Home > Articles

Maximizing the Performance a Gigabit Ethernet NIC Interface

This article describes how to get the greatest benefits from your Ethernet NIC interface. It includes information on the tools that can help you achieve the best results from that interface, as well as a section on troubleshooting. This article targets an advanced reader.
Like this article? We recommend

This article describes how to get the greatest benefits from your Sun Gigabit Ethernet network interface card (NIC) interface and a few valuable tools to help you achieve that.

Gigabit Ethernet connections create the greatest stress by far to Sun systems. Therefore, to get the maximum benefit from your gigabit Ethernet NIC interface you need to be aware of the added complications of Auto-negotiation as well as the new ways to ensure that you get the maximum performance from both the gigabit Ethernet interface and the system.

There are two parts to getting the maximum performance from your gigabit Ethernet NIC and the system: first, you need to understand the system itself; second, you need to know the traffic profile through the gigabit Ethernet NIC.

Two key parameters to Sun systems are important for maximizing gigabit Ethernet performance: the number of CPUs in the system and the access time for memory. Establishing the number of CPUs is relatively simple. The memory access time is often hidden, but a simple rule is the larger the system the longer the memory access time. These factors become important for tuning transmitting (Tx) DMA thresholds and deciding how much load balancing of incoming receiving (Rx) traffic is meaningful.

The traffic profile has many dimensions also, including any one of the following characteristics or any combination of them: Rx intensive, Tx intensive or Equal, small packets, large packets, or latency sensitive.

The combination of system parameters and the traffic profile makes it very difficult to enumerate all the possibilities and provide one set of tuning parameters that will address every combination equally and fairly.

Therefore, we can only take the alternative approach of listing the readily available tunable parameters along with an explanation of how and when to use them to get the best results based on your system and application needs.

Each NIC has kernel statistics that provide a means of measuring the traffic profile. You can use this information to adjust ndd and /etc/system parameters to get the best performance from the NIC.

For more sophisticated features like CPU load balancing, there are some other tools that allow you to look at the system behavior and determine if tuning can better utilize the system as well as the NIC, given the system and the application providing the traffic profile.

  • "Network Driver Configuration Parameters" describes the details of the three methods you can use for configuring the driver parameters.

  • "Ethernet Physical Layer Troubleshooting" discusses the physical layer because that layer is the most important with respect to creating the link between two systems.

  • "Ethernet Performance Troubleshooting" discusses the data link layer, where most problems are performance related.

This article assumes you are an experienced systems administrator, accustomed to working with gigabit Ethernet NIC interfaces.

Network Driver Configuration Parameters

Since this article discusses the network driver configuration parameters it's important to note the details of the network driver configuration methods.

There are three methods you can use for configuring the driver parameters: ndd, driver.conf, or /etc/system.

The ndd method is a dynamic form of configuration where you simply invoke the ndd command in a command line

hostname# ndd -set /dev/ge instance 0
hostname# ndd -set /dev/ge adv_autoneg_cap 1

or through an interactive session.

hostname# ndd /dev/ge
name to get/set ? instance
value ? 0
name to get/set ? adv_autoneg_cap
value ? 1
name to get/set ?

The ndd method is excellent for adjusting parameters during normal operation, but the configuration is lost once the system is rebooted. You can avoid this configuration loss by applying the chosen parameter in the driver.conf file of the driver you want to configure.

The driver.conf file for the device being configured must reside next to the driver being configured in the file system. For example, the Gigabit Ethernet driver has the following path:


The following example shows the path for the GigaSwift driver in two different platforms:

For Solaris 9 x86

For Solaris sparc

Modifying the parameters in the driver.conf file can be done with two goals in mind: configuring parameters in a global manner, where all interface instances in the machine using the same driver get the same parameter value, or on a per instance basis, where a parameter value applies to only one instance.

The global configuration method for the ge.conf file will appear as follows, applying the ndd configuration previously shown:

adv_autoneg_cap = 1;

Note that the previously shown ndd example only applied instance 1, so the global configuration may be overkill. Determine whether per instance or the global method is more appropriate for your needs.

name="ge" parent="/pci@1f,0/pci@1,1" 
	 	unit-address = "1" adv_autoneg_cap = 1;

The per instance method does require you to get the 'parent' and 'unit-address' properties associated with the instance your configuring. This can be achieved by looking at the lines associated with that instance in the path_to_inst file.

The /etc/system configuration method allows you to initialize global variables in the device driver. It has no direct association with ndd and driver.conf setting unless explicitly implemented in the driver. In cases where a driver parameter has been defined for use in either /etc/system or driver.conf, you should choose to use the preferred driver.conf method instead.

Parameters set in the /etc/system always require a system reboot to take effect, the following example shows how an /etc/system variable is set up.

hostname# vi /etc/system
set ge:ge_intr_mode = 1

The remainder of the document will discuss ndd, so you should assume that any of the following parameters described as an ndd parameter should only be initialized using the driver.conf file. Any of following parameters described as /etc/system parameters get initialized using only modifications to /etc/system parameters and do require a reboot.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020