HP ProLiant BL e-Class C-GbE Interconnect Switch Overview - White Paper

(labeled Switch A and Switch B). Each switch directly connects to one of the two NC3163 NICs on

each ProLiant BL10e series server blade (labeled as NIC).

One additional 10/100 Mb/s Fast Ethernet internal port connects the Integrated Administrator (IA) to

the switches for IA to switch Ethernet communication.

External ports

The C-GbE Interconnect Switch includes four external 10/100/1000 Mb/s Gigabit Ethernet “uplink”

ports with RJ-45 connectors, typically used to connect the interconnect switches to the network

infrastructure. However, they are standard Ethernet switch ports and may be used as desired. Two of

the ports are connected to each switch that may be bundled into an EtherChannel compatible trunk.

In addition, one 10/100T Fast Ethernet external port with an RJ-45 connector is provided from switch

A. This port is ideal for a dedicated management network or for local administration and diagnostic

tasks without unplugging a dedicated uplink. Simultaneous management access to switch A, switch B,

and the IA is possible via this single port (or any other external Ethernet port). Although ideally suited

for management, this is also a standard Ethernet switch port that may be used as desired, such as an

additional data uplink to the network.

Crosslink ports

The redundant layer 2 switches are connected through a pair of redundant, 10/100 Mb/s Fast

Ethernet “crosslink” ports that are bundled into a 200 Mb/s Cisco EtherChannel compatible multi-port

trunk. The signals are routed as Ethernet from switch to switch via individual CAT5e specified signal

traces on the passive centerwall assembly of the server blade enclosure. The crosslinks permit

communication between the switches, if desired. They also provide the ability to:

• Manage both switches, perform PXE server boots, and access the IA using just one to any number

of external switch ports. Therefore, any single external Ethernet port can be used to perform all

Ethernet management tasks.

• Configure the e-Class system for advanced ProLiant Network Adapter Teaming including switch

fault tolerance. See the section “ProLiant Network Adapter Teaming” for additional information.

• Communicate with any server network adapter from any external Ethernet port. As a result, any

single external Ethernet port may be used to communicate to all forty NICs. This permits the 40-to-1

cable reduction and provides additional system redundancy. If uplinks on one switch or the

connection to it were to fail, all NICs still can be accessed via the other switch.

Maximizing network cable reduction

For maximum (98 percent) cable reduction, the 40 Ethernet NIC signals within the server blade

enclosure can be concentrated into any one single external Ethernet port. This results in a total of only

fourteen Ethernet connections for a fully configured 42U rack of fourteen server blade enclosures

containing 560 network adapters.

Applications that utilize a single uplink port include testing and evaluation systems, server blade

enclosures with a few installed servers, and applications that require minimal bandwidth. On a

heavily utilized system, using a single uplink port for all 40 network adapters can cause a traffic

bottleneck. For example, using one uplink from interconnect switch A requires the traffic from all the

network adapters routed to switch B to travel over the two crosslink ports (a 200 Mb/s path),

previously shown in Figure 4. The crosslink ports are intended primarily as a failover route and

generally are not used as a primary path. For more optimal performance, at least one uplink port on

each switch would be used. However, system administrators may use any combination from one to all

five external Ethernet ports to increase bandwidth, to separate network and management data onto

physically isolated ports, or to add redundant connections to the Ethernet network backbone.