HP Integrity rx2800 HP Integrity Network Adapter Teaming Whitepaper - Page 55

Table 4-7 Redundancy mechanism comparison chart (continued) Detects good ports versus best ports Mechanism can be manually disabled √ √ √ √ √ Failover Events Link Loss Heartbeats (Receive and Transmit Validation) Active Path Fast Path When a network port is a member of a team and loses physical link (in other words, wire fault, lost link light), the teaming driver prevents the port from being used by the team. If this port is in use by the team, the team recovers from the failure based on the port's role in the team (Primary or Non-Primary) and the team's mode (NFT, TLB, or SLB). If this was the last available team member in the team, then the team would fail. The use of heartbeat frames for teamed port failovers was designed to detect network port communication failure even in cases when it maintained physical link. Special heartbeat frames are transmitted and received by teamed ports to validate the transmit and receive paths of each individual port. When a heartbeat frame is transmitted by one teamed port but not received by another teamed port, the teaming driver assumes that one of the ports is having a communications problem. If the Primary port in an NFT or TLB team experiences a failover event, a failover will occur to a functional non-Primary port. Heartbeat frames were not designed to monitor networking failures such as loss of connectivity between switches, or loss of client connectivity. As an Advanced Redundancy mechanism, Active Path is used to choose which teamed ports have validated connectivity with the important network segment (by testing communication with the designated Echo Node). Whenever a teamed port loses connectivity with the Echo Node while other teamed ports maintain connectivity with the Echo Node, the teamed port is considered to be in an Active Path Failed state. If the teamed port is the team's Primary port, a failover will occur and another teamed port with validated connectivity to the Echo Node will assume the role of Primary port. If all teamed ports lose connectivity with the Echo Node, no failover will occur since no teamed port is better than another in regards to the Active Path mechanism. The team will operate as if Active Path was not enabled except that all teamed ports will be labeled as Active Path Degraded and the team will be in a degraded state. Fast Path, another advanced redundancy mechanism, is used to validate that all teamed ports have connectivity with the important network segment by monitoring for connectivity to the best root switch. The best root switch is based on the IEEE 802.1D specification that says the bridge (in other words, switch) with the lowest bridge ID is the preferred root Fast Path also can choose the best Types of HP Integrity Network Adapter Teams 55