System Administration Guide: Network Interfaces and Network Virtualization

Network Interface-Based Flow Control

This section contains scenarios for using interface-based flow control. Flow control incorporates resource control and bandwidth management. This process involves organizing packet traffic into flows of related applications, and then assigning portions of an interface's overall bandwidth to the individual flows. You can also assign a specific application's traffic to a flow to isolate the traffic without assigning the flow an amount of bandwidth. Isolating particular types of traffic to flows makes the traffic more easily observed, evaluated, and possibly billed. The following scenarios are described:

Look over these scenarios to see which is most applicable for your site. For the tasks that implementing these scenarios, refer to Chapter 13, Configuring Resource Management on an Interface.

Interface-based Resource Control for a Traditional Network

Figure 10–3 shows the network topology for a small business that needs to manage the bandwidth on its proxy server. The proxy server offers a public web site as well as a proxy for internal clients that require services from various servers on the site's internal network.

Note –

This scenario does not show how to configure flow control for a virtual network, and consequentially does not include VNICs. For flow control on a virtual network, refer to Flow Control for a Virtual Network.

Figure 10–3 Resource Control for a Proxy Server on a Traditional Network

This figure is explained in the following paragraphs.

The figure shows that the company has a public network,, that also serves as a demilitarized zone (DMZ). A system on the DMZ provides name-to-address translation (NAT) through an IP Filter firewall. The company has a large system that functions as the proxy server. The system has two wired interfaces and 16 processor sets with IDs 0–16. This system is connected to the public network through the interface nge0, with IP address l0 10.6.5. The link name for the interface is DMZ0. Through DMZ0, the proxy server offers HTTP and HTTPS service through the company's public web site.

The figure also illustrates the company's internal network, The proxy server connects to the internal network through interface nge1, with the IP address The link name for this interface is internal0. Through the internal0 data link, the proxy server operates on behalf of internal clients that request the services of an application server,, database server,, and backup server,

Best Use of Interface–based Resource Control on a Traditional Network

Consider establishing flow control for heavily used systems, especially those with newer GLD.v3 interfaces with large amounts of available bandwidth. Interface-based flow control improves the efficiency of the interface, the system, and potentially the network. You can apply flow control to any system on any type of network. Furthermore, if your goal is to improve network efficiency, you can separate various services into individual flows. This action assigns separate hardware and software resources to the individual flows, thus isolating them from other services on a particular system. After you establish flows, you can observe traffic for each flow and gather statistics. Thereafter, you can assign bandwidth amount and priorities to control usage on the interfaces.

For More Information

Flow Control for the Virtual Network

This scenario shows how flow control is used within a virtual network, such as the basic virtual network that is introduced in Basic Virtual Network on a Single System.

Figure 10–4 Basic Virtual Network With Flow Controls

The illustration is explained in the next context.

The topology is described in Basic Virtual Network on a Single System. Here a host has one network interface, e1000g0, with two VNICs, vnic1 and vnic2. zone1 is configured over vnic1, and zone2 is configured over vnic2. Resource management for the virtual network involves creating flows on a per-VNIC basis. These flows define and isolate packets with similar characteristics, such as port number or IP address of the sending host. You assign bandwidth based on the usage policy for the system.

Another very common usage for flow controls on VNIC traffic is by companies that rent out zones. You create different service level agreements for customers, and rent out zones with a guaranteed amount of bandwidth. When you create flows on a per-zone basis, you can isolate and observe each customer's traffic and monitor bandwidth usage. If your service level agreement is based strictly on usage, you can use Solaris statistics and accounting features to bill customers.

Flow controls are effective for any network that requires bandwidth management for traffic over zones. Larger organizations, such as application service providers (ASPs) or Internet service providers (ISP), can take advantage of resource control for VNICs for data centers and for multiprocessor systems. The individual zones can be rented out to customers for different levels of service. Therefore, you could rent out zone1 at the standard price and offer a standard bandwidth. Then, you could rent out zone2 at a premium price and give that customer a high level of bandwidth.

ProcedureHow to Create a Usage Policy for Applications on a Virtual Network

  1. List the applications that you want to run on the host.

  2. Determine which applications have historically used the most bandwidth or require the most bandwidth.

    For example, the telnet application might not consume huge amounts of bandwidth on your system, but it could be heavily used. Conversely, database applications consume a huge amount of bandwidth, but might only be used on a sporadic basis. Consider monitoring traffic for these applications prior to assigning them to zones. You can use the statistical option of the dladm show-link command to gather statistics, as described in Gathering Usage Statistics for VNICs and Flows.

  3. Assign these applications to separate zones.

  4. Create flows for any application running in zone1 whose traffic you want to isolate and control.

  5. Assign bandwidth to flows based on usage policies in place for your site.

ProcedureHow to Create a Service Level Agreement for the Virtual Network

  1. Design a policy that offers different levels of services at different prices.

    For example, you might create a basic, superior, and high levels of service, and price each level accordingly.

  2. Decide whether you want to charge customers on a monthly, per service level basis, or charge customers on an actual bandwidth consumed basis.

    If you choose the latter pricing structure, you need to gather statistics on each customer's usage.

  3. Create a virtual network on a host, with containers for each customer.

    A very common implementation is to give each customer their own zone running over a VNIC.

  4. Create flows that isolate traffic for each zone.

    To isolate all traffic for the zone, you use the IP address that is assigned to the zone's VNIC.

  5. Assign bandwidth to each VNIC based on the service level purchased by the customer assigned to that VNIC's zone.