Running network connections between buildings using Cat5 cable beyond its recommended 100-meter (328 ft) limit creates multiple issues:

// Typical symptoms you might observe
if (cableLength > 100) {
    showSymptoms([
        "Packet loss",
        "Latency spikes",
        "Reduced throughput",
        "Increased EMI susceptibility"
    ]);
}

Here's the complete hardware stack you'll need for the migration:

networkDiagram = {
    "Building A": {
        "Switch": "Existing network switch",
        "Media Converter": "Gigabit Ethernet to Fiber",
        "Fiber Type": "Single-mode OS2",
        "Connectors": "LC duplex"
    },
    "Conduit": {
        "Cable": "Armored outdoor fiber cable",
        "Length": "400ft with service loop",
        "Protection": "UV-resistant jacket"
    },
    "Building B": {
        "Media Converter": "Fiber to Gigabit Ethernet",
        "Switch": "Existing network switch"
    }
};

Step 1: Selecting the right fiber type
For 400ft distance, single-mode fiber (OS2) is optimal despite being more expensive than multi-mode. It provides:

• Future-proof bandwidth (up to 100Gbps)
• Lower attenuation (0.4 dB/km vs 3.0 dB/km for OM4)
• No modal dispersion issues

Step 2: Media converter configuration
Most modern media converters auto-negotiate, but you might need manual settings:

# Sample media converter CLI configuration
configure terminal
interface fiber 0/1
 speed 1000
 duplex full
 flow-control on
 no shutdown

After connecting the media converters to your existing switches:

// Cisco switch port configuration example
interface GigabitEthernet1/0/24
 description "Fiber Link to Building B"
 switchport mode access
 switchport access vlan 10
 speed 1000
 duplex full
 spanning-tree portfast

Use these commands to verify the link:

# Linux test commands
ethtool eth1  # Verify 1Gbps full duplex
ping -s 8972 remote-host  # Test jumbo frames
iperf3 -c remote-host  # Bandwidth test

# Windows equivalent
Test-NetConnection -ComputerName remote-host -Port 5201
Get-NetAdapterAdvancedProperty -Name "Ethernet"

If you experience problems:

// Diagnostic flowchart logic
if (linkStatus == "down") {
    checkPhysicalLayer();
    verifyMediaConverters();
    testWithKnownGoodCable();
} else if (throughput < 900Mbps) {
    verifyDuplexSettings();
    checkForCRCErrors();
    testWithDifferentMTUSize();
}

Sample budget for 400ft fiber link (USD):

The investment typically pays for itself within 6-12 months through reduced network downtime and IT support costs.

Running network connections between buildings with Cat5 cable at 400ft is pushing the limits of Ethernet specifications. The maximum reliable distance for Cat5 is 328ft (100m) before signal degradation occurs. Common symptoms include:

• Packet loss and retransmissions
• Reduced throughput (often dropping to 100Mbps or lower)
• Increased latency and jitter

Here's the complete shopping list for a fiber upgrade:

# Fiber Optic Components
- 2x SFP/SFP+ modules (1G/10G compatible)
- 2x Media converters (if switches lack SFP ports)
- LC-LC duplex OM3 multimode fiber (400ft minimum)
- Fiber patch cables for rack connections
- Cable management and strain relief

Step 1: Terminate the fiber run
Use pre-terminated fiber with pulling eyes for easier installation. Example pulling force calculation:

max_tension = cable_weight * distance * coefficient_of_friction
# For 400ft aerial run with 0.25lb/ft cable:
max_tension = 0.25 * 400 * 1.5 = 150lbs

Step 2: Hardware configuration
For Cisco switches with SFP ports:

interface GigabitEthernet1/0/1
 media-type sfp
 speed 1000
 duplex full
!

Use these commands to verify fiber link status:

# Cisco IOS
show interface transceiver details
show interface status

# Linux (ethtool)
ethtool -m eth1

Common issues and fixes:

Benchmark results between Cat5 and fiber solutions:

# iPerf3 results (TCP, 60 sec test)
# CAT5 (400ft):
[ ID] Interval       Transfer     Bandwidth
[  4] 0.00-60.00 sec   550 MBytes  76.9 Mbits/sec

# Fiber (same distance):
[ ID] Interval       Transfer     Bandwidth
[  4] 0.00-60.00 sec  6.88 GBytes   985 Mbits/sec