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Copyright 1994 Allied Telesyn International, Corp. All rights reserved. No part of this publication may be reproduced without prior written permission from Allied Telesyn International, Corp. Allied Telesyn International, Corp. reserves the right to make changes in specifications and other information contained in this document without prior written notice.
Chapter 1 Overview CentreCOM AT-3675 SNMP-Manageable Bridge The CentreCOM AT-3675 SNMP-Manageable Learning Bridge allows you to interconnect two Ethernet sub-networks. Each sub-network may be IEEE 802.3 10BASE2 (thin) Ethernet or 10BASE5 (thick) Ethernet or pre-802.3 Ethernet. Unshielded Twisted Pair (UTP) can also be connected to the bridge through a transceiver.
Overview Management Simple Network Management Protocol (SNMP) is supported by the AT-3675. The bridge can be monitored and manipulated by many SNMP-compatible management stations. Since it supports the second version of the Management Information Base (MIB-II) and Bridge MIB, parameters of the AT-3675 can be managed under SNMP including custom filtering, static forwarding entries and STP.
CentreCOM AT-3675 SNMP-Manageable Learning Bridge Not all chassis slots must be populated and populated slots need not be contiguous. Table 2 lists chassis models available. Table 2: Department Concentrators Chassis Available Number of Modules Desktop Model Rackmount Model AT-36E1 AT-36C1 AT-36E2 AT-36C2 AT-36E3...
Chapter 2 Installation Before installing the CentreCOM AT-3675 SNMP-Manageable Learning Bridge, check to see that the package contents are complete. If any of the following items are missing or damaged, contact your sales representative. CentreCOM AT-3675 SNMP-Manageable Learning Bridge User Manual Warranty statement and registration cards Power cord (U.S.A.
Installation Changing Configuration with Transceivers You can attach cable of different media to one or both channels via a transceiver. Table 3 list the transceivers avaiable. Table 3: ATI Micro Transceiver Choices Model Description AT-MX25F Fiber Optic (FOIRL, 10BASE-FL), SMA Connector AT-MX26F Fiber Optic (FOIRL, 10BASE-FL), ST Connector AT-210T/AT-210TS/AT-MX20T...
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CentreCOM AT-3675 SNMP-Manageable Learning Bridge Caution The person handling the jumper block(s) must be grounded to prevent electrostatic discharge. 5. Carefully remove jumper block(s) with an IC puller or a flat screwdriver. 6. Carefully reposition and reinstall the jumper block(s). Check for bent pins or misalignment between the jumper block and socket.
Installation Upgrading Bridge Firmware The bridge firmware resides in PROMs on the motherboard. See Figure 3. To swap out the firmware PROMs Remove the power cord and any cables from the AT-3675 front panel. Warning Opening the bridge without unplugging the power cord may expose personnel to high voltage, risking the possibility of injury or death.
Chapter 3 Operation This chapter describes the features of the CentreCOM AT-3675 SNMP- Manageable Learning Bridge and shows the basic operating procedures. It covers how the bridge can be used to overcome common physical limitations and how to employ the bridge in such a way that network performance is improved.
Operation Backup Operation The AT-3675 bridge software allows you to establish redundant interconnections between the same two networks. This feature provides backup should the bridge or its network connection fail. The primary bridge and its backup communicate with each other in accordance with the SNMP- standard STP protocol.
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CentreCOM AT-3675 SNMP-Manageable Learning Bridge Backbone Network CentreCOM CentreCOM CentreCOM 3675 3675 3675 Sub-network A Sub-network B Sub-network C Figure 5: A Backbone Network Mixing Media The AT-3675 bridge can also be used to interconnect network segments that use different media. You may use any medium on either channel.
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Operation Increasing Maximum A bridge may be used to link sub-networks serially in the same way a repeater is used. Figure 7 shows this use of the cascaded-bridge topology. The Network Length maximum network length only applies to individual sub-networks, so that the overall network length is not bound by any limit.
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CentreCOM AT-3675 SNMP-Manageable Learning Bridge Simple Bridged Network. In many cases, workgroup boundaries are clearly defined and it is obvious where to place the bridges. This is especially true for small organizations, which will only use one or two bridges or when previously separate networks are being interconnected.
Operation Table 6: Traffic Patterns From Node To Node Frames/Second (Average) 9000 1000 1000 1000 1000 9000 In this case there are two clusters. The first contains nodes 1 and 2 and the second contains nodes 3 and 4. Within each cluster, the traffic levels are around 13,000 frames per second, while the traffic between the groups is around 4,000 per second.
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CentreCOM AT-3675 SNMP-Manageable Learning Bridge With a cascaded network, a fault will split the network into two disjointed parts. This is shown in Figure 11. CentreCOM CentreCOM CentreCOM 3675 3675 3675 Sub-network A Sub-network B Sub-network C Sub-network D Failure here partitions the network: 1) Sub-nets A and B are up.
Appendix A Data Cabling Techniques Depending on the medium you choose, there are certain wiring practices you should follow to ensure the reliability of communication throughout the network. The following sections detail cabling techniques and port specifications for IEEE 802.3 media. For comprehensive treatment of these topics, refer to the original IEEE specification.
Data Cabling Techniques Table 7: UTP Wiring Specifications Cable Twist/ 10BASE-T Cable Description AC Character Specification Level Foot Unshielded CCITT None Untwisted Individual UTP 100 W 30 W RS232 1BASE5 None AT&T PDS Typical Individual 100 W 15 W T1, AT&T ISDN 10BASE-T IBM Type 3 Enhanced Individual...
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CentreCOM AT-3675 SNMP-Manageable Learning Bridge Figure 14: Pin 1 Orientation on an Pin 1 RJ45 Connector Some situations require a DCE-to-DCE connection, for example, when hubs are cascaded. This can be accomplished with a standard cross-over cable, as illustrated in Figure 15. UTP MAU UTP MAU RJ45 PIN...
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Data Cabling Techniques Pair twisted as per Level 3, 4 or 5 cable. RJ45 Pin RJ45 Pin Not Used Not Used Not Used Not Used Not Used Not Used Not Used Not Used This cable will not work for 10BASE-T. Note that 3 and 6 are twisted, but are not a pair.
CentreCOM AT-3675 SNMP-Manageable Learning Bridge RJ 45 Pin RJ 45 Pin Not Used Not Used Not Used Not Used Not Used Not Used Pair twisted as per level 3, 4 or 5 cable Not Used Not Used Figure 17: Hub-to-Hub or MAU-to-MAU Wiring 10BASE-FL/FOIRL Ethernet The IEEE 802.3 10BASE-FL standard supports up to 2,000 meters (6,560 ft.)
Data Cabling Techniques 2165 ns. Propagation delay of 10BASE5 Ethernet coax is calculated at 4.33 ns/ meter. Both ends of the segment must be terminated with a 50 termination with a power rating of 0.5 watts or greater. Earth grounding of the segment shield must take place at only one point on the cable.
Appendix B Glossary 10BASE2 —Also called thinnet Ethernet, thinnet or CheaperNet, 10BASE2 is a 10 MHz, baseband, 185 meters (607 ft.) maximum coaxial segment. Cable impedance is 50 . 10BASE5—Also called thick Ethernet, 10BASE5 is a 10 MHz, baseband, 500 meters (1,640 ft.) maximum coaxial segment.
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Glossary BAYONET NUT COUPLE (BNC) CONNECTOR—A 10BASE2 thin coax connector with push-on BNC locking lug that quickly locks into place with a half twist. BIT RATE (BR)—This is the rate of data throughput on the medium in bits per second. Ethernet specifies 10 million bits per second. BRANCH CABLE—The AUI cable interconnecting the DTE and MAU system components also known as a Drop cable.
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CentreCOM AT-3675 SNMP-Managable Learning Bridge DATA COMMUNICATION EQUIPMENT (DCE)—In RS232 specification a unit, such as a modem, for connecting a DTE to other equipment. A repeater connected to a terminal or workstation for OMEGA LOCAL management use is wired as a DCE. DATA TERMINAL EQUIPMENT (DTE)—In RS232 specification a unit typically at the end of a segment.
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Glossary JABBER LOCK-UP—The MAU’s ability to automatically inhibit the transmit data from reaching the medium if the transmit data time exceeds a specified duration. This duration is in the range of 20 ms to 150 ms. Jabber lock-up protects the medium from being overrun with data packets from a possibly defective device.
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CentreCOM AT-3675 SNMP-Managable Learning Bridge MODULE—A single repeater when it is mounted with other repeaters in an AT-36Cx or AT-36Ex department contentrator chassis. N-SERIES—A barrel shaped, threaded connector used on 10BASE5 (thick Ethernet) coaxial cable. PATCH PANEL—A 10BASE-T patch panel may be between a punch-down block and UTP workstation.
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Glossary SIMPLE NETWORK MANAGEMENT PROTOCOL (SNMP)— SNMP is a TCP/IP protocol that generally uses the User Datagram Protocol (UDP) to exchange messages between a management information base and a management client residing on a network. Since SNMP does not rely on the underlying communication protocols, it can be made available over other protocols, such as XNS or DECNET.
Appendix C Technical Support Fax Order Name _______________________________ _ ___________________________________ Company ____________________________ _ ___________________________________ Address _____________________________ _ ___________________________________ City ____________________State/Province____________ Zip/Postal Code __________ Country _________________ Phone __________________Fax _____________________ Incident Summary Model number of ATI product I am using ___ ___________________________________ Firmware release of ATI product _________ _ ___________________________________ Other network software products I am using (e.g., network managers) ____________________________________ _ ___________________________________...
Appendix D CentreCOM AT-3675 Manual Feedback We would like you to tell us what additional information you would like to see discussed in the manual. If there are topics you would like information on that were not covered in the manual, please photocopy this page, answer the questions and fax or mail this form to ATI The mailing address and fax number are at the bottom of the page.
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Technical Bulletin Board Service 1 (206) 483-7979 CompuServe Go ALLIED World Wide Web http://www.alliedtelesyn.com For Information Regarding Allied Telesyn International Corp. Allied Telesyn International Corp. Allied Telesyn International Corp. 19015 North Creek Parkway Suite 200 950 Kifer Road Bothell, WA 98011...
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