Cabletron Systems MicroMMAC-22T User Manual

Also see for MICROMMAC-22T: User guide Reference guide User guide

Contents

Cabletron Systems MicroMMAC-22T User Manual Manual pdf 57 page image

CABLING4-34.2.1 Signal InterferenceThis section describes some of the conditions that can degrade TokenRing signals and related corrective measures.CrosstalkCrosstalk is interference caused by signal coupling between differentcable pairs contained within a multi-pair cable bundle. Multi-pair cablingjackets should not be used for routing Token Ring trunk cabling,especially at 16 Mbps. Avoid mixing Token Ring cabling with othercabling systems (e.g., telephone) within the same multi-pair jacket.NoiseNoise can be caused by crosstalk or externally imposed impulses. Ifnoise-induced errors are suspected, ensure that the electrical wiring in thearea is properly wired and grounded and/or try re-routing cabling awayfrom potential noise sources (motors, switching equipment, fluorescentlighting, high amperage equipment).TemperatureThe attenuation level of PVC-insulated cable varies significantly withtemperature. Check the cable manufacturer’s specifications. Plenum-ratedcables are strongly recommended in areas where temperatures exceed40˚C. Under such conditions, plenum-rated cables ensure that cableattenuation tolerance remains within specifications.4.2.2 Determining The Station CountAssuming optimal conditions resulting from a well-designed cabling andcabling component installation, the Token Ring can consist of 250stations when STP type 1 or 2 lobe cabling is used throughout the entireinstallation. The count decreases to 150 stations when UTP is used forany segment in the installation.!CAUTIONWhen calculating the station count for an installation thatincludes multiple MicroMMAC-Ts interconnected by ring-trunkcabling, consider that each MicroMMAC-T is equivalent tothree stations on the ring, even though the MicroMMAC-T hasa single MAC address. The management agent is a station andthe two ring ports that are in service account for the other twostations. Exceeding the recommended station-countundermines the ring’s performance capacity.