Dell PowerConnect 2808 User manual

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Dell™ PowerConnect™
28xx Systems
User Guide

Notes, Notices, and Cautions
NOTE: A NOTE indicates important information that helps you make better use of your computer.
NOTICE: A NOTICE indicates either potential damage to hardware or loss of data and tells you how to avoid the problem.
CAUTION: A CAUTION indicates a potential for property damage, personal injury, or death.
____________________
Information in this document is subject to change without notice.
© 2012 Dell Inc. All rights reserved.
Reproduction in any manner whatsoever without the written permission of Dell Inc. is strictly forbidden.
Trademarks used in this text: Dell, Dell OpenManage, the DELL logo, Inspiron, Dell Precision, Dimension, OptiPlex, PowerConnect,
PowerApp, PowerVault, Axim, DellNet, and Latitude are trademarks of Dell Inc. Microsoft and Windows are either trademarks or registered
trademarks of Microsoft Corporation in the United States and/or other countries.
Other trademarks and trade names may be used in this document to refer to either the entities claiming the marks and names or their products.
Dell Inc. disclaims any proprietary interest in trademarks and trade names other than its own.
March 4, 2012 Rev. A04

3
Contents
1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PowerConnect 2808 . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PowerConnect 2816 . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PowerConnect 2824 . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
PowerConnect 2848 . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Summary of PowerConnect Models . . . . . . . . . . . . . . . . . . . 11
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
General Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
MAC Address Supported Features . . . . . . . . . . . . . . . . . . . . 13
Layer 2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
VLAN Supported Features. . . . . . . . . . . . . . . . . . . . . . . . 14
Spanning Tree Protocol Features . . . . . . . . . . . . . . . . . . . . . 15
Class of Service (CoS) Features . . . . . . . . . . . . . . . . . . . . . 16
Ethernet Switch Management Features. . . . . . . . . . . . . . . . . . 16
2 Hardware Description . . . . . . . . . . . . . . . . . . . . . . . . 17
Switch Port Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . 17
PowerConnect 28xx Front and Back Panel Port Description . . . . . . . 17
Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
LED Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Power LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Managed Mode LED. . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Fan LED (2824/2848 only) . . . . . . . . . . . . . . . . . . . . . . . 22
Port LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Managed Mode Button. . . . . . . . . . . . . . . . . . . . . . . . . . 23
Switch Ventilation Fan . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Cables, Port Connections, and Pinout Information . . . . . . . . . . . . . . 24
1000BASE-T Cable Requirements. . . . . . . . . . . . . . . . . . . . 24
RJ-45 Connections for 10/100/1000BASE-T Ports. . . . . . . . . . . . 24
SFP Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4
Power Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Internal Power Supply Connector . . . . . . . . . . . . . . . . . . . . 26
3 Installing the PowerConnect Device . . . . . . . . . . . . . . 27
Installation Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Site Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Package Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Unpacking the Device . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Mounting the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Device Rack Installation . . . . . . . . . . . . . . . . . . . . . . . . . 29
Installing on a Flat Surface. . . . . . . . . . . . . . . . . . . . . . . . 30
Installing on a Wall . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Connecting the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Connecting the Device to the Network . . . . . . . . . . . . . . . . . . . . 33
Connecting the Terminal to the Device . . . . . . . . . . . . . . . . . . . . 33
Connecting a Device to a Power Supply . . . . . . . . . . . . . . . . . 34
Port Connections, Cables, and Pinout Information . . . . . . . . . . . . . . 35
RJ-45 Connections for 10/100/1000BaseT Ports . . . . . . . . . . . . . 35
Port Default Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Auto-Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
MDI/MDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Flow Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Back Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Switching Port Default Settings . . . . . . . . . . . . . . . . . . . . . 38
4 Starting and Configuring the Device . . . . . . . . . . . . . . 39
Management Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Transitioning Between Modes. . . . . . . . . . . . . . . . . . . . . . . . . 42
Booting the Device - Managed Mode . . . . . . . . . . . . . . . . . . . . . 44
Initial Configuration Through the Set-up Wizard . . . . . . . . . . . . . . . 44

5
Initial Configuration Through the Web . . . . . . . . . . . . . . . . . . . . 48
Basic Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Retrieving an IP Address From a DHCP Server . . . . . . . . . . . . . 49
Startup Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Software Download . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Erase FLASH File . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Erasing the Device Configuration . . . . . . . . . . . . . . . . . . . . 51
Password Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Software Download Through TFTP Server . . . . . . . . . . . . . . . 52
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
5 Using Dell OpenManage Switch Administrator. . . . . . . 54
Understanding the Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Using the Switch Administrator Buttons . . . . . . . . . . . . . . . . . . . 55
Information Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Device Management Buttons . . . . . . . . . . . . . . . . . . . . . . 56
Starting the Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Access Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6 Configuring System Information. . . . . . . . . . . . . . . . . 58
Defining General Device Information . . . . . . . . . . . . . . . . . . . . . 58
Viewing Device Information . . . . . . . . . . . . . . . . . . . . . . . 58
Viewing the Versions Page . . . . . . . . . . . . . . . . . . . . . . . . 60
Resetting the Device . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Entering Secure Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Defining Device IP Addresses . . . . . . . . . . . . . . . . . . . . . . . . 63
Defining IP Interface Parameters. . . . . . . . . . . . . . . . . . . . . 63
Running Cable Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Viewing Copper Cable Diagnostics . . . . . . . . . . . . . . . . . . . 64
Viewing Optical Transceiver Diagnostics . . . . . . . . . . . . . . . . 65
Managing Device Security . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Defining the Local User Databases. . . . . . . . . . . . . . . . . . . . 68
Configuring RADIUS Global Parameters . . . . . . . . . . . . . . . . 70

6
Defining SNMP Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Defining SNMP Global Parameters . . . . . . . . . . . . . . . . . . . 74
Defining Communities . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Defining SNMP Notification Recipients . . . . . . . . . . . . . . . . . 77
Managing Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Downloading Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Uploading Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Restoring Default Settings . . . . . . . . . . . . . . . . . . . . . . . . 82
Defining DHCP Server Settings. . . . . . . . . . . . . . . . . . . . . . . . 83
Configuring DHCP Properties . . . . . . . . . . . . . . . . . . . . . . 83
Defining Network Pool . . . . . . . . . . . . . . . . . . . . . . . . . 85
Excluding Addresses. . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Manually Allocating IP Addresses (Static Hosts) . . . . . . . . . . . . 88
Address Binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Defining Advanced Settings . . . . . . . . . . . . . . . . . . . . . . . . . 92
Configuring General Device Parameters . . . . . . . . . . . . . . . . . 92
7 Configuring Device Switching . . . . . . . . . . . . . . . . . . 93
Configuring Network Security . . . . . . . . . . . . . . . . . . . . . . . . 93
Configuring Port Based Authentication . . . . . . . . . . . . . . . . . 94
Configuring Advanced Port Based Authentication . . . . . . . . . . . . 97
Authenticating Users. . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Configuring Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Defining Port Parameters . . . . . . . . . . . . . . . . . . . . . . . 101
Aggregating Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Configuring Green Ethernet . . . . . . . . . . . . . . . . . . . . . . 106
Enabling Storm Control . . . . . . . . . . . . . . . . . . . . . . . . 108
Defining Port Mirroring Sessions . . . . . . . . . . . . . . . . . . . 110
Configuring Address Tables. . . . . . . . . . . . . . . . . . . . . . . . . 112
Viewing Dynamic Addresses. . . . . . . . . . . . . . . . . . . . . . 112
Configuring the Spanning Tree Protocol . . . . . . . . . . . . . . . . . . 114
Defining STP Global Settings . . . . . . . . . . . . . . . . . . . . . 114
Defining STP Port Settings . . . . . . . . . . . . . . . . . . . . . . 117
Defining STP LAG Settings . . . . . . . . . . . . . . . . . . . . . . 120
Configuring Rapid Spanning Tree . . . . . . . . . . . . . . . . . . . 122

7
Configuring VLANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Defining VLAN Members . . . . . . . . . . . . . . . . . . . . . . . 124
VLAN Port Membership Table . . . . . . . . . . . . . . . . . . . . 126
Defining VLAN Ports Settings. . . . . . . . . . . . . . . . . . . . . 128
Defining VLAN LAG Settings. . . . . . . . . . . . . . . . . . . . . 129
Aggregating Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Defining LAG Membership . . . . . . . . . . . . . . . . . . . . . . 132
Multicast Forwarding Support . . . . . . . . . . . . . . . . . . . . . . . 132
Defining Multicast Global Parameters . . . . . . . . . . . . . . . . . 133
Adding Bridge Multicast Address Members . . . . . . . . . . . . . . 134
Assigning Multicast Forward All Parameters . . . . . . . . . . . . . 136
IGMP Snooping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
8 Viewing Statistics. . . . . . . . . . . . . . . . . . . . . . . . . . 141
Viewing RMON Statistics. . . . . . . . . . . . . . . . . . . . . . . . . . 141
Viewing RMON Statistics Group . . . . . . . . . . . . . . . . . . . 141
Viewing Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Viewing the CPU Utilization. . . . . . . . . . . . . . . . . . . . . . 142
9 Configuring Quality of Service. . . . . . . . . . . . . . . . . 144
Defining CoS Global Parameters . . . . . . . . . . . . . . . . . . . . . . 146
Defining CoS Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Defining QoS Interface Settings. . . . . . . . . . . . . . . . . . . . . . . 147
Defining Queue Settings . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Mapping CoS Values to Queues . . . . . . . . . . . . . . . . . . . . . . . 150
Mapping DSCP Values to Queues. . . . . . . . . . . . . . . . . . . . . . 151
A Managing the Device Using the CLI . . . . . . . . . . . . . 153
Accessing the Device Through the CLI . . . . . . . . . . . . . . . . . . . 153
Console Connection . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Telnet Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

8
Using the CLI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Command Mode Overview . . . . . . . . . . . . . . . . . . . . . . 154
User EXEC Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Privileged EXEC Mode . . . . . . . . . . . . . . . . . . . . . . . . 155
Global Configuration Mode . . . . . . . . . . . . . . . . . . . . . . 155
Interface Configuration Mode . . . . . . . . . . . . . . . . . . . . . 156
CLI Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Command: copy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Command: debug-mode . . . . . . . . . . . . . . . . . . . . . . . . 158
Command: do . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Command: end. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Command: exit (configuration) . . . . . . . . . . . . . . . . . . . . 159
Command: exit (EXEC) . . . . . . . . . . . . . . . . . . . . . . . . 160
Command: help . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Command: interface ethernet . . . . . . . . . . . . . . . . . . . . . 160
Command: interface port-channel . . . . . . . . . . . . . . . . . . . 161
Command: interface vlan . . . . . . . . . . . . . . . . . . . . . . . 161
Command: ip address . . . . . . . . . . . . . . . . . . . . . . . . . 162
Command: ping . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Command: show tech-support command. . . . . . . . . . . . . . . . 165
Command: snmp-server community . . . . . . . . . . . . . . . . . . 166
Command: username. . . . . . . . . . . . . . . . . . . . . . . . . . 167
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Dell PowerConnect 28xx Systems User Guide 9
1
Introduction
This User’s Guide contains the information needed for installing, configuring and maintaining the
PowerConnect 2808, PowerConnect 2816, PowerConnect 2824, and PowerConnect 2848 Web-
managed Gigabit Ethernet switches.
The PowerConnect 28xx switches can be used to connect workstations and other network devices,
such as:
•Servers
•Hubs
•Routers
The PowerConnect devices are primarily designated for the Small Office/Home Office (SOHO) that
require high performance edge connectivity. These PowerConnect devices are ideal for the small to
medium business that requires high performance network connectivity along with advanced web
management features. The PowerConnect management features are designed to minimize
administrative management effort, while enhancing and improving network traffic control.
System Description
This section describes the hardware configurations of the PowerConnect 28xx. The switches are
managed by Dell’s OpenManage Switch Administrator.
PowerConnect 2808
The following figure illustrates the PowerConnect 2808 front panel.
Figure 1-1. PowerConnect 2808 Front Panel
The PowerConnect 2808 supports the following ports:
• 8 Gigabit Ethernet copper ports
PowerConnect 2816
The following figure illustrates the PowerConnect 2816 front panel.
1

10 Dell PowerConnect 28xx Systems User Guide
Figure 1-2. PowerConnect 2816 Front Panel
The PowerConnect 2816 supports the following ports:
• 16 Gigabit Ethernet copper ports
PowerConnect 2824
The following figure illustrates the PowerConnect 2824 front panel.
Figure 1-3. PowerConnect 2824 Front Panel
The PowerConnect 2824 supports the following ports:
• 24 Gigabit Ethernet copper ports
• 2 SFP combo ports (1000BASE-SX or 1000BASE-LX)
PowerConnect 2848
The following figure illustrates the PowerConnect 2848 front panel.
Figure 1-4. PowerConnect 2848 Front Panel
The PowerConnect 2848 supports the following ports:
• 48 Gigabit Ethernet copper ports
• 4 SFP combo ports (1000BASE-SX or 1000BASE-LX)

Dell PowerConnect 28xx Systems User Guide 11
Summary of PowerConnect Models
The following table summarizes the PowerConnect models.
Features
General Features
Management Modes
The device supports the following modes:
• Managed Mode — Provides switch management through the web interface.
•
Unmanaged Mode — In this mode, the device operates as a hub with default configuration, and
configuration cannot be changed.
•
Secure Mode — This mode keeps the existing configuration active, but it prevents users from making
configuration changes by removing the IP address of the device so that it becomes inaccessible for
configuration.
For more information about the management modes, see "Management Modes" on page 49.
Head of Line Blocking Prevention
Head of Line (HOL) blocking results in traffic delays and frame loss caused by traffic competing for the
same egress port resources. HOL blocking queues packets, and the packets at the head of the queue are
forwarded before packets at the end of the queue. By default, the device is configured so that the HOL
blocking prevention mechanism is active at all times, except when QoS (Quality of Service), Flow
Control or Back Pressure is active on a port where the HOL blocking prevention mechanism is disabled
on the whole system.
Back Pressure Support
On half-duplex links, the receiving port prevents buffer overflows by occupying the link so that it is
unavailable for additional incoming traffic. The user may enable or disable this feature on a
per-port basis. The default status on all ports is set to OFF.
Table 1-1. PowerConnect Models
Model Copper Ports/
RJ-45 Connectors
Optical Ports/
GbE
RS232 serial port -
baud rate is 9600 bps
Fans
PowerConnect 2808 8 built-in 10/100/1000 Base-T ports none Internal console port none
PowerConnect 2816 16 built-in 10/100/1000 Base-T ports none External console port none
PowerConnect 2824 24 built-in 10/100/1000 Base-T ports 2 SFP (combo) External console port 1
PowerConnect 2848 48 built-in 10/100/1000 Base-T ports 4 SFP (combo) External console port 32

12 Dell PowerConnect 28xx Systems User Guide
Auto Negotiation
Auto negotiation allows an Ethernet switch to advertise modes of operation. The auto negotiation
function provides the means to exchange information between two Ethernet switches that share a point-
to-point link segment, and to automatically configure both Ethernet switches to take maximum
advantage of their transmission capabilities. Port advertisement allows the system administrator to
configure the port speeds advertised.
Jumbo Frames Support
Jumbo frames are frames with an MTU (Maximum Transmission Unit) size of up to 10K bytes. The
Jumbo Frames Support feature, utilizes the network optimally by transporting the same data using less
frames.
The main benefits of this facility are reduced transmission overhead and reduced host processing
overhead. Jumbo frames are used for server-to-server transfers.
AutoMDI/MDIX Support
The switch automatically detects whether the cable connected to an RJ-45 port is crossed or straight
through.
Standard wiring for end stations is Media-Dependent Interface (MDI) and the
s tandard wiring for hubs
and switches is known as Media-Dependent Interface with Crossover (MDIX).
Auto MDI/MDIX works on 10/100/1000BASE-T Ethernet ports. This feature is automatically enabled for
the entire system and cannot be turned off by the user.
Flow Control Support (IEEE802.3X)
On Full Duplex links (FDX), the flow control mechanism allows the receiving side to signal to the
sending side that transmission must be halted temporarily, in order to prevent buffer overflows. Flow
control is enabled by default.
Virtual Cable Testing (VCT)
VCT technology provides the mechanism to detect and report potential cabling issues, such as cable
opens and cable shorts on copper links.
Cable analysis is available on Copper Cables (10BASE-T/100BASE-T/1000BASE-T), and is only done
when the link is down. When the system initiates a cable-testing operation, upon explicit user action, the
following parameters are detected:
• Cable Type and Status
•CableLength
• Fault-Distance

Dell PowerConnect 28xx Systems User Guide 13
MAC Address Supported Features
MAC Address Capacity Support
The PowerConnect 2808, 2816, 2824 switches support a total of 8K MAC addresses, and the
PowerConnect 2848 supports a total of 16K MAC addresses.
Auto-Learning MAC Addresses
The switch enables MAC address auto-learning from incoming packets. The MAC addresses are stored in
the Bridging Table.
Automatic Aging for MAC Addresses
MAC addresses from which no traffic is received for a given period of time are aged out. This prevents
the Bridging Table from overflowing.
VLAN-aware MAC-based Switching in Managed and Secure Modes
In Managed or Secure mode, the switch system always performs VLAN-aware bridging. Classic bridging
(IEEE802.1D) is not performed (where frames are forwarded based only on their destination MAC
address). However, a similar functionality may be configured for untagged frames. Addresses are
associated with ports by learning them from the incoming frames source address.
802.1D Bridging in Unmanaged Mode
In Unmanaged Mode, the switch performs classic bridging. Frames are forwarded based on their
destination MAC address only, regardless of the VLAN tag.
MAC Multicast Support
Multicast service is a limited broadcast service, which allows one-to-many and many-to-many
connections for information distribution. Layer 2 Multicast service is where a single frame is addressed to
a specific Multicast address, from where copies of the frame are transmitted to the relevant ports. IGMP
Snooping is supported, including IGMP Querier which simulates the behavior of a multicast router,
allowing snooping of the layer 2 multicast domain even though there is no multicast router. When
Multicast groups are statically enabled, you can set the destination port of registered groups, as well as
define the behavior of unregistered multicast frames.
Layer 2 Features
Green Ethernet
Green Ethernet, also known as Energy Efficient Ethernet, is an effort to make networking equipment
environmentally friendly, specifically by reducing power usage of Ethernet connections. The following
methods are supported by the device:
• Energy-Detect — Auto-detection of inactivity on a port, and subsequent reducing of transmit power.

14 Dell PowerConnect 28xx Systems User Guide
• Short-Reach — Reduction of power over Ethernet cables shorter than 40m.
IGMP Snooping
Internet Group Membership Protocol (IGMP) Snooping examines IGMP frame contents, when they are
forwarded by the device from work stations to an upstream Multicast router. From the frame, the device
identifies work stations configured for Multicast sessions, and which Multicast routers are sending
Multicast frames.
Port Mirroring
The port mirroring mechanism monitors and mirrors network traffic by forwarding copies of incoming
and outgoing packets from a monitored port to a monitoring port. Users can specify which target port
receives copies of all traffic passing through one or more source ports.
Storm Control
Storm Control enables limiting the amount of Multicast, Broadcast and Unknown Unicast frames
accepted and forwarded by the switch. When Layer 2 frames are forwarded, Broadcast and Multicast
frames are flooded to all ports on the relevant VLAN. All nodes connected to these ports accept and
attempt to process these frames, thus placing load on both the network links and the host operating
system.
Dynamic VLAN Assignment (DVA)
Dynamic VLAN Assignment allows automatic assignment of users to VLANs during the RADIUS server
authentication. When a user is authenticated by the RADIUS server, the user is automatically joined to
the VLAN configured on the RADIUS server.
VLAN Supported Features
VLAN Support
VLANs are collections of switching ports that comprise a single broadcast domain. Packets are classified
as belonging to a VLAN based on either the VLAN tag or based on a combination of the ingress port and
package contents. Packets sharing common attributes can be grouped in the same VLAN.
Port Based Virtual LANs (VLANs)
Port-based VLANs classify incoming packets to VLANs based on their ingress port.
Link Aggregation
The PowerConnect 28xx switches support up to eight aggregated links. Each of the eight aggregated
links may be defined with up to eight member ports to form a single Link Aggregated Group (LAG).
The benefits of this facility are:
• Fault tolerance protection from physical link disruption

Dell PowerConnect 28xx Systems User Guide 15
• Higher bandwidth connections
• Improved bandwidth granularity
• High bandwidth server connectivity
A LAG is composed of ports with the same speed set to full-duplex operation.
DHCP Server
Dynamic Host Configuration Protocol is a method of managing network parameter assignment from a
single DHCP server. The Dynamic Host Configuration Protocol (DHCP) automates the assignment of
IP addresses, subnet masks, default gateway, and other IP parameters.
BootP and DHCP Clients
DHCP (Dynamic Host Configuration Protocol) enables additional setup parameters to be received from
a network server upon system startup. DHCP service is an on-going process. DHCP is an extension to
BootP.
The BootP client is operational if there is a corrupted or invalid software image. The BootP client then
continuously attempts to find a BootP server, by sending BootP requests to all ports on the default
VLAN, until a BootP server replies. The information replied is then used to provide the switch system
with a TFTP server IP address and a download file name. The switch can then configure these values to
the TFTP client and try to download a valid runtime image.
Spanning Tree Protocol Features
Spanning Tree Protocol (STP)
802.1d Spanning tree is a standard Layer 2 switch requirement that allows bridges to automatically
prevent and resolve L2 forwarding loops. Switches exchange configuration messages using specifically
formatted frames and selectively enable and disable forwarding on ports.
Fast Link
STP can take up to 30-60 seconds to converge. During this time, STP detects possible loops, allowing
time for status changes to propagate and for relevant devices to respond. 30-60 seconds is considered too
long of a response time for many applications. The Fast Link option bypasses this delay, and can be used
in network topologies where forwarding loops do not occur.
IEEE 802.1w Rapid Spanning Tree
Spanning Tree can take 30-60 seconds for each host to decide whether its ports are actively forwarding
traffic. Rapid Spanning Tree (RSTP) detects uses of network topologies to enable faster convergence,
without creating forwarding loops.
STP Root Guard
Root guard restricts the interface from functioning as the root port for the switch

16 Dell PowerConnect 28xx Systems User Guide
Class of Service (CoS) Features
The PowerConnect 28xx system enables users to define various services for traffic classes of service. The
underlying mechanism for supporting bandwidth management and control is based on the use of
multiple priority queues for classifying traffic. The switches support four queues per port.
A CoS is defined by the user, whereby packets are related to the same Class of Service. After a packet has
been classified, it is assigned to one of the queues. The PowerConnect 28xx system can classify according
to IPv4 information (DSCP).
Class of Service 802.1p Support
The IEEE 802.1p signaling technique is an OSI Layer 2 standard for marking and prioritizing network
traffic at the data link/MAC sub-layer. 802.1p traffic is classified and sent to the destination. No
bandwidth reservations or limits are established or enforced. 802.1p is a spin-off of the 802.1Q (VLANs)
standard.
Ethernet Switch Management Features
Web-Based Management
With a Web-based management interface, the Ethernet Switches’ system can be managed from any
Web browser. The system contains an Embedded Web Server (EWS), which serves HTML pages,
through which the system can be monitored and configured.
TFTP Trivial File Transfer Protocol
The PowerConnect 28xx switches support software boot image and software download through TFTP.
Remote Monitoring
Remote Monitoring (RMON) is an extension to the Simple Network Management Protocol (SNMP),
which provides network traffic statistics. RMON defines current and historical MAC-layer statistics and
control objects, allowing real-time information to be captured across the entire network. The switches
support one RMON group for Ethernet statistics. The system provides a means to collect the statistics
defined in RMON and to view the results, using the Web management interface in the system.

Dell PowerConnect 28xx Systems User Guide 17
2
Hardware Description
Switch Port Configurations
PowerConnect 28xx Front and Back Panel Port Description
The Dell™ PowerConnect™ 28xx switches use 10/100/1000BASE-T ports on the front panel for
connecting to a network.
The Gigabit Ethernet ports can operate at 10, 100 or 1000 Mbps. These ports support auto-
negotiation, duplex mode (Half or Full duplex), and flow control. The combo 1000 Mbps optical
ports can only operate at 1000 Mbps, full-duplex mode.
The following figures illustrate the front panels and back panels of the PowerConnect 28xx switches.
Figure 2-1. PowerConnect 2808 Front Panel
On the front panel there are eight ports which are numbered 1 to 8, top down and left to right. On
each port there are LEDs (Light Emitting Diode) to indicate the port status.
On the left side of the front panel is the Managed Mode LED which indicates the Ethernet switch
operational status and the management mode. The Power LED on the front panel indicates whether
the device is powered on or not. A Mode push-button, located on the right side on the front panel is
used to transition between management modes and to reset the device. For more information about
management modes and transitioning between them, see "Management Modes" on page 49.

18 Dell PowerConnect 28xx Systems User Guide
Figure 2-2. PowerConnect 2808 Back Panel
Figure 2-3. PowerConnect 2816 Front Panel
On the front panel there are 16 ports which are numbered 1 to 16, top down and left to right. On each
port there are LEDs to indicate the port status.
On the left side of the front panel is the Managed Mode LED which indicates the Ethernet switch
operational status and the management mode. The Power LED on the front panel indicates whether the
device is powered on or not. A Mode push-button, located on the right side on the front panel, is used to
transition between management modes and to reset the device. For more information about
management modes and transitioning between them, see "Management Modes" on page 49.
Figure 2-4. PowerConnect 2816 Back Panel

Dell PowerConnect 28xx Systems User Guide 19
Figure 2-5. PowerConnect 2824 Front Panel
On the front panel there are 24 ports which are numbered 1 to 24, top down and left to right. On each
port there are LEDs to indicate the port status. There are two SFP (Small Form-Factor Plugable) ports,
designated as ports 23 and 24, for fiber connection. The two combo ports are logical ports with two
physical connections:
• An RJ-45 connection for Twisted Pair (TP) copper cabling
• An SFP port for swappable optical transceiver, which offers high-speed 1000BASE-SX or 1000BASE-
LX connection.
NOTE: Only one of the two physical connections of a combo port can be used at any one time. Port features and
port controls are determined by the physical connection used. The system automatically detects the media used on
a combo port, and utilizes the information in all the control interfaces.
NOTE: The system can switch from the RJ-45 to the SFP (or vice versa) without resetting the device. If both RJ-45
and SFP ports are present, the SFP port will be the active port, whereas the RJ-45 port will be disabled.
On the front panel is the Managed Mode LED which indicates the Ethernet switch operational status
and the management mode. The Fan LED indicates the device fan operations status, and the Power
LED on the front panel indicates whether the device is powered on or not. A Mode push-button, located
on the right side on the front panel is used to transition between management modes and to reset the
device. For more information about management modes and transitioning between them, see
"Management Modes" on page 49.

20 Dell PowerConnect 28xx Systems User Guide
Figure 2-6. PowerConnect 2824 Back Panel
Figure 2-7. PowerConnect 2848 Front Panel
On the front panel there are 48 ports, which are numbered 1 to 48, top down and left to right. On each
port, there are LEDs to indicate the port status. There are four SFP (Small Form-Factor Plugable) ports,
designated as ports 45, 46, 47 and 48, for fiber connection. The four combo ports are logical ports with
two physical connections:
• An RJ-45 connection for Twisted Pair (TP) copper cabling.
• An SFP port for swappable optical transceiver, which offers high-speed 1000BASE-SX or
1000BASE-LX connection.
NOTE: Only one of the two physical connections of a combo port can be used at any one time. Port features and
port controls are determined by the physical connection used. The system automatically detects the media used on
a combo port, and utilizes the information in all the control interfaces.
NOTE: The system can switch from the RJ-45 to the SFP (or vice versa) without resetting the device. If both RJ-45
and SFP ports are present, the SFP port will be the active port, whereas the RJ-45 port will be disabled.
On the top right side of the front panel is the Managed Mode LED which indicates the Ethernet switch
operational status and the management mode. The Fan LED indicates the device fan operations status,
and the Power LED on the front panel indicates whether the device is powered on or not. A Mode push-