Intel Express 100BASE-TX User manual

Intel Express 100BASE-TX Switching Hub
User Guide
PartNo.654655-001

First edition March 1996
Copyright © 1996, Intel Corporation. All rights reserved.
Intel Corporation, 5200 NE Elam Young Parkway, Hillsboro, OR 97124-6497
Intel Corporation assumes no responsibility for errors or omissions in this manual. Nor does Intel make any commitment to
update the information contained herein.
* Other product and corporate names may be trademarks of other companies and are used only for explanation and to the
owners’ benefit, without intent to infringe.

iii
Contents
Quick Start 1
Chapter 1 Hardware Installation and Network Topology 3
Overview ..................................................................................................................................................3
Features.....................................................................................................................................................4
Installation and Setup ...............................................................................................................................5
Using the Switch.......................................................................................................................................6
Port status LEDs ................................................................................................................................6
Management status LEDs..................................................................................................................7
Cabling Requirements ..............................................................................................................................8
UTP requirements .............................................................................................................................8
Fiber optic requirements ...................................................................................................................9
Straight-through vs. crossover cables ...............................................................................................9
Typical Configurations...........................................................................................................................10
Configuring the 100 Mbps workgroup environment ......................................................................10
Configuring the Wide Area Network (WAN) environment ...........................................................11
Connecting to a 10 Mbps segment ..................................................................................................12
Excessive flow control problems ....................................................................................................13
Chapter 2 Configuring and Managing the Switch 15
Accessing the Console Manager ............................................................................................................16
Using the Console Manager ...................................................................................................................17
Entering commands.........................................................................................................................17
Console Manager command groups................................................................................................19
Configuring a port for full duplex...................................................................................................20
Configuring the SNMP agent for IP................................................................................................20
Monitoring traffic ............................................................................................................................21
Creating VLANs .............................................................................................................................23
Configuring the spanning tree .........................................................................................................24
Creating custom filters ....................................................................................................................25

iv
CONTENTS IntelExpress100BASE-TXSwitchingHubUser’sGuide
Console Command Reference ................................................................................................................26
System commands...........................................................................................................................28
IP commands ...................................................................................................................................31
Ping commands ...............................................................................................................................34
SNMP commands............................................................................................................................36
Switching database commands .......................................................................................................38
VLAN commands ...........................................................................................................................46
Spanning tree commands ................................................................................................................49
Port configuration commands .........................................................................................................51
Switching statistics commands........................................................................................................52
Console command-line summary ...................................................................................................56
Chapter 3 Troubleshooting 59
Appendix A Technical Information 61
Default Configuration.............................................................................................................................61
Specifications .........................................................................................................................................62
SNMP and MIB Support ........................................................................................................................65
Custom Filter Port Table ........................................................................................................................66
Limited Warranty...................................................................................................................................71
Index 73
Customer Support Inside back cover

1
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
PC-3435
Xmt FC/FD Mgm
Rcv Clsn Link
Port 2
Port 7
Port 6Port 5Port 3 Port 4
Port 1
Rcv Clsn Link
Xmt FC/FD Mgm
100BASE-TX
Rubber feet for shelf or table placement.
Brackets and screws for standard
19-inch equipment rack placement.
Crossover cables to
servers/workstations
Straight-through
cables to hubs
100BASE-TX server/
workstation
100BASE-TX hub
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
PC-3436
Xmt FC/FD Mgm
Rcv Clsn Link
Port 2
Port 7
Port 6Port 5Port 3 Port 4
Port 1
Rcv Clsn Link
Xmt FC/FD Mgm
100BASE-TX
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Port 3
PC 3396
Lights when device is
plugged into the port.
Console Mgmt
SNMP Pwr
Mgmt Fault
Blinks every two seconds.
Lights briefly while the switch
performs self-tests.
Should always be on.
NOTES
•Connect only 100 Mbps devices to the
switch. See page 12 for information on
connecting to 10 Mbps segments.
•The default configuration for each port is
half duplex mode only.
•Always use Category 5 cabling.
Quick Start
1. Install the Express 100BASE-TX Switching Hub in a rack or on a shelf or table,
plug the cord in, and turn the power on. See page 5 (steps 1 and 2).
2. Connect the network devices to the switch. See page 5 (step 3) and pages 10–12.
3. Check the LEDs for power and links. See pages 6 and 7.
Next steps (Optional)
• Continue to the next page if you want to configure the switch to work with an SNMP-compliant
Network Management System (NMS).
• See Chapter 2 if you want to use the Console Manager to change port configurations (set a port for
full duplex), assign an IP address, or check port statistics.

2
(Optional) Quick Start for SNMP Management
4. Use the null-modem cable to connect the Console Mgmt port to a COM port on a
workstation.
5. Open a terminal emulation program (such as Terminal in Microsoft Windows* 3.1).
Specify these communication parameters:
•9600 baud
•8 data bits
•No parity
•1 stop bit
6. Press EE
EE
Eand log into the Console Manager:
Login:
password:
By default, no password or user name is assigned. If you enter one, it is saved upon reset.
7. Set the IP configuration using the set-ip-conf command:
set-ip-conf 192.1.1.64 255.255.255.0 192.1.1.255 E
Replace these addresses with the numbers for your network. Specify the IP address, netmask
(subnet mask), and broadcast address, in that order.
8. Download the Intel MIB (Management Information Base) file from an Intel online
service and compile into your NMS.
The MIB filename is SWCH1MIB.EXE. You can find the file on Intel’s Customer Support web
site (http://www-cs.intel.com) or the Intel BBS (see inside back cover). See your NMS
documentation for instructions on compiling the MIB for a new device.
Console Mgmt
A null-modem cable is
provided with the switch.
PC-3442

3
Hardware Installation
and Network
Topology
Overview
The Intel Express 100BASE-TX Switching Hub is a 5-port Fast
Ethernet switch featuring five 100BASE-TX ports and two slots for
optional 100BASE-TX or 100BASE-FX media adapters. Each 100
Mbps port supports a Fast Ethernet segment, up to a total of 1024
cached nodes for the switch.
The switch increases the available bandwidth and extends the distance
of Fast Ethernet installations by dividing the network into segments
and insulating each from the others’ local traffic. Additionally, by
configuring a link for full duplex, you can establish a 200 Mbps link
between the switch and another switch, server, or workstation. This is
especially useful for busy file servers that are accessed by multiple
segments.
Data transfer delays are eliminated through the switch’s parallel store-
and-forward architecture with direct port-to-port transfer. Selective
flow control improves performance by preventing lost packets due to
buffer overload.
1

4
CHAPTER 1 Intel Express 100BASE-TX Switching Hub
Security features include the creation of custom filters and virtual
networks (VLANs). You can define any custom filter based on
multicast/broadcast, source port, destination port, and destination
address. VLAN features include the ability to set broadcast or
multicast domains. See Chapter 2 for information on configuring
VLANs.
The switch also has a built-in SNMP (Simple Network Management
Protocol) agent and can be monitored and controlled through any
SNMP-compliant Network Management System (NMS). See page 20
for information on using the switch with an SNMP NMS and getting
the switch’s MIB (Management Information Base) file.
Features
• Five RJ-45 Fast Ethernet ports
• Two expansion ports for optional 100BASE-TX or 100BASE-FX
media adapters
• Standard 19-inch rack-mount chassis (rack-mount kit included)
• Auto-ranging power supply (automatically adjusts to any voltage
between 90 VAC and 264 VAC at 50/60 Hz)
• Full duplex selectable on each port
• Flow control selectable on each port
• 1024 address cache entries
• Custom filtering table
• Serial console port with password protection
• SNMP support (see Appendix A for MIB information)
• Spanning tree protocol support
• Built-in remote monitoring (RMON) support (Group 1)

5
Hardware Installation and Network TopologyCHAPTER 1
Installation and Setup
1 Install the switch in a rack or on a shelf.
For rack placement, connect the switch to a 19-inch rack using the
enclosed rack mount brackets.
For shelf placement, attach the enclosed rubber feet to each corner of
the bottom of the switch and place it on a flat, level surface.
2 Plug the switch in and turn the power on.
Plug the switch into an active AC outlet and turn the power on. A
built-in power supply automatically adjusts to any outlet providing
between 90 VAC and 264 VAC at 50/60 Hz.
3 Connect the Fast Ethernet devices.
For optimum performance, the Fast Ethernet segments connected to
the switch must be configured carefully. Follow these general
guidelines:
• Connect only 100 Mbps devices to the switch. The switch will not
work with 10 Mbps devices. See page 12 for information on
connecting to a 10 Mbps segment.
• Always use Category 5 unshielded twisted-pair (UTP) cable when
plugging devices into 100BASE-TX ports.
• Limit the distance between devices connected with UTP cable to
100 meters.
• Use a crossover cable when directly connecting a workstation,
server, or another switch to the switch. Use straight-through
cables when connecting to a repeating hub or concentrator.
• Configure the network so devices that primarily talk to each other
are on the same segment. Each port on the switch is defined as a
single Fast Ethernet segment.
4 Is setup complete?
If you’re using the switch as a stand-alone device (not under the
control of network management software), you’re done.
If you want to change the default configuration (shown in
Appendix A) or manage the switch, continue to Chapter 2.
NOTE
The switch will only work with
100 Mbps devices. For a
10BASE-T connection, see
page 12.

6
CHAPTER 1 Intel Express 100BASE-TX Switching Hub
Using the Switch
The switch requires minimal user intervention. It automatically learns
the addresses of new stations as they appear, and will relearn
addresses dynamically if the network is reconfigured.
Each of the Fast Ethernet ports has six status LEDs. There is a
separate bank of four LEDs for the management status.
Port status LEDs
Port LEDs provide information about the port’s configuration and the
status of devices connected to the ports.
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Port 3
Xmt Transmit. Lights when the switch is transmitting
packets on this port.
Rcv Receive. Lights when packets are received on this port,
even if they are not forwarded.
FC/FD Flow Control (default) or Full Duplex. Blinks on when
flow control is activated. If flow control is disabled, the
LED blinks on when a packet is lost. If full duplex is
enabled on the port, the LED is normally on
continuously, and blinks off when a packet is resent.
Flow control is not possible, nor needed, when full
duplex is enabled.
Clsn Collision. Lights whenever a collision occurs while the
port is transmitting. Collisions are normal in an Ethernet
environment. However, if the collision LED is on
continuously, you may have a problem with a device on
the segment.
NOTE
The default configuration of
all ports is half-duplex mode.
To change to full duplex, use
the Console Manager. See
page 19 for instructions.
Ports on the switch are wired
MDI for connection to MDI-X
ports using a straight-through
UTP cable. See page 9 for
more information.

7
Hardware Installation and Network TopologyCHAPTER 1
Mgmt Management. Lights when the management agent
checks the port (normally, every two seconds).
Link Link. When solid, indicates a connection is established.
If the Link LED is off, check for loose cable
connections. Also, make sure you’re using the correct
type of Category 5 cable, either straight-through or
crossover. See page 9 for more information.
Management status LEDs
Management status LEDs provide information about the overall
operation of the switch and its SNMP management components.
Console Mgmt
SNMP Pwr
Mgmt Fault
SNMP Simple Network Management Protocol. Always
on, indicating that the built-in SNMP agent is working.
Mgmt Management. Blinks on at regular intervals as the
SNMP agent is polled for updated information.
Pwr Power. Indicates the status of the power supply. It may
remain off for a few seconds during the power-on self-
test. It is normally on.
Fault Fault. Indicates that the switch has detected a
problem. It may remain on for a few seconds during the
power-on self-test. If this indicator blinks or remains lit
after self-test, there is a problem with the switch.
See Chapter 3 for troubleshooting information.

8
CHAPTER 1 Intel Express 100BASE-TX Switching Hub
Cabling Requirements
Incorrect cabling is often the cause of network configuration
problems. It’s important that you understand cabling requirements
before connecting Fast Ethernet devices to the switch.
UTP requirements
The 100BASE-TX Fast Ethernet specification requires you use
Category 5 (CAT5) unshielded twisted-pair (UTP) cabling to operate
at 100 Mbps per second. If you use lower grade cabling (CAT3 or
CAT4), you’ll get a connection, but will soon experience data loss or
slow performance.
You’re limited to 100 meters between any two devices with UTP
cable. However, you can extend the total diameter by installing a fiber
optic media adapter and using fiber optic connections between
switches, or between the switch and a router or bridge.
See pages 10–11 if you’re unsure whether your network topology
meets these distance limitations.
Fiber optic requirements
The optional 100BASE-FX fiber optic media adapter (Intel product
code ESMODFX) lets you use multimode fiber optic cable to connect
two switches, or to connect the switch with a router or bridge. The
media adapter uses an SC fiber optic connector.
With multimode fiber optic cable, signals can travel up to 412 meters
with no repeater when the link is configured at half duplex. If
configured at full duplex, the signal can travel up to 2 km.

9
Hardware Installation and Network TopologyCHAPTER 1
Straight-through vs. crossover cables
Ports on the switch are wired MDI so you can use a straight-through
cable when connecting to a Fast Ethernet repeating hub port, which is
usually wired MDI-X. For direct connection to another MDI port
(workstation, server, or another switch), you must use a crossover
cable. The pinouts of MDI and MDI-X ports are shown below.
Connector pinouts
Switch or NIC RJ-45 (MDI) Hub RJ-45 (MDI-X)
1TX+ 1RX+
2 TX- 2 RX-
3 RX+ 3 TX+
4 Unused 4 Unused
5 Unused 5 Unused
6 RX- 6 TX-
7 Unused 7 Unused
8 Unused 8 Unused
Determining which cable to use
Different switch and repeater manufacturers implement their port
configurations differently. The following guidelines are based on the
Intel Express 100BASE-TX Switching Hub (switch), the Intel Express
100BASE-TX Stackable Hub (repeater) and the EtherExpress™
family of adapters (server or workstation). These apply to the majority
of switches and hubs:
For this connection Use this cable
Switch to repeater Straight-through
Switch to server or workstation Crossover
Switch to switch Crossover
Repeater to server or workstation Straight-through
NOTE
When making your own
cables, wires 1 and 2
must be a twisted pair
and 3 and 6 must be a
twisted pair.

10
CHAPTER 1 Intel Express 100BASE-TX Switching Hub
Typical Configurations
Configuring the 100 Mbps workgroup
environment
In the 100 Mbps environment, workgroup clients should be connected
to a 100 Mbps hub such as the Intel Express 100BASE-TX Stackable
Hub. All hub stacks should be connected to the Express Switching
Hub. By connecting the hubs to a switching environment, you can
extend Fast Ethernet distance limitations.
Crossover cable
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Port 7
Port 6Port 5Port 3 Port 4
100BASE-TX
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
PC-3437
Port 1 Port2
100 Mbps clients using
Intel EtherExpress™ PRO/100 adapters
Segment 2
Segment 1
Dedicated 100 Mbps link
to file server
Straight-through cable
CAT5 UTP (100 meters max.)
Straight-through cable
Intel Express 100BASE-TX
Stackable Hubs
Straight-through
cables
100 Mbps clients using
Intel EtherExpress PRO/100 adapters

11
Hardware Installation and Network TopologyCHAPTER 1
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
PC-3438
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Port 2
Port 7
Port 6Port5Port 3 Port 4
Port 1
100BASE-TX
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Pwr Stat RPS Col Data %
ExpansionSlot
1
1
13
2
14
3
15
4
16
5
17
6
18
7
19
8
20
9
21
10
22
11
23
12
Mstr
Stat Enbl
Stat
24
PortStatus
MediaAdapter
Management
²1 5 10 15 25 ³30
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Port 2
Port 7
Port 6Port5Port 3 Port 4
Port 1
Rcv Clsn Link
Xmt FC/FD Mgm
100BASE-TX
Backbone
Router, Bridge,
or Switch of
Switches
To dissimilar LANs
CAT5 UTP (100 meters max.)
High speed 100 Mbps
servers
To T1 line
To 10 Mbps segment
NOTES
➊100BASE-FX Fiber optic media adapter optional (product code ESMODFX).
➋You can also use CAT5 UTP to connect to a backbone router or bridge.
➌Configure high-speed servers for full duplex to achieve 200 Mbps throughput.
➍If a server isn’t accessed by more than one segment, move it to a hub on the
segment.
➊➋
➌
➍
Intel Express 100BASE-TX Stackable Hubs
Multimode fiber (412 meters max. at
half duplex, 2 Km max. at full duplex)
Configuring the Wide Area Network
(WAN) environment
Connections to the backbone are most effective using fiber optic
cabling. This eliminates the 100 meter UTP restriction. Also, connect
multiple switches directly to the backbone (not each other) and
connect busy servers directly to the switch.

12
CHAPTER 1 Intel Express 100BASE-TX Switching Hub
Connecting to a 10 Mbps segment
The Express Switching Hub is a 100 Mbps-only switch. You can’t
connect a 10 Mbps device directly to the switch.
The preferred way to connect the segments is by using a bridge,
router, or a 100 Mbps uplink module for your 10 Mbps hub (there
isn’t a 10 Mbps uplink module available for the Express switching
hub). However, this is costly if you don’t already have the equipment.
An inexpensive alternative is to connect the segments through a
server.
Several adapters on the market (such as the Intel EtherExpress PRO/
100 adapter) operate at either 10 or 100 Mbps. By connecting the
Express 100BASE-TX Switching Hub to one server adapter at 100
Mbps and your 10BASE-T hub to a separate adapter at 10 Mbps in the
same server, you can route traffic from the 10 Mbps segment to the
100 Mbps segment through your Network Operating System (NOS).
If your NOS doesn’t support multi-protocol routing (Windows 95
peer-to-peer and Windows for Workgroups* don’t), you must use a
Fast Ethernet switch or router that supports both 10 Mbps and 100
Mbps.
10BASE-T repeating,
sharing, or switching hub
100 BASE-T4
Expansion Slot
Media Adapter
1
243 65871091211
Intel Express
100BASE-T4 Stackable Hub
PC-3439
Intel Express
100BASE-TX Switching Hub
Console Mgmt
SNMP Pwr
Mgmt Fault
MDI
MDI
Xmt FC/FD Mgm
Rcv Clsn Link
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
MDI
Xmt FC/FD Mgmt
Rcv Clsn Link
Xmt FC/FD Mgm
Rcv Clsn Link
Port 2
Port 7
Port 6Port5Port 3 Port 4
Port 1
Rcv Clsn Link
Xmt FC/FD Mgm
100BASE-TX
Server equipped with two
adapters, one at 100
Mbps and one at 10 Mbps
Express 100BASE-TX
Switching Hub
Crossover cable connecting the
server to the switching hub
Straight-through cable connecting the
server to the repeater
NOTE
Windows NT* 3.51 doesn’t
include the multi-protocol
router software by default.
You can download it from the
Microsoft World Wide Web
site.

13
Hardware Installation and Network TopologyCHAPTER 1
Excessive flow control problems
During times of peak network usage, you may occasionally see the
FC/FD LED blink (for a description of the LED, see page 6). This is
normal. However, if it stays lit for more than a few seconds at a time,
or if there’s an excessive number of flow controls reported by the
network management software, it could indicate a problem with your
network configuration.
A port’s FC/FD LED indicator flashes whenever a packet is received
that needs to be forwarded to a port that already has too many packets
queued. This indicates a temporary overload situation on one port; the
total traffic to the port exceeds the amount the buffer can hold. This
typically occurs when there are several fast machines on different
ports trying to access a machine across the switch. If this is
infrequent, you don’t need to do anything. However, if this occurs
often on the network, then the devices causing flow control to activate
should be identified and moved to the same segment as the device that
they are talking to.
When Ethernet bandwidth is temporarily insufficient for the traffic,
there are only three possible actions: drop packets, use flow control,
or segment the network. Buffering packets only works for a very short
while. An extended overload will eventually overflow buffers and
cause dropped packets. Flow control stops transmission on a port and
forces devices to resend packets, ensuring that packets aren’t lost.
This is the most reasonable solution, since it relies on Ethernet’s
inherent collision detection mechanism to relieve temporary overload.
Repeater count limitations
The switch doesn’t count as a repeater. Each port on the switch can
support a full Fast Ethernet network. There can be one repeater/hub
between the switch and any workstations or servers (a stack of Intel
Express 100BASE-TX Hubs counts as a single hub). Also, the total
diameter of a segment can’t exceed 200 meters when using UTP
cable. That is, the distance between any two nodes on a segment (or
the switch and a node on the other side of a hub) can’t exceed 200
meters.
NOTE
By default, flow control is
enabled on all ports.
If you configure a port for full
duplex, flow control is auto-
matically disabled.

15
2Configuring and
Managing the Switch
You don’t need to read this chapter unless you want to change the
Express Switching Hub’s default configuration (see Appendix A for a
list of defaults) or intend to manage the switch. The switch is ready to
go simply by plugging it in and turning the power on.
However, if you need to change the default configuration or manage
the switch, there are two ways:
• Use SNMP-compliant management software (not included).
However, you must first use the Console Manager to assign an IP
address to the switch.
• Use the Express Switching Hub’s internal Console Manager.

16
CHAPTER 2 Intel Express 100BASE-TX Switching Hub
Accessing the Console
Manager
The Console Manager software is contained in the switch’s
nonvolatile RAM (NVRAM); you don’t need to install any software.
To access the Console Manager:
1Use the null-modem cable (included with the switch) to connect a
workstation’s COM port to the Console Mgmt port on the switch.
Console Mgmt
2Open a terminal emulation program (such as Windows Terminal).
3Select the COM port and these communication parameters:
9600 baud, eight data bits, no parity, one stop bit
In Windows Terminal, choose Communications from the Setting
menu.
4Press E. The login prompt appears:
Login:
password:
By default, no login name or password is assigned. The password
you enter becomes active only after you reset the switch or turn
off the power. If you want the password to take effect
immediately, use the set-passwd command.
Accessing the Console Manager remotely
To access remotely through Telnet, you must first set the IP
configuration of the switch using the set-ip-conf command (see
page 32 for instructions). You can then use Telnet to reach the switch.
In a remote session, all commands work exactly as if a terminal were
directly connected to the Console Mgmt port. Note that only one
console session can be active at a time. After the first Telnet session is
established, the switch refuses other Telnet connections until the
current session is closed. To terminate an active Telnet session, press
Ethree times from the serial interface.
PC-3442