[InfiniBand Description] [InfiniBand Interface ICs]
[InfiniBand Standards]
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InfiniBand [IB] uses (Point-to-Point) 2.5 GHz differential pairs
(signalling rate)- one transmit and one receive - using LVDS and 8B/10B
encoding.
Higher bandwidth connections are made by grouping 4 or 12 pairs together,
for up to 3 GB/s full-duplex connections. InfiniBand is designed to be
used over a Backplane, Copper wire or Fiber. The impedance for the PWB
interface or cable interface is 100W. All
inter-connections are Hot-Swappable on InfiniBand.
The specification defines a data rate of 250MBytes/sec for both
electrical and optical signaling. That's a 2.5GHz signaling speed using
8B/10B
[10 bits = 1 byte]
There are 3 interface widths; 1x, 4x, and 12x.
... 1X defines a interface with 2 differential pairs (as shown
below). Same for Fiber, 1 Transmit, 1 Receive [Maximum bit rate is
2.5Gbps]
... 4X defines a interface with 8 differential pairs (4 per
direction). Same for Fiber, 4 Transmit, 4 Receive [Maximum bit rate is
10Gbps]
... 12X defines a interface with 24 differential pairs (12 per
direction). Same for Fiber, 12 Transmit, 12 Receive [Maximum bit rate is
30Gbps]
Link | Signally Wires | Signally Wires | Data Rate | Duplex Data Rate |
1x | 4 | 2.5Gbps | 2.0Gbps | 4.0Gbps |
4x | 16 | 10Gbps | 8Gbps | 16.0Gbps |
12x | 48 | 30Gbps | 24Gbps | 48.0Gbps |
Each IBA Packet [InfiniBand Architecture] begins with a Start-of-Frame [SOF], and ends with an End-of-Frame [EOF]. The Header field is made up of a Routing Header and a Transport Header. The Packet Payload follows the Header field. Two different Cyclic Redundancy Code [CRC] fields follow the Payload; ICRC [Invariant CRC] and VCRC [Variant CRC]. The Invariant CRC field covers the packets that do not change from source to destination, while the Variant CRC filed covers packets from link to link. Fill frames are used between packets.
The IB specification has allocated a fixed Total Jitter [JT]
of 0.25 UI for both the cable and connector regardless of cable
length or connector size.
The maximum allowable Deterministic Jitter
[JD] from the driver is 0.17 UI [without pre-emphasis]. The
Total Jitter [JT] allowed from the driver is 0.35 UI.
The maximum allowable Deterministic Jitter [JD] at the receiver is
0.41 UI. The Total Jitter [JT] allowed at the receiver is 0.65
UI.
The InfiniBand specification defines the Physical, Electrical and
Mechanical layers of an interface called the InfiniBand Architecture
(IBA).
Cards (InfiniBand Modules), maybe 3U (Standard Module) or 6U (Tall
Module) high, and are also a standard width (29mm) or 'Wide' modules
(59mm).
They reside with in a metal case to provide EMI shielding. The
thickness of the PWB isn't really defined, as long as it resides with in
the EMI defined case.
The Chassis is also defined in the standard, as is
cabling, Back plane and cable connectors.
The chassis requires a filler card for any empty slot.
InfiniBand Trade Association [The specification maybe down-loaded from this site]
Integrated Circuit Vendors:
Avago Technologies {8-port, 4x
switch fabric IC}
LSI Corporation {CML Based SerDes with 10 or 20 Bit Interface, Octal 1.0-3.2 Gb/s Serial Repeater/Retimer}
Mellanox Technologies {4x InfiniBand Controller ICs - InfiniBand Switch ICs}
Zarlink Semiconductor {4 x 2.7Gbps Optical Transceiver}
No OEM companies are currently listed.
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