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lag(7)
NAME
  lag - Link aggregation introductory information

DESCRIPTION
  Link aggregation, or trunking, enables administrators to combine two or
  more physical Ethernet Network Interface Cards (NICs) and create a single
  logical link. (Upper-layer software sees this link aggregation group as a
  single logical interface.) The single logical link can carry traffic at
  higher data rates than a single interface because the traffic is
  distributed across all of the physical ports that make up the link
  aggregation group.

  Using link aggregation provides the following capabilities:

    ·  Increased network bandwidth - The increase is incremental based on the
       number and type of ports, or Network Interface Cards (NICs), added to
       the link aggregation group.

    ·  Fault tolerance - If a port in a link aggregation group fails, the
       software detects the failure and reroutes traffic to the other
       available ports.	 Supported only on DEGPA (alt) and DE60x (ee) network
       interface cards (NICs).

    ·  Load sharing - Traffic is distributed across all ports of a link
       aggregation group.

  You can use a link aggregation group virtual interface for the following
  point-to-point connections: server-to-server and server-to-switch.

  Link aggregation requires an optional kernel subsystem (lag.mod).  Before
  configuring a link aggregation group, you must edit the system
  configuration file, add an options LAG entry to it, and build a new kernel
  by issuing the doconfig command. Then, reboot the system.  You can verify
  the presence of the link aggregation subsystem by issuing the sysconfig -c
  lag command.

  Link Aggregation Configuration

  You can configure link aggregation groups either in multiuser mode or at
  boot time with the lagconfig command.	 When you configure the group, you
  specify a virtual interface number, a key, and a Media Access Control (MAC)
  address.

  After you create a link aggregation group, you can then enable ports
  (interfaces) for link aggregation.  The enabled ports attach to the link
  aggregation group with the corresponding key.	 If the port fails in some
  way, the port detaches from the group and traffic is rerouted to the
  remaining port or ports.

  Any link aggregation configuration done in multiuser mode does not persist
  across system reboots.  If you want link aggregation groups configured at
  boot time, you must include the appropriate lagconfig and ifconfig commands
  in the the /etc/inet.local file.  See the Network Administration:
  Connections manual for an example.

  Load Sharing

  A link aggregation group performs load sharing of both inbound and outbound
  traffic.  When transmitting packets, the system uses a load distribution
  algorithm to determine on which attached port to transmit the packets.  The
  following load distribution algorithm is supported:

    ·  For IP packets, the port is selected based on a hash of the
       destination IP address.	For non-IP packets, the port is selected
       based on a hash of the destination MAC address.	All traffic addressed
       to a specific destination system uses the same port in the link
       aggregation group.  This ensures that the packets arrive in order.

RESTRICTIONS
  The following restrictions apply:

    ·  Supported only Ethernet (802.3 CSMA/CD) links

    ·  Ports must be operating in full duplex mode

    ·  Ports in the same link aggregation group must operate at the same data
       rate

    ·  Ports in a link aggregation group must be attached to the same system,
       either server-to-server or server-to-switch

RELATED INFORMATION
  Commands: lagconfig(8)

  System Attributes: sys_attrs_lag(5)

  Files: inet.local(4)

  Technical Overview

  Network Administration: Connections

Index for Section 7

Alphabetical listing for L

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