This kit provides enhanced support for link aggregation (LAG) by extending it to cluster LAN interconnects. It does this by decreasing the latency associated with time critical Interconnect Communication Subsystem (ICS) remote procedure calls and by increasing the available bandwidth of the LAN interconnect, thereby allowing increased interconnect throughput.
Latency is improved though multiple active interfaces decreasing queue sizes (link aggregation) and through the separation of ICS channels that prefer low latency from channels that require high bandwidth.
Throughput is improved from multiple active interfaces decreasing queue sizes.
The primary goal is to distribute cluster component channel traffic among the interfaces that form part of the link aggregation group.
These changes are implemented with the following three new sysconfigtab attributes, which configure the interfaces and create the LAG set:
| ics_tcp_lag0 | | Configures a LAN interface to be part of the LAG set. |
| ics_tcp_lag_dist | | Specifies the lag traffic distribution algorithm for a LAG interface. |
| ics_tcp_lag_serv_weights |
| | | Based on this value, the channel traffic for an ICS channel is distributed over the LAG interface. |
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 | CAUTION: Do not modify the default value of these attributes unless instructed to do so by support personnel. |
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The following restrictions apply the to the use of these attributes:
Supported only on DEGPA (alt), DEGXA (bcm), and DE60x (ee) network interface cards (NICs).
Supported only on Ethernet (802.3 CSMA/CD) links.
NetRAIN virtual interfaces cannot be included in link aggregation groups.
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.
Link aggregation enables system administrators to combine two or more physical Ethernet Network Interface Cards (NICs) and create a single virtual link. Upper-layer software sees this link aggregation group as a single virtual interface for example: lag0.
The single virtual 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.
For more information see the Tru64UNIX Technical Overview and the Network Adminstration: Connections manual. For tuning and configuration information see the lag(7), lagconfig(8), sys_attrs_ee(5), sys_attrs_lag(5), and inet_local(4) reference pages.
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