C²I² Press Release
Of all the potential causes for a failed network link, a bad cable segment or a bad port are usually at the top of the list.
However, SysKonnect's new SK-NET GE Gigabit Ethernet server adapters tackle failed network links head-on to deliver on the promise of Gigabit throughput, Gigabit performance and Gigabit reliability for high-end servers.
Optimised to support both 64-bit/66-MHz PCI and 32-bit/33-MHz PCI bus based systems, these adapters have been developed around SysKonnect's own highly advanced PCI bus ASIC. This state-of-the-art ASIC enables the SK-NET GE adapter to support true 64-bit wide throughput between the Gigabit Ethernet MAC interface and the PCI bus, ensuring complete compatibility and maximum performance, while reducing CPU utilisation.
According to C²I² Systems managing director, Richard Young, redundant Gigabit ports are implemented just as they would be in an FDDI network. C²I² Systems is the sole local distributor of SysKonnect’s award-winning products.
"By providing a redundant port, the dual-link version of the SK-NET GE can be connected to a second switch or repeater like the dual-homed devices in an FDDI network, thus making it possible to recover from failures on a cable segment, a port or even an entire switch or repeater.
"In this topology, the secondary adapter port is totally independent of the host operating system and the protocol used. One port, or link, is responsible for transmitting and receiving data on a primary path, while the availability of both links is constantly monitored. In a normal state, the second port is in standby mode.
"Should the active link go down, due to a cable or switch failure, the standby port is automatically activated and becomes the logical primary communication port. The failover transition occurs instantaneously and is totally transparent to the attached devices, the host and its operating system.
"Because this transaction is accomplished on the NIC by the SysKonnect ASIC and RLMT logic, there is no proprietary extension of the Gigabit Ethernet standard or the network protocol," he says.
The ability to switch between ports on the SK-NET GE dual-link adapter is controlled by RLMT through the use of three MAC addresses per dual-port adapter. One address is associated with each of the two MAC controllers (ports), while a third address is presented to the operating system as a logical, or virtual, address for the whole adapter. The host system always recognises the adapter by this virtual address.
The switch side of the network also identifies the primary active communications port by this virtual address as it is used to mask the actual MAC address of the primary port while it is active. The secondary port always presents its actual MAC address to the network.
When a transition occurs from primary to secondary port communications, the adapter masks the secondary port with this virtual address and continues to transmit or receive using the same virtual MAC address used on the previous port. This masking/unmasking occurs automatically as a function of the adapter and visibility of the ports and their connections to the rest of the network infrastructure.
State settings of the Redundant Link Management, including the selection of the preferred port, can also be controlled manually via SNMP commands. A network management application, with the aid of the relevant information and parameters mapped in SysKonnect's "Private Gigabit Ethernet" MIB, can also effect a transition between ports and ‘force’ a change. All state values can also be retrieved via SNMP and/or RMON (Remote Monitoring) queries.
"The failover redundancy described above is enabled by SysKonnect's RLMT (Redundant Link Management Technology)," says Young.
"RLMT is responsible for detecting the link status and evaluating the quality of the connection. It derives information from a variety of sources, including: auto negotiation values, hardware link detection and received data, as well as evidence of spanning tree packets received from spanning tree protocol enabled on the network.
"By exchanging RLMT test packets between the two ports of a dual-link adapter, both ports are kept active from the viewpoint of the attached switch or hub, thus minimising the switching time on activating the redundant link. Due to the active monitoring of both ports, even a link error on the redundant port is detected and reported just as errors on the primary enabled port would be reported. Thus errors, or failures, on the standby port are as visible as any appearing on the primary port."
SK-NET GE also supports parity checking on all data paths, monitors environmental conditions and complies with PCI "Hot Plug" standards.
"Server applications are subject to special demands for reliability, availability and accuracy. Consequently, it is very important to monitor the integrity of data at several different levels as it passes from a network through the server and back to the network. Both single-port and dual-port SK-NET GE adapters monitor data integrity by generating and checking parity information on all available data paths. All data errors are detected immediately and can be reported to a network administrator via normal network management systems.
"Network adapters, as with every electronic component, are designed to work within defined temperature and voltage ranges. A NIC subject to environmental conditions which are outside acceptable ranges could result in erratic function, or even system failure in extreme cases.
"To prevent such occurences, SK-NET GE Gigabit Ethernet server adapters are equipped with temperature and voltage sensors to monitor these critical operating environment conditions. Acceptable minimum and maximum threshold values can be set for the card and continuously monitored via an SMPT agent. Alarms can then be triggered when a threshold value is crossed. This enables the early detection of conditions which could potentially damage a NIC, or even the host system.
"SysKonnect is a member of the PCI SIG (PCI Special Interest Group), an industrial consortium for the standardisation of the PCI bus system. In October 1997, the PCI SIG published specifications for Hot Plug PCI.
"The primary goal of this standard is to ensure maximum availability of server systems by accommodating the need to add, remove or exchange PCI adapters during normal server operation. Both single-port and dual-port SK-NET GE adapters comply with Hot Plug PCI standards and are routinely kept current through regular driver updates for the adapters," concludes Young.
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