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NB20E and NB25 E
TWO PORT ETHERNET BRIDGES
USER’S MANUAL
CABLETRON SYSTEMS, P.O. BOX 6257, ROCHESTER, NH 03867-6257
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NOTICE Cabletron Systems reserves the right to make changes in specifications and other information contained in this document without prior notice. The reader should in all cases consult Cabletron Systems to determine whether any such changes have been made. The hardware, firmware, or software described in this manual is subject to change without notice. IN NO EVENT SHALL CABLETRON SYSTEMS BE LIABLE FOR ANY INCIDENTAL, INDIRECT, SPECIAL, OR CONSEQUENTIAL DAMAGES WHATSOEVER (
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FCC NOTICE FCC NOTICE This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. WARNING: This equipment uses and generates and can radiate radio frequency energy and if not installed properly and used in accordance with the instruction manual, may cause interference to r
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CONTENTS CHAPTER 1 INTRODUCTION 1.1 USING THIS MANUAL................................................................ 1-1 1.2 GETTING HELP .......................................................................... 1-2 1.3 THE NB20E AND NB25E TWO PORT ETHERNET BRIDGE .... 1-2 1.4 THE BRIDGE FILTERING METHOD .......................................... 1-3 1.5 MULTIPLE BRIDGE ENVIRONMENTS ...................................... 1-5 1.5.1 The Root Bridge....................................
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CONTENTS iv
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CHAPTER 1 INTRODUCTION Welcome to the Cabletron Systems NB20E™ and NB25E™ Two Port Ethernet Bridges User's Manual. We have designed this user’s manual to serve as a simple installation and reference guide for the NB20E and NB25E, and to explain the capabilities and special features of each individual bridge. With the appropriate design, the Cabletron Systems NB25E or NB20E can dramatically improve network performance and bandwidth efficiency on heavily utilized network segment
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INTRODUCTION 1.2 GETTING HELP If you need additional support related to the Cabletron Systems NB20E or NB25E Two Port Ethernet Bridge, or if you have any questions, comments or suggestions related to this manual, feel free to contact Cabletron Systems' Technical Support at: Cabletron Systems Inc. P.O. Box 6257 E. Rochester, NH 03867-6257 Phone: (603) 332-9400 1.3 THE NB20E AND NB25E TWO PORT ETHERNET BRIDGE With the Cabletron Systems NB20E or NB25E Two Port Ethernet Bridge, you can dr
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INTRODUCTION according to the specific needs of a network manager. The network manager's ability to set up parameters within Remote LANVIEW ensures optimal performance for each bridge, and hence, each network. For example, a network manager can manage and monitor: the flow of traffic through a bridge, the status of a database, the bridge protocol and port parameters, and the bridge setup. Both bridges also incorporate Cabletron Systems' LANVIEW Status Monitoring and Diagnostics Systems.
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INTRODUCTION NODE A NODE C LAN 1 TT TT LAN 2 NODE B Figure 1-1 Bridging Method In this example, when Node A sends a packet to Node B, the bridge learns Node A’s source address and adds the address to the Source Address Table, indicating that the node is on LAN 1. If Node C subsequently sends a packet to Node A, Node A’s address will be detected in the Source Address Table for LAN 1 and the packet will not be forwarded across the bridge to LAN 2. At the same time, the bridge will learn N
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INTRODUCTION This feature is referred to as Aging Time. Aging Time can be altered through Cabletron Systems’ Remote LANVIEW Network Control Management for the Cabletron Systems' NB20E and NB25E. 1.5 MULTIPLE BRIDGE ENVIRONMENTS Both the NB20E and NB25E Two Port Bridges are designed to promote maximum network use in multiple bridge environments. A bridge learns the bridge topology of its network from bridge protocol data that is transmitted onto the network by each bridge. The bridges
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INTRODUCTION 1.5.2 Primary and Redundant Data Paths To ensure the integrity of the network, primary data paths through designated bridges, and redundant data paths through alternative bridges are determined in each LAN or loop configuration in the network. A LAN segment’s designated bridge is the bridge in a LAN or loop configuration with the lowest cost path of transmission from that LAN segment to the root bridge. The lowest cost path can be translated in a general way to mean the dat
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INTRODUCTION if all three bridges are on line and Node A sends a packet to Node B. The packet will be forwarded through Bridges 1 and 3, and through Bridge 2, causing the packet to be circulated many times around the data loop. If Bridge 1 has priority over Bridge 2, the Spanning Tree Algorithm will place Bridge 2 in blocking, preventing the packet from being forwarded through Bridge 2. If Bridge 1 should fail, the Spanning Tree Algorithm will be modified automatically so that the pack
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INTRODUCTION For further information for refer to the Remote LANVIEW - Network Control Management for the Cabletron Systems' NB20E and NB25E User's Manual. 1.7 RELATED MANUALS The manuals listed below should be used to supplement the procedures and other technical data provided in this manual. The procedures will be referenced where appropriate, but will not be repeated. Cabletron Systems' Remote LANVIEW - Network Control Management for the Cabletron Systems' NB20E and NB25E User
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CHAPTER 2 INSTALLATION REQUIREMENTS/ SPECIFICATIONS Before you attempt to install Cabletron Systems' NB20E or NB25E Two Port Ethernet Bridge, review the location and hardware requirements outlined in this chapter. Also refer to the operating specifications and environmental requirements that are listed. All conditions, guidelines, specifications and requirements included in this chapter must be met to ensure satisfactory performance of the NB20E or NB25E. Failure to follow thes
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INSTALLATION REQUIREMENTS/ SPECIFICATIONS 2.3 OPERATING SPECIFICATIONS The operating specifications for Cabletron Systems' NB20E or NB25E Two Port Bridge Series are included in this section. Cabletron Systems reserves the right to change these specifications at any time without notice. GENERAL Parameter NB20E NB25E Packet Buffer Memory (RAM): 128K 128K Internal Processor: 16MH
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INSTALLATION REQUIREMENTS/ SPECIFICATIONS FRONT PANEL INDICATORS ON LINE When lit, this LED indicates the two port bridge is on line and operational (green indicator). STAND BY When lit, this LED indicates the bridge is not forwarding packets (yellow indicator). NOTE: There is one TRANSMIT, RECEIVE, COLLISION, and POK (Port OK) LED for each segment. The LEDs for RECEIVE, TRANSMIT and COLLISION are pulsed-stret
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INSTALLATION REQUIREMENTS/ SPECIFICATIONS FRONT PANEL SWITCHES (cont.) ROOT | / O When the switch is on ( | ), it designates the bridge as the root bridge in the network. AUI PORT (NB20E/NB25E) Interface Connector Type: 15 position D type receptacle. Pin 1 Logic Ref. Pin 9 Collision - 2 Collision + 10 Transmit - 3 Transmit + 11 Logic Ref. 4 Logi
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INSTALLATION REQUIREMENTS/ SPECIFICATIONS POWER SUPPLY REQUIREMENTS Parameter Typical Worst Value Case 120V Input Voltage: 120 V 90 to 130 V Input Current NB20E: 0.5 Amps 1.0 Amps NB25E: 0.75 Amps 1.5 Amps Frequency Range: 47 - 63 Hz 220V Input Voltage: 220 V 180 to 264 V Input Current NB20E: 0.25 Amps 0.5 Amps NB25E: 0.375 Amps 0.75 Amps Frequency Range: 47 - 63 Hz Overload Protection Input: (2) 3AG 3 amp fuses in series
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INSTALLATION REQUIREMENTS/ SPECIFICATIONS SAFETY Designed in accordance with UL478, UL910, NEC 725-2(b), CSA, IEC, TUV, VDE class A. Meets FCC part 15, Subparagraph J, Class A limits. WARNING: It is the responsibility of the person who sells the system of which the NB20E or NB25E will be a part to ensure that the total system meets allowed limits of conducted and radiated
