NB20E and NB25 E TWO PORT ETHERNET BRIDGES USER’S MANUAL CABLETRON SYSTEMS, P.O.
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.
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 radio communications.
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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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 segments.
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.
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.
INTRODUCTION NODE A NODE C LAN 1 T T T LAN 2 T 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.
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.
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.
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.
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’s Manual.
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.
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.
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-stretched for increased viewing effect.
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 Logic Ref. 12 Receive - 5 Receive + 13 Power (+12 Vdc) 6 Power return 14 Logic Ref.
INSTALLATION REQUIREMENTS/ SPECIFICATIONS POWER SUPPLY REQUIREMENTS Parameter Typical Value Worst Case 120V Input Voltage: 120 V 90 to 130 V Input Current NB20E: NB25E: Frequency Range: 0.5 Amps 0.75 Amps 1.0 Amps 1.5 Amps 47 - 63 Hz 220V Input Voltage: 220 V 180 to 264 V Input Current NB20E: NB25E: Frequency Range: 0.25 Amps 0.375 Amps 0.5 Amps 0.75 Amps 47 - 63 Hz Overload Protection Input: (2) 3AG 3 amp fuses in series with both primary inputs.
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 emissions. SERVICE MTBF (MHBK - 20E): NB20E: > 35,750 hrs. projected. NB25E: > 26,533 hrs. projected. MTTR: < 0.5 hrs.
CHAPTER 3 INSTALLING THE NB20E OR NB25E BRIDGE This section contains instructions for installing Cabletron Systems' NB20E or NB25E Two Port Ethernet Bridge, and for preparing the bridge for operation. Verify that all network design guidelines and site requirements listed in Chapter 2, Installation Requirements/ Specifications, are met before installing the bridge. 3.
INSTALLING THE NB20E OR NB25E BRIDGE 3.2.1 Installing the Rack Mount Brackets If the NB20E or NB25E will be rack mounted: 1. Remove the four screws (5, Fig. 3-1) holding the four rubber feet to the bridge. This frees the top plastic housing (1) from the bridge. 2. Carefully remove the top plastic housing. 3. Remove the four screws (6) holding the bottom plastic housing (4) to the bridge’s chassis. 1. 2. 3. 4. Top Housing Screws (4) Rack Mount Bracket Bottom Plastic Housing Figure 3-1 3-2 5. 6. 7.
INSTALLING THE NB20E OR NB25E BRIDGE 4. Remove the NB20E or NB25E from the bottom housing. 5. Remove the four screws (2) that secure the cover to the front of the bridge. The screws are located on the left and right sides of the bridge (closest to the front side), two per side. 6. Attach the rack mount brackets (3, 7) using the screws removed in step 5. The bracket should be flush with the front of the bridge. 3.2.2 Cable Support Installation To install the cable support: 1.
INSTALLING THE NB20E OR NB25E BRIDGE 1 9 10 8 2 7 3 1. 2. 3. 4. 5. 4 ST-500 Transceiver AUI Cable Bridge AUI Port 2 AUI Port 1 Figure 3-3 5 6. 7. 8. 9. 10. 6 Power Receptacle Power Cord AUI Cable ST-500 Transceiver RS232 Port (NB25E only) Installation 2. Attach an AUI cable (2, 8) no more than 50 meters in length to each of the transceivers that you connected to each network segment. 3.
INSTALLING THE NB20E OR NB25E BRIDGE NB-25E XMT ON LINE ETHERNET /IEEE 802.3 BRIDGING UNIT WITH REMOTE LANVIEW® AND MANAGEMENT RCV STAND BY FORWARD BROADCAST 1 0 ROOT 1 0 CP POK 1 Figure 3-4 3.2.5 PORT 2 Bridge Front Panel Connecting The NB20E or NB25E To The Power Source When installation of the NB20E/NB25E Bridge is complete and the switches have been set, connect the bridge to the power source in the following manner: 1. If you have not already done so, plug the power cord (7, Fig.
INSTALLING THE NB20E OR NB25E BRIDGE The following conditions indicate a problem has been detected with the bridge: • The ON-LINE, STANDBY, PORT 1 OK and PORT 2 OK LEDs do not start to flash on power up, indicating that the Real Time Clock has failed. • The ON-LINE, STANDBY, PORT 1 OK and PORT 2 OK LEDs do not stop flashing after power up, indicating that the Network Interface Chip has not been properly initialized.
CHAPTER 4 TESTING AND LANVIEW This section contains procedures to test the NB20E or NB25E Two Port Ethernet Bridge after it has been connected to the network. A description of the LANVIEW LEDs, the Forward Broadcast, and the Root Switch, is also provided. 4.1 INSTALLATION CHECK-OUT After the NB20E or NB25E is connected to the network, verify that packets can be passed between the two Ethernet network segments via the bridge.
TESTING AND LANVIEW 5. Using a transceiver (5) and an AUI cable, connect another LAN-MD (4) to the other segment connected to the bridge. 6. Select and run test 4 - NODE on the LAN-MD connected in the previous step. 7. Verify that this test passes. At least 100 packets should be sent and received by the bridge, with no errors. Packets will be sent from this LAN-MD to the other LAN-MD, acting as the Server, then echoed back.
TESTING AND LANVIEW ON LINE LED When this green LED is lit, the bridge is on line and operational. The unit has completed a self diagnostics test and is capable of forwarding packets. STAND BY LED When this yellow LED is lit, the bridge is in the “Stand by” mode and not capable of forwarding packets. NOTE: There are separate XMT, RCV, CP, and POK LEDs for each port on the NB20E and NB25E. TRANSMIT (XMT) LED When this green LED is flashing, the bridge is transmitting packets to that network segment.
TESTING AND LANVIEW 4.4 USING THE ROOT SWITCH In a multiple-bridge environment, the Root switch, Figure 4-1, for a particular bridge allows the user to set that bridge as the root bridge. Only one bridge can serve as the root bridge in a multiple bridge environment, however. In the event that two bridges have been selected as root bridges, the bridge in the environment with the lowest identifier will become the root bridge.
