IMPLEMENTATION 802. XX

IEEE produce several standardizations has about LAN. This standardization is known with IEEE 802. Several standard has difference in physical layer and sublayer MAC but compatible in layer link data as a whole.

This standard to be more specific, for example standard 802.1 that gives identification for standard nest and define primitive deliver his face, standard 802.2 that explain about on from layer link data that use LLC protocol, standard 802.3 until 802.5 that explain 3 standard of LAN, that is CSMA/CD, token bus,  and token ring.

Standard IEEE 802.3: Ethernet

This standard is attributed for LAN I-persistent CSMA/CD. CSMA/CD be mechanism for sending data all at once mechanism in the event of collision. CSMA/CD will detect when workstation sending a data.

In CSMA/CD protocol not use schedule for time sending packet data and one workstation can’t predicted when do transmission.

There are two important characteristic in CSMA technique, that is:

·         Propagation delay (pd)

·         Frame transmission time (ftm)

There are three base algorithm for CSMA, that is:

1.      Non-persistent CSMA

2.      I-persistent protocol

3.      P-persistent protocol

CSMA/CD have a base algorithm, like this :

1.      If medium idle, transmit. Other that, next to step two

2.      If medium busy, next for listen until stripe idle and live transmit.

3.      If collision happen during delivery, transmit jamming signal for sure if all workstation now that happen collision and stop the transmit.

4.      After sending jamming signal, wait until certain time unit randomly, then try to send to repeat, repeat step one.

·         10Base5 cable, a more regular is called Thicknet (Thick Ethernet) is type of cable first time to used. The connection to cable general to used vempire tap, because a pin putted  into kernel coxial cable.

·         The second cable is 10Base2 or Thinnet (Thin Ethernet). This kind can to bent easily.

·         The third cable is 10Base-T be one of the type twisted pair cable in this time used.

·         Fourth cable is 10Base-F, use fiber optic.

This is scheme 100base-T spesification IEEE 802.3u

Theoretically twisted pair category 3 can achieve maximum 100 meters every the segment. but this cable doesn't can to hold back signal load as big as 200 megabaud (mbps with Manchester code) for distance 100 meters, maximum distance twisted pair. While in category 5 distances 100 meters reachable easily,  and fiber optic can achieve further distance.

Fast Ethernet applied by IEEE in 2 groups:

1.      Fast Ethernet Alliance (100Base-T)

Implementation Fast Ethernet used UTP cable and STP. MAC layer is compatible with MAC layer IEEE 802.3.

2.      100VG-AnyLAN

Spesification IEEE for implementation 100 mbps token ring and Ethernet with 4 pair UTP. MAC layer is not compatible.

 Standard IEEE 802.4: Token Bus

In 802.3 a workstation sometimes want time very long so that can to transmit frame. Standard IEEE 802.4 apply a system that called token bus. Physically, token bus is bus topology implementation or tree where all workstation related. logically, workstation to connection according to ring, where every workstation detect workstation that reside in side" left"  and " right".

Standard IEEE 802.5: Token Ring

Ring network long there and used good to network LAN or WAN. Ring in the reality is practically link nest point to point that form circle. IEEE put into standard token ring as 802.5 with a few reason, that is because ring proved in the field and applicable in cable coaxial, twisted pair, also fiber optic.

The equal 802.3, 802.4 and 802.5

• Standard 802.3 is standard widest is used and the protocol use very simple, but the weakness is 802.3 have a analog component is very determine, 802.3 have a character non-deterministic, and 802.3 can’t distinguish frame important and not important.
• Standard 802.4 used a television cable has reability , the weakness, broadband system used analog engineer and involve modem with amplifier broad band
• Standard 802.5 wear connection point to point so that the engineer enough easy and can formed thoroughly digital, the weakness is centralisation monitor function existence, causes critical component existence