Allied Telesyn CentreCOM AT-3675 Bridge SNMP Manageable User Manual
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. The information provided herein is subject to change without notice. In no event shall Allied Telesyn International, Corp.
Table Of Contents Electrical Safety and Installation Requirements ..................................................... i Table Of Contents .......................................................................................................... xi Chapter 1 Overview ........................................................................................................................... 1 CentreCOM AT-3675 SNMP-Manageable Bridge ...........................................................................
10BASE-T....................................................................................................................................................... UTP Wiring Specifications.................................................................................................................................. 10BASE-T Point-to-Point Cabling ....................................................................................................... 10BASE-FL/FOIRL Ethernet ...................................
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. The AT-3675 bridge transparently forwards packets.
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. Physical Description The AT-3675 bridge is housed in the slim-line chassis.
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.
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. version only) Save the shipping carton and packing material in case you need to ship or store the bridge in the future.
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.
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. 7. Reinstall the top cover and screws.
Installation Upgrading Bridge Firmware The bridge firmware resides in PROMs on the motherboard. See Figure 3. To swap out the firmware PROMs 1. 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. See safety statements starting on page i. 2. Remove the three screws along the front edge of the top. 3.
Chapter 3 Operation This chapter describes the features of the CentreCOM AT-3675 SNMPManageable 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. Power On When the power is first applied, the green System Power and red Diagnostics indicators are illuminated. The green network Activity indicators are OFF.
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 SNMPstandard STP protocol. Because of this signal, the Activity indicators will blink every few seconds, even if there is no other network activity.
CentreCOM AT-3675 SNMP-Manageable Learning Bridge Backbone Network CentreCOM 3675 CentreCOM 3675 Sub-network A Sub-network B CentreCOM 3675 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. This alone is not a good reason to use a bridge since inexpensive conversion devices are available.
Operation Increasing Maximum Network Length 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 maximum network length only applies to individual sub-networks, so that the overall network length is not bound by any limit. Since there are practical limits on how many bridges can be used in this manner, however, each bridge introduces a small delay in forwarded traffic.
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. Figure 8 below shows this kind of configuration. CentreCOM 3675 Marketing Engineering Figure 8: A Simple Bridged Network Analysis of Large Networks.
Operation Table 6: Traffic Patterns From Node To Node Frames/Second (Average) 1 2 9000 1 3 1000 1 4 1000 2 3 1000 2 4 1000 3 4 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. A bridge could be placed between nodes 2 and 3.
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 3675 Sub-network A CentreCOM 3675 Sub-network B Sub-network C CentreCOM 3675 Sub-network D Failure here partitions the network: 1) Sub-nets A and B are up. 2) Sub-net D is isolated. 3) Sub-net C is down. Figure 11: Failure of a Cascaded- Bridged Network In a backbone network, two possibilities arise.
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. 10BASE-T The maximum length for 10BASE-T UTP segments is 100 meters (328 ft.).
Data Cabling Techniques Table 7: UTP Wiring Specifications Cable Description AC Character Specification Twist/ Foot 10BASE-T OK? 1 Unshielded Untwisted N/A CCITT None NO! 2 Individual UTP 100 W ± 30 W RS232 1BASE5 AT&T PDS None NO! 3 Typical Individual UTP 100 W ± 15 W T1, AT&T ISDN 10BASE-T IBM Type 3 3-5 YES 4 Enhanced Individual STP 100 W ± 30 W EIA, TIA 10BASE-T NEMA 5-8 YES 5 Individual STP 100 W ± 30 W EIA, TIA 10BASE-T 8-10 YES IBM Type 1 Individual STP 150 W P
CentreCOM AT-3675 SNMP-Manageable Learning Bridge Figure 14: Pin 1 Orientation on an RJ45 Connector Pin 1 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.
Data Cabling Techniques A 1 Pair twisted as per Level 3, 4 or 5 cable. RJ45 Pin 1 RJ45 Pin TD+ 1 1 TD+ TD- 2 2 TD- RD+ 3 3 RD+ Not Used 4 4 Not Used Not Used 5 5 Not Used RD- 6 6 RD- Not Used 7 7 Not Used Not Used 8 8 Not Used 1 B This cable will not work for 10BASE-T. Note that 3 and 6 are twisted, but are not a pair. Figure 16: Hub-to-MAU Wiring A.Usable and B.
CentreCOM AT-3675 SNMP-Manageable Learning Bridge RJ 45 Pin RJ 45 Pin 1 TD+ 1 1 TD+ TD- 2 2 TD- RD+ 3 3 RD+ 1 Not Used 4 4 Not Used Not Used 5 5 Not Used RD- 6 6 RD- Not Used 7 7 Not Used 8 Not Used 1 Pair twisted as per level 3, 4 or 5 cable Not Used Figure 17: Hub-to-Hub or MAU-to-MAU Wiring 8 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 Ω 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. AUI Drop Cables 24 AUI or Drop cables can be no longer than 50 meters (164 ft.) each. Attachments may be made only to the cable ends at the 15-pin D-shell connector.
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 Ω. 10BASE5—Also called thick Ethernet, 10BASE5 is a 10 MHz, baseband, 500 meters (1,640 ft.) maximum coaxial segment. The cable is commonly referred to as yellow cable. Cable impedance is 50 Ω. Thick Ethernet cable is typically used as a trunk or backbone path of the network. 10BASE-FL—IEEE 802.3 fiber optic Ethernet.
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. BIT TIME—The duration of one bit symbol (1/BR). Ethernet specifies a bit time of 100 ns.
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. The DTE could be an Ethernet workstation, repeater or bridge.
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. JAM—This is a term used to describe the collision reinforcement signal output by the repeater to all ports. The jam signal consists of 96 bits of alternating 1s and 0s.
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.
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. SLAVE— A repeater that behaves as a “dumb” module managed by a Master in a department concentrator chassis.
Appendix C Technical Support Fax Order Name _______________________________ ____________________________________ Company ________________________________________________________________ Address _________________________________________________________________ City ____________________State/Province____________ Zip/PostalCode __________ Country _________________ Phone __________________Fax_____________________ Incident Summary Model number of ATI product I am using ______________________________________ F
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. Your comments are valuable when we plan future revisions of the manual.
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