Ethernet ve Kablolama

Giriş
Açıklaması şöyle

Ethernet is a set of standards (IEEE 802.3) which covers transmitting data via coaxial cable, twisted pairs as well as fibre.

802.3a - 10Base2 - coax
802.3i - 10Base-T - twisted pairs
802.3u - 100Base-Tx, or more colloquially 100Base-T - twisted pairs
802.3z - 1000Base-X - fibre
802.3ab - 1000Base-T - twisted pairs

10Base5

10Base5 ve 10Base2 coax kablolar. İkisinin arasındaki en önemli farkın açıklaması şöyle

10BASE5 had a maximum length of 500 meters. 10BASE2 reduced the maximum length to 185 meters, but where that much lower length was sufficient this was a good trade-off for having cable that was cheaper and easier to handle. In part this was due to 10BASE2 cable being thinner, but the really big advantage was that, while the 10BASE5 medium was a single cable long cable, the 10BASE2 medium could be constructed from many segments of short cable, joined together with "T" connectors at each station. This allowed much easier re-routing of the transmission medium to include, e.g., a new room off to the side of the existing run.

CAT-3, CAT5E, CAT-6, CAT-7 kablo çeşitleri var. Tüm kablolar aslında 4 çift Unshielded Twisted Pair (UTP) 'den oluşuyor. 10MB ethernet için CAT-3 ve üstü gerekir. 

Topraklama

Ethernet kablosunda ground (topraklama) kablosu gerekmez. Ground gerekmemesiniz sebebi Unshielded Twisted Pair'in differential signaling kullanması. Açıklaması şöyle.

Twisted pair uses differential signaling - in a pair, one wire is always the negative/complimentary signal of the other. In the simplest example, Transmit+ > Transmit- means 1 and Transmit+ < Transmit- means 0. Put in another way, each wire is a reference for the other. There is no reference to ground.

For 10BASE-T and 100BASE-TX there's a dedicated pair each for transmitting data and receiving data.

CAT-3

CAT-3 ve CAT-6 yan yana kullanılabilir. Açıklaması şöyle

...as each cable has twisted pairs to prevent EMF interference, with each twisted pair's twist being a different length than the others.

CAT-5

100 MB ethernet için CAT5E ve üstü gerekir. Eski 8 pinli telefon kablosunu RJ55 ile sonlandırarak CAT5 elde edilebilir. Kablolar şöyle

Cross Cable
Eğer hub kullanmayacaksak Ethernet kablosunu çapraz bağlamaya (crossover cable) gerek yoktur. Ethernet kartları artık Auto MDI-X teknolojisi ile çapraz çalışması gerektiğini anlayabiliyor.

RJ-45
RJ-45 sadece duvardaki giriş yeri. Ethernet standardı ile alakası yok. Bazen telefon için bile kullanılıyor.

10Base2 - İlkel Ethernet
Coax kablo kullanırdı. Açıklaması şöyle.

Early Ethernet did use coax cabling.

Modern Ethernet uses twisted pairs to eliminate EMI, but only 10 and 100 Mbit/s have dedicated pairs for transmit and receive - Gbit upwards uses all pairs in both directions simultaneously.

10BaseT Ethernet - Unshielded Twisted Pair (UTP)
Açıklaması şöyle.

10BaseT and 10BaseFx are standards of connectivity for Ethernet.

10BaseT defines the use of UTP cabling for Ethernet, that includes cable features, male (in cable) and female (in wall boxes) connectors, max distances, etc.

10BaseFx Ethernet - Fiber
Açıklaması şöyle

10BaseFx defines the use of fiber optics for Ethernet, including type of fiber, max distances, connectors (in cable and in wall boxes), etc.

Açıklaması şöyle

10BASE-FX is no official IEEE 802.3 standard - various, non-compatible versions may exist. The 10 Mbit/s standard PHY is (was) 10BASE-FL. Fast Ethernet has 100BASE-FX as common standard.

10 G Ethernet
Saniyede 10 milyar bit olarak düşünürsek inanılmaz bir rakam. Verinin nasıl gönderildiğini burada.

Auto Negotiation
Tüm ethernet kartları Auto Negotiation özelliğini kullanırsa daha iyi. Açıklaması şöyle

The classic reason for a duplex mismatch is forcing one side to full duplex while keeping the other side set to Auto Negotiation. Failing AN, that side falls back to half duplex, creating the mismatch.

Ethernet Sürücüsü Kablonun Çekildiğini Nasıl Algılar?
Açıklaması şöyle

-The original coax Ethernet did not really have link state detection (some PHYs had a mechanism for detecting termination during transmission but it only worked when the device was actually trying to transmit something)

-10BASE-T uses "link state pulses" which are sent when the line is idle to monitor link status.
Twisted pair auto-negotiation uses "Fast link pulse bursts" to both determine the state of the link and to exchange auto-negotiation information. Once a link type has been negotiated link type specific mechanisms are used to monitor link status.

-Faster Ethernet standards generally transmit idle codes continuously.

Benzer bir açıklama şöyle

In the original 100BASE-TX, nothing is transmitted in the Inter Packet Gap (IPG) period. Energy-efficient Ethernet adds low-power idle (LPI) mode which sends idle symbols generated by the Packet Coding Sublayer (PCS).

1 GB Ethernet Aynı Kablo İle Nasıl Daha Çok Veri Gönderir?
100 MB ethernet tek bir kablo çiftini kullanır ve sadece 1 ve 0 değerini taşıyan voltajı 100 MHz'de gönderebilir.

1 GB Ethernet ise tüm kablo çiftlerini kullanır ve 00,01,10,11 değerlerini taşıyan voltajı 125 MHz'de gönderebilir. Dolayısıyla daha çok veri taşıyabilir. Açıklaması şöyle.

Most commonly, 1000BASE-T - the common gigabit-over-copper variant - splits the encoded data stream into four lanes and transmits each separately on one of the four twisted pairs in a Cat-5 cable. All copper variants from gigabit upwards use these four lanes.