Quantities And Priorities - Dell PowerEdge M1000e Technical Manual

transmit positive signal, a transmit negative signal, a receive positive signal, and a receive
negative signal. Differential pair signaling provides improved noise immunity for these high speed
lanes. Various terminology is used by fabric standards when referring to lanes. PCIe calls this a
lane, InfiniBand calls it a physical lane, and Fibre Channel and Ethernet call it a link.

A link is defined here as a collection of multiple fabric lanes used to form a single
communication transport path between I/O end devices. Examples are two-, four- and
eight-lane PCIe, or four-lane 10GBASE‐KX4. PCIe, InfiniBand and Ethernet call this a link. The
differentiation has been made here between lane and link to prevent confusion over Ethernet's
use of the term link for both single and multiple lane fabric transports. Some fabrics such as Fibre
Channel do not define links as they simply run multiple lanes as individual transports for
increased bandwidth. A link as defined here provides synchronization across the multiple lanes,
so they effectively act together as a single transport.

A port is defined as the physical I/O end interface of a device to a link. A port can have single or
multiple lanes of fabric I/O connected to it.

Quantities and priorities

There are three supported high-speed fabrics per M1000e half-height server module, with two
flexible fabrics using optional plug-in mezzanine cards on the server, and one connected to the
LOMs on the server. The ports on the server module connect through the midplane to the
associated I/O modules (IOM) in the back of the enclosure, which then connect to LAN/SAN/IPC
networks.
The optional mezzanine cards are designed to connect through the eight-lane PCIe to the server
module's chipset in most cases. Mezzanine cards have either one dual port ASIC with four- or eight-
lane PCIe interfaces or dual ASICs, each with four-lane PCIe interfaces. External fabrics are routed
through high-speed, 10Gbps-capable air dielectric connector pins through the planar and midplane.
For best signal integrity, the signals isolate transmit and receive signals for minimum crosstalk.
Differential pairs are isolated with ground pins and signal connector columns are staggered to
minimize signal coupling.
The M1000e system management hardware and software includes fabric consistency checking,
preventing accidental activation of any misconfigured fabric device on a server module. The system
will automatically detect a misconfiguration and alert you of the error. No damage occurs to the
system, and you can reconfigure the faulted module.
M1000e I/O is fully scalable to current and future generations of server modules and I/O Modules.
There are three redundant multi-lane fabrics in the system, as illustrated in Figure 13.
In its original configuration, the M1000e midplane is enabled to support up to four Gigabit Ethernet
links per server module on Fabric A. Thus, potential data bandwidth for Fabric A is 4 Gbps per
half-height server module. A future midplane upgrade may enable higher bandwidth on Fabric A.
The M1000e provides full 10/100/1000M Ethernet support when using Ethernet pass-through
modules enabling you to connect to any legacy infrastructure whether using Ethernet pass-through
or switch technology. This technical advance uses in-band signaling on 1000Base-KX transport and
requires no user interaction for enablement.
PowerEdge M1000e Technical Guide
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