Cisco InfiniBand 4x User's Guide download pdf (Page 52)

38 Implementing Cisco InfiniBand on IBM BladeCenter

3.3 Hardware

This section describes the hardware used in an InfiniBand configuration:

򐂰 Host Channel Adapters

A Host Channel Adapter (HCA) provides a processor node, such as a server or

workstation, with a connection port to other InfiniBand devices. An HCA can have one or

multiple ports and can be an add in card on a standard interconnect bus or onboard the

system main board. The adapter can be connected to an InfiniBand switch, a target device

or another HCA.

Verbs are an abstract representation that defines the required interface between the client

software and the functions of the HCA. Verbs do not specify the application programming

interface (API) for the operating system, but define the operation for OS vendors to

develop a usable API.

򐂰 Target Channel Adapters

A Target Channel Adapter (TCA) provides I/O nodes, such as storage devices, with an

InfiniBand connection port. It can be connected to an InfiniBand switch or an HCA.

򐂰 Switches

An InfiniBand switch forwards packets from one device to another based on the Local ID

contained within the Local Route Header of a packet (see 3.1.4, “Data link layer” on

page 33). The only type of packets generated on a switch are management packets.

򐂰 Routers

InfiniBand routers forward packets between subnets. The router reads the Global Route

Header within a packet. (See 3.1.3, “Network layer” on page 33.)

򐂰 Gateways

InfiniBand to Ethernet or InfiniBand to Fibre Channel gateways allow nodes on InfiniBand

subnets to be connected to Ethernet networks or to Fibre Channel SANs. The use of a

gateway merges other fabric networks while eliminating the need for additional HCAs in

every processor node.

3.4 Management

The InfiniBand Architecture defines two methods of system management for handling all

subnet bringup, maintenance, and general service functions associated with the devices in

the subnet. Each method has a dedicated queue pair (QP) that is supported by all devices on

the subnet to distinguish management traffic from all other traffic

3.4.1 Subnet management

The first method, subnet management, is handled by a subnet manager. All subnet

management uses QP0 and is handled exclusively on a high-priority virtual lane (VL15) to

ensure the highest priority within the subnet. Subnet Management Packets (SMPs) are the

only packets allowed on QP0 and VL15. This VL uses the Unreliable Datagram transport

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Cisco InfiniBand 4x User's Guide Page 52