Latency; Hp Supported 10Gbe Media Standards; Physical Medium Dependent Connections For 10Gbe - Compaq BL10e - HP ProLiant - 512 MB RAM Introduction Manual

Latency

Transmission latency within networks typically has three components – time of flight, data rate, and
queuing or buffer delays.
Time of flight is the propagation delay across the cable, and that delay increases in a linear fashion
with distance.
The data rate affects how long a packet takes to complete transmission, from first bit sent to last bit
received.
Queuing or buffer delays increase with congestion and are an issue for all network cards, switches
and routers. Older NICs and switches stored a complete packet then forwarded it to the destination
port after checking the integrity. Newer 1GbE, and most 10GbE, NICs and switches now employ
cut-through packet forwarding techniques which allow the beginning of the packet to be forwarded
to a destination port before the remainder of the packet has been completely received by the NIC
or switch. This significantly reduces latency and makes 10GbE more attractive for HPC
environments.

HP supported 10GbE media standards

All HP supported media specifications for cable, connections, and connection modules employed in
the design and construction of 10GbE networks are standards certified by IEEE.

Physical medium dependent connections for 10GbE

The 10GbE standard specifies various physical medium dependent (PMD) connections to different
transmission media. Several versions of the10GbE standard exist, with each version specifying a
different medium, media connection (PMD type), and 10GbE Transmit/Receive range for the medium.
Table 1 lists the key versions of the 10GbE standard and their distinguishing attributes, summarizes
the options supported, and indicates distances achieved, depending on the grade of fiber.
Table 1. Cable media specification
Protocol
10GBASE-SR
10GBASE-LR
10GBASE-LRM
10GBASE-KX4
10GBASE-KR
10GBASE-CX4
10GBASE-T
The physical media supported includes both copper and fiber cabling. For copper, the twin-axial
copper cabling (10GBASE-CX4) specification supports a maximum of 15m (49 feet).
Fiber cabling, on the other hand, supports multiple derivatives of the standard related to the different
optical types required for the various WAN and LAN applications.
IEEE STD Distance
802.3ae 26, 33, 82, 300m
10km
802.3ae
802.3aq 220m
802.3ap 1m
802.3ap 15m
802.3ak 15m
802.3an 55m on Cat6
100m on Cat6A, 7
Media Media Specification
fiber FDDI, OM1, OM2, OM3
fiber Single-mode fiber (SMF),
10um
fiber Multi-mode fiber (MMF),
50-62um
backplane 4-Lane Backplane
backplane 1-Lane Backplane
copper Twinax ( IBx4 Cable )
copper Cat6, Cat6A UTP,
Cat6-FTP, or Cat7
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