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Managing Oracle Solaris 11.1 Network Performance     Oracle Solaris 11.1 Information Library
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Document Information


1.  Introduction to Network Performance Management

2.  Using Link Aggregations

Overview of Link Aggregations

Trunk Aggregations

Policies and Load Balancing

Aggregation LACP Mode and Switches

Datalink Multipathing Aggregations

Requirements for Link Aggregations

Administering Link Aggregations

How to Create a Link Aggregation

How to Switch Between Link Aggregation Types

How to Modify a Trunk Aggregation

How to Add a Link to an Aggregation

How to Remove a Link From an Aggregation

How to Delete a Link Aggregation

3.  Working With VLANs

4.  Administering Bridged Networks (Tasks)

5.  Introduction to IPMP

6.  Administering IPMP (Tasks)

7.  Exchanging Network Connectivity Information With LLDP

8.  Working With Data Center Bridging Features in Oracle Solaris

9.  Edge Virtual Bridging in Oracle Solaris

10.  Integrated Load Balancer (Overview)

11.  Configuring Integrated Load Balancer

12.  Managing Integrated Load Balancer

13.  Virtual Router Redundancy Protocol (Overview)

A.  Link Aggregation Types: Feature Comparison

B.  Link Aggregations and IPMP: Feature Comparison


Overview of Link Aggregations

Link aggregation, also referred to as trunking, consists of several interfaces on a system that are configured together as a single, logical unit to increase throughput of network traffic. The following figure shows an example of a link aggregation configured on a system.

Figure 2-1 Link Aggregation Configuration

image:The figure shows a block for the link aggr1. Three physical interfaces, net0–net2, descend from the link block.

Figure 2-1 shows an aggregation aggr1 that consists of three underlying datalinks,net0 through net2. These datalinks are dedicated to serving the traffic that traverses the system through the aggregation. The underlying links are hidden from external applications. Instead, the logical datalink aggr1 is accessible.

Link aggregation has the following features:

Note - Link aggregations perform similar functions as IP multipathing (IPMP) to improve network performance and availability. For a comparison of these two technologies, see Appendix B, Link Aggregations and IPMP: Feature Comparison.

Oracle Solaris supports two types of link aggregations:

For a quick view of the differences between these two types of link aggregations, see Appendix A, Link Aggregation Types: Feature Comparison.

The following sections describe each type of link aggregation in greater detail.

Trunk Aggregations

Trunk aggregation benefits a variety of networks with different traffic loads. For example, if a system in the network runs applications with distributed heavy traffic, you can dedicate a trunk aggregation to that application's traffic to avail of the increased bandwidth. For sites with limited IP address space that nevertheless require large amounts of bandwidth, you need only one IP address for a large aggregation of interfaces. For sites that need to hide the existence of internal interfaces, the IP address of the aggregation hides its interfaces from external applications.

In Oracle Solaris, trunk aggregations are configured by default when you create an aggregation. Typically, systems that are configured with link aggregations also use an external switch to connect to other systems. See the following figure.

Figure 2-2 Link Aggregation Using a Switch

image:The figure is explained in the preceding context.

Figure 2-2 depicts a local network with two systems, and each system has an aggregation configured. The two systems are connected by a switch on which link aggregation control protocol (LACP) is configured.

System A has an aggregation that consists of two interfaces, net1 and net2. These interfaces are connected to the switch through aggregated ports. System B has an aggregation of four interfaces, net1 through net4. These interfaces are also connected to aggregated ports on the switch.

In this link aggregation topology, the switch must support aggregation technology. Accordingly, its switch ports must be configured to manage the traffic from the systems.

Trunk aggregations also supports back-to-back configuration. Instead of using a switch, two systems are directly connected together to run parallel aggregations, as shown in the following figure.

Figure 2-3 Back-to-Back Link Aggregation Configuration

image:The figure is explained in the following context.

Figure 2-3 shows link aggregation aggr0 on System A directly connected to link aggregation aggr0 on System B by means of the corresponding links between their respective underlying datalinks. In this way, Systems A and B provide redundancy and high availability, as well as high-speed communications between both systems. Each system also has net0 configured for traffic flow within the local network.

The most common application for back-to-back link aggregations is the configuration of mirrored database servers. Both servers must be updated together and therefore require significant bandwidth, high-speed traffic flow, and reliability. The most common use of back-to-back link aggregations is in data centers.

Note - Back-to-back configurations are not supported on DLMP aggregations.

The following sections describe other features that are unique to trunk aggregations. Do not configure these features when creating DLMP aggregations.

Policies and Load Balancing

If you plan to use a trunk aggregation, consider defining a policy for outgoing traffic. This policy can specify how you want packets to be distributed across the available links of an aggregation, thus establishing load balancing. The following are the possible layer specifiers and their significance for the aggregation policy:

Any combination of these policies is also valid. The default policy is L4.

Aggregation LACP Mode and Switches

If your setup of a trunk aggregation includes a switch, you must note whether the switch supports LACP. If the switch supports LACP, you must configure LACP for the switch and the aggregation. The aggregation's LACP can be set to one of three values:

Datalink Multipathing Aggregations

A trunk aggregation generally suffices for the requirements of a network setup. However, a trunk aggregation is limited to work with only one switch. Thus, the switch becomes a single point of failure for the system's aggregation. Past solutions to enable aggregations to span multiple switches present their own disadvantages:

DLMP aggregations overcome these disadvantages. The following figure shows how a DLMP aggregation works.

Figure 2-4 DLMP Aggregation

image:This figure shows a DLMP aggregation topology.

Figure 2-4 shows System A with link aggregation aggr0. The aggregation consists of four underlying links, from net0 to net3. In addition to aggr0, the primary interface, VNICs are also configured over the aggregation: vnic1 through vnic4. The aggregation is connected to Switch A and Switch B which, in turn, connect to other destination systems in the wider network.

In a trunk aggregation, every port is associated with every configured datalink over the aggregation. In a DLMP aggregation, a port is associated with any of the aggregation's configured datalinks as well as with the primary the interface and VNICs over that aggregation.

If the number of VNICs exceeds the number of underlying links, then an individual port is associated with multiple datalinks. As an example, Figure 2-4 shows that vnic4 shares a port with vnic3.

Similarly, if an aggregation's port fails, then all the datalinks that use that port are distributed among the other ports. For example, if net0 fails, then aggr0 will share a port with one of the other datalinks. The distribution among the aggregation ports occurs transparently to the user and independently of the external switches connected to the aggregation.

If a switch fails, the aggregation continues to provide connectivity to its datalinks by using the other switches. A DLMP aggregation can therefore use multiple switches.

In summary, DLMP aggregations support the following features:

Requirements for Link Aggregations

Your link aggregation configuration is bound by the following requirements:

Devices must support link state notification as defined in the IEEE 802.3ad Link Aggregation Standard in order for a port to attach to an aggregation or to detach from an aggregation. Devices that do not support link state notification can be aggregated only by using the -f option of the dladm create-aggr command. For such devices, the link state is always reported as UP. For information about the use of the -f option, see How to Create a Link Aggregation.