ServerNet Cluster 6780 Planning and Installation Guide (G06.29+, H06.06+, J06.03+)

Using the Long-Distance Option
ServerNet Cluster 6780 Planning and Installation Guide—527301-008
G-3
Hardware Requirements
Hardware Requirements
To use the long-distance option, your cluster must meet these hardware requirements:
•
All processors on all NonStop S-series servers in the cluster must be S76000,
S86000, or later.
•
The cluster must be built with 6780 switches.
•
Zone-to-zone connections between 5 and 15 km can use either single-mode fiber-
optic cables or Dense Wave Division Multiplexers (DWDMs). A DWDM can
transmit multiple optical signals over a single fiber-optic connection and extend
optical signal strength.
•
If DWDMs are used, the connections between the 6780 switches and the DWDMs
must be single-mode fiber-optic cables.
•
If DWDMs are not used, these requirements apply:
°
Your service provider must perform margin testing on the transceivers used for
long-distance connections that are between 10 and 15 km.
°
The margin test requires an attenuator fiber cable which can be ordered with
the long-distance option.
For more information on the margin test and its requirements, your service provider
should refer to hardware technical bulletin TB20041.
Note. Contact your HP representative for information about specific DWDM equipment
that has been certified for use with 6780 cluster switches. Your HP representative can
provide details about DWDM vendors and the configuration aspects of DWDM hardware
that has been tested with 6780 cluster switches. One particularly important consideration
is to ensure that the 6780 cluster switch zone ports are connected to DWDM line cards
that can transparently forward bytes represented through the standard 1 Gbit/s Ethernet
8b/10b encoding technique. This byte-forwading functionality must be transparent and
protocol-independent because:
•
ServerNet is compatible with 1 Gbit/s Ethernet at the physical layer (from the viewpoint
of byte-level signaling and encoding). However, ServerNet has proprietary packet
formats aimed at ensuring very low-latency wormhole routing through ServerNet
switches. ServerNet packet formats are not compatible with Ethernet packet formats.
•
Certain DWDM line cards (line cards that perform time-domain multiplexing) are
compatible only with Ethernet packets. Such line cards cannot forward ServerNet
packets properly, thereby preventing zone-to-zone connectivity between 6780 cluster
switches from being established.
•
ServerNet zone-to-zone links require DWDM line cards that provide transparent and
protocol-independent byte forwarding. Such line cards typically implement only
wavelength-division multiplexing, as opposed to time-domain multiplexing.