catalyst 3850 Switch Models:

The C3850-NM-4-1G module is compatible with most Catalyst 3850 series switches EXCEPT the following SFP+ models:

• WS-C3850-12S (12-port SFP+)
• WS-C3850-24S (24-port SFP+)
• WS-C3850-12XS (12-port 10GbE SFP+)
• WS-C3850-24XS (24-port 10GbE SFP+)

Supported Switch Models Include:

• 24-Port Models: WS-C3850-24T, WS-C3850-24P, WS-C3850-24U (and variants with -E, -L, -S, -BA suffixes)
• 48-Port Models: WS-C3850-48T, WS-C3850-48P, WS-C3850-48U, WS-C3850-48F (and variants with -E, -L, -S suffixes)
• Multi-Gigabit Models: WS-C3850-12X48U, WS-C3850-24XU (48U and 24XU models)

Installation & Configuration:

Hot-Swappable Design:

• Install or remove without powering down the switch
• Automatic recognition and configuration upon insertion
• Minimal service disruption during installation or upgrades

Installation Process:

1. Align module with network module slot on rear of Catalyst 3850 switch
2. Slide module into slot until fully seated
3. Secure with captive screws (hand-tighten, no tools required for initial seating)
4. Switch automatically detects and configures ports
5. Insert appropriate SFP transceivers into module ports

Port Configuration Notes:

• All four ports are natively Gigabit Ethernet interfaces
• Ports are configured as GigabitEthernet1/1/1 through GigabitEthernet1/1/4
• Only these four interfaces are valid for use
• Additional phantom interfaces may appear in CLI but should not be used

Advanced Features:

Integrated with Cisco Catalyst 3850 Capabilities:

• StackWise-480 Technology: Participate in switch stack with 480 Gbps stacking bandwidth
• Quality of Service (QoS): Hardware-based traffic prioritization and classification
• Layer 2 & Layer 3 Switching: Full wire-speed routing and switching
• Energy Efficient Ethernet (EEE): IEEE 802.3az energy savings
• Cisco UADP ASIC: Unified Access Data Plane for high-performance packet processing
• Application Visibility: Deep packet inspection and application recognition
• Flexible NetFlow: Comprehensive traffic analysis and monitoring

Network Management:

• Cisco IOS XE Software: Native integration with Cisco IOS XE operating system
• Cisco DNA Center: Cloud-managed networking with automation and analytics
• SNMP: v1/v2c/v3 for traditional network management
• CLI & GUI: Full command-line and web-based management
• Zero-Touch Provisioning: Automatic configuration for rapid deployment

Use Cases & Applications:

Campus Network Uplinks:

• Aggregate traffic from access layer to distribution switches
• High-speed uplinks for departmental or floor switches
• Fiber-based connectivity across building infrastructure

Data Center Access:

• Server connectivity in top-of-rack deployments
• Storage network connections (iSCSI)
• Management network uplinks

Branch Office Connectivity:

• WAN router uplinks
• Site-to-site interconnection over fiber
• Redundant uplink configurations

Wireless Network Infrastructure:

• High-speed uplinks to wireless controllers
• Aggregate multiple wireless access point connections
• Distribution of wireless traffic to network core

Link Aggregation & Redundancy:

• Configure multiple ports as EtherChannel for increased bandwidth and redundancy
• Active-active uplink configurations with automatic failover
• Load balancing across multiple uplink paths

Physical Specifications:

• Form Factor: Modular network expansion card
• Installation Slot: Rear-mounted network module slot on Catalyst 3850 switches
• Weight: Lightweight modular design (approximately 0.5-1 lb)
• Cooling: Passive cooling, uses switch chassis airflow

Power Requirements:

• Power Source: Powered by host Catalyst 3850 switch
• No External Power Required: Module draws power from switch backplane
• Energy Efficient: Low power consumption per port

LED Indicators:

• Port Status LEDs: Individual LED per port indicating link status and activity
• Link LED: Green when link is established
• Activity LED: Flashing green during data transmission/reception

Standards Compliance:

• Ethernet: IEEE 802.3, 802.3z (Gigabit Ethernet)
• Energy Efficiency: IEEE 802.3az (Energy Efficient Ethernet)
• Quality of Service: IEEE 802.1p, 802.1Q
• Safety: UL, CSA, CE compliance
• EMC: FCC Part 15, VCCI, CE electromagnetic compatibility

What's Typically Included:

• 1 x Cisco C3850-NM-4-1G network module
• Captive installation screws (attached to module)
• Quick start documentation

Sold Separately:

• SFP transceivers (choose based on fiber type and distance requirements)
• Fiber optic cables (single-mode or multimode)
• Cisco Catalyst 3850 host switch

Warranty & Support:

• Cisco standard hardware warranty
• Cisco SMARTnet Service (optional):
  • 24/7/365 technical support
  • Hardware replacement
  • Software updates and firmware
  • Access to Cisco Technical Assistance Center (TAC)

Key Advantages:

• Modular Flexibility: Upgrade switch uplink capacity without replacing entire switch
• Hot-Swappable: Install or replace without network downtime
• Investment Protection: Extend lifespan of existing Catalyst 3850 infrastructure
• Cost-Effective: Lower cost per port than purchasing new switches
• Scalable Architecture: Add capacity incrementally as network demands grow
• Multi-Vendor SFP Support: Use Cisco or compatible third-party SFP modules
• Future-Proof: Easily upgrade to higher-speed modules (10G/40G) when needed
• Seamless Integration: Native support in Cisco IOS XE with zero configuration
• Enterprise Reliability: Cisco quality and support for mission-critical networks

Migration & Upgrade Path:

Organizations can start with the C3850-NM-4-1G module and upgrade to higher-performance modules as bandwidth requirements increase:

• C3850-NM-2-10G: 2 x 1GbE + 2 x 10GbE mixed-speed uplinks
• C3850-NM-4-10G: 4 x 10GbE SFP+ uplinks (requires 48-port or higher models)
• C3850-NM-8-10G: 8 x 10GbE SFP+ uplinks (for multigigabit switches)
• C3850-NM-2-40G: 2 x 40GbE QSFP+ uplinks (for multigigabit switches)

Why Choose the Cisco C3850-NM-4-1G Network Module:

The C3850-NM-4-1G delivers exceptional value for organizations requiring modular Gigabit Ethernet uplink expansion for Cisco Catalyst 3850 switches. With four flexible SFP ports supporting any combination of fiber or copper Gigabit transceivers, hot-swappable installation enabling zero-downtime upgrades, and seamless integration with Cisco IOS XE software requiring no manual configuration, this module provides a cost-effective path to increased network capacity. Whether deploying fiber uplinks across campus buildings, aggregating access layer traffic to the distribution core, connecting to wireless controllers, or implementing redundant EtherChannel uplinks, the C3850-NM-4-1G extends the capabilities of your Catalyst 3850 investment while maintaining the flexibility to upgrade to 10GbE or 40GbE modules as bandwidth demands evolve.