Windows Network Adapter Jargon

Over the past few years I’ve always had a curiosity for trying to tweak my network adapter settings as you can see from some of my past posts; Fixing Vistas Slow Network Speed, Vista VPN == Slow Net Access, End of my wireless woes and Wireless network ping spikes. I’ve always found it rather difficult to find defintitions for what each of the settings do. It usually comes down to me googling specific setting names and hoping to find something relevant in understandable English. Today I decided to update my Marvell network driver and found that the readme file actually has a complete description of each setting. For the sake of posterity I’m posting it here incase anyone else attempts to search for these options and their meanings.

The following is extracted from the readme for a Marvell Yukon 88E8056 PCI-E Gigabit Ethernet Controller v10.66.4.3 driver zip file.

‪©Copyright 2002-2008 Marvell®.‬
All rights reserved.

yk60x64.sys: 64-bit Miniport driver, NDIS6.0

Parameters
The driver allows you to modify several options in order to optimize the
operation of your adapter.

  1. In “Network Connections”, right-click the adapter you want to configure.
  2. Select “Properties”.
  3. Click “Configure”.
  4. Click “Advanced”.
  5. In the “Property” box, select the option you want to change.
  6. Enter the desired value in the “Value” box.
  7. Click OK.
  8. The operating system will reload the driver with the changed settings.

The parameters supported by the driver are described below.

Network Address
Default value: burned-in adapter address
Valid range: “02-00-00-00-00-01” to “FE-FF-FF-FF-FF-FF” (hexadecimal), where at least the “multicast” bit (bit 0) must not be set (it indicates that the address field contains an individual address) and the “locally administered” bit (bit 1) is set (the address has been assigned by a local administrator). These two bits are the first and second bit transmitted on the LAN medium.

CAUTION: Each individual network MAC address can only be used once in a network. Assigning the same address to more than one adapter in the same network is not allowed and can cause serious problems.

To use a network MAC address other than the one burned into the adapter, enter the network address in the following hexadecimal format: 02-00-5A-98-12-34

If the network address field is left blank (or a different number of digits is specified), the network address burned into the adapter will be used.

Jumbo Packet
Specifies the frame size the driver supports. The performance of your network usually increases when Jumbo frames with a size > 1514 are used.

Default value: “1514 Bytes”
Valid values:

  • “4088 Bytes”
  • “9014 Bytes”

NOTE: If you are not sure whether your network supports Jumbo frames, do not set the size to > 1514.
NOTE: For Fast Ethernet adapters, the valid range is limited to 1514.

IPv4 Checksum Offload
Used to control the hardware checksum offload for IPv4 traffic. There should be no need to disable checksum offload.

Default value: “Tx & Rx Enabled”
Valid values:

  • “Tx & Rx Enabled”
  • “Tx Enabled”
  • “Rx Enabled”
  • “Disabled”

TCP Checksum Offload (IPv4), UDP Checksum Offload (IPv4), TCP Checksum Offload (IPv6), UDP Checksum Offload (IPv6)
Used to control the hardware checksum offload for the combinations of TCP/UDP and IP versions. There should be no need to disable checksum offload.

Default value: “Tx & Rx Enabled”
Valid values:

  • “Tx & Rx Enabled”
  • “Tx Enabled”
  • “Rx Enabled”
  • “Disabled”

NOTE: The IPv6 parameters are not available for every adapter type.

Wake-Up Capabilities
Default value: “Magic Packet & Pattern Match”
Valid values:

  • “None” – Wake On LAN capabilities are disabled
  • “Magic Packet” – Wake-up with Magic Packet from Shutdown state, wake-up OS-controlled from Hibernate or Standby state
  • “Pattern Match” – Wake-up with a packet containing a special pattern from Shutdown state, wake-up OS-controlled from Hibernate or Standby state
  • “Magic Packet & Pattern Match” – Wake-up with both from Shutdown state, wake-up OS-controlled from Hibernate or Standby state
  • “Link Change” – Wake-up with link change from Shutdown state, wake-up OS-controlled from Hibernate or Standby state

Wake From Shutdown
Default value: “Off”
Valid values:

  • “Off” – Disable the capabilities of the adapter to wake up the system from Shutdown state.
  • “On” – Allow the adapter to wake up the system from Shutdown state.

Energy Star
Used to reduce power consumption in Standby and Hibernate state when Wake On LAN capabilities are enabled.

Default value: “Enabled”
Valid values:

  • “Disabled” – No energy saving functions are switched on in the adapter.
  • “Enabled” – The link speed is switched to 10 Mbps to reduce power consumption.

NOTE: This parameter is not available for every adapter type.

Receive Buffers
Defines the number of receive buffers allocated by the driver. If the system does not have enough resources, the driver will fail to load.
Increasing this value may improve the performance.

For Yukon family based Ethernet adapters, the following values are used:
Default value: 50 (decimal)
Valid range: 3..500 (decimal)

For Yukon2 family based Ethernet adapters, the following values are used:
Default value: 256 (decimal)
Valid range: 256..512 (decimal)

Transmit Buffers
Defines the number of transmit buffers allocated by the driver. If the system does not have enough resources, the driver will fail to load. Increasing this value may improve the performance.

For Yukon family based Ethernet adapters, the following values are used:
Default value: 50 (decimal)
Valid range: 4..200 (decimal)

For Yukon2 family based Ethernet adapters, the following values are used:
Default value: 256 (decimal)
Valid range: 256..512 (decimal)

Interrupt Moderation
If more than the specified rate of interrupts occur, the Interrupt Moderation
function groups these interrupts so that several data packets can be handled
per interrupt. This will lead to lower CPU utilization but may increase the
latency.

Default value: “Enabled”
Valid values:

  • “Enabled”
  • “Disabled”

Max IRQ per Sec
Specifies the interrupt rate for Interrupt Moderation. If Interrupt Moderation is set to “Off”, it will be ignored.

Default value: 5000 (decimal)
Valid range: 1000..30000 (decimal)

Log Status Messages
Specifies the messages which are to be logged in the event log.

Default value: “Status Messages”
Valid values:

  • “All Messages” – Should only be used for test purposes.
  • “Status Messages” – The driver will generate an event log entry every time the link status changes.
  • “Warnings” – Only warning or error messages will be generated.
  • “Errors” – Only error messages will be generated.
  • “None” – All driver messages will be suppressed (not recommended).

Speed & Duplex
Contains information regarding auto-negotiation, duplex capabilities, and link speed.

Default value: “Auto-Negotiation”
Valid values:

  • “Auto-Negotiation”
  • “10 Mbps Half Duplex”
  • “10 Mbps Full Duplex”
  • “100 Mbps Half Duplex”
  • “100 Mbps Full Duplex”
  • “1000 Mbps Full Duplex”

NOTE: This parameter is not valid for fiber adapters.

Preferred Port
Sets the preferred port for RLMT (Redundant Link Management Technology). This port will be used for all network traffic when more than one port has an active link to the network.

Default value: “A”
Valid values:

  • “A”
  • “B”

NOTE: This parameter is only available for dual link adapters.

RLMT Mode
Default value: “CLS”
Valid values:

  • “CLS” (Check Link State) – RLMT uses the link state reported by the adapter hardware for each individual port to determine whether a port can be used for all network traffic or not.
  • “CLP” (Check Local Port) – RLMT monitors the network path between the two ports of an adapter by regularly exchanging packets between them. This mode requires a network configuration in which the two ports “see” each other (i.e., there must not be any router between the ports).
  • “CLPSS” (Check Local Ports and Segmentation Status) – Supports the same functions as “CLP” mode, and additionally checks network segmentation by sending BPDU hello packets. This mode only works when Gigabit Ethernet switches are installed on the network that have been configured to use the Spanning Tree protocol.

NOTE: RLMT modes “CLP” and “CLPSS” are designed to operate in configurations where a network path between the ports on one adapter exists. Moreover, they are not designed to work where adapters are connected back-to-back. This parameter is only available for dual link adapters.

Priority & VLAN
Enables/disables 802.1p (QoS) and/or 802.1q (VLAN) capability.

Default value: “Priority Enabled”
Valid values:

  • “Priority Enabled”
  • “VLAN Enabled”
  • “Priority & VLAN Enabled”
  • “Priority & VLAN Disabled”

NOTE: This will only enable the capability of the driver to handle such packets. There must be a protocol or application that passes such packets to the driver.

Battery Mode Link Detection
Sets the mode in which the adapter works if there is no link and the system is battery-powered.

Default value: “EnergyDetect+(TM)”
Valid values:

  • “No Energy Saving” – No energy saving functions are switched on in the adapter.
  • “Maximum Energy Saving” – If there is no link, the adapter is switched off. The driver wakes up the adapter every 20 seconds to check if there is a new link.
  • “EnergyDetect+(TM)” – In “EnergyDetect+(TM)” mode the link is activated faster than in “Maximum Energy Saving” mode, but the adapter requires more power.

NOTE: This parameter is not available for every adapter type.

Battery Speed Settings
Sets the link speed for the adapter when the system is battery-powered.

Default value: “Full Speed”
Valid values:

  • “Smart Speed Down” – The link speed is switched to 10/100 Mbps to reduce power consumption.
  • “Full Speed”- The adapter works with maximum speed and maximum power consumption (no energy saving, same as when the system is supplied by AC power).

NOTE: This parameter is not available for every adapter type.

Flow Control
Sets the flow control capabilities for auto-negotiation.

Default value: “Tx & Rx Enabled”
Valid values:

  • “Disabled” – No link partner is allowed to send PAUSE frames.
  • “Tx & Rx Enabled” – Both link partners are allowed to send PAUSE frames.

This parameter can be set for each port individually, which is helpful if the port at the other end of the cable cannot handle all possible combinations. Using the default setting, the adapter should automatically detect the capabilities of the peer port.

Large Send Offload (IPv4)
Used to control the capability of Large Send Offload for IPv4 traffic.

Default value: “Enabled”
Valid values:

  • “Enabled” – The big packets are segmented on the adapter before sent to the network. Using this method, load will be taken from the processor.
  • “Disabled” – The packets are not segmented by the adapter.

NOTE: This parameter is only available starting with adapters based on the Yukon2 chip.

Large Send Offload v2 (IPv4), Large Send Offload v2 (IPv6)
Used to control the capability of Large Send Offload version 2 for IPv4 and IPv6 traffic.

Default value: “Enabled”
Valid values:

  • “Enabled”
  • “Disabled”

NOTE: These parameters are not available for every adapter type.

Receive-Side Scaling
Enables/disables balancing the receive network load from a network adapter across multiple CPUs.

Default value: “Disabled”
Valid values:

  • “Enabled”
  • “Disabled”

NOTE: This parameter is not available for every adapter type.

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