HP Integrity rx2800 HP Integrity Network Adapter Teaming Whitepaper - Page 72

SLB Redundancy Mechanisms The only redundancy mechanisms used by SLB are link loss and transmit validation heartbeats. None of the advanced redundancy mechanisms (for example, Active Path and Fast Path) are supported by SLB. The advanced redundancy mechanisms require the ability to predict and control which ports in a team will receive a particular frame. Since the switch connected to an SLB team controls how the team receives frames, the advanced redundancy mechanisms would not function reliably. Any SLB teamed port that loses link or fails the transmit validation heartbeat test will be set to a failed state and will not be used by the team until the issue is resolved. SLB Network Adapter Failure Recovery With SLB, the recovery mechanism is somewhat different than those discussed previously. All members of the team transmit and receive frames with the same source MAC address in the Ethernet header and there is no concept of a Primary or Non-Primary port as there is in NFT and TLB. With SLB, there are no receive validation heartbeat frames, and consequently no receive validation heartbeat failures. In a two-port SLB team, all members are capable of receiving data frames (based on the switch's load-balancing algorithm), and transmitting data frames (based on the teaming Driver's load balancing algorithm). In the event of a failover, all transmit traffic is redistributed among the working teamed ports. After a teamed port failure occurs in a two-port team, all transmit traffic is sent using a single teamed port since only one port is currently working. All receive traffic is determined by the switch, which should detect that only one teamed port is functional. If a failed teamed port is restored, all transmit and receive traffic is once again load balanced among all teamed ports. A failure on any teamed port within the same SLB team has the same effect as a failure on any other teamed port because all teamed ports are considered "equal" (except for link loss or transmit validation heartbeat failures). SLB Applications Switch-assisted Load Balancing is deployed in environments that require fault tolerance and additional transmit and receive throughput greater than the capacity of the Primary port. SLB environments also require a switch manually configured to provide Port Trunking. Recommended Configurations for SLB Environments HP recommends the following: • Transmit validation heartbeats should be enabled (default). • MAC addresses should not be manually set to a locally administered address (LAA) via the Microsoft Adapter Properties User Interface. A user should not implement LAAs on individual network ports that are members of a team; otherwise teaming may not function correctly. Setting an LAA for the team is permitted via the NCU. • Spanning Tree's blocking, listening, and learning stages should be disabled or bypassed on all switch ports to which an HP Integrity Network adapter team port is attached. These stages are not needed when a non-switch networking device (for example, server) is attached to the switch port. HP ProCurve switches have a feature called STP Fast Mode that is used to disable these Spanning Tree stages on a port-by-port basis. Cisco switches have an equivalent feature called PortFast. • SLB teams that communicate with TCP/IP network devices via a router should use the Automatic, TCP port or the IP address-based load-balancing algorithm (configured via the NCU). • Implementers thoroughly understand the configuration guidelines set by the switch vendor because SLB is dependent on the switch being configured in a compatible mode. HP's SLB 72 The Mechanics of Teaming for the Advanced User