Windows XP used a straightforward approach for automatic route metric assignment based solely on interface speed, as documented in KB299540. However, Windows 7 introduced a more complex algorithm that considers multiple factors beyond just link speed.

The automatic metric in Windows 7 is calculated using this formula:

Metric = InterfaceMetric + DestinationPrefixMetric + GatewayMetric

Where:

• InterfaceMetric: Based on the interface speed (similar to XP but with different values)
• DestinationPrefixMetric: Length of the destination prefix
• GatewayMetric: Additional cost if the route uses a gateway

Let's analyze your specific routing table entries:

0.0.0.0/0 via 192.168.0.1 (Gigabit) - Metric 10
0.0.0.0/0 via 10.202.254.254 (VPN) - Metric 286
192.168.0.0/24 - Metric 266
10.202.0.0/16 - Metric 286
127.0.0.0/8 - Metric 306

You can manually set metrics using the route command:

route change 0.0.0.0 mask 0.0.0.0 10.202.254.254 metric 20

Or disable automatic metrics entirely via PowerShell:

Get-NetAdapter | ForEach-Object {
    Set-NetIPInterface -InterfaceIndex $_.ifIndex -AutomaticMetric Disabled
}

For granular control, modify these registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DisableDHCPMediaSense
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\EnableDeadGWDetect

When debugging routing problems:

1. Verify interface speeds with Get-NetAdapter
2. Check current metrics with route print
3. Test connectivity with Test-NetConnection

While Windows XP used a straightforward speed-based metric calculation as documented in KB299540, Windows 7 introduced a more complex algorithm that considers multiple factors:

// Windows XP metric calculation (simplified)
int CalculateMetricXP(int interfaceSpeed) {
    if (interfaceSpeed > 200000) return 10;
    if (interfaceSpeed > 20000) return 20;
    if (interfaceSpeed > 4000) return 30;
    if (interfaceSpeed > 500) return 40;
    return 50;
}

Windows 7 considers these additional parameters:

• Interface speed (still primary factor)
• Interface type (wired vs wireless)
• Historical reliability data
• Connection state (VPN tunneling overhead)
• Network location type (Public/Private/Domain)

Examining your routing table reveals several interesting patterns:

IPv4 Route Table
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      192.168.0.1      192.168.0.3     10
          0.0.0.0          0.0.0.0   10.202.254.254       10.202.1.2    286
       10.202.0.0      255.255.0.0         On-link        10.202.1.2    286
      192.168.0.0    255.255.255.0         On-link       192.168.0.3    266
===========================================================================

Key observations:

• The direct Gigabit connection gets base metric 10
• Other routes through same interface get 256 + base metric (10 + 256 = 266)
• VPN connections get higher penalty (base 10 + 256 + 20 for VPN overhead = 286)
• Loopback gets highest metric (306)

To override automatic metrics, use the netsh command:

netsh interface ipv4 set interface "Local Area Connection" metric=10
netsh interface ipv4 add route 0.0.0.0/0 "Local Area Connection" 192.168.0.1 metric=10 store=active

Use WMI to retrieve detailed interface information:

using System.Management;

var query = new SelectQuery("SELECT * FROM Win32_NetworkAdapterConfiguration WHERE IPEnabled = 'TRUE'");
var searcher = new ManagementObjectSearcher(query);

foreach (ManagementObject mo in searcher.Get())
{
    Console.WriteLine($"Interface: {mo["Description"]}");
    Console.WriteLine($"Metric: {mo["IPConnectionMetric"]}");
    Console.WriteLine($"Speed: {mo["Speed"]} bps");
}

While not officially documented, analysis suggests this formula:

base_metric = speed_based_value (from XP table)
if (is_vpn) base_metric += 20
if (is_wireless) base_metric += 20
route_metric = base_metric + (interface_index * 256)

This explains why you see metrics like 266 (256 + 10) and 286 (256 + 30).

Use these commands to gather more information:

route print -4
netsh interface ipv4 show interfaces
netsh interface ipv4 show addresses