DGS-3224TGR Gigabit Ethernet Switch User’s Guide

9

4

Connecting The Switch

This chapter describes how to connect the DGS-3224TGR to your Gigabit Ethernet network.

Switch to End Node

End nodes include PCs outfitted with a 10, 100, or 1000 Mbps RJ-45 Ethernet/Fast Ethernet/Gigabit Ethernet Network

Interface Card (NIC) and most routers.

An end node can be connected to the switch via a Category 3, 4, 5, or 5e UTP/STP cable—for optimal performance,

Category 5e is recommended. The end node should be connected to any of the ports of the switch.

Figure 4-1.

Switch connected to an End Node

The

Link/Act

LEDs

light green when the link is valid. A blinking green LED indicates packet activity on that port. The

Speed LEDs indicate port speed and will light solid green for 1000 Mbps connections. They will remain off for 10 or 100

Mbps connections.

DGS-3224TGR Gigabit Ethernet Switch User’s Guide

10

Switch to Hub or Switch

These connections can be accomplished in a number of ways using a normal cable.

•

A 10BASE-T hub or switch can be connected to the switch via a two-pair Category 3, 4, 5, or 5e UTP/STP cable.

•

A 100BASE-TX hub or switch can be connected to the switch via a two-pair Category 5 or 5e UTP/STP cable.

•

A 1000BASE-T switch can be connected to the switch via four-pair straight Category 5 or 5e UTP/STP cable.

Figure 4-2.

Switch connected to a normal (non-Uplink) port on a hub or switch using a straight or

crossover cable

DGS-3224TGR Gigabit Ethernet Switch User’s Guide

11

5

Switch Management and Operating Concepts

This chapter discusses many of the concepts and features used to manage the switch, as well as the concepts necessary for

the user to understand the functioning of the switch. Further, this chapter explains many important points regarding these

features.

Configuring the switch to implement these concepts and make use of its many features is discussed in detail in the next

chapters.

Local Console Management

A local console is a terminal or a workstation running a terminal emulation program that is connected directly to the switch

via the RS-232 console port on the front of the switch. A console connection is referred to as an ‘Out-of-Band’ connection,

meaning that console is connected to the switch using a different circuit than that used for normal network communications.

So, the console can be used to set up and manage the switch even if the network is down.

Local console management uses the terminal connection to operate the console program built-in to the switch (see the

DGS-

3224TGR Command Line Interface Reference

manual). A network administrator can manage, control and monitor the

switch from the console program.

The DGS-3224TGR contains a CPU, memory for data storage, flash memory for configuration data, operational programs,

and SNMP agent firmware.

Diagnostic (console) port (RS-232 DCE)

Out-of-band management requires connecting a terminal, such as a VT-100 or a PC running a terminal emulation program

(such as HyperTerminal, which is automatically installed with Microsoft Windows) a to the RS-232 DCE console port of

the switch. Switch management using the RS-232 DCE console port is called

Local

Console Management

to differentiate it

from management performed via management platforms, such as D-View, HP OpenView, etc.

The console port is set at the factory for the following configuration:

•

Baud rate:

9,600

•

Data width:

8 bits

•

Parity:

none

•

Stop bits:

1

•

Flow Control

None

Make sure the terminal or PC you are using to make this connection is configured to match these settings.

If you are having problems making this connection on a PC, make sure the emulation is set to VT-100. If you still don’t see

anything, try hitting <Ctrl> + r to refresh the screen.

DGS-3224TGR Gigabit Ethernet Switch User’s Guide

12

IP Addresses and SNMP Community Names

Each switch must be assigned its own IP Address, which is used for communication with an SNMP network manager or

other TCP/IP application (for example BOOTP, TFTP). The switch’s default IP address is 10.90.90.90. You can change the

default switch IP Address to meet the specification of your networking address scheme.

The switch is also assigned a unique MAC address by the factory. This MAC address cannot be changed, and can be found

when using the command “show switch.”

In addition, you can also set an IP address for a gateway router. This becomes necessary when the network management

station is located on a different IP network from the switch, making it necessary for management packets to go through a

router to reach the network manager, and vice-versa.

For security, you can set in the switch a list of IP Addresses of the network managers that allow you to manage the switch.

You can also change the default SNMP Community Strings in the switch and set the access rights of these Community

Strings. In addition, a VLAN may be designated as a Management VLAN.

Setting an IP Address

The IP address for the switch must be set before it can be managed with the Web-based manager. The switch IP address

may be automatically set using BOOTP or DHCP protocols, in which case the actual address assigned to the switch must be

known.

The IP address may alternatively be set using the Command Line Interface (CLI) over the console serial port as follows

:

1.

Starting at the command line prompt

local>

, enter the commands

config ipif System ipaddress

xxx.xxx.xxx.xxx/yyy.yyy.yyy.yyy

. Where the

x

’s represent the IP address to be assigned to the IP interface

named

System

and the

y

’s represent the corresponding subnet mask.

2.

Alternatively, you can enter

the commands

config ipif System ipaddress xxx.xxx.xxx.xxx/z

. Where the

x

’s

represent the IP address to be assigned to the IP interface named

System

and the

z

represents the

corresponding number of subnets in CIDR notation.

Using this method, the switch can be assigned an IP address and subnet mask that can then be used to connect a

management station to the switch’s Web-based management agent.

Traps

Traps are messages that alert you of events that occur on the switch. The events can be as serious as a reboot (someone

accidentally turned OFF the switch), or less serious like a port status change. The switch generates traps and sends them to

the network manager (trap recipient).

Trap recipients are special users of the network who are given certain rights and access in overseeing the maintenance of

the network. Trap recipients will receive traps sent from the switch; they must immediately take certain actions to avoid

future failure or breakdown of the network.

You can also specify which network managers may receive traps from the switch by entering a list of the IP addresses of

authorized network managers. Up to four trap recipient IP addresses, and four corresponding SNMP community strings can

be entered.

SNMP community strings function like passwords in that the community string entered for a given IP address must be used

in the management station software, or a trap will be sent.

The following are trap types the switch can send to a trap recipient:

•

Cold Start

–This trap signifies that the switch has been powered up and initialized such that software settings are

reconfigured and hardware systems are rebooted. A cold start is different from a factory reset in that configuration

settings saved to non-volatile RAM used to reconfigure the switch.

•

Authentication Failure

– This trap signifies that someone has tried to logon to the switch using an invalid SNMP

community string. The switch automatically stores the source IP address of the unauthorized user.

DGS-3224TGR Gigabit Ethernet Switch User’s Guide

13

•

New Root

– This trap indicates that the switch has become the new root of the Spanning Tree, the trap is sent by

the switch soon after its election as the new root. This implies that upon expiration of the Topology Change Timer

the new root trap is sent out immediately after the switch’s election as the new root.

•

Topology Change (STP)

– A Topology Change trap is sent by the switch when any of its configured ports

transitions from the Learning state to the Forwarding state, or from the Forwarding state to the Blocking state. The

trap is not sent if a new root trap is sent for the same transition.

•

Connected and Working

– This trap is sent when the Redundant Power Supply is connected and working.

•

Disconnect or Malfunction

– This trap is sent whenever the Redundant Power Supply malfunctions.

•

MAC Notification

–

This trap indicates that the switch had learned a new MAC address.

MIBs

Management and counter information are stored in the switch in the Management Information Base (MIB. The switch uses

the standard MIB-II Management Information Base module. Consequently, values for MIB objects can be retrieved from

any SNMP-based network management software. In addition to the standard MIB-II, the switch also supports its own

proprietary enterprise MIB as an extended Management Information Base. These MIBs may also be retrieved by specifying

the MIB’s Object-Identity (OID) at the network manager. MIB values can be either read-only or read-write.

Read-only MIBs variables can be either constants that are programmed into the switch, or variables that change while the

switch is in operation. Examples of read-only constants are the number of port and type of ports. Examples of read-only

variables are the statistics counters such as the number of errors that have occurred, or how many kilobytes of data have

been received and forwarded through a port.

Read-write MIBs are variables usually related to user-customized configurations. Examples of these are the switch’s IP

Address, Spanning Tree Algorithm parameters, and port status.

If you use a third-party vendors’ SNMP software to manage the switch, a diskette listing the switch’s propriety enterprise

MIBs can be obtained by request. If your software provides functions to browse or modify MIBs, you can also get the MIB

values and change them (if the MIBs’ attributes permit the write operation). This process however can be quite involved,

since you must know the MIB OIDs and retrieve them one by one.

SNMP

The Simple Network Management Protocol (SNMP) is an OSI layer 7 (the application layer) protocol for remotely

monitoring and configuring network devices. SNMP enables network management stations to read and modify the settings

of gateways, routers, switches, and other network devices. SNMP can be used to perform many of the same functions as a

directly connected console, or can be used within an integrated network management software package such as HP

OpenView or DView.

SNMP performs the following functions:

•

Sending and receiving SNMP packets through the IP protocol.

•

Collecting information about the status and current configuration of network devices.

•

Modifying the configuration of network devices.

The DGS-3224TGR has a software program called an ‘agent’ that processes SNMP requests, but the user program that

makes the requests and collects the responses runs on a management station (a designated computer on the network). The

SNMP agent and the user program both use the UDP/IP protocol to exchange packets.