Gigabit Ethernet
From DpWiki
|
|
This article is a stub. You can help DPWiki by expanding it. |
Contents |
Introduction
A faster variant of the Ethernet standard that allows birdirectional data transfer rates of up to 1000mbps (~125MB/s). This allows high-speed transfer of large blocks of data on local networks with commonly available networking equipment. In order to achieve these speeds, users must use Category 5 (or better) cables with all four pairs intact.
Please see the Ethernet article for more detail on this family of standards.
Bottlenecks
The bandwidth provided by Gigabit Ethernet is often large enough to push the limits of the internal buses used to feed the adapters. When fully saturated, a Gigabit Ethernet adapter can theoretically drive up to 250MB/s of bandwidth (125MB/s upstream + 125MB/s downstream). As conventional PCI buses max out at 132MB/s they can form a bottleneck and prevent these adapters from reaching that potential.
Thankfully, many modern implementations use faster PCI Express interfaces to communicate with Gigabit Ethernet adapters. Asside from providing sufficient throughput, PCI Express uses point-to-point links so that that bandwidth doesn't need to be shared with any other devices.
Jumbo Frames
Due to the higher transfer rates some protocol overheads become significantly more significant than they were with slower networks. In order to combat this, some networking hardware allows packets larger than the standard 1518 byte limit. When enabled, the reduction in overhead can lead to significant increases in throughput. Unfortunately, using this feature can create compatibility issues so users must verify that all equipment on the network supports this mode of operation.
See Also
- Ethernet - The group of standards that Gigabit Ethernet is based on.
- Fast Ethernet - A slower variant of the Ethernet standard that operates at speeds up to 100mbps.
