Instruction/ maintenance manual of the product 2500 3Com
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® 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 reser ved . No part of this documentation may be reproduced in any form or by any means or used to make any derivative w ork (such as translation, transformation, or adaptation) without permission from 3Com Corporation.
C ONTENTS A BOUT T HIS G UIDE Introduction 1 How to Use This Guide 1 Conv entions 2 LANplex 2500 Documentation 3 Documentation Comments 5 P ART IG ETTING S TARTED 1 LAN PLEX ® E XTENDED S WITCHING F .
Modifying the Default VLAN 2-5 How the LANplex® System Makes Flooding Decisions 2-5 VLAN Exception F looding 2-6 Overlapped IP VLANs 2-7 Routing Between VLANs 2-8 VLAN Examples 2-10 Example 1 2-10 Ex.
5 R OUTING WITH IP M ULTICAST About IP Multicast Routing 5-1 IGMP 5-1 DVMRP 5-2 The MBONE 5-2 Multicast Routing Algorithms 5-3 Flooding 5-3 Spanning T rees 5-3 Reverse P ath Forwarding 5-4 Pruning 5-5.
7 R OUTING IN AN A PPLE T ALK ® E NVIRONMENT About AppleT alk® 7-1 AppleT alk® Net work Elements 7-1 AppleT alk® Networks 7-2 AppleT alk® Nodes 7-2 Named Entities 7-2 AppleT alk® Zones 7-3 Seed .
Defining a Static Route 9-11 Removing a Route 9-12 Flushing a Route 9-12 Setting the Default Route 9-12 Removing the Default Route 9-13 Administering the ARP Cache 9-13 Displaying the ARP Cache 9-14 .
Displaying Routes 10-8 Displaying the Multicast Cache 10-9 11 A DMINISTERING IPX R OUTING Administering Interfaces 11-2 Displaying IPX Interfaces 11-3 Defining an IPX Inter face 11-3 Modifying an Int.
Configuring F or warding 12-11 Configuring Checksum 12-12 Pinging an AppleT alk Node 12-12 Viewing Appletalk Statistics 12-13 Displaying DDP Statistics 12-13 Displaying RTMP Information 12-14 Displa.
Support from 3Com A-4 Returning Products for Repair A-4 I NDEX.
A BOUT T HIS G UIDE Introduction The L ANplex® 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 A TM, IPX, and AppleT alk routing, virtual LAN ( VLAN) configuration, and remote monitoring (RMON).
2 A BOUT T HIS G UIDE C onv entions T able 1 and T able 2 list conventions that are used thr oughout this guide. IPX routing and its protocols Chapter 6 AppleTalk routing, network elements, and protoc.
LANplex 2500 Documentation 3 LANplex 2500 Documentation The f ollowing documents comprise the LANplex 2500 documentation set. If you want to order a document that y ou do not have or order additional documents, contact your sales representative f or assistance.
4 A BOUT T HIS G UIDE ■ LANplex® 2500 Sof tware Release Notes Pr ovide information about the software release , including new features and bug fixes.
Documentation Comments 5 ■ Module Installation Guides Pr ovide an overview , installation instruc tions , LED status information, and pin-out information for the particular option module. (Shipped with individ- ual modules) Documentation C omments Y our suggestions are ver y important to us and will help make our documentation more useful to you.
6 A BOUT T HIS G UIDE.
1 LAN PLEX ® E XTENDED S WITCHING F EATURES This chapter provides an o ver view of the Extended Switching software, and describes the enhanced Administration Console menus . About LANplex Extended Switching The LANplex Extended Switching soft ware replaces y our existing LANplex software and adds new functionalit y to y our system.
1-2 C HAPTER 1: LAN PLEX ® E XTENDED S WITCHING F EATURES Using Menus When you gain access to the Administration C onsole, the top-level menu appears.
Using Menus 1-3 Bridge Menu F rom the bridge menu, you can view information about and configur e Ethernet LANs, including VLANs. Figur e 1-1 shows the bridge menu.
1-4 C HAPTER 1: LAN PLEX ® E XTENDED S WITCHING F EATURES IP Menu F rom the ip menu, you can view information about and configure Internet Protocol (IP) interfaces and routes as well as IP Multicast routing .
Using Menus 1-5 IPX Menu F rom the ipx menu, you can view information about and configure Internet P ack et Exchange (IPX) interfaces, routes, and servers. Y ou can also administer the Routing Information P rotocol (RIP), Enhanced RIP mode, Ser vice A dver tising P rotocol (SAP), and statistics.
1-6 C HAPTER 1: LAN PLEX ® E XTENDED S WITCHING F EATURES Appletalk Menu F rom the appletalk menu, you can view information about and configur e Appletalk inter faces , routes, and zones. Y ou can also administer the Appletalk Address Resolution P rotocol (AARP), AppleT alk for warding , and statistics.
2 VLAN S ON THE LAN PLEX ® S YSTEM This chapter contains: ■ A description of Vir tual LAN ( VLAN) concepts and their operational aspects in the LANplex® 2500 system ■ Examples of VLAN configurations About VLANs The VLAN concept in LAN technology helps minimize broadcast and multicast traffic.
2-2 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM the data contained in the frames. P or t groups ar e useful when traffic patterns are known to be directly associated with par ticular ports. They can benefit the user by restricting traffic based on a set of simple rules.
About VLANs 2-3 layer 3 subnet address inf ormation. Protocol-sensitive VLANs allow the restriction of flood traffic for both routable and nonroutable protocols . They have a relativ ely simple configuration comprising one or more protocols and groups of switch ports.
2-4 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM Switch P or ts A group of switch ports is any combination of switch por ts on the LANplex system. Included are switch ports created as A TM LAN Emulation Clients (A TM LECs).
About VLANs 2-5 Default VLAN When you start up the LANplex system, the system automatically creates a VLAN inter face called the default VLAN. Initially , the default VLAN includes all of the switch ports in the system.
2-6 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM This example shows how flooding decisions are made according to VLANs set up by protocol (assuming an 18-port switch): VLAN Exc eption Flooding If da.
About VLANs 2-7 Overlapped IP VLANs The LANplex system also gives you the ability to assign network la yer information to IP VLANs. This capabilit y allows network administrators to manage their VLANs by subnet.
2-8 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM As shown in this example, when the subnet address of an IP packet does not match any subnet address of an y defined IP VLAN in the system, it is flooded to all of the IP VLANs that share the source switch port, in this case, por t 6.
About VLANs 2-9 If layer 3 inf ormation is provided in the IP VLAN for which you are configuring an IP inter face , the subnet por tion of both addr esses must be compatible. F or example: IP VLAN subnet 157.103.54.0 with subnet mask of 255.255.255.0 IP host inter face addr ess 157.
2-10 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM VLAN Examples Example 1 F igure 2-1 is an example of a simple configuration that contains three protocol-sensitive VLANs (2 IP and 1 IPX) that share a high-speed FDDI link. The end-stations and servers are on 10Mbps por ts with traffic segregated by protocol.
About VLANs 2-11 Example 2 F igure 2-2 is an example of a configuration that contains two different protocol-sensitive VLANs (IP and IPX) with servers on separate high-speed 100BASE-T por ts. The end-station clients share the same switch por ts , yet the IP and IPX traffic stays separate.
2-12 C HAPTER 2: VLAN S ON THE LAN PLEX ® S YSTEM.
3 B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM This chapter shows how the LANplex® system operates in a subnetworked routing envir onment and describes the LANplex routing methodology — specifically , how the LANplex bridging and routing model compares with traditional models.
3-2 C HAPTER 3: B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM Figur e 3-1 Traditional Architecture of a Routed Network LANplex in a Subnetworked Envir onment The LANplex system allows you to fit E thernet switching capabilit y into highly subnetworked environments.
What Is Routing? 3-3 Integrating Bridging and Routing The LANplex system integrates bridging and routing . Multiple switch por ts can be assigned to each subnet.
3-4 C HAPTER 3: B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM In the traditional model, if you want to increase the level of segmentation in your network, you must create additional subnets and assign new network addresses to your existing hosts .
Bridging and Routing Models 3-5 Figur e 3-4 Bridging in the T raditional Bridging and Routing Model In the traditional bridging and routing model, a packet is rou ted as follows (see F igure 3-5): 1 The packet enters the bridge or router .
3-6 C HAPTER 3: B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM LANplex Bridging and Routing Model The LANplex 2500 system uses the destination MAC addr ess to determine whether it will bridge or route a packet.
Bridging and Routing Models 3-7 In the LANplex bridging and routing model, a packet is rou ted as follows (see F igure 3-7): 1 The packet enters the LANplex system.
3-8 C HAPTER 3: B RIDGING AND R OUTING IN THE LAN PLEX ® S YSTEM.
4 R OUTING WITH IP T ECHNOLOGY This chapter gives an ov er view of IP routing technology , specifically defining: ■ What IP routing inv olves ■ What elements are necessary for IP routers to effe.
4-2 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY When an IP router sends a packet, it does not k now the complete path to a destination — only the next hop. Each hop in volves three steps: ■ The IP routing algorithm computes the nex t hop IP address , and nex t router inter face, using the r outing table entries.
Elements of IP Routing 4-3 Addr ess Classes The boundary of the net work part and the host par t depends on the class that the central agency assigns to your network. The primary classes of IP addresses are Class A, Class B , and Class C. ■ Class A addresses — have 8 bits for the network part and 24 bits for the host par t.
4-4 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY Figur e 4-3 How a Subnet Mask Is Applied to the IP Address An example of an IP address that includes network, subnet, and host par ts is 158.101.230.52 with a subnet mask of 255.255.255.0 . This address is divided as follows: ■ 158.
Elements of IP Routing 4-5 Figur e 4-4 Router Inter faces in the LANplex System Routing T able A routing table allows a router or host to determine how to send a packet toward the packet ’ s ultimate destination.
4-6 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY Figur e 4-5 Example of a Routing T able in the LANplex Routing Model Routing table information is generated and updated in either of the following ways: ■ Statically — Y ou manually enter routes, which do not change until you change them (that is, they will not time out).
Elements of IP Routing 4-7 An active router sends a RIP message ever y 30 seconds. This message contains both the IP address and a metric (the distance to the destination from that router) for each destination. In RIP , each router that a packet must travel through to reach a destination equals one hop .
4-8 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY protocol. The two k ey elements of the ARP request are the tar get and source addresses for both the har dware (MAC addresses) and the protocol (IP addresses).
IP Routing Transmission Errors 4-9 IP Routing T ransmission Errors Because each router only knows about the nex t hop , it is not aware of problems that might be further “ down the road” towar d the destination.
4-10 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY Routing with Classical IP ov er AT M LANPlex Extended Switching soft ware supports classical IP routing over A TM ARP in an A TM network. Classical IP ov er A TM uses Logical IP Subnets (LISs) to forward packets within the net work envir onment.
IP Routing References 4-11 F or w arding to Nodes within an LIS Nodes can forward packets direc tly to other nodes in the same LIS. T o forward a packet within the same LIS, the sending node requests a translation from the destination IP address to the corresponding A TM address from the A TM ARP server .
4-12 C HAPTER 4: R OUTING WITH IP T ECHNOLOGY.
5 R OUTING WITH IP M ULTICAST This chapter describes the IP multicast routing implementation on the LANplex® system. About IP Multicast Routing IP multicast routing is an extension of the Internet Protocol.
5-2 C HAPTER 5: R OUTING WITH IP M ULTICAST DVM RP The Distance V ec tor Multicast Routing P rotocol (DVMRP) establishes the multicast delivery path over a series of routing devices. DVMRP is a simple distance vector routing protocol, similar to the IP Routing Information P rotocol (RIP).
Multicast Routing Algorithms 5-3 Multicast Routing Algorithms The LANplex system uses three algorithms that support multicast routing: ■ Flooding ■ Spanning T rees ■ Reverse P ath F or warding F.
5-4 C HAPTER 5: R OUTING WITH IP M ULTICAST F igure 5-1 shows a simple network with five links . Figur e 5-1 Simple Network Implemented Without Using Spanning Tr ee A spanning tree for this network consists of links 1, 2, 3, and 4.
Multicast Interfaces 5-5 Pruning P runing is a method used in the RPF algorithm to for war d pack ets to a spanning tree only if group members exist in the tree . This method results in fewer spanning trees , but it requires dynamic updates to the routing table.
5-6 C HAPTER 5: R OUTING WITH IP M ULTICAST Rate Limit The rate limit determines how man y multicast pack ets can travel o ver the inter face in kilobytes-per-second. The LANplex system drops multicast traffic that travels faster than this rate . The default is set to 0, which implies no rate limit is set.
This chapter provides an o ver view of IPX routing , including: ■ What par t IPX plays in the NetW are envir onment ■ How IPX works ■ What elements are necessary for IPX routers to transmit pack.
6-2 C HAPTER 6: R OUTING WITH IPX Figur e 6-1 NetW are Protocols and the OSI Refer ence Model The LANplex system uses the following protocols f or routing in a Netware environment: ■ Internet P ack .
IPX Routing in the NetWare® Environment 6-3 Routing Information Protoc ol (RIP) RIP allows the exchange of routing inf ormation on a NetWare network. IPX routers use RIP to dynamically create and maintain their routing tables . RIP allows one router to exchange r outing information with a neighboring router .
6-4 C HAPTER 6: R OUTING WITH IPX How IPX Routing Wo r k s A router operates at the network la yer of the OSI Reference Model. This means that it receives its instructions to route packets from one segment to another from a network-layer pr otocol. IPX, with the help of RIP , per forms these network layer tasks .
How IPX Routing Works 6-5 The packet format consists of the following elements: ■ Checksum — The IPX packet begins with a 16-bit checksum field that is set to 1 s. ■ Packet L ength — This 16-bit field contains the length, in bytes, of the complete network packet.
6-6 C HAPTER 6: R OUTING WITH IPX IPX Pack et Delivery On a NetWare network, the successful delivery of a packet depends both on the proper addressing of the packet and on the internetwork configuration. P ack et addressing is handled in the packet’ s Media Access Control (MA C) protocol header and IPX header address fields.
How IPX Routing Works 6-7 T o find this router , the sending node broadcasts a RIP packet requesting the best route to the destination node ’ s network number . The router residing on the sending node’ s segment with the shortest path to the destination segment responds to the RIP request.
6-8 C HAPTER 6: R OUTING WITH IPX The Elemen ts of IPX Routing IPX routers use the following elements to transmit packets ov er an intranetwork: ■ Router inter faces ■ Routing tables ■ Ser vice Advertising Protocol (SAP) Router Inter faces A router inter face is the connection between the router and the network number (address).
The Elements of IPX Routing 6-9 ■ Hops to Network — Pro vides the number of routers that must be crossed to reach the network segment. ■ Ticks to Network — Pr ovides an estimate of the time necessar y to reach the destination segment. ■ Node — The node address of the r outer that can for war d pack ets to each segment.
6-10 C HAPTER 6: R OUTING WITH IPX system uses RIP (one of the most widely used IGPs), to dynamically build its routing tables. RIP operates in terms of active and passive devices. The activ e devices , usually routers, broadcast their RIP messages to all devices in a network; they update their own routing tables when they receive a RIP message .
The Elements of IPX Routing 6-11 A workstation must first know a ser v er ’ s network address before it can initiate a session with a file ser v er.
6-12 C HAPTER 6: R OUTING WITH IPX A SAP packet consists of the following fields: ■ Operation — This field indicates the t ype of operation the SAP packet per f orms.
The Elements of IPX Routing 6-13 The SAP broadcasts that servers and routers send are local and , therefore, only received by SAP agents on their connected segments.
6-14 C HAPTER 6: R OUTING WITH IPX Static Ser v ers. A static ser ver is one y ou manually configure in the ser ver information table. Static ser vers are useful in en vironments where no routing protocol is used or where y ou want to override some of the ser v ers generated with a routing/server protocol.
The Elements of IPX Routing 6-15 elapsed since information was received concerning a particular table entr y . Since this information is either new or changed , the SAP agent that receives this information immediately passes it on, and the change is quickly learned throughout the internetwork.
6-16 C HAPTER 6: R OUTING WITH IPX.
This chapter provides an o ver view of AppleT alk® routing, and includes these topics: ■ AppleT alk Network Elements ■ AppleT alk Protocols ■ About AARP About AppleT alk® AppleT alk is a suite of protocols defined by Apple Computer , Inc., for connecting computers, peripherals devices, and other equipment on a network.
7-2 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT AppleT alk® Networks A network in an AppleT alk internet is a cable segment attached to a router . Each network is identified by a network number or range of network numbers. The network administrator assigns these numbers from a range of valid network numbers.
AppleTalk® Network Elements 7-3 AppleT alk® Zones An AppleT alk zone is a logical collection of nodes on an AppleT alk internet. A zone can include all nodes in a single network or a collection of nodes in different networks. Y ou assign a unique name to each zone to identify it in the internet.
7-4 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT quickly within the zone because the zone includes fewer devices than the entire internet does. Seed Routers A seed router initializes the internet with AppleT alk configuration information, including network numbers and zone names.
AppleTalk Protocols 7-5 Figur e 7-2 AppleT alk P rotocols and the OSI Reference Model The AppleT alk six-layer protocol suite is not fully compliant with the OSI seven-layer r eference model. However , AppleT alk provides many of the functions and ser vices pro vided by OSI.
7-6 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT because it is closely related to the Ethernet and token ring LAPs . This protocol is usually included in the definition of each LAP , so it does not appear in the reference model. S ee the section “ About AARP” later in this chapter for more inf ormation about this protocol.
AppleTalk Protocols 7-7 Each router builds a routing table that is the basis of dynamic routing operations in an AppleT alk internet. Ever y 10 seconds, each router sends an RTMP data packet to the network. Routers use the information that they receive in the RTMP broadcasts t o build their routing tables.
7-8 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT Figur e 7-3 A Simple AppleT alk Network Y ou can view the AppleT alk routing tables in y our network through the Administration Console . AppleT alk Echo Protocol (AEP). AppleT alk nodes use the AEP to send datagrams to other nodes in the network.
AppleTalk Protocols 7-9 AppleT alk T ransaction Protocol (A TP). This protocol, along with the AppleT alk Data Stream Protocol (ADSP), ensur es that DDP pack ets are delivered to a destination without any losses or corruption. Name Binding Protocol (NBP).
7-10 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT AppleT alk Data Stream Protocol (ADSP). The ADSP works with the A TP to ensure reliable data transmission. Unlike A TP , however , ADSP provides full-duplex byte-stream delivery . This means that two nodes can communicate simultaneously .
About AARP 7-11 The AARP maintains an Address Mapping T able (AMT ) with the most recently used hardware addr esses and their corresponding AARP addresses. If an address is not in this table, AARP sends a request to the pr otocol address and adds the hardware addr ess to the table when the destination node replies.
7-12 C HAPTER 7: R OUTING IN AN A PPLE T ALK ® E NVIRONMENT.
8 A DMINISTERING VLAN S This chapter describes how to display inf ormation about VLANs and how t o configure VLANs. Through the Administration C onsole, you can: ■ Display summary or detailed infor.
8-2 C HAPTER 8: A DMINISTERING VLAN S Index Name Layer 3 1 none 2 eastgroup 158.101.111.16 255.255.255.0 3 westgroup none 4 northgroup 158.101.112.14 255.
Defining VLAN Information 8-3 Defining VLAN Information F ollow these steps to create a VLAN definition: 1 F rom the top level of the Administration Console , enter : bridge vlan define 2 Enter the appropriate protocol suite: (IP, IPX, AppleTalk, XNS, DECnet, SNA, Banyan, X.
8-4 C HAPTER 8: A DMINISTERING VLAN S Example: Select menu option (bridge/vlan): define Enter Protocol Suite (IP,IPX,AppleTalk,XNS,DECnet,SNA,Banyan,X.
Removing VLAN Information 8-5 Example: Select menu option (bridge/vlan): modify Select VLAN interface [1-2]: 2 Protocol Suite (IP,IPX,AppleTalk,XNS,DECnet,SNA, Banyan,X.
8-6 C HAPTER 8: A DMINISTERING VLAN S.
9 A DMINISTERING IP R OUTING This chapter describes how to set up your LANplex® system to use the Internet Protocol (IP). For more inf ormation about how IP works, see P ar t III of this guide.
9-2 C HAPTER 9: A DMINISTERING IP R OUTING LIS Interfaces A logical IP subnet (LIS) inter face supports logical IP over A TM. Y ou define LIS inter faces f or the por ts on A TM modules only . See the Chapter 11 of the LANplex® 2500 Operation Guide for more inf ormation about the A TM protocol.
Administering interfaces 9-3 this option, the system displays a list of av ailable VLAN index es and the bridge por ts associated with them. ■ LIS Inter fac e — When y ou selec t LIS as the inter face type, the Administration Console pr ompts you for LIS inter face information.
9-4 C HAPTER 9: A DMINISTERING IP R OUTING Example summar y display : Example detail display : Defining an IP LIS Inter face When you define an IP LIS interface, you specify several general IP interface characteristics and IP LIS charac teristics.
Administering interfaces 9-5 The Console pr ompts you for the inter face ’ s parameters. T o use the value in brackets, press [Return] at the prompt. 2 Enter the IP address of the inter face. 3 Enter the subnet mask of the network to which the inter face is to be connected.
9-6 C HAPTER 9: A DMINISTERING IP R OUTING Defining an IP VLAN Interface When you define an IP VLAN inter face, y ou specify several inter face characteristics, as well as the index of the VLAN associated with the inter face .
Administering interfaces 9-7 Modifying an Inter face Y ou might want to change the configuration of an inter face you hav e already defined . Y ou can add one or more advertisement addresses or PVCs to an interface through the addAdvertisement and addPVC commands as well as through the IP interface modify command.
9-8 C HAPTER 9: A DMINISTERING IP R OUTING Adding an Adv er tisement Addr ess This command adds an advertisement address to the adver tisement address list associated with the inter face.
Administering Routes 9-9 Adding a P ermanent Virtual Circuit (PVC) T his command adds a PVC to an LIS inter face. T o add a PVC: 1 F rom the top level of the Administration Console , enter : ip interface addPvc 2 Enter the index inter face number that y ou want to associate with the PVC.
9-10 C HAPTER 9: A DMINISTERING IP R OUTING more than one routing table entry matching an address, it uses the most specific route , which is the route with the most bits set in its subnet mask. F or example, the route to a subnet within a destination network is more specific than the route to the destination network.
Administering Routes 9-11 Displaying the Routing T able Y ou can display a switching module ’ s routing table to determine which routes are configured and whether the r outes are operational.
9-12 C HAPTER 9: A DMINISTERING IP R OUTING Example: Enter destination IP address: 158.101.4.0 Enter subnet mask [255.255.0.0]: 255.255.255.0 Enter gateway IP address: 158.101.2.8 Removing a Route T o remove a route: 1 F rom the top level of the Administration Console , enter : ip route remove 2 Enter the destination IP address of the route.
Administering the ARP Cache 9-13 T o statically configure the default route: 1 F rom the top level of the Administration Console , enter : ip route default 2 Enter the gateway IP address of the route . The default route is immediately added to the routing table .
9-14 C HAPTER 9: A DMINISTERING IP R OUTING Displaying the ARP Cache Y ou can display the contents of the ARP cache for your system. T o display the contents of the ARP cache, enter the following comm.
Administering ATM ARP Servers 9-15 Flushing the ARP Cache Y ou might want to delete all entries from the ARP cache if the MAC address has changed. T o remove all entries from the ARP cache , from the top level of the Administration Console , enter: ip arp flush The ARP cache entries are immediately remo ved from the table.
9-16 C HAPTER 9: A DMINISTERING IP R OUTING Defining an A T M ARP Ser ver D etermine the location of the A TM ARP server you want to use. Y ou can define the A TM ARP ser ver externally on another LANplex system or on an A TM switch, such as 3Com ’ s CELLplex™ 7000 system.
Administering ATM ARP Servers 9-17 Displaying the A TM ARP Cache T o display the contents of the A TM ARP cache , from the top level of the Administration Console , enter : ip atmArpServer arp display.
9-18 C HAPTER 9: A DMINISTERING IP R OUTING Flushing the A TM ARP Cache T o remove all entries fr om the A TM ARP cache, from the top level of the Administration Console , enter: ip atmarpserver arp flush The A TM ARP cache entries are immediately remo ved from the table.
Administering UDP Helper 9-19 Displaying UDP Helper Information Y ou can display the hop count and threshold configuration and list the por ts with their IP forwarding addresses that are defined for your LANplex system.
9-20 C HAPTER 9: A DMINISTERING IP R OUTING Setting the BOO TP Hop Co unt Limit Y ou can set the maximum hop count for a packet to be for war ded through the router .
Enabling and Disabling ICMP Router Discovery 9-21 Enabling and Disabling ICMP Router Disco very The Internet Contr ol Message Protocol (ICMP) Router Discovery protocol (RFC 1256) allows an appropriately configured end station to locate one or more routers on the LAN to which it is attached .
9-22 C HAPTER 9: A DMINISTERING IP R OUTING RIP default mode By default, RIP operates in passive mode. T o set the RIP operating mode: 1 F rom the top level of the Administration Console , enter : ip rip 2 Enter the RIP mode ( off , passive , o r active ).
Displaying IP Statistics 9-23 Displaying IP Statistics T o display IP statistics, enter the f ollowing from the top level of the Administration Console: ip statistics Example: IP routing is enabled, RIP is active, ICMP router discovery is disabled.
9-24 C HAPTER 9: A DMINISTERING IP R OUTING.
10 A DMINISTERING IP M ULTICAST R OUTING This chapter describes how to set up your LANplex® system to use IP multicast routing . Y ou should have previously defined IP inter faces and routes as described in Chapter 9: Administering IP Routing , before you define any IP multicast interfaces.
10-2 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING Enabling and Disabling DVMRP DVMRP is the simple Distance V ector Multicast Routing Protocol, similar to the IP Routing Information P rotocol. Multicast routers exchange distance vector updates that contain lists of destinations and the distance in hops to each destination.
Administering IP Multicast Interfaces 10-3 When you select the IGMP option, the inter face prompts y ou to enable or disable IGMP snooping mode and IGMP quer y mode. Both are enabled by default. Under most conditions, IGMP snooping mode and IGMP query mode should remain enabled .
10-4 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING Rate Limit The rate limit determines how fast multicast traffic can trav el over the inter face in kilobytes per second . Multicast traffic may not exceed this rate limit or the LANplex system will drop packets in order to maintain the set rate.
Administering IP Multicast Interfaces 10-5 Disabling Multicast Inter faces T o disable multicast routing on an inter face: 1 F rom the top level of the Administration Console , enter : ip multicast interface disable 2 Enter the index number of the inter face y ou want to disable.
10-6 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING Administ ering Multicast T unnels A multicast tunnel allows multicast packets to cross several unicast routers to a destination router that supports multicast. A tunnel has two end points. The local end point is associated with an inter face on the LANplex router .
Administering Multicast Tunnels 10-7 Defining a Multicast T unnel T o define an IP multicast tunnel: 1 F rom the top level of the Administration Console , enter : ip multicast tunnel define 2 Enter the index number(s) of the inter face(s) with which y ou want to associate a multicast tunnel.
10-8 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING Displaying Routes T o display all av ailable routes in the IP multicast routing table: 1 F rom top level of the Administration Console , enter : ip multicast routeDisplay The DVMRP status and IGMP status appear on the screen.
Displaying the Multicast Cache 10-9 Displaying the Multicast Cache The IP multicast cache contains the IP source address and destination address for packets obser v ed on the system. The multicast cache shows you how information is routed ov er inter faces and ports in your system.
10-10 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING Example: Enter multicast source address [131.188.0.0] Enter multicast group address [244.2.0.2] DVMRP is enabled, IGMP snooping is enabled The .
Displaying the Multicast Cache 10-11 T able 10-2 describes the fields in the cache display . T able 10-2 Information in the cache display Field Description Origin The source of the incoming packets. Entries preceded by an angle bracket (>) indicate a multicast subnetwork.
10-12 C HAPTER 10: A DMINISTERING IP M ULTICAST R OUTING.
11 A DMINISTERING IPX R OUTING This chapter describes how to set up your LANplex® system to use the Internet P ack et Exchange (IPX) protocol to r oute pack ets.
11-2 C HAPTER 11: A DMINISTERING IPX R OUTING Administ ering Inter faces An IPX interface defines the relationship between an IPX V ir tual LAN ( VLAN) and the IPX network. Every IPX inter face has one IPX VLAN associated with it. Each switching module has one IPX interface defined for each subnet directly connected to it.
Administering Interfaces 11-3 Displaying IPX Inter faces Y ou can display a table that shows all IPX inter faces and their parameter settings configured for the system.
11-4 C HAPTER 11: A DMINISTERING IPX R OUTING Example: Modifying an Inter face Y ou might want to change the configuration of an inter face that y ou have already defined . T o modify an IPX inter face: 1 F rom the Administration Console top-level menu , enter : ipx interface modify Y ou are prompted for the interface parameters.
Administering Routes 11-5 Administ ering Routes Y our system maintains a table of routes to other IPX networks. Y ou can either use the Routing Information P rotocol (RIP) to exchange routing information automatically or make static entries in this table using the Administration Console .
11-6 C HAPTER 11: A DMINISTERING IPX R OUTING Displaying the Routing T able Y ou can display the routing tables for the system to determine which routes are configured and if they ar e operational.
Administering Routes 11-7 5 Enter the node address of the route. A static route is defined in the following example: Removing a Route T o remove a route: 1 F rom the Administration Console top-level menu , enter : ipx route remove 2 Enter the 4-byte IPX network address.
11-8 C HAPTER 11: A DMINISTERING IPX R OUTING Administ ering Ser vers Y our system maintains a table of servers that reside on other IPX networks. Y ou can either use the S er vice Adv er tising P rotocol (SAP) to exchange server information automatically or make static entries in this ser ver table using the Administration C onsole.
Administering Servers 11-9 Displaying the Ser ver T able Y ou can display the ser ver table for the system to determine which ser vers are learned and if they are operational.
11-10 C HAPTER 11: A DMINISTERING IPX R OUTING 8 Enter the number of hops to the ser ver . Example: Removing a Server T o remove a ser v er : 1 F rom the Administration Console top-level menu , enter : ipx server remove 2 Enter the ser vice type of the ser ver .
Setting IPX Forwarding 11-11 Setting IPX F or warding Y ou can control whether the system forwards or discards IPX packets addressed to other routers. When you enable IPX for war ding, the system acts as a normal IPX router , forwarding IPX packets from one network to another when required .
11-12 C HAPTER 11: A DMINISTERING IPX R OUTING RIP default mode By default, RIP is off . T o set the RIP operating mode: 1 F rom the Administration Console top-level menu , enter : ipx rip 2 Enter the RIP mode ( off , passive , o r active ). T o use the value in brackets, press [Return] at the prompt.
Setting the SAP Mode 11-13 Setting the SAP Mode Y ou can selec t a SAP mode that is appropriate for y our network. SAP can operate in any of three modes: ■ Off — The system ignores all incoming SAP packets and does not generate any SAP packets of its own.
11-14 C HAPTER 11: A DMINISTERING IPX R OUTING Displaying Statistics The A dministration Console allows you to display f our t ypes of IPX-related statistics: ■ IPX summar y statistics ■ IPX RIP s.
Displaying Statistics 11-15 Displaying IPX RIP Statistics T o display IPX RIP statistics, from the Administration C onsole top-level menu, enter: ipx statistics rip Example below : T able 11-2 describers the IPX RIP statistics.
11-16 C HAPTER 11: A DMINISTERING IPX R OUTING Displaying IPX SAP Statistics T o display IPX SAP statistics, from the Administration C onsole top-level menu, enter: ipx statistics sap Example: T able 11-1 describes the IPX SAP statistics.
Displaying Statistics 11-17 Displaying IPX F or warding Statistics T o display IPX Forwarding statistics, from the A dministration Console top-level menu, enter: ipx statistics forwarding Example: T able 11-4 describes the IPX forwarding statistics.
11-18 C HAPTER 11: A DMINISTERING IPX R OUTING T able 11-4 IPX Forwarding Statistics Field Description Received Number of IPX forwarding packets received Transmitted Number of IPX forwarding packets t.
12 A DMINISTERING A PPLE T ALK ® R OUTING This chapter describes how to set up your LANplex® system to use the AppleT alk protocol to route packets. F or more information on how AppleT alk routing works, see Chapter 7: Routing with AppleT alk.
12-2 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING Administ ering Inter faces An AppleT alk inter face defines the relationship between an AppleT alk Vir tual LAN ( VLAN) and the AppleT alk network. Every AppleT alk inter face has one AppleT alk VLAN associat ed with it.
Administering Interfaces 12-3 Displaying AppleT alk Inter faces Y ou can display a table that shows all AppleT alk inter faces and their parameter settings configured for the system.
12-4 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING 6 Enter the zone name. Y ou can enter up to 16 zone names per inter fac e. 7 Ty p e q after entering all the zone names. 8 Enter the index of the AppleT alk VLAN associated with this int er face.
Administering Routes 12-5 Administ ering Routes Y our system maintains a table of routes to other AppleT alk networks. The routing table is generated automatically by the Routing T able Maintenance Protocol (RTMP).
12-6 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING The following example shows a routing table displa y : Flushing all Routes Flushing deletes all dynamically learned routes fr om the routing table.
Administering the AARP Cache 12-7 Administ ering the AARP Cache AARP allows hardware addresses to be mapped to an AppleT alk protocol address. AppleT alk uses dynamically assigned 24-bit addresses, unlike the statically-assigned 48-bit addresses used by Ethernet and token ring.
12-8 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING Displaying the AARP Cache Y ou can display the AARP cache for the system to determine which routes are configured and if they are operational.
Administering the AARP Cache 12-9 Removing an Entry in the Cache T o remove an AARP cache entr y: 1 At the Administration C onsole’ s top-level menu, enter: appletalk aarp remove 2 Enter the AARP address at the prompt.
12-10 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING Displaying the Zone T able AppleT alk allows for the logical grouping of nodes into zones to make navigation through the netw ork easier . This is done with the Zone Information P rotocol (ZIP).
Configuring Forwarding 12-11 Depending on the command entered, the z one table is displayed by network or zone. An example of each type of display is shown below: C onfiguring F or warding Y ou can control whether the router forwards or discards AppleT alk packets addressed to other hosts.
12-12 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING C onfiguring Checksum Checksum is a simple method used for detecting errors in the transmission of data. Checksum generation totals the bytes comprising the data and adds this sum to the end of the data packet.
Viewing Appletalk Statistics 12-13 Viewing Appletalk Statistics Y ou can view statistics specific to the following AppleT alk protocols: ■ Datagram Deliver y P rotocol (DDP) ■ Routing T able Main.
12-14 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING Displaying RTMP Information T o display RTMP statistics: F rom the Administration Console top-level menu , enter : appletalk statistics rtmp An example of summar y statistics is shown below : T able 12-2 describes the RTMP statistics you can view .
Viewing Appletalk Statistics 12-15 Displaying ZIP Information T o display ZIP statistics: F rom the Administration Console top-level menu , enter : appletalk statistics zip T able 12-2 RTMP Statistics.
12-16 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING An example of summar y statistics is shown below : T able 12-3 describes the ZIP statistics you can view : DDP forwarding is enabled.
Viewing Appletalk Statistics 12-17 Displaying NBP Information The NBP handles the translations between the numeric internet address and the alphanumeric entity names used by AppleT alk.
12-18 C HAPTER 12: A DMINISTERING A PPLE T ALK ® R OUTING T able 12-4 describes the NBP statistics you can view . T able 12-4 NBP Statistics Field Description inLkupReqs Number of NBP Lookup Requests.
V Chapter 13 Remote Monitoring (RMON) T echnology R EMOTE M ONITORING (RMON) AND THE LAN PLEX ® S YSTEM.
13 R EMOTE M ONITORING (RMON) T ECHNOLOGY This chapter provides an o ver view of RMON and describes the specific LANplex® RMON implementation. What Is RMON? The Remote Monitoring (RMON) Management Information Base (MIB) provides a way to monitor and analyz e a local area network LAN from a remote location.
13-2 C HAPTER 13: R EMOTE M ONITORING (RMON) T ECHNOLOGY Benefits of RMON T raditional network management applications poll network devices such as switches, bridges , and routers at regular inter v als from a network management console. The console gathers statistics, identifies trends, and can highlight network events.
LANplex RMON Implementation 13-3 3Com T ransc end RMON Agents RMON requires one probe per LAN segment. Because a segment is a por tion of the LAN separated by a bridge or router , the cost of implementing many probes in a lar ge net work can be high.
13-4 C HAPTER 13: R EMOTE M ONITORING (RMON) T ECHNOLOGY Figur e 13-1 Embedded RMON Implemented on the LANplex System Management Information Base (MIB) A MIB is a structured set of data that describes the way the network is functioning.
Management Information Base (MIB) 13-5 Figur e 13-2 Example of an RMON MIB Counter Object The displayed inf ormation includes these items: ■ The formal name of the counter is etherStatsPkts.
13-6 C HAPTER 13: R EMOTE M ONITORING (RMON) T ECHNOLOGY Alarms The LANplex system supports the following syntax for alarms: counters , gauges, integers and timeticks. These mechanisms repor t information about the network to the network administrator .
Alarms 13-7 Setting Alarm Thresholds T hresholds determine when an alarm repor ts that a counter has exceeded a cer tain value . Y ou can set alarm thresholds through the network manually , and choose any value f or them that is appropriate for your application.
13-8 C HAPTER 13: R EMOTE M ONITORING (RMON) T ECHNOLOGY RMON Hysteresis Mechanism The RMON hysteresis mechanism pr ovides a way to prevent small fluctuations in counter values from causing alarms.
VI Appendix A T echnical Support A PPENDIX.
A T ECHNICAL S UPPORT 3Com pro vides easy access to technical suppor t information thr ough a variety of ser vices. This appendix describes these services.
A-2 A PPENDIX A: T ECHNICAL S UPPORT Acc ess by Digital Modem ISDN users can dial in to 3ComBBS using a digital modem for fast access up to 56 Kbps. T o access 3ComBBS using ISDN, dial the following n.
Support from Your Network Supplier A-3 3ComF ac ts ™ Automated F ax S ervice 3Com Corporation ’ s interactive fax ser vice , 3ComF acts, provides data sheets , technical ar ticles, diagrams , and troubleshooting instruc tions on 3Com products 24 hours a day , seven days a week.
A-4 A PPENDIX A: T ECHNICAL S UPPORT Suppor t from 3C om If you are unable to receive support from your network supplier , technical suppor t contracts are available from 3C om. In the U.S. and Canada, call (800) 876-3266 for customer ser vice. If you are outside the U.
I NDEX Numerics 3Com Bulletin Board Service (3ComBBS) A-1 3Com sales offices A-4 3ComF acts A-3 A AARP 7-10 AARP cache administering 12-7 displaying 12-8 removing an entr y from 12-9 address classes 4-3 IP to MAC, translating 9-13 MAC 3-3 network 3-3 Address Resolution P rotocol.
2 I NDEX bridging/routing LANplex model 3-4 traditional model 3-4 bulletin board ser vice A-1 C cache displaying the IP multicast 10-9 checksum configuring AppleT alk 12-12 chooser , Macintosh 7-2 Co.
I NDEX 3 displaying an 11-3 modifying an 11-4 removing an 11-4 Interior Gateway Protocols (IGP) 4-6, 6-9 Internet address. See IP address Internet Control Message P rotocol.
4 I NDEX LIS inter faces characteristics of 9-3 defining 9-4 M MAC (Media Access Contr ol). See FDDI MAC MAC address 3-3 ARP and 9-13 bridging in switching modules, and 3-6 compared to IP address 4-2.
I NDEX 5 management console 13-1 MIB 13-1, 13-2, 13-4 probe 13-1, 13-2 route, IP default 9-10 defining static 9-11 removing default 9-13 removing from table 9-12 status 9-10 route, IPX removing a 11-.
6 I NDEX timing out, IP route status 9-10 T-notify configuring 8-4 transmission errors ICMP Redirect 4-9 reasons for 4-9 T TL threshold 5-5 IP multicast 10-3 tunnels IP multicast 5-6, 10-6 V VLAN inf.
An important point after buying a device 3Com 2500 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought 3Com 2500 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data 3Com 2500 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, 3Com 2500 you will learn all the available features of the product, as well as information on its operation. The information that you get 3Com 2500 will certainly help you make a decision on the purchase.
If you already are a holder of 3Com 2500, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime 3Com 2500.
However, one of the most important roles played by the user manual is to help in solving problems with 3Com 2500. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device 3Com 2500 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
