Some standards Ethernet which can satisfy the increased requirements are known, we shall consider 2 of them:

• 100BaseVG-AnyLAN Ethernet;
• 100BaseX Ethernet (Fast Ethernet).

And Fast Ethernet, and 100 Base VG-Any LAN work approximately in five-ten times more quickly, than standard Ethernet. Besides they are compatible to existing cable system 10BaseT. It means what to pass from l0BaseT to these standards simply enough and quickly.

This standard sometimes named Fast Ethernet, is expansion of existing standard Ethernet. It is under construction on UTP categories 5, uses a method of access of CSMA/CD and topology "star-trunk" (similarly to 10BaseT) where all cables are connected to the concentrator.

• 100BaseX includes three specifications of the environment of transfer:
• 100BaseT4 (UTP categories 3, 4 or 5 with four pairs wires);
• 100BaseTX (UTP or STP categories 5 with two pairs wires);
• 100BaseFX (a two-core fibre-optical cable).

100VG (Voice Grade) AnyLAN - new network technology which combines elements Ethernet and Token Ring. This technology developed by firm Hewlett-Packard, now is improved by standard IEEE 802.12. The specification 802.12-standard of transfer staff Ethernet 802.3 and packages Token Ring 802.5.

This technology has some names:

• l00VG-AnyLAN;
• 100Base VG;
• VG;
• AnyLAN.

Let's list opportunities of some of specifications existing now l00VG-AnyLAN:

• The minimal speed of data transmission 100 Mbit/sec;
• Support stackable topology "star" on the basis of twisted pair a category 3, 4 or 5 and a fibre-optical cable;
• A method of access on a priority of inquiry (two levels of a priority differ: low and high);
• Support of means of a filtration of personally addressed staff in the concentrator (for increase of a degree of confidentiality);
• Support of transfer of staff Ethernet and Token Ring.

The network 100VG-AnyLAN is under construction on topology "star" where all computers are connected to the concentrator. It is possible to expand a network, adding "child" concentrators to central, "parent" which concerns to them the same as and to computers, i.e. parental concentrators operate transfer of the computers connected to "children".

The presented technology demands use of special concentrators and payments. Besides the length of a cable 100BaseVG, in comparison with 10BaseT and other realizations Ethernet, is limited: the general length of pair cables from the concentrator 100BaseVG up to computers cannot exceed 250 m. to overcome this restriction, it is necessary to use the special equipment. Restrictions of length of a cable will lead to that for 100BaseVG is required more than cable racks, than for 10BaseT.