The IBM eServer BladeCenter JS20 - IBM Redbooks
The IBM eServer BladeCenter JS20 - IBM Redbooks
The IBM eServer BladeCenter JS20 - IBM Redbooks
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Application subnet<br />
<strong>The</strong> primary reason you install <strong>BladeCenter</strong> <strong>JS20</strong>s is to support applications.<br />
Many applications have requirements to communicate with other systems. You<br />
use one or more application subnets for this purpose.<br />
<strong>The</strong> primary application subnet is implemented using a VLAN provided by the<br />
LAN Switch I/O Modules installed in I/O module bay 1 of each <strong>BladeCenter</strong><br />
chassis. <strong>The</strong> same LAN Switch I/O Module is used to support the SoL subnet<br />
and VLAN.<br />
Where different <strong>BladeCenter</strong> <strong>JS20</strong>s participate in different applications and there<br />
is a requirement to separate application traffic, you may need to define multiple<br />
application subnets and VLANs. Each <strong>BladeCenter</strong> <strong>JS20</strong> is connected to the<br />
appropriate application subnet based on the applications that are installed on the<br />
blade server.<br />
If application communication requirements with other systems are complex, you<br />
can install an additional pair of Gigabit Ethernet interfaces on each <strong>BladeCenter</strong><br />
<strong>JS20</strong>. You do this using the Gigabit Ethernet Expansion Card in conjunction with<br />
compatible I/O modules installed in I/O module bays 3 and 4.<br />
4.1.2 High-performance, low-latency network requirements<br />
Distributed memory parallel applications may require the installation of a<br />
high-performance, low-latency interconnection network between <strong>BladeCenter</strong><br />
<strong>JS20</strong>s. This requirement can be supported through the use of an optional<br />
Myrinet network.<br />
To install a Myrinet network, you must install a Myrinet Expansion Card on each<br />
<strong>BladeCenter</strong> <strong>JS20</strong> that requires connectivity to the high-performance,<br />
low-latency interconnection network. You must also install an Optical Pass-Thru<br />
I/O Module in I/O module bay 4 of each <strong>BladeCenter</strong> chassis that contains blade<br />
servers equipped with Myrinet Expansion Cards.<br />
<strong>The</strong>n connect the Optical Pass-Thru I/O Module to external Myrinet switches to<br />
complete the Myrinet network infrastructure. This is illustrated in Figure 4-2.<br />
58 <strong>The</strong> <strong>IBM</strong> Eserver <strong>BladeCenter</strong> <strong>JS20</strong>