Top Of Rack Switches; Ethernet Switches - IBM NeXtScale System Planning And Implementation Manual

Table 5-10 Part number for Rear Door Heat eXchanger for IBM 42U 1100 mm rack
Part number
175642X
For more information, see Rear Door Heat eXchanger V2 Type 1756 Installation
and Maintenance Guide, which is available at this website:
http://www.ibm.com/support/entry/portal/docdisplay?lndocid=migr-5089575

5.6 Top of rack switches

The IBM NeXtScale System does not include integrated switching in the chassis,
unlike IBM BladeCenter or IBM Flex Systems. This was done to maximize the
modularity and flexibility of the system and prevent any chassis-level networking
contention. The IBM Intelligent Cluster offering includes various switches from
IBM System Networking and others that can be configured and ordered as an
integrated solution. People that are building solutions (including NeXtScale
systems) can combine them with switches of their own choosing. In the following
sections, we describe the switches that are available from IBM.
Note: There is no rule that smaller rack mountable switches (typically 1U or
2U) must be mounted in the top of a rack, but "top-of-rack" is the common
name they were given. This is in contrast to larger switches that are deployed
for rows of rack-mounted servers, which are referred to as "end-of-row"
switches; or the often large, modular switches, which also often contain
routing functionality, which are commonly called "core switches".

5.6.1 Ethernet switches

The IBM NeXtScale System features forward-facing cabling. To connect cables
from the NeXtScale servers to Ethernet switches, it is easiest to mount the
switches in the racks with the switch ports facing the front of the racks as well.
It is important that the cooling air for the switches flow from the front (port side) of
the switch to the rear (non-port side). The switches that are listed in Table 5-11
on page 144 meet this criteria. Switches that are cooled from rear to front can be
used, but these must be mounted facing the rear of the rack, and all the cables
from the servers are routed from the front of the rack to the back to connect.
Description
Rear Door Heat eXchanger for IBM 42U 1100 mm Enterprise V2
Dynamic Racks
Chapter 5. Rack planning
143