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DUA1840-0AAA01

 

Port Statistics

 

5-5

 

Frames Forwarded

 

 This counter provides a running average of the 

 

proportion of the received frames that are forwarded and is expressed 

 

as a percentage of all received frames. A sampling period of 1 minute is 

 

used.

 

Broadcast Frame Bandwidth

 

 This counter provides a running average 

 

of the Broadcast frame bandwidth in use and is expressed as a 

 

percentage of a theoretical maximum bandwidth. A sampling period of 

 

5 seconds is used. 

 

Error Frames

 

 This counter provides a running average of the number 

 

of errors per 10,000 frames received and is expressed as a percentage. 

 

See the field description for Errors on 

 

page 5-7

 

.

 

TRAFFIC STATISTICS

 

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ERROR ANALYSIS

 

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Summary of Contents for MSH 1005

Page 1: ... MSH SWITCH 1005 USER GUIDE Part No DUA1840 0AAA01 Published June 1996 ...

Page 2: ...hts in Technical Data and Computer Software clause at 48 C F R 52 227 7013 3Com Ireland c o Isolan House Brindley Way London Road Hemel Hempstead Herts HP3 9XJ 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...

Page 3: ...tions 1 3 10BASE T Switch Ports 1 3 Internal Switch Ports 1 3 Transceiver Module Ports 1 4 The Backbone Port 1 4 Adding an Expansion Module 1 4 Switch Operation and Features 1 5 How the Switch Compares to a Bridge 1 5 Forwarding of Packets 1 5 Intelligent Flow Management 1 7 Full Duplex 1 8 Security 1 8 Resilient Links 1 8 Virtual LANs VLANs 1 8 PACE 1 9 MSH Switch 1005 on Your Network 1 11 Server...

Page 4: ...MSH Switch 1005 for Management 1 21 2 INSTALLATION AND INITIAL SETUP Safety Information 2 1 Pre installation Configuration 2 2 Setting the Links on the Switch 1005 2 2 Advice for Setting Backplane Connections and Avoiding Loops 2 4 Fitting a Transceiver Module 2 5 Fitting an Expansion Module 2 5 Switch 1005 Installation and Removal 2 6 Installing the Switch 1005 2 6 Removing the Switch 1005 2 7 Op...

Page 5: ...3 4 Port Setup 3 7 Specifying the Backbone Port 3 11 The Switch Database SDB 3 12 Configuring the Switch Database 3 14 Searching the Switch Database 3 15 By MAC Address 3 15 By Port 3 15 Adding an Entry into the SDB 3 16 Deleting an Entry from the SDB 3 16 Resilient Links 3 17 Viewing Resilient Setup 3 18 Configuring Resilient Links 3 20 Creating a Resilient Link 3 22 Deleting a Resilient Link 3 2...

Page 6: ...ons 4 6 Example 1 4 6 Example 2 4 8 Example 3 4 10 Setting Up VLANs on the Switch 4 12 Assigning a Port to a VLAN 4 15 Specifying a Backbone Port 4 15 Specifying that a Backbone Port is Part of a VLT 4 15 5 STATUS MONITORING AND STATISTICS Summary Statistics 5 2 Port Statistics 5 4 Port Traffic Statistics 5 6 Port Error Analysis 5 9 Status Monitoring 5 11 Remote Polling 5 13 6 PROBLEM SOLVING Spot...

Page 7: ...ces C 1 3Com Bulletin Board Service C 1 Access by Modem C 1 Access by ISDN C 2 World Wide Web Site C 2 3ComForum on CompuServe C 3 3ComFacts Automated Fax Service C 3 Support from Your Network Supplier C 4 Support from 3Com C 5 Returning Products for Repair C 6 GLOSSARY INDEX LIMITED WARRANTY ...

Page 8: ......

Page 9: ...information a brief overview of the installation process and a complete guide the initial setup required Chapter 2 Information and steps telling you how you can manage the Switch 1005 using the VT100 screens Chapter 3 Information on the more advanced functionality you can manage using the VT100 screens Chapter 4 Details on viewing Switch 1005 statistics using the VT100 screens Chapter 5 Ideas on s...

Page 10: ...g then press the Return or Enter key Do not press the Return or Enter key when an instruction simply says type Text represented as screen display This typeface is used to represent displays that appear on your terminal screen for example NetLogin Text represented as commands This typeface is used to represent commands that you enter for example SETDefault 0 IP NETaddr 0 0 0 0 Keys When specific ke...

Page 11: ... intended to answer all your questions concerning the MSH While using the MSH Switch 1005 you may need to refer to the following publications LinkBuilder MSH User Guide part number DUA1800 0AAA0x LinkBuilder MSH Management Module User Guide part number DUA1850 0AAA0x ...

Page 12: ...4 ABOUT THIS GUIDE ...

Page 13: ... limits of a repeater and provide your users with greater bandwidth faster throughput and high speed connections The MSH Switch 1005 is an intelligent module with its own on board management agent This means that even in an unmanaged MSH chassis you can access the manageable features of the Switch using a Telnet application or an SNMP Network Manager and configure internal port connections using t...

Page 14: ...rward mode No runts in fragment free mode No runts errors in store and forward mode Low latency or no runts errors in intelligent mode Intelligent Flow Management when packet buffers are full Prevents packets being discarded Suppresses transmissions at source Full duplex on Fast Ethernet Transceiver Modules Security Resilient Links Port based Virtual LANs VLANs Support for up to 16 VLANs on a sing...

Page 15: ... on the front panel of the Switch 1005 internal backplane connections provide an additional four switch ports These ports are enabled and disabled through management or using the set of links LK1 to LK5 located on the Switch 1005 Three of these ports provide switched connections to the three 10Mbps repeater backplanes located in the MSH chassis and therefore to any modules connected to the same ba...

Page 16: ...all a Switch 1005 into your MSH chassis it will configure its backbone port to be the first Fast Ethernet port it finds either on the Switch or on the Expansion Module if fitted You can change your designated backbone port to be any switch port internal or external Changing the default backbone port is described in Specifying the Backbone Port in Chapter 3 You can only have one backbone port per S...

Page 17: ...e Store and forward Fast Forward Fragment Free Store and Forward or Intelligent Operation when packet buffers full Discard packets Invoke Intelligent Flow Management to suppress transmissions at source Spanning Tree Supported Not supported Action on Unknown Destination Address Flood all ports Forward to backbone port only Database size Variable 500 addresses Packet Source Destination Address Actio...

Page 18: ...their destination The forwarding delay for this mode varies between 64µs and 1 2ms depending on frame length In Store and Forward mode latency is measured as the time between receiving the last bit of the frame and transmitting the first bit For the Switch 1005 this is 8µs Intelligent In this mode the Switch 1005 monitors the amount of error traffic on the network and changes the forwarding mode a...

Page 19: ...sage This can take as long as 30 seconds and depending on the protocol you are running may not happen until many packets have been sent The transmitting device then has to retransmit the packets effectively wasting bandwidth Switch modules implementing IFM are aware of congestion and prevent packet loss by inhibiting the transmitting device from transmitting the packet in the first place It does t...

Page 20: ... different address is then seen on that port the port will be disabled Until security is disabled no other address can be learned Resilient Links The Resilient Link feature in the Switch 1005 enables you to protect critical links and prevent wasteful network downtime should that link fail Setting up resilience ensures that should a main communication link fail a standby duplicate link will immedia...

Page 21: ...s to communicate with devices in VLAN 2 it must be configured to cross the router between them Further information can be found in Chapter 4 PACE PACE Priority Access Control Enabled technology allows multimedia applications using voice and video traffic to be carried over standard Ethernet and Fast Ethernet Local Area Networks LANs PACE provides the quality of service that these applications requ...

Page 22: ...AA01 1 10 CHAPTER 1 GETTING STARTED You can enable PACE on the whole Switch 1005 module or on an individual port Before configuring PACE you should refer to sections Switch 1005 Setup and Port Setup in Chapter 3 ...

Page 23: ...is not possible connect the local server to a dedicated 10Mbps port If that s not possible and the local server is connected to a repeated segment where the traffic is mainly local to that segment disable Intelligent Flow Management IFM on the port to which the repeater is connected Whenever you have multiple workstations connected to a single port of the Switch 1005 we recommend that you disable ...

Page 24: ...TTING STARTED Figure 1 1 Workgroup Switch I Figure 1 1 shows how the Switch 1005 fits into a large corporate network with a Fast Ethernet infrastructure A Switch is positioned on each floor and servers are centralized in the basement ...

Page 25: ... Figure 1 2 Workgroup Switch II Figure 1 2 shows the Switch 1005 in a second workgroup situation This setup could be that of a small office within a large corporation or part of a larger corporate network Each switch port has mainly muliple end stations ...

Page 26: ...esktop Switch Figure 1 3 shows the Switch 1005 used for a group of heavy traffic users in a large corporate network Here switching is brought to the desktop with a single end station per switch port Local servers are connected via a 100Mbps Fast Ethernet link ...

Page 27: ...ologies 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 desktops Configuration Rules with Full Duplex The MSH Switch 1005 provides full duplex support for any Fast Ethernet Transceiver Modules that are installed Full duplex allows frames to be ...

Page 28: ...DUA1840 0AAA01 1 16 CHAPTER 1 GETTING STARTED Switch Overview Front Panel Figure 1 4 Switch 1005 front view ...

Page 29: ...nternal Ethernet 10Mbps backplanes are enabled All three internal Ethernet backplanes are disabled There is network activity on the enabled backplane s Connection to the internal Fast Ethernet 100Mbps backplane is enabled Connection to the internal Fast Ethernet 100Mbps backplane is disabled There is network activity on the Fast Ethernet backplane 1 12 External port status Green Green flash Yellow...

Page 30: ...nnection to for example your network infrastructure Use 62 5 125 micron fiber optic cable with SC connectors The maximum supported distance is 412m 1352ft or 2km 6562ft if the devices at both ends of the link support full duplex 4 Port 10BASE T Transceiver Module 3C18409 Adds an additional four 10BASE T ports to your Switch 1005 with the same operating conditions as the eight fixed ports described...

Page 31: ... View Figure 1 5 Switch 1005 PCB view Transceiver Module Connector 1 2x20 pin connector for any of the Transceiver Modules listed in Transceiver Module slot on page 1 18 Installation of the Transceiver Modules is described in the documentation that accompanies them ...

Page 32: ...These connectors engage with the backplane located in the MSH chassis Switch Defaults The following table shows factory defaults for the MSH Switch 1005 Port Status Enabled Forwarding Mode Fast Forward Intelligent Flow Management IFM Enabled on external ports Disabled on internal ports PACE Disabled module VLANs All ports in the Default VLAN VLAN 1 Power On Self Test POST Normal RMON 1 Ethernet St...

Page 33: ...Network Manager can communicate with the device To do this perform the following steps 1 Ensure your MSH Management Module is running v4 2 or higher of the management agent software 2 Connect a terminal to the serial port located on the MSH front panel You can find instructions for doing this in the LinkBuilder MSH Management Module User Guide part number DUA1850 0AAA0x 3 Press Return one or more ...

Page 34: ...ter 2 8 If you need the Switch to send SNMP traps to the network manager you may need to setup the address of the network manager in the Trap Table See Setting Up Traps in Chapter 3 3Com Network Managers such as Transcend WorkGroup Manager for Windows may automatically configure intelligent modules to send traps to them Please read the documentation supplied with your network management software 9...

Page 35: ...equipment to which it is connected is also operational under SELV The MSH chassis must be earthed Switch 1005 modules can easily be damaged by static Do not remove the Switch 1005 from its anti static packaging until you are ready to install it into the MSH chassis Do not touch the pins leads connections or any components on the Switch 1005 Always handle the Switch 1005 by its edges only Always we...

Page 36: ...s that must be carried out prior to installation include Setting links located on the Switch 1005 Fitting a Transceiver Module if required Fitting an Expansion Module if required Setting the Links on the Switch 1005 Five links located on the Switch 1005 allow you to set up its backplane connections The links are located on the Switch 1005 PCB as shown in Figure 2 1 Figure 2 1 Locating links LK1 LK...

Page 37: ... Setting LK1 LK5 for internal port connections Position and Link Number Connection Provided LK1 ENABLED LK2 ENABLED LK3 ENABLED Switch port 25 connected to 10Mbps Ethernet backplane E1 Switch port 26 connected to 10Mbps Ethernet backplane E2 Switch port 27 connected to 10Mbps Ethernet backplane E3 LK1 LK2 LK3 DISABLED None LK4 DISABLED LK5 DISABLED Switch port 28 disabled LK4 DISABLED LK5 ENABLED ...

Page 38: ...s on the backplane E1 destined for an end station on backplane E2 both Switch modules will independently switch the packet onto E2 resulting in duplication Packets with broadcast destination addresses will loop continuously between the two Switch modules You can avoid this situation by following these guidelines If all ports on your network are in the same VLAN you should connect all Switch 1005 m...

Page 39: ...BASE T Transceiver Modules with all backplane connections enabled Ethernet backplane E3 port 27 will automatically disable and you will lose the ability to configure it Removing one of the Transceiver Modules will reinstate port 27 Fitting an Expansion Module Fitting an Expansion Module allows you to increase the number of ports for your Switch 1005 you should fit it to the Switch 1005 before inst...

Page 40: ...f the MSH chassis and lift the bar away from the chassis 3 Undo the screws from the blanking plate of the slot of your choice Keep the blanking plate in a safe place If you remove the Switch 1005 you must cover any open slot with a blanking plate to maintain the circulation of cooling air and prevent the entry of dust and debris into the MSH 4 Holding the Switch 1005 by the front panel insert it i...

Page 41: ...ted slot immediately cover with a blanking plate 4 Replace the locking bar and secure with the screws removed earlier Operation after Power up In an Unmanaged System The links LK1 to LK5 are used to set the Switch s backplane connections in an unmanaged MSH chassis These settings are used when the MSH chassis containing the Switch is first powered up Subsequent changes made to the settings directl...

Page 42: ...anagement Module derives default backplane settings that are different from the set on the Switch 1005 If the Management Module has no stored configuration data for the Switch 1005 it will apply the following default backplane settings the first Switch 1005 detected in the chassis will have all backplane ports enabled subsequent Switch 1005 modules will have only the Fast Ethernet backplane enable...

Page 43: ...ities You can find further information on connecting equipment to the MSH serial port in the user documentation that accompanies the MSH Management Module Using the VT100 Interface The menu driven interface built into the Switch 1005 is known as the VT100 or Local Management interface This interface gives a forms based structure with pre defined security levels enabling access to be restricted to ...

Page 44: ...ly type in a new value for this field the default entry will be 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 select one or more items from...

Page 45: ...o the next field on a form after you have made changes to the data in a field Left Arrow move to the previous field on the screen or the next charac ter in an editable field Right Arrow move to the next field on the screen or the previous charac ter in an editable field Ctrl R refresh the screen Ctrl B move the cursor to the next Button Ctrl P abort the current screen and return to the previous sc...

Page 46: ...ection to a Telnet session is lost inadvertently the connection is closed by the Switch 1005 after 2 to 3 minutes of inactivity Using an SNMP Network Manager Once you have set up the IP parameters of the Switch 1005 you can use any SNMP Network Manager for in band management provided the Management Information Base MIB is correctly installed at your network management station 3Com provides the Tra...

Page 47: ...ce 2 13 Accessing the Switch 1005 VT100 Interface The following sections explain how to access the VT100 management screens for the Switch 1005 You may find it useful to refer to Figure 2 2 when locating the screens you require Figure 2 2 VT100 screen map ...

Page 48: ...er Main Menu From the list of options select SERVICE SELECTION 3 From the list of services available for this MSH select Switch 1005 the LinkBuilder MSH Address Table appears Choose the Switch 1005 you wish to setup and select the MANAGE button The Switch Main Banner screen appears 4 From the Switch 1005 Main Banner screen press Return to display the Logon screen shown in Figure 2 3 5 Enter your u...

Page 49: ...d a user name access level and password enter those details After Logging On When you have successfully logged on to the Switch 1005 the Main Menu appears as shown in Figure 2 4 Figure 2 4 Switch 1005 Main Menu Table 2 4 Default Users User Name Default Password Access Level monitor monitor monitor this user can view but not change a subset of the manageable parameters manager manager manager this ...

Page 50: ...ing the management facility for the first time we suggest that you Assign a new password for the security access level as described in Editing User Details on page 2 23 Assign new passwords for the other default users as described in Editing User Details on page 2 23 Set up user names and passwords for any other users and assign each user an appropriate security level as described in Creating a Ne...

Page 51: ...the Setup screen from the Switch Main Menu screen select the MANAGEMENT SETUP option The Setup screen appears as shown in Figure 2 5 Figure 2 5 Switch Management Setup screen The screen shows the following MAC Address The Switch 1005 MAC address required for management Power On Self Test POST Type Normal Extended Use this field to determine the type of self test that the Switch 1005 carries out wh...

Page 52: ...005 BOOTP Select Enabled Disabled If BOOTP is enabled and you have a BOOTP server on your network an IP address will be automatically mapped to the Switch when it is first powered up In addition to mapping an IP address BOOTP can assign the subnet mask and default router Using a BOOTP server avoids having to configure devices individually There are four entries under the following four fields one ...

Page 53: ...on the VT100 interface If you do not press any keys for three minutes the management facility will warn you that the inactivity timer is about to expire If you do not press a key within 10 seconds the timer will expire and the screen will be locked any displayed statistics will continue to be updated When you next press a key the display changes to the Auto Logout screen shown in Figure 2 6 Figure...

Page 54: ...2 20 CHAPTER 2 INSTALLATION AND INITIAL SETUP If you connected to the Switch 1005 via the MSH Management Module screens the LinkBuilder MSH Address Table screen is displayed once you have entered the correct password ...

Page 55: ...ou can access LOCAL SECURITY screen Lets you set up access levels for users on the Switch 1005 CREATE USER screen In addition to the default users set up on the Switch 1005 you can add up to ten new users DELETE USERS screen Lets you delete users from the Switch 1005 The default users cannot be deleted EDIT USER screen Lets you change your own password and community string You cannot change detail...

Page 56: ...completed select OK The Create User screen shows the following fields User Name Type in the name of this new user The name can consist of up to 10 characters and is case sensitive Password Type in the password for this new user The password can consist of up to 10 characters and is case sensitive For security reasons the password is not displayed on screen Access Level Assign an access level for t...

Page 57: ... The community string is only needed for SNMP access If you are using a remote SNMP network manager the community string specified in the Network Manager s database must be the same as that for the device Deleting a User These steps assume the User Access Levels screen is displayed 1 Select the DELETE USER option The Delete Users screen appears as shown in Figure 2 9 Figure 2 9 Delete Users screen...

Page 58: ...ng fields User Name This read only field shows the name of the user This field cannot be changed if you need to change the user name you must delete this user and create a new one Old Password Type in the old password for this user New Password Type in a new password for this user Confirm Password Retype the new password into this field Community String Type a new community string into this field ...

Page 59: ...Fill in the fields as required 3 When you have filled in the form select OK Options for the access methods are Serial Port Enabled Disabled To prevent access to the management facilities via the serial port disable access to the facility for each access level Serial Port access for Security is enabled and cannot be changed This prevents accidental disabling of all access levels from management Rem...

Page 60: ...Disabled The Switch 1005 can be managed via SNMP using a remote network manager Community SNMP does have some simple security features but it is an insecure protocol You may want to disable all access to the management facilities if there is important or sensitive data on your network ...

Page 61: ...DUA1840 0AAA01 Setting Up Users 2 27 ...

Page 62: ...r a VLAN Display screens showing statistical information Display the Switch Database configuration screen Display the Switch Unit Resilience Summary screen Display Setup screens for the Switch 1005 From the Main Menu select SWITCH MANAGEMENT The Switch Management screen appears as shown in Figure 3 1 Figure 3 1 Switch Management screen port level ...

Page 63: ...s at the foot of the screen relate to the Switch 1005 If you choose Port the screen that appears is similar to that shown in Figure 3 1 and all options relate to an individual port If you choose VLAN the screen that appears is similar to that shown in Figure 3 3 and all options relate to VLANs Figure 3 2 Switch Management screen module level Figure 3 3 Switch Management screen VLAN level ...

Page 64: ...ackplane 100Mbps STATISTICS Use this button to display statistics screens for the level of management you have chosen module port or VLAN See Chapter 5 SDB Use this button to display the Switch Database Configuration screen See Configuring the Switch Database on page 3 14 RESILIENCE Use this button to display the resilience screen for the module or specified port See Resilient Links on page 3 17 S...

Page 65: ... object You can edit the first 30 characters of this field to make the name more meaningful This name is displayed on the Main Banner when you first access the VT100 screens and is also accessible to an SNMP Network Manager Forwarding Mode Fast Forward Fragment Free Store and Forward Intelligent This field allows you to set the forwarding mode Fast Forward In this mode frames are forwarded as soon...

Page 66: ...ent In this mode the Switch 1005 monitors the amount of error traffic on the network and changes the forwarding mode accordingly If the Switch 1005 detects less than 18 error packets per second it will operate in Fast Forward mode If the Switch 1005 detects more than 18 packets per second it will operate in Store and Forward mode until the number of error packers per second returns to 0 PACE Enabl...

Page 67: ...rts 10Mbps are on this module Internal 100Mbps Ports This read only field shows how many internal connections to the Fast Ethernet 100Mbps backplane are available for this module Internal 10Mbps Ports This read only field shows how many internal connections to the Ethernet backplane 10Mbps are available for this module Transceiver Module This read only field shows the type of Transceiver Module in...

Page 68: ...ou have chosen to setup Media Type This read only field shows the media type of the link connected to the port Port Speed This read only field shows the speed of the link Link State Present Not Available For twisted pair and fiber ports only this read only field shows the state of the link Present The port is operating normally Not Available The link has been lost Port State Enable Disable This op...

Page 69: ... traffic is local to that segment Security Enable Disable When Security is enabled the port enters a single address learning mode The Switch 1005 removes all addresses currently stored against the port in the Switch Database The Switch 1005 then learns the source address from the first packet it receives on the port since security was enabled The port then enters a secure mode Once security is ena...

Page 70: ...port forms part of a Virtual LAN Trunk VLT A Virtual LAN Trunk is a connection which carries traffic for multiple VLANs between Switch 1005 modules You can find more information about VLANs in Chapter 5 Duplex Mode Half Duplex Full Duplex This field allows you to enable full duplex on Fast Ethernet ports Full Duplex Full duplex allows packets to be transmitted and received simultaneously and in ef...

Page 71: ...ger will be reset This prevents the rising threshold events being triggered continuously The default is 10 Rising Action none event disable port disable port notify blip blip port notify Use this field to specify the action for the alarm to take when it reaches the rising threshold none no action takes place event an SNMP trap is generated disable port the port is disabled disable port notify the ...

Page 72: ...us 20 second interval The average is based on 4 samples which are taken at 5 second intervals When the average value exceeds the rising threshold value the rising action is triggered The action will not be triggered again until the average broadcast bandwidth falls below the falling threshold level Specifying the Backbone Port Specifying the backbone port for your Switch 1005 is carried out throug...

Page 73: ...nnected to the rest of the network infrastructure Entries are added into the SDB in two ways The module can learn entries that is the unit updates the SDB with the source MAC address and the port identifier on which the source MAC address is seen The system administrator can enter and update entries using a MIB browser an SNMP Network Manager or the Switch Database screen described over the follow...

Page 74: ...reset For more information about setting an ageing time see see Switch 1005 Setup on page 3 4 Permanent entries Permanent entries are retained in the database if the Switch 1005 is reset or a power off on cycle occurs It is up to the system administrator to make entries permanent You can do this with single addresses or all addresses in the database using an SNMP Network Manager All entries entere...

Page 75: ...screen is displayed see Choosing a Switch Management Level on page 3 1 From the foot of the screen select the SDB button The screen shows the following Database Entries This read only field shows the number of entries currently in the SDB The database holds a maximum of 500 addresses MAC Address If an entry in the listbox is highlighted and you press Return this field shows the device MAC address ...

Page 76: ...information INSERT This button lets you insert an entry into the database DELETE This button allows you to delete entries from the database Searching the Switch Database You can search the switch database in two ways by MAC address or port number By MAC Address To locate the port number against which a particular MAC address is entered in the SDB 1 In the MAC Address field type in the MAC address ...

Page 77: ...port only Adding an Entry into the SDB 1 In the MAC Address field type in the MAC address of the device 2 In the Port Number field type in the port identifier for this device 3 Select INSERT Entries inserted this way are permanent entries Deleting an Entry from the SDB 1 In the listbox highlight the entry you want to delete and press Return or type the MAC address into the MAC Address field 2 Sele...

Page 78: ...e with fitted expansion module Resilient links can be set up on any of the external ports Resilient links can only be set up on fiber or twisted pair links The main and standby links in the same pair however can use any combination of these media or speed 10Mbps 100Mbps A backbone port can be configured as a main port in a resilient link pair If a resilient backbone port fails the standby port is ...

Page 79: ...ng read only information is displayed MAIN Port The ID of the port configured as the main port for this resilient link pair STANDBY Port The ID of the port configured as the standby port for this resilient link pair Pair State Active Both Failed Unknown Not Available The current operating state of this resilient link pair Active The resilient link pair is enabled and operating normally with both m...

Page 80: ...tandby port is carrying the traffic You should rectify the fault and switch operation back to the main link as soon as possible Swapping the main and standby ports is not carried out automatically Use the Port Resilience screen described in the next section to swap the main and standby ports Both Failed Both ports of the resilient link pair have failed This could be due to loose connections or cab...

Page 81: ... 3 8 Port Resilience screen The screen shows the following Main Port ID The identifier for the main port Media Type Twisted Pair Fiber This read only field shows the media type connected to the main port Link State Available Not Available Not Present This read only field shows the connection state of the main port in the link Available The port is operating normally Not Available The resilient lin...

Page 82: ... pair is enabled and operating normally with both main and standby port capable of carrying traffic Both Failed Although the resilient link is correctly configured both links have failed This could be due to loose connections or cable damage Unknown The network configuration has changed and the resilient link pair no longer conforms to the rules Not Available The resilient link pair is disabled Ac...

Page 83: ...ort to be configured as the main port in the link Select the RESILIENCE button at the foot of the screen 4 Select the standby port from the Standby Links Available listbox or enter the port ID in the Standby Port ID field 5 Enable the pair in the Pair Enabled field Select APPLY 6 Connect the cabling for the standby port Deleting a Resilient Link To delete the resilient link pair set up on the port...

Page 84: ... Table Check the documentation accompanying the network management software To access the Trap Setup screen from the Switch 1005 Management Setup screen described in Setting up the Switch 1005 in Chapter 2 select the SETUP TRAPS button The Trap Setup screen is shown in Figure 3 9 Figure 3 9 Trap Setup screen The screen shows the following IP or IPX Address Type into this text field the IP or IPX a...

Page 85: ...the community string of the remote Network Manager into the trap table The default community string is public Throttle To prevent a remote Network Manager receiving too many traps at once you can configure the Switch 1005 to transmit traps with a delay between them If several traps are generated at one time they will be transmitted with the specified delay between them The unit of throttle is one ...

Page 86: ...elect the RESET option The Reset screen appears as shown in Figure 3 10 2 Select OK Figure 3 10 Reset screen CAUTION Resetting the Switch 1005 in this way is similar to performing a power off on cycle No setup information is lost Performing a reset however may cause some of the data being transmitted at that moment to be lost and statistic counters will be reset to zero ...

Page 87: ...om the Main Menu select the INITIALIZE option The Initialization screen appears as shown in Figure 3 11 2 Select OK Figure 3 11 Initialization screen CAUTION Use Initialize with great care The Switch 1005 configuration 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 a...

Page 88: ...2 4 Ports which form part of a VLT will fail and you will not be able to manage the Switch if your management station communicates via the VLT To avoid this a Remove the VLT configuration from both ends of the VLT link before you initialize the Switch Note that the port furthest from your management station should have its VLT configuration removed first b Reconfigure the VLT once the initializati...

Page 89: ...f a software download over IPX fails you should enter the MAC address and port ID of your server into the switch database via the Database View screen and then attempt the download again 1 From the Main Menu select the SOFTWARE UPGRADE option The Software Upgrade screen is displayed as shown in Figure 3 12 Figure 3 12 Software Upgrade screen 2 In the File Name field type the name of the file that ...

Page 90: ...e Server Address field type the IP or IPX address of the host containing the software image to load 4 Select OK During the download the MGMT LED flashes green fast flash 1Hz and the screen is locked When the download is complete the module is reset ...

Page 91: ...DUA1840 0AAA01 3 30 CHAPTER 3 SWITCH CONFIGURATION ...

Page 92: ...hat communicate as if they are on the same physical LAN This means that LAN segments are not restricted by the hardware which 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 Organizational groups for example you can have one VLAN for the Marketing department and one for the Finance departme...

Page 93: ... a port in another part of the network the network administrator only needs to configure the new port to belong to VLAN 1 It helps to control broadcast traffic With traditional networks congestion can be caused by broadcast traffic which is directed to all network devices whether they require it or not VLANs increase the efficiency of your network because each VLAN can be set up to contain only th...

Page 94: ... restricted to ports 1 2 3 4 and 5 of Switch A membership of VLAN 2 is restricted to ports 4 5 6 7 and 8 of Switch B while VLAN 3 spans both Switches containing ports 6 7 8 of Switch A and 1 2 3 of Switch B In this simple example each of these VLANs can be seen as a broadcast domain physical LAN segments that are not constrained by their physical location Specific configurations using the Switch a...

Page 95: ...ed to a port should belong to another VLAN you need to use the VLAN Setup screen to place the port in that VLAN For more information about the VLAN Setup screen see Setting Up VLANs on the Switch on page 4 12 Connecting VLANs to a Router If the devices in 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 i...

Page 96: ...l the VLANs VLTs can only be used for links between Switch 1005 modules SuperStack II Switch 1000 units and SuperStack II Switch 3000 units You cannot use VLTs for Switch router links If you specify that a backbone port on one VLAN is part of a VLT that backbone port will become a backbone port for all the VLANs on the Switch even if they had no backbone port before If you then disable the VLT fun...

Page 97: ... to talk to VLAN 2 using the backbone port connection between each VLAN and the router To set up this configuration 1 Use the VT100 screens to a Place ports 1 6 in VLAN 1 b Place ports 7 12 in VLAN 2 2 Connect a port in VLAN 1 to the router 3 Use the VT100 screens to specify that the VLAN 1 port connected to the router is a backbone port 4 Repeat steps 2 and 3 for VLAN 2 You can set up this config...

Page 98: ...DUA1840 0AAA01 Virtual LANs VLANs 4 7 Figure 4 2 VLAN configuration with a single Switch 1005 module ...

Page 99: ...both Switch 1005s in VLAN 2 2 Connect port 1 of the right Switch 1005 to Server 1 3 Connect port 1 of the left Switch 1005 to Server 2 4 Use the VT100 screens to a Place port 1 of the right Switch 1005 in VLAN 2 b Place port 1 of the left Switch 1005 in VLAN 1 5 Connect port 28 on the right Switch 1005 to port 28 in the left Switch 1005 6 Use the VT100 screens to specify that port 28 on the right ...

Page 100: ...DUA1840 0AAA01 Virtual LANs VLANs 4 9 You can set up this configuration more easily using 3Com s Transcend Enterprise Manager applications Figure 4 3 VLAN configuration with two Switch 1005s ...

Page 101: ...itch 1005s in VLAN 2 2 Connect port 1 on each Switch 1005 to a port in the Switch 3000 FX 3 Use the VT100 screens to a Specify that port 1 on each Switch 1005 is a backbone port b Specify that port 1 on each Switch 1005 is part of a VLT c Specify that each Switch 3000 FX port connected to a Switch 1005 is part of a VLT 4 Connect port 1 of the Switch 3000 FX to Server 1 5 Connect port 2 of the Swit...

Page 102: ...40 0AAA01 Virtual LANs VLANs 4 11 You can set up this configuration more easily using 3Com s Transcend Enterprise Manager applications Figure 4 4 VLAN configuration with a Switch 3000 FX as a basement switch ...

Page 103: ...een appears 2 In the Management Level field choose VLAN 3 Choose the SETUP button The VLAN Setup screen appears as shown in Figure 4 5 Figure 4 5 VLAN Setup screen The screen shows the following Port ID 1 2 3 26 27 28 This field allows you to enter the ID of the port that you want to set up VLAN ID 1 2 3 14 15 16 This field allows you to enter the ID of the VLAN to which the specified port is to b...

Page 104: ...lled this automatically becomes the backbone port for the Default VLAN when you initialize the Switch If the Switch has more than one Fast Ethernet Transceiver Module the Transceiver Module with the lowest port number automatically becomes the backbone port for the Default VLAN If the Switch has no Fast Ethernet Transceiver Module but it uses port 28 to connect to the Fast Ethernet backplane port ...

Page 105: ...ED MANAGEMENT ResBP This field displays the resilient backbone port for the VLAN if one exists For more information about creating resilient links see Resilient Links on page 3 17 APPLY This button applies any changes to the VLAN database ...

Page 106: ...ws an SNMP Network Manager to access the management agent of the unit If you remove all ports from VLAN 1 then an SNMP Network Manager cannot manage the Switch Specifying a Backbone Port 1 In the Port ID field type the ID of the required port 2 In the VLAN ID field type the ID of the required VLAN 3 In the Select Port Type field select Backbone Port 4 Select APPLY Specifying that a Backbone Port i...

Page 107: ...DUA1840 0AAA01 4 16 CHAPTER 4 ADVANCED MANAGEMENT ...

Page 108: ...5 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 emerging and notice problems arising before they cause major network faults...

Page 109: ...freshed approximately every two seconds Once values have reached approximately 4 2 billion they are reset to zero To view values for a particular counter select the first button displayed at the foot of the Summary Statistics screen Pressing the Space bar toggles through the available counters and as soon as you move away from the button the screen is refreshed to show values for that counter FRAM...

Page 110: ...oadcast address MULTI BROADCASTS TX Displays the total number of frames transmitted by each port that are addressed to a multicast or broadcast address ERRORS Displays the total number of errors that have occurred on each port See the field description for Errors on page 5 7 CLEAR SCREEN COUNTERS Use this button to set all counters shown on the screen to zero Use this button for analysis if you wi...

Page 111: ...een shows the following Port ID The ID of the port you are currently managing Bandwidth Used This counter provides a running average of the occupied bandwidth and is expressed as a percentage of the theoretical maximum bandwidth available A sampling period of 1 minute is used The value gives an indication of the general traffic level of the network A high utilization for single station segments is...

Page 112: ...unning average of the Broadcast frame bandwidth in use and is expressed as a percentage of a theoretical maximum bandwidth A sampling period of 5 seconds is used Error Frames This counter provides a running average of the number of errors per 10 000 frames received and is expressed as a percentage See the field description for Errors on page 5 7 TRAFFIC STATISTICS Select this button to access traf...

Page 113: ...frames received by the port including fragments and frames with errors Frames Transmitted The number of frames that have been successfully transmitted by the port Octets Received The number of octets received by the port The calculation includes the MAC header and Cyclical Redundancy Check CRC but excludes preamble Start of Frame Delimiter SFD Octet counters are accurate to the nearest 256 octet b...

Page 114: ...roblem with a device or cabling on the network particularly if this is not accompanied by an increase in general network traffic Fragments The total number of packets received that were not an integral number of octets in length or that had a bad Frame Check Sequence FCS and were less than 64 octets in length excluding framing bits but including FCS octets Frames Forwarded The total number of fram...

Page 115: ...es on the network The frame size ranges are 64 octets 65 to 127 octets 128 to 255 octets 256 to 511 octets 512 to 1023 octets 1024 to 1518 octets The composition of frames on your network may help you to analyze the efficiency of your network layer protocol CLEAR SCREEN COUNTERS Select this button to set all counters shown on the screen to zero It is useful for trend analysis if you wish to see ch...

Page 116: ... Errors This counter is incremented by one for each frame with an CRC error or an alignment error A CRC occurs if a frame of legal length has an invalid CRC and does not have a framing error An alignment error occurs if a frame has a CRC error and does not contain an integral number of octets Alignment errors may be caused by a fault at the transmitting device Change the transceiver or adapter car...

Page 117: ...nt is also counted as a collision Long Frames This counter is incremented by one each time a frame is received whose octet count is greater than the maximum frame size but less than Jabber frame size Long Frames are frames that exceed the maximum size defined for 802 3 frames 1518 octets If you see a high number of long frames on your network you should isolate the source of these frames and exami...

Page 118: ... or power off on cycle Number Of Resets The total number of system resets since the Switch 1005 was first installed or initialized either power on manual reset or a watchdog expiry If you have a problem this information may be useful for your technical support representative Last Reset Type other command watchdog power reset system error This field indicates the cause of the last reset It may be d...

Page 119: ...are Version The version number of the software image stored in Flash EPROM This version number is automatically updated when you download new software You should note this number in case you need to quote it to your technical support representative Boot Software Version This is the version number of the Boot software stored on the Switch 1005 You should note this number in case you need to quote i...

Page 120: ...2 In the Target Address field type in 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 the Switch 1005 If the target device does not respond after approximately 10 seconds this field ...

Page 121: ...DUA1840 0AAA01 5 14 CHAPTER 5 STATUS MONITORING AND STATISTICS ...

Page 122: ... should flash their two colors alternately Cabling Check that all external cabling connections are secure and that no cables are pulled taut Modules Check that all modules are secured in position and that their ejectors are locked All modules should be flush in the chassis with each other If individual LEDs do not respond to the Lamp Test the LEDs are faulty If however all LEDs on a single module ...

Page 123: ...Check that the Power LED on the MSH chassis is not lit red If it is refer to your chassis user documentation Ensure the MSH chassis is powered up correctly with all power leads securely connected Ensure the module is fully engaged into the chassis Contact your supplier for advice Faulty LED Test LEDs to confirm Amber Fault occurred on this module during POST or normal operation BACKPLANE E FE Off ...

Page 124: ...ved by the SNMP Network Manager Check the SNMP Network Manager s IP address and that the community string is correctly configured The SNMP Network Manager or Telnet workstation can no longer access the device Check that Remote Telnet access or Community SNMP access is enabled Check that the port through which you are trying to access the device has not been disabled see Port Setup in Chapter 3 If ...

Page 125: ...005 Operation Problems You see network problems and the Packet LED is on continuously with constant collisions viewed using the Port Traffic Statistics screen see Port Traffic Statistics in Chapter 5 You are using PACE equipped devices and have PACE enabled at both ends of the link PACE must only be enabled at one end of the Switch device link Disable PACE on the Switch port as described in Port S...

Page 126: ...h 1005 module installed and you have just installed another Switch module One or more of the backplane LEDs are continuously lit You have installed the latest Switch 1005 into the chassis when the chassis and the Management Module were powered off and due to the way the Management Module behaves when it is powered on see Operation after Power up in Chapter 2 this has caused a network loop on the c...

Page 127: ...DUA1840 0AAA01 6 6 CHAPTER 6 PROBLEM SOLVING ...

Page 128: ...access rights granted to Monitor level are all read only All other access rights are read and write Screen Available to Logon Monitor Manager Security Main Menu Monitor Manager Security Switch Management Monitor Manager Security Port Statistics Monitor Manager Security Port Statistics Traffic Monitor Manager Security Port Statistics Errors Monitor Manager Security ...

Page 129: ...it Setup Monitor Manager Security Port Setup Monitor Manager Security Unit Resilience Monitor Manager Security Port Resilience Monitor Manager Security Remote Poll Manager Security Security Menu Monitor Manager Security Create User Security Delete User Security Local Security Security Change User Monitor Manager Security Screen Available to ...

Page 130: ...A1840 0AAA01 A 3 Status Monitor Manager Security Setup Monitor Manager Security Trap Setup Monitor Manager Security Software Upgrade Security Initialize Security Reset Manager Security Screen Available to ...

Page 131: ...DUA1840 0AAA01 A 4 APPENDIX A SCREEN ACCESS RIGHTS ...

Page 132: ... to 122 F Operating Humidity 10 to 95 relative humidity non condensing Standards EN60068 IEC68 Safety Agency Certifications UL 1950 EN60950 CSA 22 2 No 950 ECMA 97 Electromagnetic Emissions Agency Certification Note that to comply with these standards shielded cables must be used EN55022 Class B FCC Part 15 Class A C108 8 M1983 Class A EN 50082 1 IEC801 Parts 2 5 Heat Dissipation 24 watts maximum ...

Page 133: ...SNMP SNMP protocol RFC 1157 MIB II RFC 1213 Bridge MIB RFC 1286 Repeater MIB RFC 1516 VLAN MIB RFC 1573 RMON MIB RFC 1271 BOOTP RFC 951 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 ...

Page 134: ...he following online systems 3Com Bulletin Board Service 3ComBBS World Wide Web site 3ComForum on CompuServe 3ComFactsSM automated fax service 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 seven days a week 24 hours a day Access by Modem To reach the service by modem set your ...

Page 135: ...tures news and information about 3Com products customer service and support 3Com s latest news releases selected articles from 3TECH 3Com s award winning technical journal and more Country Data Rate Telephone Number Australia up to 14400 bps 61 2 9955 2073 France up to 14400 bps 33 1 69 86 69 54 Germany up to 9600 bps 49 89 627 32 188 or 49 89 627 32 189 Hong Kong up to 14400 bps 852 2537 5608 Ita...

Page 136: ...rovides data sheets technical articles diagrams and troubleshooting instructions on 3Com products 24 hours a day seven days a week Call 3ComFacts using your touch tone telephone International access numbers are Local numbers are available within the following countries Country Telephone Number Hong Kong 852 2537 5610 U K 44 1442 278279 U S 1 408 727 7021 Country Telephone Number Country Telephone ...

Page 137: ...rvices including network planning installation hardware maintenance application training and support services When you contact your network supplier for assistance have the following information ready Diagnostic error messages A list of system hardware and software including revision levels Details about recent configuration changes if applicable If you are unable to contact your network supplier ...

Page 138: ...toll free Country Telephone Number Country Telephone Number Australia Sydney 61 2 959 3020 Japan 81 3 33457251 Melbourne 61 3 653 9515 Mexico 525 531 0591 Belgium 0800 71429 Netherlands 06 0227788 Brazil 55 11 546 0869 Norway 800 13376 Canada 416 498 3266 Singapore 65 538 9368 Denmark 800 17309 South Africa 27 11 803 7404 Finland 0800 113153 Spain 900 983125 France 05 917959 Sweden 020 795482 Germ...

Page 139: ...s Authorization RMA number A product sent to 3Com without an RMA number will be returned to the sender unopened at the sender s expense To obtain an RMA number call or fax Country Telephone Number Fax Number U S and Canada 800 876 3266 option 2 408 764 7120 Europe 31 30 60 29900 option 5 44 1442 275822 Outside Europe U S and Canada 1 408 492 1790 1 408 764 7290 ...

Page 140: ...ger valid backbone The part of a network used as the primary path for transporting traffic between network segments backbone port A port which does not learn device addresses and which receives all frames with an unknown address Backbone ports are normally used to connect the Switch to the backbone of your network backplane The internal path between modules within the MSH chassis bandwidth Informa...

Page 141: ...neous broadcasts that typically absorb available network bandwidth and can cause network failure CSMA CD Channel access method used by Ethernet and IEEE 802 3 in which devices transmit only after finding the data channel clear for some period of time When two devices transmit simultaneously a collison occurs and the colliding devices delay their retransmissions for a random length of time data cen...

Page 142: ...IPX Internetwork Packet Exchange A protocol allowing communication in a NetWare network IP address Internet Protocol address A unique identifier for a device attached to a network using TCP IP The address is written as four octets separated with full stops periods and is made up of a network section an optional subnet section and a host section LAN Local Area Network A network of connected computi...

Page 143: ...acket PACE Priority Access Control Enabled 3Com s innovative technology which works in conjunction with a switch to control the latency and jitter associated with the transmission of multimedia traffic over Ethernet and Fast Ethernet protocol A set of rules for communication between devices on a network The rules dictate format timing sequencing and error control resilient link A pair of ports tha...

Page 144: ...oriented traffic on the network standby port The port in a resilient link that will take over data transmission if the main port in the link fails switch A device which filters forwards and floods frames based on the frame s destination address The switch learns the addresses associated with each switch port and builds tables based on this information to be used for the switching decision TCP IP A...

Page 145: ...tandard protocol that allows an application program on one device to send a datagram to an application program on another device VLAN Virtual LAN A group of location and topology independent devices that communicate as if they are on a common physical LAN VLT Virtual LAN Trunk A connection which carries traffic for multiple VLANs between Switch 1005 modules SuperStack II Switch 1000 units and Supe...

Page 146: ...plane LEDs 1 17 boot software version number 5 12 BOOTP enabling disabling 2 18 bridges vs Switch 1005 1 5 broadcast storm control 3 10 bulletin board service C 1 C cable maximum length 1 15 community SNMP enabling disabling 2 25 community strings and traps 3 24 changing 2 23 entering 2 22 CompuServe C 3 counters resetting to zero 5 3 5 8 5 10 Create User screen 2 21 D database See switch database...

Page 147: ... Switch 1005 2 6 Transceiver Modules 2 5 Intelligent Flow Management default state 1 20 definition 1 7 enabling disabling 3 8 when to disable 1 11 internal ports 1 3 IP addresses 1 21 configuring parameters 2 17 IP address assigning 1 21 device 2 18 entering 1 21 IPX addresses 1 21 configuring parameters 2 17 K keyboard shortcuts 2 11 L LEDs 1 17 link state 3 7 resilient 3 20 LinkBuilder MSH 1 1 l...

Page 148: ...ort Error Analysis screen 5 9 port LEDs 1 17 port number for database entry 3 14 Port Resilience screen 3 20 Port Setup screen 3 7 Port Statistics screen 5 4 Port Traffic Statistics screen 5 6 POST See Power On Self Test Power On Self Test default setting 1 20 setting type 2 17 problem solving 6 1 PWR LED 1 17 R Remote Poll screen 5 13 remote polling 5 13 remote telnet enabling disabling 2 24 Rese...

Page 149: ...en 5 11 subnet mask assigning 1 22 device 2 18 Summary Statistics screen 5 2 Switch 1005 assigning an IP address 1 21 connecting servers 1 11 default settings 1 20 description 1 1 dimensions C 1 features 1 2 front panel 1 16 installing 2 6 LEDs 1 17 logging off 2 19 logging on 2 14 management setup 1 21 2 17 operation 1 5 PCB 1 19 ports 1 3 removing 2 7 resilient links 1 8 security 1 8 size C 1 st...

Page 150: ...oftware 5 12 hardware 5 12 upgradable software 5 12 Virtual LAN Trunks See VLTs Virtual LANs See VLANs VLAN Setup screen 4 12 VLANs 4 1 assigning ports 4 15 Default 4 4 4 13 default membership 1 20 definition 1 8 setting up 4 12 using Non routable protocols 4 5 using unique MAC addresses 4 5 VLT mode enabling disabling 3 9 VLTs 3 9 4 5 4 13 VT100 interface accessing 2 13 definition 2 9 field types...

Page 151: ...6 CHAPTER INDEX ...

Page 152: ...oftware products will be uninterrupted or error free or that all defects in the software products will be corrected For any third party products listed in the 3Com software product documentation or specifications as being compatible 3Com will make reasonable efforts to provide compatibility except where the non compatibility is caused by a bug or defect in the third party s product STANDARD WARRAN...

Page 153: ...F ANY KIND OR FOR LOSS OF REVENUE LOSS OF BUSINESS OR OTHER FINANCIAL LOSS ARISING OUT OF OR IN CONNECTION WITH THE SALE INSTALLATION MAINTENANCE USE PERFORMANCE FAILURE OR INTERRUPTION OF ITS PRODUCTS EVEN IF 3COM OR ITS AUTHORIZED RESELLER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES Some states do not allow the exclusion of implied warranties or the limitation of incidental or consequent...

Page 154: ...tion 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 If n...

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