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ONTENTS

How to Use This Guide 1

Conventions 2

Содержание SuperStack II Switch 3000 10/100

Страница 1: ... http www 3com com SuperStack II Switch 3000 10 100 User Guide Agent Software Version 3 1 Document No DUA1694 2AAA03 Published June 1997 ...

Страница 2: ...ted 3Com Centre Boundary Way Hemel Hempstead Herts HP2 7YU United Kingdom For civilian agencies Restricted Rights Legend Use reproduction or disclosure is subject to restrictions set forth in subparagraph a through d of the Commercial Computer Software Restricted Rights Clause at 48 C F R 52 227 19 and the limitations set forth in 3Com Corporation s standard commercial agreement for the software U...

Страница 3: ...dant Power System Socket 1 10 Reset Button 1 10 Console Port 1 10 Plug in Module Slot 1 10 Ethernet Address 1 10 Unit Defaults 1 11 Managing the Switch 3000 10 100 1 12 Quick Start For SNMP Users 1 12 Entering an IP Address for the Switch 1 13 2 INSTALLATION AND SETUP Following Safety Information 2 1 Positioning the Switch 3000 10 100 2 1 Configuration Rules for Fast Ethernet 2 2 Configuration Rul...

Страница 4: ...4 19 By Port 4 19 Adding an Entry into the SDB 4 19 Deleting an Entry from the SDB 4 19 Specifying that an Entry is Permanent 4 19 Setting Up Resilient Links 4 20 Configuring Resilient Links 4 21 Creating a Resilient Link Pair 4 22 Deleting a Resilient Link Pair 4 22 Viewing the Resilient Setup 4 23 Setting Up Traps 4 25 Setting Up the Console Port 4 26 Resetting the Switch 3000 10 100 4 28 Initia...

Страница 5: ...5 22 Matrix 5 23 Filter 5 23 Capture 5 23 Events 5 23 Benefits of RMON 5 24 How RMON Improves Your Efficiency 5 24 How RMON Allows Proactive Management 5 24 How RMON Reduces the Traffic Load 5 24 RMON and the Switch 5 25 RMON Features of the Switch 5 25 About Alarm Actions 5 27 About Default Alarm Settings 5 28 About the Audit Log 5 28 6 STATUS MONITORING AND STATISTICS Summary Statistics 6 2 Port...

Страница 6: ...TIONS F TECHNICAL SUPPORT Online Technical Services F 1 World Wide Web Site F 1 3Com Bulletin Board Service F 1 Access by Analog Modem F 1 Access by Digital Modem F 2 3ComFacts Automated Fax Service F 2 3ComForum on CompuServe Online Service F 2 Support from Your Network Supplier F 3 Support from 3Com F 3 Returning Products for Repair F 4 GLOSSARY INDEX 3COM CORPORATION LIMITED WARRANTY ELECTRO MA...

Страница 7: ... 10 100 or Switch How to Use This Guide This table shows where to find specific information in this guide If you are looking for Turn to An overview of the Switch 3000 10 100 Chapter 1 Information about installing the Switch 3000 10 100 into your network Chapter 2 Information about the methods you can use to man age the Switch 3000 10 100 Chapter 3 Information about managing the Switch 3000 10 100...

Страница 8: ... word enter in this guide you must type something and then press the Return or Enter key Do not press the Return or Enter key when an instruction simply says type Key names Key names appear in text in one of two ways Referred to by their labels such as the Return key or the Escape key Written with brackets such as Return or Esc If you must press two or more keys simulta neously the key names are l...

Страница 9: ...Database Store and forward forwarding mode ensuring the Switch forwards all valid Ethernet frames and discards invalid Ethernet frames such as those with an incorrect CRC Intelligent Flow Management for congestion con trol Full Duplex on all ports including Fast Ethernet Plug in Module ports Resilient Links Support for 16 Virtual LANs VLANs Spanning Tree Protocol STP per VLAN PACE Priority Access ...

Страница 10: ... could be used for example to provide a Fast Ethernet or Asynchronous Transfer Mode ATM backbone connection to the rest of your network Switch Operation and Features The Switch 3000 10 100 uses the same algorithm as a conventional 802 1d bridge for filtering forward ing and learning packets Intelligent Flow Management Intelligent Flow Management IFM is a system for controlling congestion on your n...

Страница 11: ...n and standby link pair is referred to as a resilient link pair For more information about resilient links refer to Setting Up Resilient Links on page 4 20 Virtual LANs VLANs The Switch 3000 10 100 has a Virtual LAN VLAN feature which allows you to build your network seg ments without being restricted by physical connec tions A VLAN is defined as a group of location and topology independent device...

Страница 12: ... Fast Ethernet LANs PACE provides two fea tures Implicit Class of Service When multimedia traf fic is transmitted it is given a higher priority than other data and is therefore forwarded ahead of other data when it arrives at the Switch The Implicit Class of Service feature minimizes latency through the Switch and protects the quality of multimedia traffic Interactive Access When two way multimedi...

Страница 13: ...s The following two illustrations show some exam ples of how the Switch 3000 10 100 can be used on your network Examples of how the Switch 3000 10 100 can be used in a VLAN based network are given in Chapter 5 Figure 1 1 The Switch 3000 10 100 used in a data center ...

Страница 14: ...1 6 CHAPTER 1 GETTING STARTED Figure 1 2 Increasing port density with the Switch 3000 10 100 ...

Страница 15: ...Unit Overview Front 1 7 Unit Overview Front Figure 1 3 Switch 3000 10 100 front view ...

Страница 16: ...rames are being transmitted received on the port Status Green Link is present port is enabled Green flashing Link is present port is disabled Off Link is not present Plug in Module Status LEDs port 13 Packet Yellow Frames are being transmitted received on the Plug in Module port Status Green Link is present port is enabled Green flashing Link is present port is disabled Green flashing long on shor...

Страница 17: ...Unit Overview Rear 1 9 Unit Overview Rear Figure 1 4 Switch 3000 10 100 rear view ...

Страница 18: ...he reset button simulates a power off on cycle This has the same effect as carrying out a reset via the VT100 interface refer to Resetting the Switch 3000 10 100 on page 4 28 Console Port Connect a terminal to the console port to carry out remote or local out of band configuration and man agement The console port is set to auto baud 8 data bits no parity and 1 stop bit Plug in Module Slot Use this...

Страница 19: ...t Plug in Mod ule ports are half duplex Virtual LANs All ports use Port VLAN Mode and belong to the Default VLAN VLAN 1 PACE Disabled Spanning Tree STP Disabled Power On Self Test POST Normal Fast Boot System Alarm broadcast band width used Enabled High threshold 20 Notify and blip Low threshold 10 No action System Alarm errors per 10 000 packets Enabled High threshold 2 Notify Low threshold 1 No ...

Страница 20: ...10 100 supports SNMP over both IP and IPX protocols Quick Start For SNMP Users This section describes how to get started if you want to use an SNMP Network Manager to manage the Switch It assumes you are already familiar with SNMP management If you are using IP and you have a BOOTP server set up correctly on your network the IP address for the Switch is detected automatically and you can start man...

Страница 21: ...e Switch Man agement Setup screen is displayed 5 On the Management Setup screen fill in the follow ing fields Device IP Address Device SubNet Mask if necessary Default Router if necessary For further information on the Management Setup screen refer to Setting Up the Switch for Manage ment on page 3 6 6 If you need the Switch 3000 10 100 to send SNMP traps to the Network Manager you may need to set...

Страница 22: ...1 14 CHAPTER 1 GETTING STARTED ...

Страница 23: ...ng kit containing two mounting brack ets and six screws is supplied with the Switch When deciding where to site the unit ensure that You are able to meet the configuration rules detailed in the following section It is accessible and cables can be connected eas ily Cabling is away from Sources of electrical noise such as radios transmitters and broadband amplifiers Power lines and fluorescent light...

Страница 24: ... single repeater topologies one hub stack per wiring closet with a fiber run to the collapsed backbone For example a 225m 738ft fiber downlink from a repeater to a router or switch plus 100m 328ft UTP run from a repeater out to the endstations Configuration Rules with Full Duplex The Switch 3000 10 100 provides full duplex sup port for all its ports and Fast Ethernet Plug in Module ports Full dupl...

Страница 25: ...Configuration Rules with Full Duplex 2 3 Figure 2 1 Fast Ethernet configuration rules ...

Страница 26: ...ighten with a suit able screwdriver 4 Repeat steps 2 and 3 for the other side of the unit 5 Insert the unit into the 19 inch rack and secure with suitable screws not provided Ensure that ventila tion holes are not obstructed 6 Connect network cabling Stacking the Switch and Other Units If the units are free standing up to four units can be placed on top of one another If mixing a variety of SuperS...

Страница 27: ...en with a suitable screwdriver 4 Repeat for the other side of the unit 5 Ensure that the wall you are going to use is smooth flat dry and sturdy Attach a piece of plywood approximately 305mm x 510mm x 12mm 12in x 20in x 0 5in securely to the wall if necessary and mount the Switch as follows a Position the base of the unit against the wall or plywood ensuring that the ventilation holes face sidewar...

Страница 28: ...Check the status LEDs to ensure the Switch is oper ating correctly refer to LEDs on page 1 8 Connecting an Advanced Redundant Power System Advanced RPS You can connect a SuperStack II Advanced RPS to an RPS socket on the Switch At 5V the current requirement for the Switch is 9A excluding any Plug in Module that may be fit ted Check the documentation supplied with your Plug in Module for power cons...

Страница 29: ... Terminal To connect a VT100 terminal directly to the console port on the Switch you need a standard null modem cable 1 Connect one end of the cable to the console port on the Switch and the other to the console port on the VT100 terminal 2 Ensure that your terminal is set to 8 data bits no parity 1 stop bit If auto configuration is enabled for the Switch the terminal s line speed baud rate is det...

Страница 30: ...P Cables required for this connection depend on the type of workstation you are using You must config ure the workstation to run SLIP Refer to the docu mentation supplied with the workstation for more details You must configure the console port of the Switch to accept SLIP and set up the SLIP parameters address and subnet mask Refer to Switch Man agement Setup on page 3 9 You may need a 5 wire cab...

Страница 31: ...t up to four management user sessions concurrently for example one con sole port and three Telnet connections You can establish VT100 management communica tion with the Switch through two different inter faces Via the Console Port You can access the local management interface using a VT100 termi nal or PC using suitable terminal emulation soft ware The terminal can be connected directly to the Swi...

Страница 32: ...r The Network Any Network Manager running the Simple Network Management Protocol SNMP can manage the Switch 3000 10 100 provided the MIB Manage ment Information Base is installed correctly on the management workstation Each Network Manager provides its own user inter face to the management facilities 3Com s Transcend range of Network Managers all have facilities for managing the Switch 3000 10 100...

Страница 33: ...f you do not have a registered IP address you may be using an identical address to someone else and your network will not operate correctly Obtaining a Registered IP Address InterNIC Registration Services is the organization responsible for supplying registered IP addresses The following contact information is correct at the time of publication Network Solutions Attn InterNIC Registration Service ...

Страница 34: ... wish to replace the default simply enter a new value for this field the default entry is erased Press Down Arrow or Return to move to the next field Button OK Text for a button is always shown in uppercase letters A button carries out an action for example OK or CANCEL To operate a button move the cursor to the button and press Return List Box monitor manager security A list box allows you to sel...

Страница 35: ...aracter in an editable field Ctrl R refreshes the screen Ctrl B moves the cursor to the next button Ctrl P aborts the current screen and returns you to the previous screen Ctrl N actions the inputs for the current screen and moves to the next screen Ctrl K displays a list of the available key strokes Correcting Text Entry Use Delete on a VT100 terminal or Backspace on a PC This moves the cursor on...

Страница 36: ...without any fur ther configuration If you are using the IPX protocol the Switch is allocated an IPX address automatically You can start the SNMP Network Manager and begin managing the Switch If you are using IP without a BOOTP server you must enter the IP address of the Switch before the SNMP network manager can communicate with the device To do this take the following steps Figure 3 1 Main Banner...

Страница 37: ...ments The defaults are shown in Table 3 1 If you are setting up the Switch for management we suggest that you log on as admin Figure 3 2 Logon screen Table 3 1 Default Users User Name Default Password Access Level monitor monitor monitor this user can view but not change all manageable parame ters manager manager manager this user can access and change the operational parameters but not special se...

Страница 38: ...cess to options depends on the access level you have been assigned Access rights to the VT100 screens of the Switch are listed in Appendix B If you are a user with security access level and are using the management facility for the first time we suggest that you Assign a new password for your user using the Edit User screen as described in Editing User Details on page 4 5 Log on as each of the oth...

Страница 39: ...ermine the type of self test that the Switch carries out when it is powered up If the field is set to Normal the Switch performs a Fast Boot a basic confidence check lasting approximately 18 seconds When the Switch per forms a Fast Boot it carries out the following tests Checksum test of boot and system areas of Flash memory System memory tests MAC address verification test Figure 3 4 Management S...

Страница 40: ...k an IP address is automatically mapped to the Switch when it is first powered up In addition to mapping an IP address BOOTP can also assign the subnet mask and default router Using a BOOTP server avoids having to configure devices individu ally SLIP Address If you are using SLIP enter an address that has a network part different to the network address of the Switch For more information con tact y...

Страница 41: ...on to display the setup screen for trap parameters Trap setup is described in Setting Up Traps on page 4 25 CONSOLE PORT Select this button to display the setup screen for console port parameters Console port setup is described in Setting Up the Console Port on page 4 26 ...

Страница 42: ... for 3 min utes the management facility warns you that the inactivity timer is about to expire If you do not press a key within 10 seconds the timer expires and the screen is locked any displayed statistics continue to be updated When you next press any key the display changes to the Auto Logout screen The Auto Logout screen shown in Figure 3 5 requests you to enter your password again If the pass...

Страница 43: ... ities for the Switch While following steps in these chapters you may find the screen map below use ful If an ATM OC 3c Module is installed in the Switch extra screens are available Refer to the SuperStack II Switch ATM OC 3c Module User Guide for more information Figure 4 1 Screen map ...

Страница 44: ... This allows you to set up access levels for users on the Switch CREATE USER screen This allows you to create up to 10 users in addition to the default users set up on the Switch DELETE USERS screen This allows you to delete users from the Switch The default users cannot be deleted EDIT USER screen This allows you to change your own password and community string You cannot change details for other...

Страница 45: ...en Access Level Assign an access level for the new user as follows monitor access to view but not change a subset of the manageable parameters of the Switch secure monitor as monitor manager access to all the manageable param eters of the Switch except security features specialist as manager security access to all manageable parameters of the Switch Figure 4 3 Create User screen Community String B...

Страница 46: ...reen is displayed 1 Select the DELETE USERS option The Delete Users screen is displayed as shown in Figure 4 4 2 Use the spacebar to highlight the user that you want to delete Note that you cannot delete default users or the current user that is yourself 3 Select DELETE USERS Figure 4 4 Delete Users screen ...

Страница 47: ...t be changed if you need to change the user name you must delete this user and create a new one Old Password This field allows you to enter the old password for the user New Password This field allows you to enter a new password for the user Confirm Password This field allows you to re enter the new password for the user Community String This field allows you to enter a new community string for th...

Страница 48: ... the console port disable access to the facility for each access level Console port access for Security is enabled and cannot be changed This prevents accidental dis abling of all access levels from management Remote Telnet Enabled Disabled Telnet is an inse cure protocol You may want to disable all access to the management facilities via Telnet if there is important or sensitive data on your netw...

Страница 49: ... Unit VLAN If you choose Port the screen is displayed similar to Figure 4 7 and all options at the foot of the screen relate to an individual port If you choose Unit the screen is displayed similar to Figure 4 8 and all options relate to the Switch unit If you choose VLAN the screen is displayed similar to Figure 4 9 and all options relate to VLANs Port ID 1 2 3 11 12 13 If you choose to manage th...

Страница 50: ...sen port or unit Refer to Chapter 6 Status Monitoring and Statistics SDB Use this button to display the Unit Database View screen which is used to manage the Switch Database Refer to The Database View on page 4 18 RESILIENCE Use this button to display resilient link management screens for the level of management you have chosen port or unit Refer to Setting Up Resilient Links on page 4 20 You cann...

Страница 51: ...licit Class of Service When multimedia traf fic is transmitted it is given a higher priority than other data and is therefore forwarded ahead of other data when it arrives at the Switch The Implicit Class of Service feature minimizes latency through the Switch and protects the quality of multimedia traffic Figure 4 10 Unit Setup screen Interactive Access When two way multimedia traffic passes over...

Страница 52: ...nning Tree Protocol STP on the Switch For more information about STP refer to Spanning Tree Protocol on page 5 11 Speed Duplex Mode Auto Negotiated 10Mbps Half Duplex 10Mbps Full Duplex 100Mbps Half Duplex 100Mbps Full Duplex This field allows you to specify the speed and Duplex Mode of ports which have Unit Default spec ified in the Speed Duplex Mode field of the Port Setup screen If the Speed Du...

Страница 53: ... the ATM OC 3c Module Consequently the Oversize Frames field is not displayed if an ATM OC 3c Module is installed Default RMON Host Matrix Enable Disable This field allows you to specify whether Hosts and Matrix RMON sessions are defined on the Default VLAN The default setting for this field is Disable For more information about RMON sessions refer to RMON Features of the Switch on page 5 25 Plug ...

Страница 54: ...Mode of the link HD indicates half duplex FD indicates full duplex Port State Enable Disable This field allows you to enable or disable the port To prevent unauthorized access we recommend that you disable any unused ports Figure 4 11 Port Setup screen Link State Present Not Available This read only field shows the state of the link Present The port is operating normally Not Available The link has...

Страница 55: ...T ports For more information about VLTs refer to VLANs and the Switch 3000 10 100 on page 5 3 If the port uses AutoSelect VLAN Mode refer to the VLAN Configuration Mode field you cannot specify that the port is a VLT port Speed Duplex Mode Unit Default Auto Negoti ated 10Mbps Half Duplex 10Mbps Full Duplex 100Mbps Half Duplex 100Mbps Full Duplex This field allows you to specify the speed and Duple...

Страница 56: ... The port is set to 100Mbps and its Duplex Mode is set to full duplex Plug in Module ports are not auto negotiating If the port is a Plug in Module port the Speed Duplex Mode field is replaced by a Duplex Mode field with the following settings Half Duplex Full Duplex Unit Default The Duplex Mode of the port is defined by the Speed Duplex Mode field in the Unit Setup screen This is the default sett...

Страница 57: ...and specify an action to take place if the threshold is exceeded Rising Threshold This field allows you to specify the percentage of broadcast traffic on the current port which triggers the alarm for the port The default is 20 Falling Threshold This field allows you to specify the percentage of broadcast traffic on the current port required to reset the alarm for the port The falling threshold pre...

Страница 58: ...5 7 seconds to recognize that a broadcast storm is occurring Broadcast Storm Control calculates the average broadcast bandwidth over the previous 20 second interval The average is based on four samples taken at 5 second intervals When the average value exceeds the rising threshold value the rising action is triggered The action is not triggered again until the aver age broadcast bandwidth falls be...

Страница 59: ...ntries using a MIB browser an SNMP Network Manager or the Unit Database View screen described in the following sections There are three types of entries in the SDB Ageing entries Initially all entries in the data base are ageing entries Entries in the database are removed aged out if after a period of time ageing time the device has not transmitted This prevents the database from becoming full wit...

Страница 60: ...he port identifier for the entry Permanent Yes No This field allows you to specify that the current entry is permanent Refer to the previous section Setting Up the Switch Database SDB for a description of permanent and ageing entries You cannot specify that the current entry is perma nent if the port uses AutoSelect VLAN Mode For more information about AutoSelect VLAN Mode refer to Using AutoSelec...

Страница 61: ...addresses entered against a par ticular port ID in the SDB 1 Clear the MAC Address field by moving into the field and pressing the spacebar 2 In the Port Number field enter the port ID for which you want MAC addresses displayed 3 Select FIND The listbox will show entries in the database for that port only Adding an Entry into the SDB 1 In the MAC Address field type in the MAC address of the device...

Страница 62: ...so that it carries the data In addition the main port is disabled If a main link has a higher bandwidth than its standby link traffic is automatically switched back to the main link provided no loss of link is detected for two minutes Otherwise you need to manually switch traffic back to the main link When setting up resilient links you should note the following Up to six resilient link pairs can ...

Страница 63: ...nt The port is not present in the cur rent hardware Standby Port ID This field shows the current standby port ID and allows you to enter a new port ID The standby port must be in the same VLAN as the main port Media Type Twisted Pair Fiber This read only field shows the standby port media type Figure 4 14 Port Resilience screen Link State Available Not Available Not Present This read only field sh...

Страница 64: ...pair you must remove cabling from the ports to avoid creating loops in your network configuration Creating a Resilient Link Pair 1 Ensure that the port nominated as the standby port is not physically connected to the unit 2 Ensure both ports have an identical port security mode configuration and that they are members of the same VLAN 3 At the Switch Management screen select the port to be configur...

Страница 65: ...rying traffic Both Failed Although the resilient link pair is correctly configured both links have failed Check for any loose connections or cable damage Unknown The network configuration has changed and the resilient link pair no longer con forms to the rules Not Available The resilient link pair is disabled Figure 4 15 Unit Resilience Summary screen Active Port Main Standby Both Failed This read...

Страница 66: ...plays whether the resilient link pair is currently enabled or disabled You enable or disable a resilient link pair using the Port Resilience screen described in Configuring Resilient Links on page 4 21 OK This button allows you to access the Port Resil ience screen for the current resilient link pair ...

Страница 67: ...s should be sent Community String This field allows you to enter community strings for each remote Network Man ager allowing a very simple method of authentica tion between the Switch and the remote Network Manager The text string can be of 32 characters or less If you want a Network Manager to receive traps generated by the device you must enter the community string of the Network Manager into th...

Страница 68: ...t to Local DCD Control Enabled Disabled This field is only applicable to local connection types It determines if DCD is required for a local connection and whether the connection is closed if DCD is removed Refer to your terminal or modem user documenta tion if you are unsure of the correct setting Figure 4 17 Console Port Setup screen DSR Control Enabled Disabled This field is only applicable to ...

Страница 69: ...et automatically Char Size 8 This read only field displays the charac ter bit data bit size for the Switch You should set your terminal to the same value Parity NONE This read only field displays the parity setting for the Switch You should configure your terminal to the same setting Stop Bit 1 This read only field displays the stop bit setting for the Switch You should configure your terminal to ...

Страница 70: ...t it 1 From the Main Menu select the RESET option The Reset screen is displayed as shown in Figure 4 18 2 Select OK Resetting the Switch in this way is similar to per forming a power off on cycle No setup information is lost CAUTION Performing a reset may cause some of the data being transmitted at that moment to be lost Figure 4 18 Reset screen ...

Страница 71: ...ration is cleared from memory and cannot be recovered After initialization all user information is lost and only default users are available All ports are set to their default values and are therefore enabled and available to all users When initializing the Switch take particular note of the following Network loops occur if you have set up resilient links Before initializing the Switch ensure you ...

Страница 72: ...hrough the console port The download does not work over an ATM link 1 From the Main Menu select the SOFTWARE UPGRADE option The Software Upgrade screen is displayed as shown in Figure 4 20 2 From the Destination field select Switch this is the default Figure 4 20 Software Upgrade screen 3 In the File Name field enter the name of the file that contains the software image to be down loaded to the Sw...

Страница 73: ...ich physically connects them the segments are defined by flexible user groups that you create using software With VLANs you can define your network according to Departmental groups For example you can have one VLAN for the Marketing department another for the Finance department and another for the Development department Hierarchical groups For example you can have one VLAN for directors another fo...

Страница 74: ...quire it or not VLANs increase the efficiency of your network because each VLAN can be set up to contain only those devices which need to communicate with each other How VLANs Provide Extra Security Devices within each VLAN can only communicate with devices in the same VLAN If a device in VLAN 1 needs to communicate with devices in VLAN 2 the traffic must cross a router An Example Figure 5 1 shows...

Страница 75: ...the Switch 3000 10 100 on page 5 8 Connecting VLANs to a Router If the devices of a VLAN need to talk to devices in a different VLAN each VLAN requires a connection to a router Communication between VLANs can only take place if they are all connected to the router A VLAN not connected to a router is an isolated VLAN You need one port for each VLAN connected to the router Connecting Common VLANs Be...

Страница 76: ...port to another the Switch learns the MAC address of the endstation Figure 5 2 Switch learns the endstation s MAC address 2 If the relevant port uses AutoSelect VLAN Mode the Switch refers to the VLAN Server to determine the VLAN membership of the endstation Figure 5 3 Switch refers to the VLAN Server 3 Having obtained the VLAN membership for the end station the Switch places the relevant port in ...

Страница 77: ...refer to Setting Up VLANs Using AutoSelect VLAN Mode on page 5 10 For more information about the VLAN Server data base refer to the documentation supplied with 3Com s Transcend Enterprise Manager Using Non routable Protocols If you are running non routable protocols on your network for example DEC LAT or NET BIOS devices within one VLAN are not be able to commu nicate with devices in a different V...

Страница 78: ... backbone port For more information about backbone ports refer to the SuperStack II Switch 1000 User Guide b Specify that each Switch 1000 port connected to the Switch 3000 10 100 is a VLT port c Specify that each Switch 3000 10 100 port con nected to a Switch 1000 is a VLT port 4 Connect port 1 of the Switch 3000 10 100 to Server 1 5 Connect port 2 of the Switch 3000 10 100 to Server 2 6 Use the ...

Страница 79: ...Virtual LANs VLANs 5 7 Figure 5 5 VLAN configuration with a Switch 3000 10 100 as a basement switch ...

Страница 80: ...tch link which carries traffic for all the VLANs on each Switch For more information about VLTs in general refer to VLANs and the Switch 3000 10 100 on page 5 3 To specify that a port is a VLT port refer to Setting Up the Switch Ports on page 4 12 Figure 5 6 VLAN Setup screen Standby The port is the standby port of a resilient link pair The main port of the pair is displayed in brackets For more i...

Страница 81: ...his button applies any changes to the VLAN database ATM LEC Setup If the port is an ATM OC 3c Module port this button allows you access the VLAN LEC Setup screen for extending your VLANs into an ATM network For more information refer to the SuperStack II Switch ATM OC 3c Module User Guide Assigning a Port to a VLAN When Using Port VLAN Mode 1 In the Port ID field enter the ID of the required port ...

Страница 82: ...f a backup VLAN Server A backup VLAN Server can be used to supply VLAN allocations when the Switch cannot access the main VLAN Server VLAN Server Community String This field allows you to enter a community string for the VLAN Server s The default community string is public Figure 5 7 VLAN Server screen Throttle 0 99999 This field allows you to specify the time delay in milliseconds between the tra...

Страница 83: ...for network traffic and ensure that Redundant paths are disabled when the main paths are operational Redundant paths are enabled if the main paths fail As an example Figure 5 8 on page 5 12 shows a network containing three LAN segments separated by three bridges With this configuration each seg ment can communicate with the others using two paths This configuration creates loops which cause the ne...

Страница 84: ...5 12 CHAPTER 5 ADVANCED MANAGEMENT Figure 5 8 A network configuration that creates loops Figure 5 9 Traffic flowing through Bridges C and A Figure 5 10 Traffic flowing through Bridge B ...

Страница 85: ...has one Designated Bridge Port All traffic destined to pass in the direction of or through the Root Bridge flows through this port The Designated Bridge Port is the port which has the lowest Root Path Cost for the segment The Root Path Cost consists of the path cost of the Root Port of the bridge plus the path costs across all the Root Ports back to the Root Bridge Table 5 1 shows the default path...

Страница 86: ... Path Cost the route through Bridge C and B has a cost of 200 the route through Bridge Y and B has a cost of 300 You can set the path cost of a bridge port to influence the configuration of a net work with a duplicate path Once the network topology is stable all the bridges listen for special Hello BPDUs transmitted from the Root Bridge at regular intervals If the STP Max Age time of a bridge expi...

Страница 87: ...rs a duplicate path and disables one of the links If the enabled link breaks the disabled link becomes re enabled therefore maintaining con nectivity Configuration 2 Redundancy through Meshed Backbone In this configuration four Switch 3000 10 100 units are connected such that there are multiple paths between each one STP discovers the dupli cate paths and disables two of the links If an enabled li...

Страница 88: ...anagement screen is dis played 2 In the Management Level field choose Unit 3 Choose the SETUP button The Unit Setup screen is displayed as shown in Figure 5 13 4 In the Spanning Tree field specify Enable 5 Choose OK You cannot enable STP if you have set up resilient links on any of the Switch ports or if you are using VLAN 16 Figure 5 13 Unit Setup screen ...

Страница 89: ...d allows you to specify the VLAN to be configured If you are using STP you cannot use VLAN 16 Also if you are using AutoSelect VLAN Mode you cannot use VLAN 15 In these cases the relevant VLANs are used internally by the Switch and are therefore not available Figure 5 14 VLAN STP screen Topology Changes This read only field shows the number of network topology changes that have occurred in the cur...

Страница 90: ...ot change the priority of the Switch unless absolutely necessary Bridge Max Age 6 40 This field allows you to specify the time in seconds that the Switch waits before trying to re configure the network when it is the Root Bridge If the Switch has not received a BPDU within the time specified in this field it will try to re configure the STP topology The default set ting for this field is 20 second...

Страница 91: ...te is preparing to forward packets but has temporarily blocked to prevent a loop During the Listening state BPDUs are transmitted received and processed Blocking A port in this state does not forward packets to prevent more than one active path existing on the network The port is included in STP calculations and BPDUs can be transmitted received and processed Figure 5 15 Port STP screen Learning A...

Страница 92: ... or less likely to become the Root Port The lower the number the more likely it is that the port will be the Root Port The default setting for this field is 128 Path Cost 0 65535 This field allows you to spec ify the path cost of the port The Switch automatically assigns the default path costs shown in Table 5 1 on page 5 13 If you spec ify a new path cost in this field this automatic system is di...

Страница 93: ...n for the Remote Monitoring MIB Management Information Base a system defined by the IETF documents RFC 1271 and RFC 1757 which allows you to monitor LANs remotely A typical RMON setup consists of two components The RMON probe An intelligent remotely controlled device or software agent that continually collects statistics about a LAN segment or VLAN and transfers the information to a management wor...

Страница 94: ...arms The Alarms group provides a versatile general mechanism for setting thresholds and sampling intervals to generate events on any RMON variable Both rising and falling thresholds are supported and thresholds can be on the absolute value of a vari able or its delta value In addition alarm thresholds may be autocalibrated or set manually Alarms are used to inform you of a network perfor mance pro...

Страница 95: ... specific criterion or condition Capture The Capture group allows you to create capture buffers on the probe that can be requested and uploaded to the management workstation for decoding and presentation Events The Events group provides you with the ability to create entries in an event log and or send SNMP traps to the management workstation Events can originate from a crossed threshold on any RM...

Страница 96: ...iver information before problems occur This means that you can take action before they impact on users In addition probes record the behavior of your network so that you can analyze the causes of problems How RMON Reduces the Traffic Load Traditional network management involves a man agement workstation polling network devices at regular intervals to gather statistics and identify problems or tren...

Страница 97: ...ttached to a non secure port Implementing RMON in the Switch means all ports can have security features enabled RMON Features of the Switch Table 5 2 details the RMON support provided by the Switch Table 5 2 RMON support supplied by the Switch RMON Group Support supplied by the Switch Statistics A new or initialized Switch has one Statistics ses sion per port VLAN History A new or initialized Swit...

Страница 98: ... can specify that a Hosts session is defined on the Default VLAN for more information refer to Setting Up the Switch Unit on page 4 9 Hosts Top N Although Hosts Top N is supported by the Switch there are no Hosts Top N sessions defined on a new or initialized Switch Matrix Although Matrix is supported by the Switch there are no Matrix sessions defined on a new or initialized Switch by default You ...

Страница 99: ...ort Block broadcast and mul ticast traffic on the port for 5 seconds Disable port Turn port off Enable port Turn port on Notify and move resilient port Send Trap If port is the main port of a resilient link pair then move to standby Notify and blip device Send Trap Block broad cast and multicast traffic on all ports for 5 seconds Notify and disable device Send trap Turn all ports on device off Not...

Страница 100: ...ss level using an SNMP Network Manager Each entry in the log contains information in the fol lowing order Entry number Timestamp User ID Item ID including qualifier New value of item There is a limit of 16 records on the number of changes stored The oldest records are overwritten first Table 5 4 Initial settings for the default alarms Statistic High Threshold Low ThresholdR ecovery Samples per Ave...

Страница 101: ...reens for the Switch and advises you on actions to take if you see unexpected values for the statistics Please note however that as all networks are different any actions listed are only suggestions Viewing statistics on a regular basis allows you to see how well your network is performing If you keep simple daily records you will see trends emerg ing and notice problems arising before they cause ...

Страница 102: ...al number of frames successfully transmitted by the current port FRAMES FORWARDED Displays the total number of frames that were received by the current port and forwarded to other ports FRAMES FILTERED Displays the total number of frames that were filtered because the destination station was on the same segment port as the source station Figure 6 1 Summary Statistics screen MULTI BROADCAST RX Disp...

Страница 103: ...raffic level of the network A high utiliza tion for single endstation segments is an indication that your network is operating efficiently However if multiple endstations are connected to this port and you see values of around 40 you should reconsider the topology of your network because each user will see degraded network performance Figure 6 2 Port Statistics screen Frames Forwarded This counter...

Страница 104: ...6 4 CHAPTER 6 STATUS MONITORING AND STATISTICS TRAFFIC STATISTICS Select this button to access traffic counters for the port ERROR ANALYSIS Select this button to access error counters for the port ...

Страница 105: ...ry Octets Transmitted The number of octets transmit ted by the port The calculation includes the MAC header and CRC but excludes preamble SFD Octet counters are accurate to the nearest 256 octet boundary Figure 6 3 Port Traffic Statistics screen Multicasts Received The number of frames suc cessfully received that have a multicast destination address This does not include frames directed to a broad...

Страница 106: ...bbers The value shown should be a very small proportion of the total data traffic IFM Count The number of times Intelligent Flow Management IFM has had to operate to minimize packet loss Frame Size Analysis The number of frames of a specified length as a percentage of the total number of frames of between 64 and 1518 octets This indi cates the composition of frames on the network The frame size ra...

Страница 107: ...ion is less than the short event maximum time Short events are error frames smaller than the minimum size defined for Ethernet frames They may indicate externally generated noise causing problems on the network Check the cabling routing and re route any cabling which may be affected by external noise sources Figure 6 4 Port Error Analysis screen Late Events This counter is incremented by one each ...

Страница 108: ...ect this button to set all counters shown on the screen to zero It is useful for trend analysis if you wish to see changes in counters over a short period of time This button does not clear the counters on the device or affect counters at the network management workstation ...

Страница 109: ...nstalled or initial ized either power on manual reset or a watchdog expiry Last Reset Type Other Command Watchdog Power reset System error This field indicates the cause of the last reset It may be due to manage ment command watchdog timeout expiry power interruption a manual reset or a system error Hardware Version The hardware version number of the Switch Upgradable Software Version The version ...

Страница 110: ...e FAULT LOG button The Fault Log is screen is displayed as shown in Figure 6 6 The Fault Log screen shows the following Reset Count The number of resets recorded at the time of the fault Time seconds The time elapsed since the last reset when the fault occurred Area This information may be used for fault diagno sis by your technical support representative Fault Number The hexadecimal number in thi...

Страница 111: ...rom the Main Menu select Remote Poll The Remote Poll screen is displayed as shown in Figure 6 7 2 In the Target Address field enter the IP or IPX address of the device you want to poll 3 Select the POLL button at the foot of the screen When the poll is complete the Round Trip Time field shows the interval in milliseconds between sending the frame to the target device and receiving a response at th...

Страница 112: ...6 12 CHAPTER 6 STATUS MONITORING AND STATISTICS ...

Страница 113: ...ts This unit must be Earthed Connect the unit to an Earthed power supply to ensure compliance with European safety stan dards The power cord set must be approved for the country where it will be used The appliance coupler that is the connector to the device itself and not the wall plug must have a configuration for mating with an EN60320 IEC320 appliance inlet For U S A and Canada The cord set mus...

Страница 114: ...equipment to which it is connected is also opera tional under SELV The unit should never be connected to an A C outlet power supply without an Earth Ground connection To comply with European safety standards a spare fuse must not be fitted to the appliance inlet Only fuses of the same manufacturer make and type should be used with the unit Ensure that the power supply lead is discon nected before ...

Страница 115: ...nly 5A Time Delay anti surge fuses of the same type and manufacture as the original should be used Sockets for Redundant Power System RPS Only connect a 3Com Redundant Power System to this socket For details follow the installation instructions in the manuals accompanying the Redundant Power System RJ45 Ports WARNING The RJ45 ports are shielded RJ45 data sockets They cannot be used as telephone so...

Страница 116: ...vec une admission d appareil EN60320 IEC320 Pour U S A et le Canada Le cordon surmoulé doit être UL Certifié et CSA Certifié Les spécifications minimales pour le cordon souple sont No 18 AWG Type SV ou SJ 3 conducteur Le cordon surmoulé doit avoir une capacité de courant calculée au moins de 10A La fiche de fixation doit être un type mis à la terre avec une configuration NEMA 5 15P 15A 125V ou NEM...

Страница 117: ...étiqueté Neutre branché directement à la Terre à la Masse Ne pas enlever le Plug in Module ou la plaque d occultation de module d émetteur récepteur avec la puissance encore branchée La Source de Courant et Le Fusible L unité s ajuste automatiquement à la tension d ali mentation Le fusible est convenable aux deux opérations 110 V C A et 220 240 V C A AVERTISSEMENT Assurer que l alimentation soit d...

Страница 118: ...ne l alimentation multiple Les Ports RJ45 AVERTISSEMENT Ceux ci sont les prises de courant de données RJ45 protégées Ils ne peuvent pas être utilisés comme prises de courant télépho niques Brancher seulement les connecteurs RJ45 de données à ces prises de courant Les câbles de données blindés ou non blindés avec les jacks blindés ou non blindés l un ou l autre peuvent être branchés à ces prises de...

Страница 119: ...en satz zum Wandstecker muß in den EN60320 IEC320 Zuführungsstecker am Gerät passen Es ist wichtig daß der Netzstecker sich in unmit telbarer Nähe zum Gerät befindet und leicht erre ichbar ist Das Gerät kann nur durch Herausziehen des Verbindungssteckers aus der Steckdose vom Stromnetz getrennt werden Das Gerät wird mit Sicherheits Kleinspannung nach IEC 950 SELV Safety Extra Low Voltage betrieben...

Страница 120: ... die Originalsicherung ersetzen Sicherung auswech seln und die Klappe der Sicherungshalterung wieder schließen Steckdose für Redundant Power System RPS Nur ein 3Com Redundant Power System an diese Steckdose anschließen Für weitere Angaben die genauen Einbauanweisungen im Handbuch zum Redundant Power System befolgen RJ45 Anschlußen WARNUNG Hierbei handelt es sich um abge schirmte RJ45 Datenbuchsen ...

Страница 121: ...ty Switch Management Monitor Manager Security Port STP Monitor read only Manager Security Port Statistics Monitor Manager Security Port Traffic Statistics Monitor Manager Security Port Error Analysis Monitor Manager Security Port Resilience Monitor Manager Security Port Setup Monitor read only Manager Security Unit Statistics Monitor Manager Security Unit Database View Monitor Manager Security Uni...

Страница 122: ...ity Create User Security Delete Users Security Edit User Monitor Manager Security Status Monitor Manager Security Fault Log Monitor Manager Security Management Setup Monitor read only Manager Security Screen Available to Trap Setup Monitor read only Manager Security Console Port Setup Monitor read only Manager Security Software Upgrade Security Initialize Security Reset Manager Security Remote Pol...

Страница 123: ...ng the Plug in Module ensuring that it is properly seated If the problem persists contact your supplier for advice The Plug in Module Status LED lights yellow If the MGMT LED is flashing yellow the Module has failed its Power On Self Test refer to the previ ous advice Otherwise the Module s agent software is not installed correctly Refer to the User Guide supplied with the Module The Plug in Modul...

Страница 124: ... cannot access the device Check that the device s IP address subnet mask and default router are correctly configured and that the device has been reset Check that the device s IP address is correctly recorded by the SNMP Network Manager refer to the user documentation for the Network Manager The Telnet workstation cannot access the device Check the device s IP address subnet mask and default route...

Страница 125: ...ords to the initial values In the case where no one knows a password for a security level user contact your supplier Using the Switch You see network problems and the Packet LED is on continuously with constant collisions refer to Port Traffic Statistics on page 6 5 You are using PACE equipped devices and have the Interactive Access feature of PACE enabled at both ends of the link Interactive Acce...

Страница 126: ...o Configuring the STP Parameters of Ports on page 5 19 2 Specify that the endstation entries are Non ageing refer to Setting Up the Switch Database SDB on page 4 17 3 Consider disabling STP on the Switch and using resilient links to provide network resilience refer to Enabling STP on the Switch on page 5 16 and Setting Up Resilient Links on page 4 20 You are trying to manage the Switch over a netw...

Страница 127: ... late events on the port refer to Port Error Analysis on page 6 7 The port connected to the Switch 3000 10 100 port is not auto negotiating and is operating in full duplex If you want the link to operate in full duplex set the Switch 3000 10 100 port to operate in full duplex If you want the link to operate in half duplex set the port on the other end of the link to operate in half duplex ...

Страница 128: ...C 6 APPENDIX C TROUBLE SHOOTING ...

Страница 129: ...D PIN OUTS Null Modem Cable 9 pin to RS 232 25 pin PC AT Serial Cable 9 pin to 9 pin ...

Страница 130: ...D 2 APPENDIX D PIN OUTS Modem Cable 9 pin to RS 232 25 pin RJ45 Pin Assignments ...

Страница 131: ...ay Fuse Electromagnetic Compatibility EN55022 Class B FCC Part 15 Subpart B Class A ICES 003 Class A VCCI Class 2 AS NZS 3548 Class B EN50082 1 Category 5 screened cables must be used to ensure compliance with the Class B Class 2 require ments of this standard The use of unscreened cables category 3 or 5 for 10BASE T ports or cate gory 5 for 100BASE TX ports complies with the Class A Class 1 requi...

Страница 132: ...ocol RFC 1157 MIB II RFC 1213 Bridge MIB RFC 1286 Repeater MIB RFC 1516 VLAN MIB RFC 1573 RMON MIB RFC 1271 and RFC 1757 Terminal Emulation Telnet RFC 854 Protocols Used for Administration UDP RFC 768 IP RFC 791 ICMP RFC 792 TCP RFC 793 ARP RFC 826 TFTP RFC 783 BOOTP RFC 951 ...

Страница 133: ... features news and information about 3Com products customer service and support 3Com Corporation s latest news releases NetAge Magazine technical documentation and more 3Com Bulletin Board Service 3ComBBS contains patches software and drivers for all 3Com products as well as technical articles This service is available via modem or ISDN 24 hours a day 7 days a week Access by Analog Modem To reach ...

Страница 134: ...atches software drivers and technical articles about all 3Com products as well as a messaging section for peer support To use 3ComForum you need a CompuServe account To use 3ComForum 1 Log on to your CompuServe account 2 Type go threecom 3 Press Return to see the 3ComForum main menu Taiwan up to 14400 bps 886 2 377 5840 U K up to 28800 bps 44 1442 438278 U S A up to 28800 bps 1 408 980 8204 Countr...

Страница 135: ...are available from 3Com Contact your local 3Com sales office to find your authorized service provider using one of these numbers Regional Sales Office Telephone Number 3Com Corporation U S 3Com ANZA East West 3Com Asia Limited P R of China Hong Kong India Indonesia Korea Malaysia Singapore Taiwan R O C Thailand 3Com Benelux B V Belgium Netherlands 3Com Canada Calgary Montreal Ottawa Toronto Vancou...

Страница 136: ...taly 3Com Middle East 3Com Nordic AB Denmark Finland Norway Sweden 3Com Russia 3Com South Africa 3Com U K Limited 54 1 312 3266 55 11 546 0869 56 2 633 9242 57 1 629 4110 52 5 520 7841 51 1 221 5399 58 2 953 8122 39 2 253011 Milan 39 6 5279941 Rome 971 4 349049 45 39 27 85 00 358 0 435 420 67 47 22 18 40 03 46 8 632 56 00 007 095 2580940 27 11 807 4397 44 131 2478558 Edinburgh 44 161 8737717 Manch...

Страница 137: ... 100BASE TX port to be set auto matically by detecting the speed and Duplex Mode of the port at the other end of the link backbone The part of a network used as the primary path for transporting traffic between network segments bandwidth Information capacity measured in bits per second that a channel can transmit The bandwidth of Ethernet is 10Mbps the bandwidth of Fast Ether net is 100Mbps baud r...

Страница 138: ...data center switching The point of aggregation within a corporate net work where a switch provides high performance access to server farms a high speed backbone con nection and a control point for network manage ment and security Ethernet A LAN specification developed jointly by Xerox Intel and Digital Equipment Corporation Ethernet networks operate at 10Mbps using CSMA CD to run over cabling Fast...

Страница 139: ...hrough twisted pair cabling MDI to MDI and MDIX to MDIX links use cross over twisted pair cabling MIB Management Information Base Stores a device s management characteristics and parameters MIBs are used by the Simple Network Management Proto col SNMP to contain attributes of their managed systems The Switch contains its own internal MIB multicast Single packets copied to a specific subset of net ...

Страница 140: ... work SNMP Simple Network Management Protocol A protocol originally designed to be used in managing TCP IP internets SNMP is presently implemented on a wide range of computers and networking equip ment and may be used to manage many aspects of network and endstation operation Spanning Tree Protocol STP A bridge based system for providing fault tolerance on networks STP works by allowing you to imp...

Страница 141: ...upgrades from a remote device using your Switch s local management capa bilities Transcend 3Com s umbrella management system used to manage all of 3Com s networking solutions UDP User Datagram Protocol An Internet standard proto col that allows an application program on one device to send a datagram to an application pro gram on another device VLAN Virtual LAN A group of location and topol ogy ind...

Страница 142: ...6 GLOSSARY ...

Страница 143: ... field 5 18 Bridge Priority field 5 18 Bridge Protocol Data Units 5 13 Broadcast Storm Control field 4 15 Bulletin Board Service F 1 C cable maximum length 1 2 2 2 pin outs D 1 Capture RMON group 5 23 5 26 Char Size field 4 27 Community String field 4 3 4 5 4 25 community strings changing 4 5 entering 4 3 role in trap setup 4 25 CompuServe F 2 Confirm Password field 4 5 Connection Type field 4 26 ...

Страница 144: ... 10 BOOTP Select 3 10 Bridge Forward Delay 5 18 Bridge Hello Time 5 18 Bridge Max Age 5 18 Bridge Priority 5 18 Broadcast Storm Control 4 15 Char Size 4 27 Community String 4 3 4 5 4 25 Confirm Password 4 5 Connnection Type 4 26 Data Link Protocol 3 10 Database Entries 4 18 DCD Control 4 26 Default RMON Host Matrix 4 11 Default Router 3 10 Designated Bridge 5 20 Designated Cost 5 20 Designated Por...

Страница 145: ... 3 2 of the unit 3 10 IP or IPX Address field 4 25 IPX configuring parameters 3 9 protocol 1 12 IPX address allocation 1 12 IPX Network field 3 10 K keyboard shortcuts 3 5 L LEDs 1 8 line speed 4 27 Link State field 4 12 4 21 link state resilient 4 21 Local Security screen 4 6 logging off 3 12 logging on 3 7 Logon screen 3 7 Lost Links field 4 12 M MAC address entering into the Switch Database 4 1...

Страница 146: ... Remote Poll screen 6 11 remote polling 6 11 reset button 1 10 Reset screen 4 28 resets number of 6 9 time since last 6 9 type 6 9 resetting the Switch 4 28 resilient link pair 4 20 resilient links 1 3 configuring 4 21 creating 4 22 deleting 4 22 rules 4 20 setting up 4 20 viewing 4 23 returning products for repair F 4 Rising Action field 4 15 Rising Threshold field 4 15 RMON alarm actions 5 27 be...

Страница 147: ...STP State field 5 19 subnet mask of the unit 3 10 Summary Statistics screen 6 2 Switch 3000 10 100 configuration examples 1 5 dimensions E 1 features 1 1 front view 1 7 initializing 4 29 installing 2 4 introduction 1 1 LEDs 1 8 logging off 3 12 logging on 3 7 management setup 3 9 port setup 4 12 positioning 2 1 rack mounting 2 4 rear view 1 9 resetting 4 28 size E 1 stacking with other units 2 4 u...

Страница 148: ...LAN Server 5 4 specifying information 5 10 VLAN Server Community String field 5 10 VLAN Server IP Address field 5 10 VLAN Server screen 5 10 VLAN Setup screen 5 8 VLAN STP screen 5 17 VLANs 1 3 5 1 assigning ports 5 9 AutoSelect VLAN Mode 5 4 Default 5 3 extending into an ATM network 5 5 Port VLAN Mode 5 4 setting up 5 8 using non routable protocols limitation for VLAN based networks 5 5 using uni...

Страница 149: ...ithin the warranty period Products returned to 3Com s Corporate Service Center must be pre authorized by 3Com with a Return Material Authorization RMA number marked on the outside of the package and sent prepaid insured and packaged appropriately for safe shipment The repaired or replaced item will be shipped to Customer at 3Com s expense not later than thirty 30 days after receipt of the defectiv...

Страница 150: ...ception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient the receiving antenna Relocate the equipment with respect to the receiver Move the equipment away from the receiver Plug the equipment into a different outlet so that equipment and receiver are on different branch circuits I...

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