You’ve probably seen the settings on the Advanced tab of a network adapter’s Properties before—it’s the same place where you access the driver details—but the settings aren’t so easy to understand.
Keep in mind, the exact advanced settings and their names differ between vendors, adapter models, and even between different driver versions.
Speed and Duplex: Allows you to select the desired speed and duplex of the network adapter, the default of which is usually auto negotiation.
Gigabit Master Slave Mode: Determines which end of the connection designated as the master; the other of which would be the slave. When left at the default setting (Auto Detect or Hardware Default) the devices automatically negotiate this based upon the IEEE 802.3ab standard: multi-port devices such as switches become the master when connected to a single port device. If both ends are multi-port devices, the one with higher seed bits becomes the master.
MAC Address: Enables you to enter a MAC address for the adapter, overriding the default MAC address. This is an example of how easy it is to bypass MAC address filtering techniques; do a simple packet capture to find an authorized MAC address and apply it here in the advanced settings. However, a more legitimate use of this could be changing the MAC to match the address authorized by your ISP when you’re connecting a PC directly to the modem.
Log Link State Event: This allows you to enable or disable logging of the adapter’s link state changes (such as up/down, duplex mismatch, and STP detection) in the system logs.
QoS Packet Tagging: Enables the adapter to send and receive 802.1p QoS and 802.1Q VLAN indications.
Jumbo Frames: This increases the standard Ethernet frame size of 1514 bytes, such as to 4088, 9014, or 16128 bytes. This can help increase throughput and decrease CPU utilization. However, the functionality and the same frame size typically needs to be supported by all devices across the network. Furthermore, the Jumbo Frames functionality may not work well across different vendors.
Receive Side Scaling: This enables the distribution of incoming network processing across multiple processor cores in multi-core computers, to help increase performance.
Adaptive Inter-Frame Spacing: This setting enables a time gap between packets to help compensate for excessive Ethernet packet collisions on the network.
Flow Control: Helps increase the efficiency of traffic regulation for connections that both support flow control frames. These frames are sent by an adapter when their receive queues reach a pre-defined limit, to signal the sending station to pause transmission so the adapter does not drop the packets.
Interrupt Moderation Rate: Sets the rate at which an adapter interrupts the system to handle incoming or outgoing packets. A lower rate causes the system to be more responsive to packet handling, but can decrease performance of other applications and services on the machine. A higher rate means less responsiveness of packet handling but can help increase machine performance, especially useful for when the adapter is sending and receiving larger packets.
Receive Descriptors: Sets the number of Receive Descriptors that are allocated in the host memory and used to store the received packets. This can be increased if performance of received traffic is lacking.
Transmit Descriptors: Sets the number of Receive Descriptors that enable the adapter to track transmit packets in the system memory. This can be increased if performance of transmission traffic is lacking.
IPv4 Checksum Offload: Enables the adapter to compute the IPv4 checksum of packets instead of the host OS, which can help increase adapter performance while also reducing CPU utilization.
TCP Checksum Offload: Allows the adapter to compute the TCP checksum of outgoing packets rather than the host OS, which can help increase transmission performance while also reducing CPU utilization.
UDP Checksum Offload: Enables the adapter to compute the UDP checksum of outgoing packets instead of the host OS, which can help increase transmission performance while also reducing CPU utilization.
Offload TCP Segmentation: Allows the adapter to perform any necessary TCP segmentation of outgoing packets instead of the host OS, which can help increase transmission performance while also reducing CPU utilization.
ARP Offload: Enables the adapter to respond to ARP requests, which prevents the computer from having to wake for them when asleep.
NS Offload: Enables the adapter to respond to Neighbor Discovery Neighbor Solicitation requests, which prevents the computer from having to wake for them when asleep.
Receive Buffers: The buffer size of system memory that can be used by the adapter for received packets, which can be increased to help improve the performance of outgoing network traffic, but it consumes system memory.
Transmit Buffers: The buffer size of system memory that can be used by the adapter for sending packets, which can be increased to help improve the performance of outgoing network traffic, but it consumes system memory.
Power Saving Settings
Energy Efficient Ethernet: Allows the network adapter to toggle power saving mode on or off when not in use, while still keeping the connection active.
Green Ethernet (Short Reach Mode): Reduces the adapter’s power consumption if the connected cable is detected under a certain length, such as 10 meters.
Auto Disable Gigabit: When enabled, any Ethernet connections will be limited to 100Mbps, which requires less power. You can choose to enable this at all times or, for laptops, just when a battery is being used.
Wake on Magic Packet: Enables you to remotely power on the computer from sleep, hibernation, or when fully powered off by using the magic packet of the Wake-On-LAN feature.
Wake on pattern match: Enables you to remotely power on the computer from sleep, hibernation, or when fully powered off by using the pattern of the Wake-On-LAN feature.
Shutdown Wake-On-LAN: Enables Wake-On-LAN functionality if the computer is fully shutdown.
Wake-On-LAN and Shutdown Link speed: Specifies the link speed of the adapter when the computer is in sleep or hibernation.
Again, these advanced network adapter settings can vary between different models and drivers. Before playing around with the settings, you may want to check if there’s a driver update from the vendor and install it if there is.
Keep in mind that these settings can significantly affect performance and reliability—in a good or bad way. Consider testing performance using some type of network analyzer or even a simple throughput test before and after each setting change. Though some settings and adjustments are supposed to help, they almost always depend upon your particular network and usage. If all else fails and you seem to have “broken” your network connection, a re-install of the driver should restore the factory defaults.
In the future I’ll discuss the additional advanced settings you’ll find in Wi-Fi adapters, which let you fine-tune the wireless connectivity.