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integrated services LAN (ISLAN)

ISLAN(Integrated Services LAN) technology pursues the integration of IEEE 802 and ISDN protocols. This will allow parallel processing of data, voice and video from personal computers. This function should become possible without changing the current network infrastructure. Therefore, this standard provides for the use of existing transmission media. The transmission speeds vary depending on the distance to be bridged: 4.096 Mbit/s up to 450 m or 20.48 Mbit/s up to 135 m.

The services offered by ISLAN

Isochronous and asynchronous services are offered, as is necessary for data, voice and video. Standardization was started in the IEEE 802.9 working group in 1987 and has reached a stable state today with Draft 19, so that the first implementations are appearing on the market. The standard provides the user with a number of channels that he can use for his applications: The P, D, B and C channels.

ISLAN Structure

ISLAN Structure

The P channel (Packet Channel) provides the user with an IEEE 802 MAC layer service. It is a full-duplex channel that can optionally also be used for setting up connections in accordance with ITU Q.93x. In this case, it is referred to as a PD channel.

As with ISDN, the D channel is responsible for setting up connections according to the Q.93x protocols. It has a transmission rate of 16 or 64 kbit/sData transmission takes place in duplex mode and is packet-oriented. B channel: Furthermore, two 64 kbit/s channels are offered for use as voice channels (isochronous transmission).

There are several C channels for circuit switching, each with a transmission speed of a multiple of 64 kbit/s: C1 has a transmission rate of 64 kbit/s and thus corresponds to the ISDN B channel. C6 has a transmission rate of 384 kbit/s, C24 of 1,536 kbit/s and C30 of 1,920 kbit/s.

The configuration of ISLAN

In ISLAN technology, the terminals are coupled to the various networks via access units. These access units have to ensure that the respective channel is served with the appropriate quality of service.

To make these configurations possible, a three-part protocol structure is proposed in the IEEE 802.9 proposal. The P channel represents the direct access to the IEEE 802.1 layer. The D channel handles the Link Access Procedure D/LAP D as known from ISDN. The activities of the IEEE 802.9 working group and thus of ISLAN were discontinued, and the standard was withdrawn.

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Englisch: integrated services LAN - ISLAN
Updated at: 09.11.2013
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