Subject: Storage Network Management and Retrieval

Difficulty: Medium.

Marks: 05M

The existence of InfiniBand is mainly to provide a remedy for the drawbacks of the PCI bus. In replaces the PCI bus with a serial network. In the data centre, there are different I/O techniques which include FC, Ethernet and SCSI. InfiniBand acts as a communication medium for devices which supports different I/O techniques. These devices communicate with each other by means of messages over InfiniBand switch forwarding and receiving the data packets to and from the intended end devices. InfiniBand is used as a fast interconnect for the interprocess communication within parallel cluster computers. It supports fll duplex communication with very high transmission rates in each direction. InfiniBand bundles multiple links to achieve a higher transmission rate in each direction.

As a medium, InfiniBand defines various copper and fibre-optic cables along with their maximum specified length.

The channel adapters are the end points defined in an InfiniBand network. The following are the different types of channel adapters:

1. Host channel adapters (HCAs): Act as a bridge between InfiniBand network and the system bus to which CPUs and RAM are connected.

2. Target channel adapters (TCAs): Connect InfiniBand network and peripheral devices via SCSI, FC or Ethernet.

Figure 33 shows a typical interconnection between CPU, memory, I/O cards and storage devices and InfiniBand interface. The peripheral devices are connected via InfiniBand network. The CPU and RAM together provide the computing power for the interconnection of the modules that are connected via a direct InfiniBand link for the benefit of lightweight interprocess communication. For additional computing power, more CPU and RAM module can be added.

The InfiniBand protocol stack was designed by keeping in mind that the performance feature could be implemented in the hardware and thus there should be efficient I/O communication. The InfiniBand standard incorporates performance features such as flow control, zoning and various service classes.