3Com LANPLEX 2500 EXTENDEDPLEX 2500 EXTENDED User manual

®
LAN PLEX
®
2500 E XTENDED
S WITCHING U SER G UIDE
Part No.801-00343-000
Published November 1996
Revision 02

3Com Corporation
■
5400 Bayfront Plaza
■
Santa Clara,California
■
95052-8145
© 3Com Corporation,1996.All rights reserved.No part of this documentation may be reproduced in any form or by any means or used to make
any derivative work (such as translation,transformation,or adaptation) without permission from 3Com Corporation.
3Com Corporation reserves the right to revise this documentation and to make changes in content from time to time without obligation on the
part of 3Com Corporation to provide notification of such revision or change.
3Com Corporation provides this documentation without warranty of any kind,either implied or expressed,including,but not limited to,the
implied warranties of merchantability and fitness for a particular purpose.3Com may make improvements or changes in the product(s) and/or
the program(s) described in this documentation at any time.
UNITED STATES GOVERNMENT LEGENDS:
If you are a United States government agency, then this documentation and the software described herein are provided to you subject to the
following restricted rights:
For units of the Department of Defense:
Restricted Rights Legend: Use,duplication or disclosure by the Government is subject to restrictions as set forth in subparagraph (c) (1) (ii) for
restricted Rights in Technical Data and Computer Software clause at 48 C.F.R.52.227-7013.3Com Corporation, 5400 Bayfront Plaza,Santa Clara,
California 95052-8145.
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’s standard commercial agreement for
the software.Unpublished rights reserved under the copyright laws of the United States.
3ComFacts,Ask3Com,CardFacts,NetFacts,and CardBoard are service marks of 3Com Corporation.
3Com,LANplex,Transcend,and NETBuilder II are registered trademarks of 3Com Corporation.
CompuServe is a registered trademark of CompuServe,Inc.
3Com registered trademarks are registered in the United States, and may or may not be registered in other countries.
Other brand and product names may be registered trademarks or trademarks of their respective holders.
Guide written, edited, and illustrated by Trish Crawford, Lynne Gelfand, Michael Jenness, Dave Sullivan, Patricia Johnson, Michael Taillon, Iain
Young,and Bonnie Jo Collins.

C ONTENTS
A BOUT T HIS G UIDE
Introduction 1
HowtoUseThis Guide 1
Conventions 2
LANplex2500Documentation 3
Documentation Comments 5
P ART IG ETTING S TARTED
1 LAN PLEX ® E XTENDED S WITCHING F EATURES
AboutLANplexExtendedSwitching 1-1
UsingMenus 1-2
BridgeMenu 1-3
IPMenu 1-4
IPXMenu 1-5
AppletalkMenu 1-6
P ART II V IRTUAL LAN T ECHNOLOGY
2 VLAN S ON THE LAN PLEX ® S YSTEM
AboutVLANs 2-1
Types ofVLANs 2-1
PortGroupVLANs 2-1
MACAddressGroupVLANS 2-2
Application-OrientedVLANS 2-2
Protocol-SensitiveVLANS 2-2
LANplexProtocol-SensitiveVLAN Configuration 2-3
ProtocolSuite 2-3
SwitchPorts 2-4
Layer3AddressingInformation 2-4
DefaultVLAN 2-5

ModifyingtheDefaultVLAN 2-5
Howthe LANplex® System Makes FloodingDecisions 2-5
VLANExceptionFlooding 2-6
Overlapped IPVLANs 2-7
RoutingBetweenVLANs 2-8
VLANExamples 2-10
Example1 2-10
Example2 2-11
P ART III A BOUT R OUTING P ROTOCOLS
3 B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM
WhatIs Routing? 3-1
LANplexin a SubnetworkedEnvironment 3-2
IntegratingBridging and Routing 3-3
Bridgingand Routing Models 3-4
TraditionalBridging and Routing Model 3-4
LANplexBridging and Routing Model 3-6
4 R OUTING WITH IP T ECHNOLOGY
IPRouting and the OSIModel 4-1
Elementsof IP Routing 4-2
IPAddresses 4-2
AddressClasses 4-3
SubnetPartof an IP Address 4-3
RouterInterfaces 4-4
RoutingTable 4-5
StaticRoutes 4-6
DynamicRoutesUsingRIP 4-6
Default Route 4-7
AddressResolution Protocol(ARP) 4-7
IPRoutingTransmission Errors 4-9
Routingwith Classical IP overATM 4-10
AboutLogicalIPSubnets(LISs) 4-10
ATM ARPServers 4-10
Forwardingto Nodes withinan LIS 4-11
IPRouting References 4-11

5 R OUTING WITH IP M ULTICAST
AboutIP Multicast Routing 5-1
IGMP 5-1
DVMRP 5-2
TheMBONE 5-2
MulticastRouting
Algorithms 5-3
Flooding 5-3
SpanningTrees 5-3
ReversePathForwarding 5-4
Pruning 5-5
MulticastInterfaces 5-5
DVMRP MetricValue 5-5
Time-To-Live(TTL)Threshold 5-5
Rate Limit 5-6
MulticastTunnels 5-6
6 R OUTING WITH IPX
IPXRouting in the NetWare® Environment 6-1
InternetPacketExchange(IPX) 6-2
RoutingInformationProtocol(RIP) 6-3
ServiceAdvertisingProtocol(SAP) 6-3
HowIPX RoutingWorks 6-4
IPXPacketFormat 6-4
IPXPacketDelivery 6-6
SendingNode’s Responsibility 6-6
Router’s Responsibility 6-7
TheElementsof
IPXRouting 6-8
RouterInterfaces 6-8
RoutingTables 6-8
Generating RoutingTable Information 6-9
Selecting the Best Route 6-10
ServiceAdvertisingProtocol 6-10
InternetworkServiceInformation 6-10
SAPPacketStructure 6-11
ServerInformationTable 6-13
ServerInformationMaintenance 6-14

7 R OUTING IN AN A PPLE T ALK ® E NVIRONMENT
AboutAppleTalk® 7-1
AppleTalk®NetworkElements 7-1
AppleTalk®Networks 7-2
AppleTalk®Nodes 7-2
NamedEntities 7-2
AppleTalk®Zones 7-3
Seed Routers 7-4
AppleTalkProtocols 7-4
PhysicalConnectivity 7-5
TheDatagramDeliveryProtocol(DDP) 7-6
End-to-EndServices 7-6
TransportLayerProtocols 7-6
TheSessionLayerProtocols 7-9
PresentationLayer 7-10
AboutAARP 7-10
P ART IV A DMINISTERING E XTENDED S WITCHING F EATURES
8 A DMINISTERING VLAN S
DisplayingVLANInformation 8-1
DefiningVLAN Information 8-3
ModifyingVLANInformation 8-4
RemovingVLANInformation 8-5
9 A DMINISTERING IP R OUTING
Administeringinterfaces 9-1
LISInterfaces 9-2
InterfaceCharacteristics 9-2
DisplayingInterfaces 9-3
Defining an IP LISInterface 9-4
Defining an IPVLAN Interface 9-6
Modifying an Interface 9-7
Removingan Interface 9-7
AddinganAdvertisement Address 9-8
Removingan Advertisement Address 9-8
AddingaPermanentVirtual Circuit(PVC) 9-9
RemovingaPermanentVirtual Circuit(PVC) 9-9
AdministeringRoutes 9-9
DisplayingtheRoutingTable 9-11

Defining a Static Route 9-11
Removinga Route 9-12
Flushinga Route 9-12
Setting the Default Route 9-12
RemovingtheDefault Route 9-13
AdministeringtheARPCache 9-13
DisplayingtheARPCache 9-14
Removingan ARP Cache Entry 9-14
Flushingthe ARPCache 9-15
AdministeringATM ARPServers 9-15
DisplayingATM ARPServers 9-15
Defining an ATMARP Server 9-16
Removingan ATMARPServer 9-16
DisplayingtheATMARPCache 9-17
Removingan ATMARPCache Entry 9-17
Flushingthe ATMARPCache 9-18
AdministeringUDPHelper 9-18
DisplayingUDPHelperInformation 9-19
Defining a Port andan IP Forwarding Address 9-19
Removinga Port or anIP Forwarding Address 9-19
Settingthe BOOTPHop CountLimit 9-20
Settingthe BOOTPRelayThreshold 9-20
Enablingand Disabling IP Routing 9-20
Enablingand Disabling ICMP RouterDiscovery 9-21
Settingthe RIP Mode 9-21
Pingingan IP Station 9-22
DisplayingIPStatistics 9-23
10 A DMINISTERING IP M ULTICAST R OUTING
Enablingand Disabling DVMRP 10-2
Enablingand Disabling IGMP 10-2
AdministeringIPMulticastInterfaces 10-3
DVMRP MetricValue 10-3
TimeToLive(TTL)Threshold 10-3
Rate Limit 10-4
DisplayingMulticastInterfaces 10-4
DisablingMulticast Interfaces 10-5
EnablingMulticast Interfaces 10-5
AdministeringMulticastTunnels 10-6
DisplayingMulticastTunnels 10-6
Defining a MulticastTunnel 10-7
RemovingaMulticastTunnel 10-7

DisplayingRoutes 10-8
DisplayingtheMulticastCache 10-9
11 A DMINISTERING IPX R OUTING
AdministeringInterfaces 11-2
DisplayingIPXInterfaces 11-3
Defining an IPX Interface 11-3
Modifying an Interface 11-4
Removingan Interface 11-4
AdministeringRoutes 11-5
DisplayingtheRoutingTable 11-6
Defining a Static Route 11-6
Removinga Route 11-7
FlushingRoutes 11-7
AdministeringServers 11-8
DisplayingtheServerTable 11-9
Defining a Static Server 11-9
Removinga Server 11-10
FlushingServers 11-10
SettingIPX Forwarding 11-11
Settingthe RIP Mode 11-11
Setting the Enhanced RIP Mode 11-12
Settingthe SAP Mode 11-13
DisplayingStatistics 11-14
DisplayingIPXSummaryStatistics 11-14
DisplayingIPXRIPStatistics 11-15
DisplayingIPXSAPStatistics 11-16
DisplayingIPXForwardingStatistics 11-17
12 A DMINISTERING A PPLE T ALK ® R OUTING
AdministeringInterfaces 12-2
DisplayingAppleTalkInterfaces 12-3
Defining an Interface 12-3
Removingan Interface 12-4
AdministeringRoutes 12-5
DisplayingtheRoutingTable 12-5
Flushingall Routes 12-6
AdministeringtheAARPCache 12-7
DisplayingtheAARPCache 12-8
Removingan Entryin the Cache 12-9
FlushingAll CacheEntries 12-9
DisplayingtheZoneTable 12-10

ConfiguringForwarding 12-11
ConfiguringChecksum 12-12
Pingingan AppleTalk Node 12-12
Viewing Appletalk Statistics 12-13
DisplayingDDPStatistics 12-13
DisplayingRTMPInformation 12-14
DisplayingZIPInformation 12-15
DisplayingNBPInformation 12-17
P ART VR EMOTE M ONITORING (RMON) AND THE
LAN
PLEX ® S YSTEM
13 R EMOTE M ONITORING (RMON) T ECHNOLOGY
WhatIs RMON? 13-1
Benefitsof RMON 13-2
LANplexRMON Implementation 13-2
3ComTranscendRMONAgents 13-3
Management InformationBase (MIB) 13-4
MIBObjects 13-4
Alarms 13-6
SettingAlarmThresholds 13-7
Exampleof an AlarmThreshold 13-7
RMONHysteresisMechanism 13-8
P ART VI A PPENDIX
A T ECHNICAL SUPPORT
On-lineTechnicalServices A-1
3ComBulletinBoardService A-1
AccessbyAnalogModem A-1
AccessbyDigitalModem A-2
WorldWideWeb Site A-2
3ComForum on CompuServe® A-2
3ComFacts™ Automated Fax Service A-3
Support fromYourNetwork Supplier A-3

Support from3Com A-4
ReturningProductsforRepair A-4
INDEX

ABOUT THIS GUIDE
Introduction The LANplex® 2500 Extended Switching User Guide provides information
about the features included with the LANplex Extended Switching
software.These features include IP,IP Multicast,classical IP over ATM,IPX,
and AppleTalk routing,virtual LAN (VLAN) configuration,and remote
monitoring (RMON).
Use this guide with the LANplex® 2500 Administration Console User Guide
when you configure your LANplex 2500 system.
See the LANplex® 2500 Software Installation and Release Notes for
information about how to install Extended Switching software on your
LANplex system.
Audience description This guide is intended for the system or network administrator who is
responsible for configuring,using,and managing the LANplex 2500 system.It
assumes a working knowledge of local area network (LAN) operations and a
familiarity with communications protocols used on interconnected LANs.
If the information in the release notes shipped with your product differs from
the information in this guide,follow the release notes.
How to Use This
Guide The following table shows where to find specific information.
If you are looking for... Turn to...
An overview of Extended Switching features Chapter 1
Virtual LANs (VLANs) on the LANplex System Chapter 2
General routing and routing models in the LANplex system Chapter 3
IP routing strategies Chapter 4
IP multicast routing and its protocols Chapter 5
continued

2ABOUT THIS GUIDE
Conventions Table 1 and Table2 list conventions that are used throughout this guide.
IPX routing and its protocols Chapter 6
AppleTalk routing, network elements, and protocols Chapter 7
How to administer VLANs Chapter 8
How to administer IP routing Chapter 9
How to administer IP mulitcast routing Chapter 10
How to administer IPX routing Chapter 11
How to administer AppleTalk routing Chapter 12
Remote Monitoring (RMON) Chapter 13
3Com Technical Support Appendix A
If you are looking for... Turn to...
Table1 Notice Icons
Icon Type Description
Information Note Information notes call attention to important features or
instructions.
Caution Cautions alert you to personal safety risk, system damage,
or loss of data.
Warning Warnings alert you to the risk of severe personal injury.

LANplex 2500 Documentation 3
LANplex 2500
Documentation The following documents comprise the LANplex 2500 documentation set.
If you want to order a document that you do not have or order additional
documents,contact your sales representative for assistance.
■LANplex® 2500 Unpacking Instructions
Describe how to unpack your LANplex system.It also provides you with
aninventory list of all the items shipped with your system.(Shipped
withsystem/Part No.801-00353-00)
Table2 Text Conventions
Convention Description
“Enter” “Enter” means type something, then press the [Return] or [Enter] key.
“Syntax” vs. “Command” “Syntax” indicates that the general command syntax form is provided. You must
evaluate the syntax and supply the appropriate value; for example:
Set the date by using the following syntax:
mm/DD/yy hh:mm:ss xm
“Command” indicates that all variables in the command syntax form have been
supplied and you can enter the command as shown in text; for example:
To update the system software, enter the following command:
system software Update
screen display This typeface indicates text that appears on your terminal screen; for example:
NetLogin:
commands This typeface indicates commands that you enter; for example:
bridge port stpState
Italic Italic is used to denote emphasis and buttons.
Keys When specific keys are referred to in the text, they are called out by their labels, such
as “the Return key” or “the Escape key,” or they may be shown as [Return] or [Esc].
If two or more keys are to be pressed simultaneously, the keys are linked with a plus
sign (+), for example:
Press [Ctrl]+[Alt]+[Del].

4ABOUT THIS GUIDE
■LANplex® 2500 Software Release Notes
Provide information about the software release,including new features and
bug fixes.It also provides information about any changes to the LANplex
system’s documentation.(Shipped with system)
■LANplex® 2500 Getting Started
Describes all the procedures necessary for installing,cabling,powering up,
configuring management access to,and troubleshooting your LANplex sys-
tem.(Shipped with system/Part No.801-00355-000)
■LANplex® 2500 Operation Guide
Provides information to help you understand system management and
administration,bridging,Fast Ethernet,ATM,and FDDI technology. It also
describes how these concepts are implemented in the LANplex system.
(Shipped with system/Part No.801-00344-000)
■LANplex® 2500 Administration Console User Guide
Provides information about using the Administration Console to configure
and manage your LANplex system.(Shipped with system/Part No.
801-00322-000)
■LANplex® 2500 Extended Switching User Guide (This book)
Describes® how the routing protocols,VLAN,and RMON are implemented
in the LANplex system and provides information about using the
Administration Console to configure and manage these features.(shipped
with the option package/Part No.801-00343-000)
■LANplex® 2500 Intelligent Switching Administration Console Command Quick
Reference card
Contains the Administration Console Intelligent Switching commands for
the LANplex system.(Shipped with the system/Part No.801-000318-000)
■LANplex® 2500 Extended Switching ADMINISTRATION CONSOLE Command Quick
Reference card
Contains the Administration Console Extended Switching commands for the
LANplex system.(Shipped with the option package/Part No.801-00319-000)

Documentation Comments 5
■Module Installation Guides
Provide an overview,installation instructions,LED status information,and
pin-out information for the particular option module.(Shipped with individ-
ual modules)
Documentation
Comments Your suggestions are very important to us and will help make our
documentation more useful to you.Please email comments about this
document to 3Com at:[email protected]
Please include the following information when commenting:
■Document title
■Document part number (listed on back cover of document)
■Page number (if appropriate)
Example: LANplex® 2500 Operation Guide
Part No.801-00344-000
Page 2-5 (chapter 2,page 5)

6ABOUT THIS GUIDE

1LANPLEX®EXTENDED SWITCHING
FEATURES
This chapter provides an overview of the Extended Switching software,and
describes the enhanced Administration Console menus.
About LANplex
Extended
Switching
The LANplex Extended Switching software replaces your existing LANplex
software and adds new functionality to your system.Extended Switching
software contains all the features of LANplex Intelligent Switching software,
in addition to:
■Virtual LANs (VLANs)
■Internet Protocol (IP) Routing (an enhanced version of IP from the standard
system software)
■IP multicast routing
■Classical IP routing over Asynchronous Transfer Mode (ATM)
■Internet Packet Exchange (IPX) routing
■AppleTalk® routing
■Remote Monitoring (RMON)
For information on how to gain access to online help,to use scripts,and to
exit from the Administration Console,see the LANplex® 2500 Administration
Console User Guide.
See the LANplex® 2500 Software Installation and Release Notes for
information about how to install Extended Switching software on your
LANplex system.

1-2 CHAPTER 1: LANPLEX® EXTENDED SWITCHING FEATURES
Using Menus When you gain access to the Administration Console,the top-level menu
appears.The Extended Switching software contains top-level menus and
additions to the Bridge and IP menu options not available with Intelligent
Switching software:
Menu options:
--------------------------------------------------------------------
system - Administer system-level functions
ethernet- Administer Ethernet ports
fddi - Administer FDDI resources
ATM - Administer ATM resources
bridge - Administer bridging/VLANs
ip - Administer IP
ipx - Administer IPX
appletalk- Administer Appletalk
snmp - Administer SNMP
analyzer- Administer Roving Analysis
script - Run a script of console commands
logout - Logout of the Administration Console
Type ? for help.
--------------------------------------------------------------------
Select a menu option:
The following sections show the enhanced menus provided with Extended
Switching software.All other menu items appear in the LANplex® 2500
Administration Console User Guide.
The RMON feature is available through SNMP only.This feature is not
available through the Administration Console.See Chapter 13,Remote
Monitoring (RMON)Technology,for more information about this feature.
Menu options vary
by level of access
Option Descriptions

Using Menus 1-3
Bridge Menu From the bridge menu,you can view information about and configure
Ethernet LANs,including VLANs.Figure 1-1 shows the bridge menu.
Figure1-1 Bridge Menu Hierarchy
Top-Level Menu bridge menu interface menu
system display summary
ethernet mode detail
fddi ipFragmentation define
atm ipxSnapTranslation modify
➧bridge addressThreshold remove
ip agingTime
ipx stpState
appletalk stpPriority
snmp stpMaxAge
analyzer stpHelloTime
script stpForwardDelay
logout stpGroupAddress
port
packetFilter
vlan

1-4 CHAPTER 1: LANPLEX® EXTENDED SWITCHING FEATURES
IP Menu From the ip menu,you can view information about and configure Internet
Protocol (IP) interfaces and routes as well as IP Multicast routing.You can
administer the Address Resolution Protocol (ARP),the Routing Information
Protocol (RIP),UDP Helper,IP Forwarding,and ping IP stations.You can also
define ATM ARP servers from the ip menu if you are running classical IP
over ATM.Figure1-2 shows the ip menu.To define a new IP interface,for
example,enter ip at the top-level menu,interface at the ip menu,and then
define at the interface menu.
Figure1-2 IP Menu Hierarchy
Top-Level Menu ip menu interface menu
system ➧interface summary
ethernet ➧route detail
fddi ➧arp define
atm ➧atmArpServer modify
bridge ➧multicast remove
➧ip ➧udpHelper addAdvertisement
ipx routing removeAdvertisement
appletalk icmpRouterDiscovery addPvc
snmp rip removePvc
analyzer ping
script statistics route menu
logout display
static
remove
flush
default
noDefault
arp menu
display
remove
flush
atmArpServer
display
define
remove
arp
multicast
dvmrp
igmp
interfaces
tunnel
RouteDisplay
cacheDisplay
udpHelper menu
display
define
remove
hopCountLimit
threshold