3Com 3C996B-T manual NIC Teaming, Load Balancing, Link Aggregation 802.3ad

NIC Teaming

NIC Teaming

Teaming provides traffic load balancing and redundant NIC operation in the event that a network connection fails. When multiple Gigabit Ethernet NICs are installed in the same server, they can be grouped into teams. Each team, with up to 8 ports or 8 NICs, can be configured on the server. If traffic is not identified on any of the NIC team member connections due to failure of the NIC, cable, switch port, or switch (where the teamed NICs are attached to separate switches), the load distribution is re-evaluated and re- assigned among the remaining team members. In the event all the primary NICs are down, the hot stand-by NIC becomes active. Existing sessions are maintained, causing no user impact.

The Advanced Server Features program supports three schemes of load balancing: Load

Balancing, Link Aggregation (802.3ad), and Generic Link Aggregation (Trunking).

NOTE: Gigabit Ethernet NICs can be grouped into failover teams with an Intel 82559 LOM.

Load Balancing

Implementation of load balancing is based on IP flow. This feature supports balancing IP traffic across multiple NICs (that is, team members) in a bi-directional mode. Each NIC in the team has a separate MAC address. It provides automatic fault detection and dynamic failover to another team member or to a hot stand-by member; this is done independently of layer 3 protocol (IP, IPX, NetBEUI). It works with existing layer 2 and 3 switches.

Link Aggregation (802.3ad)

This mode supports Link Aggregation Control Protocol (LACP) and conforms to the IEEE 802.3ad specification. Configuration software allows you to statically configure which NICs are to participate in a given team. Because this mode supports LACP, a valid link aggregation group should be negotiated with the link partner. The negotiated group must satisfy the terms established by the configuration SW (physical NICs are not able to move dynamically from one team to another team). If the link partner is not correctly configured for 802.3ad link configuration, errors are detected and noted. With this mode, all NICs in the team are configured to receive packets for the same MAC address. The outbound load-balancing scheme is determined by the Advanced Server Features driver. The team’s link partner determines the load-balancing scheme for inbound packets.

Generic Link Aggregation (Trunking)

This mode is very similar to 802.3ad in that all NICs in the team must be configured to receive packets for the same MAC address. However, this mode does not provide LACP or marker protocol support. This mode supports a variety of environments where a NIC’s link partners are statically configured to support a proprietary trunking mechanism. For instance, this mode could be used to support the (Lucent) “OpenTrunk” or the (Cisco Systems) Fast EtherChannel (FEC). This mode is a “light” version of the 802.3ad link aggregation. This approach is much simpler, in that there is not a formal link aggregation control protocol. As with the other modes, the creation of teams, and the allocation of physical NICs to various teams, is done statically via user configuration software.

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