Table Of Contents
Managing Configuration Conflicts
Saving Changes to the Startup Configuration
Managing Switches through Switch Network View
Understanding a Switch Network View Stack
Displaying the Switch Network View Page
Displaying Switch Connection Information
Checking Port Speed and Duplex Settings
Managing Your Switch through CVSM
CLI Procedure for Changing the Password
Enabling the Switch as a Command Switch
CLI Procedure for Enabling the Command Switch and Naming the Cluster
Configuring Ports on the Switch Home Page
Connecting to Devices That Do Not Autonegotiate
CLI Procedure for Setting Speed and Duplex Parameters
CLI Procedure for Configuring Flow Control on Gigabit Ethernet Ports
Creating EtherChannel Port Groups
Understanding EtherChannel Port Grouping
Port Group Restrictions on Static-Address Forwarding
CLI Procedure for Creating EtherChannel Port Groups
CLI Procedure for Enabling Switch Port Analyzer
CLI Procedure for Disabling Switch Port Analyzer
CLI Procedure for Enabling a Network Port
CLI Procedure for Disabling a Network Port
Enabling Broadcast Storm Control
CLI Procedure for Enabling Broadcast Storm Control
CLI Procedure for Disabling Broadcast Storm Control
Blocking Flooded Traffic on a Port
CLI Procedure for Blocking Flooded Traffic on a Port
CLI Procedure for Resuming Normal Forwarding on a Port
Reloading and Upgrading the Switch Software
Entering the System Reload Options
CLI Procedure for Upgrading the Switch Software
Setting the System Date and Time
Setting the System Date and Time
CLI Procedure for Setting the System Date and Time
Configuring the Network Time Protocol
Configuring the Switch as an NTP Client
Configuring the Switch for NTP Broadcast-Client Mode
CLI Procedure for Configuring NTP
Assigning IP Information to the Switch
CLI Procedure for Assigning IP Information to the Switch
CLI Procedure for Removing an IP Address
Configuring the Management VLAN Interface
Management VLAN Characteristics
Guidelines for Changing the Management VLAN
CLI Procedure for Configuring the Management VLAN Interface through a Console Connection
CLI Procedure for Configuring the Management VLAN Interface through a Telnet Connection
Specifying a Domain Name and Configuring the DNS
CLI Procedure for Configuring DNS
CLI Procedure for Configuring SNMP and Community Strings
CLI Procedure for Adding a Trap Manager
CLI Procedure for Managing the ARP Table
Managing the MAC Address Tables
Changing the Address Aging Time
CLI Procedure for Configuring the Aging Time
CLI Procedure for Removing Dynamic Address Entries
CLI Procedure for Adding Secure Addresses
CLI Procedure for Removing Secure Addresses
Adding and Removing Static Addresses
Configuring Static Addresses for EtherChannel Port Groups
CLI Procedure for Adding Static Addresses
CLI Procedure for Removing Static Addresses
Defining the Maximum Secure Address Count
CLI Procedure for Enabling Port Security
CLI Procedure for Disabling Port Security
Configuring the Cisco Discovery Protocol
CLI Procedure for Configuring CDP
Controlling IP Management Packets through CGMP
Enabling the Fast Leave Feature
CLI Procedure for Enabling the CGMP Fast Leave Feature
CLI Procedure for Disabling the CGMP Fast Leave Feature
CLI Procedure for Changing the Router Hold-Time
CLI Procedure for Removing Multicast Groups
Configuring the Spanning-Tree Protocol
Using STP to Support Redundant Connectivity
Accelerating Aging to Retain Connectivity
CLI Procedure for Disabling STP Protocol
Changing STP Parameters for a VLAN
CLI Procedure for Changing the STP Implementation
CLI Procedure for Changing the Switch Priority
CLI Procedure for Changing the BPDU Message Interval
CLI Procedure for Changing the Hello BPDU Interval
CLI Procedure for Changing the Forwarding Delay Time
Enabling the Port Fast Feature
CLI Procedure for Enabling STP Port Fast
CLI Procedure for Changing the Path Cost
CLI Procedure for Changing the Port Priority
Creating and Maintaining VLANs
VLAN Membership for an ATM Port
CLI Procedure for Assigning Static-Access Ports to a VLAN
CLI Procedure for Assigning Ports for Multi-VLAN Membership
Configuring the Switch to Log Information
CLI Procedure for Configuring Logging
Configuring the Switch for Remote Monitoring
Managing Your Switches
You can use the IOS Release 12.0(5)XP software to manage a single switch, a stack of switches that are managed individually, or a cluster of switches that is managed through a single IP address. You can use any of the management interfaces to manage a switch or cluster. This chapter describes the switching features provided by this software release and how you can change them.
This chapter describes how to manage a single switch by using the following methods:
•
Cisco Switch Network View, a graphical application that displays a map of the devices that are connected to your switch.
•
Note
•
Cisco IOS command-line interface (CLI) procedures are included for many tasks in this chapter. However, this guide describes only the use of IOS commands that have been created or changed for use with the 2900 and 3500 XL switches. These commands are further described in the Cisco IOS Desktop Switching Command Reference (online only). For information on other IOS Release 12.0 commands, refer to the IOS documentation set available from the CCO home page by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
For information on clustering, see "."
Changing Default Settings
You can configure the software features of this release by using any of the available interfaces. lists the most important features, their defaults, and where they are described in this guide.
Table 3-1 Default Settings and Where to Find Them
Creating clusters
None
Cluster Builder
Removing cluster members
None
Cluster Builder
Upgrading cluster software
Enabled
Cluster Manager
"CLI Procedure for Upgrading Catalyst 2900 or 3500 XL Member Switches" section
Displaying reports
Enabled
Cluster Manager and Cluster Builder
—
Displaying VLAN membership information
None
Cluster Manager
—
Configuring SNMP community strings and trap managers
None
Cluster Manager
—
Configuring a port
None
Cluster Manager
—
Switch IP address, subnet mask, and default gateway
0.0.0.0
CVSM: System>IP Management
"CLI Procedure for Assigning IP Information to the Switch" section
Management VLAN
VLAN 1
CVSM: System>IP Management
"CLI Procedure for Configuring the Management VLAN Interface through a Console Connection" section
Domain name
None
CVSM: System>IP Management
Documentation set for Cisco IOS Release 12.0 on CCO
Cisco Discovery Protocol (CDP)
Enabled
CVSM: Device>Cisco Discovery Protocol
Documentation set for Cisco IOS Release 12.0 on CCO
Address Resolution Protocol (ARP)
Enabled
CVSM: System>ARP Table
Documentation set for Cisco IOS Release 12.0 on CCO
System Time Management
None
CVSM: System>System Time Management
Documentation set for Cisco IOS Release 12.0 on CCO
Static address assignment
None assigned
CVSM: Security>Address Management
Dynamic address management
Enabled
CVSM: Security>Address Management
"Managing the MAC Address Tables" section and "Changing the Address Aging Time" section
"CLI Procedure for Configuring the Aging Time" section
"CLI Procedure for Removing Dynamic Address Entries" section
Cisco Switch Network View
Enabled
—
VLAN membership
Static-
access ports in VLAN 1CVSM: VLAN>VLAN Membership
"CLI Procedure for Assigning Static-Access Ports to a VLAN" section
"CLI Procedure for Assigning Ports for Multi-VLAN Membership" section
Autonegotiation of duplex mode and port speeds
Enabled
CVSM: Port>Port Configuration
"CLI Procedure for Setting Speed and Duplex Parameters" section
"CLI Procedure for Setting Speed and Duplex Parameters" section
Gigabit Ethernet flow control
Any
CVSM: Port>Port Configuration
"CLI Procedure for Configuring Flow Control on Gigabit Ethernet Ports" section
Broadcast storm control
Disabled
CVSM: Port>Flooding Controls
"CLI Procedure for Enabling Broadcast Storm Control" section
Flooding unknown unicast and multicast packets
Enabled
CVSM: Port>Flooding Controls
"CLI Procedure for Blocking Flooded Traffic on a Port" section
Network port
Disabled
CVSM: Port>Flooding Controls
Cisco Group Management Protocol (CGMP)
Enabled
CVSM: Device>Cisco Group Management Protocol
"CLI Procedure for Enabling the CGMP Fast Leave Feature" section
"CLI Procedure for Changing the Router Hold-Time" section
Spanning-Tree Protocol
Enabled
CVSM: Device>Spanning-Tree Protocol
"CLI Procedure for Disabling STP Protocol" section
"CLI Procedure for Changing the Path Cost" section
"CLI Procedure for Changing the Port Priority" section
Port grouping
None assigned
CVSM: Port>Port Grouping (EC)
"CLI Procedure for Creating EtherChannel Port Groups" section
SPAN port monitoring
Disabled
CVSM: Port>Switch Port Analyzer (SPAN)
Console, buffer, and file logging
Disabled
CVSM: Fault>Logging Config
Documentation set for Cisco IOS Release 12.0 on CCO
Remote monitoring (RMON)
Disabled
—
Documentation set for Cisco IOS Release 12.0 on CCO
Password
None
CVSM: Visual Switch Manager Home
Addressing security
Disabled
CVSM: Security>Address Management
Trap manager
0.0.0.0
CVSM: System>SNMP Configuration
Community strings
public
CVSM: System>SNMP Configuration
Documentation set for Cisco IOS Release 12.0 on CCO
Port security
Disabled
CVSM: Security>Port Security
Managing Configuration Conflicts
Certain combinations of port features conflict with one another. For example, if you define a port as the network port for a VLAN, all unknown unicast and multicast traffic is flooded to the port. You could not enable port security on the network port because a secure port limits the traffic allowed on it. In , no means that the two referenced features are incompatible.
If you try to enable incompatible features by using CVSM, CVSM issues a warning message and prevents you from making the change. Reload the web page to refresh CVSM.
Table 3-2 Incompatible Features
ATM Port
—
No
No
No
No
No
Yes
Port Group
No
—
No
No
Yes
Yes2
Yes
Port Security
No
No
—
No
No
No
Yes
SPAN Port
No3
No
No
—
No
No
Yes
Multi-VLAN Port
No
Yes
No
No
—
Yes
Yes
Network Port
No
Yes (source-based only)
No
No
Yes
—
No4
Connect to Cluster
Yes
Yes
Yes
Yes
Yes
No
—
1 Catalyst 2900 XL switches only.
2 Cannot be in a destination-based port group.
3 An ATM port cannot be a monitor port but can be monitored.
4 Cannot connect cluster members to the command switch.
Saving Changes to the Startup Configuration
The configuration file that loads when the switch is restarted is stored in Flash memory. The configuration in this file is not necessarily the same as the running configuration. If you want the running (current) configuration to be used when the switch restarts, use CVSM or the CLI to save the configuration file. The CVSM procedure is described in the "Reloading and Upgrading the Switch Software" section. The CLI procedure is described in the "Working with Files in Flash Memory" section.
Managing Switches through Switch Network View
Switch Network View extends web-based network management to the other devices in your network. By exchanging Cisco Discovery Protocol (CDP) messages with attached CDP-enabled devices, Switch Network View graphically displays the surrounding star topology that consists of 2900 and 3500 XL switches and Cisco edge devices.
Supported switches must be running the IOS Release 12.0(5)XP or 11.2(8.x)SA6. Catalyst 2900 XL switches with 4 MB of DRAM must be running IOS Release 11.2(8.x)SA6. For more information, see . In addition, you need to enable SNMP and set the community string to public on all stack members.
Switch Network View differs from Cluster Management in the following ways:
•
•
•
Understanding a Switch Network View Stack
The center node in a star topology acts as a primary switch in Switch Network View. Up to four directly connected supported switches can be stack members. These switches can be displayed in a consolidated physical view called the visual stack. You can access device and link information about the stack from the Switch Network View page and the Visual Stack page.
If more than four switches are connected, Switch Network View displays only the four connected to the lowest port numbers of the primary switch. All other devices are considered edge devices.
For a complete description of the Switch Network View interface, see "Using Switch Network View" section.
Displaying the Switch Network View Page
The Switch Network View page (Figure 3-1) displays a map of the devices and links that are directly connected to your switch. From this page, you can display switch connection information, device reports, and link reports. This page also displays Cisco routers, switches, hubs, and Cisco Micro Web Servers, but these devices must be directly attached to one of the supported switches. Other devices using CDP display as generic edge devices.
Note
Follow these steps to display the Switch Network View page:
Step 1
You will see the Switch Network View button only if the switch is not part of a cluster.
Step 2
You do not need to enter a username.
You can launch Switch Network View from any member switch but the topology that is shown may not display all the switch members. Recall that Switch Network View displays directly connected members one hop from the primary switch. Therefore, pointing your browser at the primary switch in a star topology ensures the most complete view of the network.
Figure 3-1 Switch Network View Page
Displaying Switch Connection Information
Figure 3-2 shows connection information for the switches being managed by Switch Network View. Click on the Switch Manager button on the Switch Network View page to display this table.
Figure 3-2 Visual Switch Manager Connection Information
Displaying the Visual Stack
The visual stack is an image of up to five 2900 or 3500 XL switches or both (Figure 3-3) with the primary switch at the top. This stack contains the same switches as those on the Switch Network View page (Figure 3-1), which displays the primary switch in the middle and stack members connected to it. The stack images display real-time information about the switches and their ports. You can use the stack to monitor port status, check port speed and duplex settings, configure switch ports, and start the CVSM application.
Follow these steps to display the visual stack:
Step 1
Step 2
The visual stack displays in a separate browser window (see Figure 3-3).
Figure 3-3 Visual Stack
Monitoring Port Status
The visual stack shows LED colors to depict the port status:
•
•
•
Checking Port Speed and Duplex Settings
To check the transmission speed settings for all switch ports, click MODE, and highlight SPD (speed). Blue means 10 Mbps; green means 100 Mbps or higher.
To check the duplex setting, click MODE, and highlight FDUP (full-duplex). Blue means half-duplex mode; green means full-duplex mode.
Configuring Switch Ports
On the visual stack, double-click a port to launch the Port Configuration window, which shows the port settings and status. (You can also right-click a port to display the pop-up menu. Select Port Configuration to display the Port Configuration pop-up window.) Select Enable to enable or disable the port and STP Port Fast setting, and select a speed and duplex setting from the drop-down lists. This window is the same as the one described in the "Configuring Ports on the Switch Home Page" section.
In addition, you can configure multiple ports as a group. To do so, press Ctrl and left-click the ports, and then right-click the selected ports and select Port Configuration from the pop-up menu.
Accessing CVSM
The visual stack displays the IP address of each switch next to the switch image. Click the IP address to open a separate browser window displaying the CVSM home page for that switch. End the browser session when you want to return to the visual stack.
Note
Managing Your Switch through CVSM
You access CVSM through one of the supported browsers described in the "Hardware and Software Requirements" section. Ensure that you have the browser configured correctly before starting CVSM.
Using the Switch Home Page
When you click Visual Switch Manager on the Cisco Systems Access page, the Cisco Visual Switch Manager Home page (Figure 3-4) is displayed. All CVSM pages have a Home button you can click to return to the home page.
Use this page to perform the following tasks:
•
•
•
•
•
Changing the Password
If you change the enable secret password on this page, your connection with the switch breaks, and the browser prompts you for the new password. For information on how to change the password, click Help. If you have forgotten your password, see the "Recovering from a Lost or Forgotten Password" section.
CLI Procedure for Changing the Password
This guide describes how to use the IOS commands that have been created or changed for switches that support IOS Release 12.0(5)XP. For information on other IOS commands, refer to the IOS documentation set available from the CCO home page by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Figure 3-4 CVSM Home Page
Enabling the Switch as a Command Switch
If the switch is command-capable, you can enable it and name the cluster that it controls. After you enable the command switch, the Cluster Management button displays on the home page. lists the switches that can be command switches and those that can be command-enabled by a software upgrade.
CLI Procedure for Enabling the Command Switch and Naming the Cluster
Beginning in privileged EXEC mode, follow these steps to enable the command switch and name the cluster:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Monitoring Port Settings
CVSM refreshes the switch image every 30 seconds to provide the most up-to-date information. The LEDs on the switch image present the same information as the actual LEDs, but they use colors instead of the on/off methods used on the switch front panel. Click the Mode button to highlight STAT (status), SPD (speed), or FDUP (duplex), thus changing the information conveyed by the port LEDs. The legend under the image describes the meaning of the colors in each mode.
You can also use the switch images in Cluster Manager to display VLAN membership information and detailed information about the links between switches. For more information, see "."
Monitoring Other Switch LEDs
The other LEDs function as follows:
•
•
•
Configuring Ports on the Switch Home Page
You configure a port by using one of the following methods:
•
•
•
Figure 3-5 shows the Port Configuration pop-up window, which has the same features as the Port Configuration window in Figure 3-6. The LEDs on the image of the switch reflect any changes you make. If your switch is part of a cluster, you can also configure the ports with the Cluster Management application. For more information, see "."
This software release supports 10/100, Gigabit Ethernet, ATM, and Catalyst GigaStack Gigabit Interface Converters (GBICs). For defaults and guidelines for configuring the different types of ports, see the "Configuring Port Parameters" section.
Figure 3-5 Port Configuration Pop-up
Configuring Ports
Use the Port Configuration page (Figure 3-6) to perform the following tasks:
•
•
•
describes the column headings and fields. The "Configuring Port Parameters" section contains guidelines for using this page.
To display this page, select Port>Port Configuration from the menu bar.
Figure 3-6 Port Configuration
Table 3-3 Port Configuration Parameters
Port
Displays Fa (Fast Ethernet), Gi (Gigabit Ethernet), or AT (ATM); the module number: 0 (fixed), 1 (right slot), or 2 (left slot); and the port number. In Figure 3-6, the port is a fixed port (0) and port number 1: Fa0/1.
Note
Status: Admin/Actual
Administratively enables or disable the port. The field also displays the current port status.
Duplex: Requested/Actual
Displays the current duplex setting. You can set a port to full-duplex (Full), half-duplex (Half), or autonegotiate (Auto). The default is Auto. For ATM ports, this field is read-only and displays Full.
Speed: Requested/Actual
Displays the current speed setting. You can set a port to 10 Mbps (10), 100 Mbps (100), or autonegotiate (Auto). The default is Auto.
For Gigabit Ethernet ports, the field displays 1000 (1000 Mbps) and is read-only. For ATM ports, the field displays 155 (155 Mbps) and is read-only.
Port Name
Names the port or describes how it is connected.
Statistics
Displays transmit and receive statistics for the port. Click Reset to clear the statistics and close the statistics window. Click View to display statistics.
Flow Control
Enables or disables flow control on Gigabit Ethernet ports. Flow control enables the connected Gigabit Ethernet ports to control traffic rates during congestion. If one port experiences congestion and cannot receive any more traffic, it notifies the other port to stop transmitting until the condition clears.
Select Symmetric when you want the local port to perform flow control of the remote port only if the remote port can also perform flow control on the local port.
Select Asymmetric when you want the local port to perform flow control on the remote port. For example, if the local port is congested, it notifies the remote port to stop transmitting. This is the default setting.
Select Any when the local port can support any level of flow control required by the remote port.
Select None to disable flow control on the port.
This field is displayed only when a Gigabit Ethernet port is present; it does not apply to Fast Ethernet or ATM ports.
Configuring Port Parameters
The Port Configuration page displays the Requested and Actual settings for each port. A port connected to a device that does not support the requested setting or that is not connected to a device can cause the Requested and Actual settings to differ.
Caution
Follow these guidelines when configuring the duplex and speed settings:
•
•
•
•
•
•
Connecting to Devices That Do Not Autonegotiate
To connect to a remote 100BaseT device that does not autonegotiate, do not configure AUTO for the duplex setting on the local device. Autonegotiation of the port speed works correctly even if the attached device does not autonegotiate.
To connect to a remote Gigabit Ethernet device that does not autonegotiate, disable autonegotiation on the local device, and set the duplex and flow control parameters to be compatible with the other device. For more information, see the "Identifying an Autonegotiation Mismatch" section.
CLI Procedure for Setting Speed and Duplex Parameters
Beginning in privileged EXEC mode, follow these steps to set the speed and duplex parameters on a port:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Configuring Flow Control on Gigabit Ethernet Ports
Beginning in privileged EXEC mode, follow these steps to configure flow control on a Gigabit Ethernet port.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Creating EtherChannel Port Groups
Use the Port Group (EtherChannel) page (Figure 3-8) to create Fast EtherChannel and Gigabit EtherChannel port groups. These port groups act as single logical ports for high-bandwidth connections between switches or between switches and servers.
Note
To display this page, select Port>Port Grouping (EC) from the menu bar.
For the restrictions that apply to port groups, see the "Managing Configuration Conflicts" section.
Understanding EtherChannel Port Grouping
This software release supports two different types of port groups: source-based forwarding port groups and destination-based forwarding port groups.
Source-based forwarding port groups distribute packets forwarded to the group based on the source address of incoming packets. You can configure up to eight ports in a source-based forwarding port group. Source-based forwarding is enabled by default.
Destination-based port groups distribute packets forwarded to the group based on the destination address of incoming packets. You can configure an unlimited number of ports in a destination-based port group.
You can create up to 12 port groups of all source-based, all destination-based, or a combination of source- and destination-based ports. All ports in the group must be of the same type; for example, they must be all source based or all destination based. You can independently configure port groups that link switches, but you must consistently configure both ends of a port group.
In , a port group of two workstations communicates with a router. Because the router is a single-MAC address device, source-based forwarding ensures that the switch uses all available bandwidth to the router. The router is configured for destination-based forwarding because the large number of stations ensures that the traffic is evenly distributed through the port-group ports on the router.
Figure 3-7 Source-Based Forwarding
The switch treats the port group as a single logical port; therefore, when you create a port group, the switch uses the configuration of the first port for all ports added to the group. If you add a port and change the forwarding method, it changes the forwarding for all ports in the group. After the group is created, changing STP or VLAN membership parameters for one port in the group automatically changes the parameters for all ports. Each port group has one port that carries all unknown multicast, broadcast, and STP packets.
Figure 3-8 Port Group (EtherChannel)
Port Group Restrictions on Static-Address Forwarding
The following restrictions apply to entering static addresses that are forwarded to port groups:
•
•
Note
CLI Procedure for Creating EtherChannel Port Groups
Beginning in privileged EXEC mode, follow these steps to create a two-port group:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Enabling Switch Port Analyzer
Use the Switch Port Analyzer (SPAN) page (Figure 3-9) to enable port monitoring. You can monitor traffic on a given port by forwarding incoming and outgoing traffic on the port to another port in the same VLAN. A SPAN port cannot monitor ports in a different VLAN, and a SPAN port must be a static-access port. Any number of ports can be defined as SPAN ports, and any combination of ports can be monitored.
To display this page, select Port>Switch Port Analyzer (SPAN) from the menu bar.
For the restrictions that apply to SPAN ports, see the "Managing Configuration Conflicts" section.
Figure 3-9 Switch Port Analyzer (SPAN)
CLI Procedure for Enabling Switch Port Analyzer
Beginning in privileged EXEC mode, follow these steps to enable switch port analyzer:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Disabling Switch Port Analyzer
Beginning in privileged EXEC mode, follow these steps to disable switch port analyzer:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring Flooding Controls
Use the Flooding Controls page (Figure 3-10) to block the forwarding of unnecessary flooded traffic. You can use three flooding techniques:
•
•
•
To display this page, select Port>Flooding Controls from the menu bar.
Figure 3-10 Flooding Controls
Enabling a Network Port
Network ports are assigned per VLAN and can reduce flooded traffic on your network. The switch forwards all traffic with unknown destination addresses to the network port instead of flooding the traffic to all ports in the VLAN.
When you configure a port as the network port, the switch deletes all associated addresses from the address table and disables learning on the port. If you configure other ports in the VLAN as secure ports, the addresses on those ports are not aged. If you move a network port to a VLAN without a network port, it becomes the network port for the new VLAN.
You cannot change the settings for unicast and multicast flooding on a network port. You can assign only one network port per VLAN.
Caution
For restrictions that apply to a network port, see the "Managing Configuration Conflicts" section.
CLI Procedure for Enabling a Network Port
Beginning in privileged EXEC mode, follow these steps to define a port as the network port:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Disabling a Network Port
Beginning in privileged EXEC mode, follow these steps to disable the network port:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Enabling Broadcast Storm Control
A broadcast storm occurs when a large number of broadcast packets are received. Forwarding these packets can cause the network to slow down or to time out. Broadcast storm control is configured for the switch as a whole but operates on a per-port basis. By default, broadcast storm control is disabled.
Broadcast storm control uses specific high and low numbers of broadcast packets to block and then to restore forwarding of broadcast packets. The rising threshold is the number of broadcast packets that a switch port can receive before forwarding is blocked. The falling threshold reenables the normal forwarding of broadcast packets. In general, the higher the threshold, the less effective the protection against broadcast storms. The maximum half-duplex transmission on a 100BaseT link is 148,000 packets per second, but you can enter a threshold up to 4294967295 broadcast packets per second.
CLI Procedure for Enabling Broadcast Storm Control
Beginning in privileged EXEC mode, follow these steps to enable broadcast-storm control.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0) documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Disabling Broadcast Storm Control
Beginning in privileged EXEC mode, follow these steps to disable broadcast-storm control.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0) documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Blocking Flooded Traffic on a Port
By default, the switch floods packets with unknown destination MAC addresses to all ports. Some configurations do not require flooding. For example, a port that has only manually assigned addresses has no unknown destinations, and flooding serves no purpose. Therefore, you can disable the flooding of unicast and multicast packets on a per-port basis. Ordinarily, flooded traffic does not cross VLAN boundaries, but multi-VLAN ports flood traffic to all VLANs they belong to.
CLI Procedure for Blocking Flooded Traffic on a Port
Beginning in privileged EXEC mode, follow these steps to disable the flooding of multicast and unicast packets to a port:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0) documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Resuming Normal Forwarding on a Port
Beginning in privileged EXEC mode, follow these steps to resume normal forwarding on a port:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0) documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Reloading and Upgrading the Switch Software
Use the System Configuration page (Figure 3-11 and Figure 3-12) to specify the Flash memory filenames that the switch uses when it starts or resets. You can also use this page to upgrade your switch software. If your switch is part of a cluster, you can also upgrade its software with the Cluster Management application. For more information, see "."
You can use this page to perform the following tasks:
•
•
•
•
To display this page, select System>System Configuration from the menu bar.
Saving the Configuration File
The startup configuration file (config.text) contains the IP address, passwords, and other configuration information you enter. The switch reloads this file when it restarts. However, the startup configuration file might not be the running (current) configuration. Configuration changes made through CVSM or the CLI take effect immediately on the switch but must be explicitly saved to be included in the startup configuration.
Use this page to save the running configuration to the startup configuration file. The following buttons control the switch startup:
Figure 3-11 System Configuration (Part 1)
Entering the System Reload Options
By default, the System Reload Options fields contain the correct information to reboot the system. Some of the fields display filenames in Flash memory. To determine the filenames to use, enter the following EXEC mode command at the CLI:
switch# dir flash:Directory of flash:2 -rwx 843947 Mar 01 1993 00:02:18 C2900XL-hs-mz-112.8-SA6.bin4 drwx 3776 Mar 01 1993 01:23:24 html66 -rwx 130 Jan 01 1970 00:01:19 env_vars68 -rwx 1296 Mar 01 1993 06:55:51 config.text1728000 bytes total (456704 bytes free)In the previous command display, the image file that runs the switch has a .bin extension, the html directory contains the web management application files, and config.text contains the current configuration. If you need more information about accessing the switch by using the CLI, refer to the "Configuring the Switch for Telnet" section.
Click Help for procedures on how to configure the fields on this page.
Upgrading Switch Software
When you upgrade a switch, the switch continues to operate normally while the new software is copied to Flash memory. If Flash memory does not have enough space for two images, the new image is copied over the existing one. If Flash memory has enough space, the new image is copied to the selected switch but does not replace the current running image. Only after the new image is completely downloaded is the old one erased. If you experience a failure during the copy process, you can still reboot your switch using the old image. The new software is loaded the next time you reboot.
If you group switches into a cluster, you can upgrade the entire cluster from Cluster Manager. For more information, see the "Upgrading Software for a Group of Switches" section.
New releases of switch software are available on Cisco Connection Online (CCO). The process of upgrading your switch consists of the following steps:
Step 1
Step 2
Step 3
Note
Click Help for the complete procedures for this process.
Figure 3-12 System Configuration (Part 2)
CLI Procedure for Upgrading the Switch Software
This procedure is for switches with 8 MB of DRAM. Switches running earlier IOS releases might have less memory and require slightly different procedures. To upgrade a 2900 XL switch with 4 MB of DRAM, refer to the Release Notes for Catalyst 2900 Series XL and Catalyst 3500 Series XL, for Cisco IOS Release 11.2(8.1)SA6 or 11.2(8.2)SA6. These switches cannot be upgraded to IOS Release 12.0(5)XP. To determine the switch DRAM size, enter the user level show version command.
The upgrade procedure consists of these general steps:
•
•
•
Beginning in privileged EXEC mode, follow these steps to upgrade the switch software:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Setting the System Date and Time
Use the System Time Management page (Figure 3-13) to set the system time for a switch or enable an external source such as Network Time Protocol (NTP) to supply time to the switch.
You can use this page to set the switch time by using one of the following techniques:
•
•
•
To display this page, select System>System Time Management from the menu bar.
Figure 3-13 System Time Management
Setting the System Date and Time
Enter the date and a 24-hour clock time setting on the System Time Management page. If you are entering the time for an American time zone, enter the three-letter abbreviation for the time zone in the Name of Time Zone field, such as PST for Pacific Standard Time. If you are identifying the time zone by referring to Greenwich Mean Time, enter UTC (Universal Time Coordinated) in the Name of Time Zone field. You then must enter a negative or positive number as an offset to indicate the number of time zones between the switch and Greenwich, England. Enter a negative number if the switch is west of Greenwich, England, and east of the International Date Line. For example, California is eight time zones west of Greenwich, so you would enter -8 in the Hours Offset From UTC field. Enter a positive number if the switch is east of Greenwich. You can also enter negative and positive numbers for minutes.
To configure daylight saving time, select an option from the drop-down list, and click Configure Summer/Daylight Saving Time. You can configure the switch to change to daylight saving time on a particular day every year, on a day that you enter, or not at all.
CLI Procedure for Setting the System Date and Time
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Network Time Protocol
In complex networks it is often prudent to distribute time information from a central server. The NTP can distribute time information by responding to requests from clients or by broadcasting time information. You can use the Network Time Protocol page (Figure 3-14) to enable these options and to enter authentication information to accompany NTP client requests.
To display this page, click Configure NTP on the System Time Management page.
Figure 3-14 Network Time Protocol
Configuring the Switch as an NTP Client
You configure the switch as an NTP client by entering the IP addresses of up to ten NTP servers in the IP Addr field. Click Preferred to specify which server should be used first. You can also enter an authentication key to be used as a password when requests for time information are sent to the server.
Enabling NTP Authentication
To ensure the validity of information received from NTP servers, you can authenticate NTP messages with public-key encryption. This procedure must be coordinated with the administrator of the NTP servers: the information you enter on this page will be matched by the servers to authenticate it.
Click Help for more information about entering information in the Key Number, Key Value, and Encryption Type fields.
Configuring the Switch for NTP Broadcast-Client Mode
You can configure the switch to receive NTP broadcast messages if there is an NTP broadcast server, such as a router, broadcasting time information on the network. You can also enter a delay in the Estimated Round-Trip Delay field to account for round-trip delay between the client and the NTP broadcast server.
CLI Procedure for Configuring NTP
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring IP Information
Use the IP Management page (Figure 3-15) to change or enter IP information for the switch. Some of this information, such as the IP address, you had previously entered.
You can use this page to perform the following tasks:
•
•
•
•
To display this page, select System>IP Management from the menu bar.
Figure 3-15 IP Management
Assigning IP Information to the Switch
You can use a BOOTP server to automatically assign IP information to the switch; however, the BOOTP server must be set up in advance with a database of physical MAC addresses and corresponding IP addresses, subnet masks, and default gateway addresses. In addition, the switch must be able to access the BOOTP server through one of its ports. Upon startup, a switch without an IP address requests the information from the BOOTP server; the requested information is saved in the switch running configuration file. You must log into the CLI and enter the write memory command to preserve this information.
You can also manually assign an IP address, mask, and default gateway to the switch through the management console. This information is required before you can access the switch using CVSM and is displayed in the IP Address, IP Mask, and Default Gateway fields of the IP Management page.
You can change the information in these fields. The mask identifies the bits that denote the network number in the IP address. When you use the mask to subnet a network, the mask is then referred to as a subnet mask. The broadcast address is reserved for sending messages to all hosts. The CPU sends traffic to an unknown IP address through the default gateway.
Caution
You can also configure the management VLAN interface and specify a domain name. For more information, see the "Configuring the Management VLAN Interface" section and "Specifying a Domain Name and Configuring the DNS" section.
CLI Procedure for Assigning IP Information to the Switch
Beginning in privileged EXEC mode, follow these steps to enter the IP information:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Removing an IP Address
Beginning in privileged EXEC mode, follow these steps to remove an IP address:
Caution
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Management VLAN Interface
By default, the switch IP address belongs to VLAN 1, the default management VLAN interface. However, you can configure any VLAN to be the management VLAN. Workstations connected to ports assigned to the management VLAN can establish IP connections to the switch. These connections allow access to the CVSM and SNMP. For a static-access or multi-VLAN port to access one of these management interfaces, it must also belong to the management VLAN.
If your switch is configured as a member switch in a cluster, it might not have an IP address assigned to it. If your switch is configured as a command switch in a cluster, its IP information supports the IP connectivity of all its member switches. To manage switches in a cluster, the port connections among the command, member, and candidate switches must all be on the same VLAN as the management VLAN, which is VLAN 1 by default. To change the management VLAN on an existing cluster, use the CLI and a console connection. For more information, see the "Changing the Management VLAN on an Existing Cluster" section.
Caution
Management VLAN Characteristics
The management VLAN interface has the following characteristics:
•
•
•
•
•
Guidelines for Changing the Management VLAN
Before changing the management VLAN on your switch network, make sure you follow these guidelines:
•
•
•
CLI Procedure for Configuring the Management VLAN Interface through a Console Connection
Beginning in privileged EXEC mode, follow these steps to configure the management VLAN interface through a console connection:
Step 1
Step 2
configure terminal
Step 3
interface vlan n
Step 4
ip address ip_address subnet_mask
Step 5
If no IP information was previously assigned, this command copies the information from the old management VLAN to the new one.
management
Step 6
exit
Step 7
exit
Step 8
end
Step 9
show interface vlan n
Step 10
copy running-config startup-config
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Configuring the Management VLAN Interface through a Telnet Connection
Beginning in privileged EXEC mode, follow these steps to configure the management VLAN interface through a Telnet connection:
Step 1
Step 2
configure terminal
Step 3
interface vlan n
Step 4
ip address ip_address subnet_mask
Step 5
management
Note
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Specifying a Domain Name and Configuring the DNS
Each unique IP address can have a host name associated with it. The IOS software maintains a cache of host name-to-address mappings for use by the EXEC mode connect, telnet, ping, and related Telnet support operations. This cache speeds the process of converting names to addresses.
IP defines a hierarchical naming scheme that allows a device to be identified by its location or domain. Domain names are pieced together with periods (.) as the delimiting characters. For example, Cisco Systems is a commercial organization that the IP identifies by a com domain name, so its domain name is cisco.com. A specific device in this domain, the File Transfer Protocol (FTP) system for example, is identified as ftp.cisco.com.
To keep track of domain names, IP has defined the concept of a name server, whose job is to hold a cache (or database) of names mapped to IP addresses. To map domain names to IP addresses, you must first identify the host names and then specify a name server and enable the DNS, the Internet's global naming scheme that uniquely identifies network devices.
Specifying the Domain Name
You can specify a default domain name that the software will use to complete domain name requests. You can specify either a single domain name or a list of domain names. Any IP host name that does not contain a domain name will have the domain name you specify appended to it before being added to the host table.
To specify a domain name, enter the name into the Domain Name field, and click OK. Do not include the initial period that separates an unqualified name (names without a dotted-decimal domain name) from the domain name.
To specify a list of domain names, enter the names separated by a comma and no space.
Specifying a Name Server
You can specify up to six hosts that can function as a name server to supply name information for the DNS. Enter the IP address into the New Server field, and click <<Add<<.
Enabling the DNS
If your network devices require connectivity with devices in networks for which you do not control name assignment, you can assign device names that uniquely identify your devices within the entire internetwork. The Internet's global naming scheme, the DNS, accomplishes this task. This service is enabled by default.
CLI Procedure for Configuring DNS
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring SNMP
Use the SNMP Configuration page (Figure 3-16) to configure your switch for SNMP management. If your switch is part of a cluster, you can also configure SNMP with the Cluster Management application. For more information, see "."
You can use this page to perform the following tasks:
•
•
•
•
•
•
To display this page, select System>SNMP Configuration from the menu bar.
Figure 3-16 SNMP Configuration (Part 1)
Disabling and Enabling SNMP
SNMP must be enabled for some Switch Network View and Cluster Management features to work properly. If you deselect Enable SNMP and click Apply, SNMP is disabled, and the SNMP parameters on the page disappear. For information on SNMP and Cluster Management, see "Managing Clusters through SNMP" section.
Entering Community Strings
Community strings serve as passwords for SNMP messages to permit access to the agent on the switch. You can enter them with the following characteristics:
Read only (RO)
Requests accompanied by the string can display MIB-object information.
Read write (RW)
Requests accompanied by the string can display MIB-object information and set MIB objects.
If you are entering community strings for a cluster member, the string must be unique in the cluster.
CLI Procedure for Configuring SNMP and Community Strings
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Adding Trap Managers
A trap manager is a management station that receives and processes traps. When you configure a trap manager, community strings for each member switch must be unique. If a member switch has an IP address assigned to it, the management station accesses the switch by using its assigned IP address.
By default, no trap manager is defined, and no traps are issued.
Figure 3-17 SNMP Configuration (Part 2)
Select a check box to enable one of the following classes of traps:
CLI Procedure for Adding a Trap Manager
Beginning in privileged EXEC mode, follow these steps to add a trap manager and community string:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Managing the ARP Table
To communicate with a device (on Ethernet, for example), the software first must determine the 48-bit MAC or local data link address of that device. The process of determining the local data link address from an IP address is called address resolution.
The Address Resolution Protocol (ARP) is used to associate a host IP address with the corresponding media or MAC addresses and VLAN ID. Taking an IP address as input, ARP determines the associated media address. Once a media or MAC address is determined, the IP address/media address association is stored in an ARP cache for rapid retrieval. Then the IP datagram is encapsulated in a link-layer frame and sent over the network. Encapsulation of IP datagrams and ARP requests and replies on IEEE 802 networks other than Ethernet is specified by the Subnetwork Access Protocol (SNAP). By default, standard Ethernet-style ARP encapsulation (represented by the arpa keyword) is enabled on the IP interface.
Use the ARP Table page (Figure 3-18) to display the table and change the timeout value. Figure 3-19 shows the meaning the of ARP table contents.
To display this page, select System>ARP Table from the menu bar. ARP entries added manually to the table do not age and must be manually removed.
Figure 3-18 ARP Table
Figure 3-19 Contents of the ARP Table
CLI Procedure for Managing the ARP Table
From the CLI, you can manually add entries to the ARP Table; however, these entries do not age and must be manually removed.
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Managing the MAC Address Tables
Use the Address Management page (Figure 3-21) to manage the MAC address tables that the switch uses to forward traffic between ports. These MAC tables include the following addresses:
•
•
•
To display this page, select Security>Address Management from the menu bar.
The address tables list the destination MAC address and the associated VLAN ID, module, and port number associated with the address. Figure 3-20 shows an example list of addresses as they would appear in the dynamic, secure, or static address table.
Figure 3-20 Contents of the Address Table
MAC Addresses and VLANs
All addresses are associated with a VLAN. An address can exist in more than one VLAN and have different destinations in each. Multicast addresses, for example, could be forwarded to port 1 in VLAN 1 and ports 9, 10, and 11 in VLAN 5.
Each VLAN maintains its own logical address table. A known address in one VLAN is unknown in another until it is learned or statically associated with a port in the other VLAN. An address can be secure in one VLAN and dynamic in another. Addresses that are statically entered in one VLAN must be static addresses in all other VLANs.
Figure 3-21 Address Management
Changing the Address Aging Time
Dynamic addresses are source MAC addresses that the switch learns and then drops when they are not in use. Use the Aging Time field to define how long the switch retains unseen addresses in the table. This parameter applies to all VLANs.
CLI Procedure for Configuring the Aging Time
Beginning in privileged EXEC mode, follow these steps to configure the dynamic address table aging time.
Note
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Removing Dynamic Address Entries
Beginning in privileged EXEC mode, follow these steps to remove a dynamic address entry:
You can remove all dynamic entries by using the clear mac-address-table dynamic command in privileged EXEC mode.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Adding Secure Addresses
The secure address table contains secure MAC addresses and their associated ports and VLANs. A secure address is a manually entered unicast address that is forwarded to only one port per VLAN. If you enter an address that is already assigned to another port, the switch reassigns the secure address to the new port. Secure addresses do not age and can be either manually entered into the address table or learned.
You can enter a secure port address even when the port does not yet belong to the VLAN. When the port is later assigned to the VLAN, packets destined for that address are forwarded to the port.
To display this page, select Security>Address Management from the menu bar.
After you have entered the secure address, select Security>Port Security from the menu bar to secure the port on the Port Security page.
CLI Procedure for Adding Secure Addresses
Beginning in privileged EXEC mode, follow these steps to add a secure address:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Removing Secure Addresses
Beginning in privileged EXEC mode, follow these steps to remove a secure address:
You can remove all secure addresses by using the clear mac-address-table secure command in privileged EXEC mode.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Adding and Removing Static Addresses
A static address has the following characteristics:
•
•
•
The Static Address Forwarding map (Figure 3-22) displays when you add a static address and click Forwarding. On the Static Address Forwarding map, you determine how a port that receives a frame forwards it to another port for transmission. Because all ports are associated with at least one VLAN, the switch acquires the VLAN ID for the address from the ports that you select on the forwarding map.
The Rx On column on the left lists the source ports. The Forward to columns lists the destination ports. Ports without check boxes belong to VLANs that a source port cannot access.
A static address in one VLAN must be a static address in other VLANs. A packet with a static address that arrives on a VLAN where it has not been statically entered is flooded to all ports and not learned.
To display this page, select Security>Address Management from the menu bar, and enter or select an address in the Static Address Table.
Note
Figure 3-22 Static Address Forwarding Map
Configuring Static Addresses for EtherChannel Port Groups
Follow these rules if you are configuring a static address to forward to ports in an EtherChannel port group:
•
•
CLI Procedure for Adding Static Addresses
Static addresses are entered in the address table with an in-port-list, an out-port-list, and a VLAN ID, if needed. Packets received from the in-port are forwarded to ports listed in the out-port-list.
Note
Beginning in privileged EXEC mode, follow these steps to add a static address:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Removing Static Addresses
Beginning in privileged EXEC mode, follow these steps to remove a static address:
You can remove all secure addresses by using the clear mac-address-table static command in privileged EXEC mode.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Enabling Port Security
Use the Port Security page (Figure 3-23) to enable port security and to define the size of the secured port address table.
To display this page, select Security>Port Security from the menu bar.
Secured ports restrict a port to a user-defined group of stations. When you assign secure addresses to a secure port, the switch does not forward any packets with source addresses outside the group. If you define the address table of a secure port to contain only one address, the workstation or server attached to that port is guaranteed the full bandwidth of the port.
Secured ports generate address-security violations under the following conditions:
•
•
Limiting the number of devices that can connect to a secure port has the following advantages:
•
•
The following fields validate port security or indicate security violations:
Secure Addresses
The number of addresses in the address table for this port. Secure ports have at least one in this field.
Security Rejects
The number of unauthorized addresses seen on the port.
For the restrictions that apply to secure ports, see the "Managing Configuration Conflicts" section.
Figure 3-23 Port Security
Defining the Maximum Secure Address Count
A secure port can have from 1 to 132 associated secure addresses. Setting one address in the MAC address table for the port ensures the attached device has the full bandwidth of the port.
CLI Procedure for Enabling Port Security
Beginning in privileged EXEC mode, follow these steps to enable port security.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Disabling Port Security
Beginning in privileged EXEC mode, follow these steps to disable port security.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Cisco Discovery Protocol
Use the Cisco Discovery Protocol (CDP) page (Figure 3-24) to enable CDP for the switch, set global CDP parameters, and display information about neighboring Cisco devices. CDP enables CVSM and other network management applications to display a graphical view of the network. For example, the switch uses CDP to find cluster candidates and maintain information about cluster members and other devices. The information exchanged in CDP messages includes the device type, links between devices, and the number of ports within each device. Based on the CDP messages sent, the switch displays these devices in the Switch Network View and Cluster Builder.
Note
To display this page, select Device>Cisco Discovery Protocol from the menu bar.
Figure 3-24 Cisco Discovery Protocol
Configuring CDP
Some CDP options are global to the switch, and some are entered on a per-port basis. CDP is enabled by default. Click Help for the defaults and possible values of the fields on this page. You can use this page for the following tasks:
•
The CDP Neighbors list shows the devices with which this switch is exchanging CDP messages. Depending on the management interfaces supported on the neighboring device, you can access it by using Telnet or through an HTML interface, and you can display the most recent information received from the device.
•
When you deselect the Run CDP check box, you disable CDP for the entire switch and changes in the Individual Port Enable section have no effect.
•
CLI Procedure for Configuring CDP
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Controlling IP Management Packets through CGMP
Use the Cisco Group Management Protocol (CGMP) page (Figure 3-25) to enable CGMP and the CGMP Fast Leave feature. CGMP reduces the unnecessary flooding of IP multicast packets by limiting the transmission of these packets to CGMP clients that request them. The Fast Leave feature accelerates the removal of unused CGMP groups. By default, CGMP is enabled, and the Fast Leave feature is disabled.
End stations issue join messages to become part of a CGMP group and issue leave messages to leave the group. The membership of these groups is managed by the switch and by connected routers through the further exchange of CGMP messages.
CGMP groups are maintained by VLAN: a multicast IP address packet can be forwarded to one list of ports in one VLAN and to a different list of ports in another VLAN. When a CGMP group is added, it is added on a per-VLAN, per-group basis. When a CGMP group is removed, it is only removed in a given VLAN.
You can use this page to perform the following tasks:
•
•
•
To display this page, select Device>Cisco Group Management Protocol from the menu bar.
Figure 3-25 Cisco Group Management Protocol
Enabling the Fast Leave Feature
The CGMP Fast Leave feature reduces the delay when group members leave groups. When an end station requests to leave a CGMP group, the group remains enabled for that VLAN until all members have requested to leave. With the Fast Leave feature enabled, the switch immediately checks if there are other members attached to its ports in that group. If there are no other members, the switch removes the port from the group. If there are no other ports in the group, the switch sends a message to routers connected to the VLAN to delete the entire group.
The Fast Leave feature functions only if CGMP is enabled. The client must be running IGMP version 2 for the Fast Leave feature to function properly.
CLI Procedure for Enabling the CGMP Fast Leave Feature
Beginning in privileged EXEC mode, follow these steps to enable the CGMP Fast Leave feature:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Disabling the CGMP Fast Leave Feature
Beginning in privileged EXEC mode, follow these steps to disable the CGMP Fast Leave feature:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Changing the Router Hold-Time
The router hold-time is the number of seconds the switch waits before removing (aging) a router entry and ceasing to exchange messages with it. If it is the last router entry on a VLAN, then all groups on that VLAN are removed. You can thus enter a lower number in the Router Hold-Time field to accelerate the removal of CGMP groups.
CLI Procedure for Changing the Router Hold-Time
Beginning in privileged EXEC mode, follow these steps to change the router hold-time.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Removing Multicast Groups
You can reduce the forwarding of IP multicast packets by removing groups from the Current Multicast Groups table. Each entry in the table consists of the VLAN, IGMP multicast address, and ports.
CLI Procedure for Removing Multicast Groups
You can use the CLI to clear all CGMP groups, all CGMP groups in a VLAN, or all routers, their ports, and their expiration times. Beginning in privileged EXEC mode, follow these steps to remove all multicast groups.
Step 1
clear cgmp group
Step 2
show cgmp
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Spanning-Tree Protocol
Use the Spanning-Tree Protocol (STP) page (Figure 3-26) to change parameters for STP, an industry standard for avoiding loops in switched networks. The switch supports up to
64 instances of STP.You can use this page to perform the following tasks:
•
•
•
To display this page, select Device>Spanning-Tree Protocol from the menu bar.
Because each VLAN has its own instance of STP, you must first select a VLAN ID, and then click Modify STP Parameters to display the rest of the page.
This page is shown in three illustrations. Figure 3-26 shows the page with no parameters; Figure 3-27 shows the parameters currently used by the switch and the parameters that this switch would use if it became the root switch. Figure 3-28 shows the fields that you use to define port-level parameters.
Figure 3-26 Spanning-Tree Protocol (Selection)
Using STP to Support Redundant Connectivity
You can create a redundant backbone with STP by connecting two of the switch ports to another device or to two different devices. STP automatically disables one port, but enables it if the other port is lost. If one link is high-speed and the other low-speed, the low-speed link is always disabled. If the speed of the two links is the same, the port priority and port ID are added together, and STP disables the link with the lowest value.
You can also create redundant links between switches by using EtherChannel port groups. For more information on creating port groups, see the "Creating EtherChannel Port Groups" section.
Accelerating Aging to Retain Connectivity
The default for aging dynamic addresses is 5 minutes. However, a reconfiguration of the spanning tree can cause many station locations to change. Because these stations could be unreachable for 5 minutes or more during a reconfiguration, the address-aging time is accelerated so that station addresses can be dropped from the address table and then relearned. The accelerated aging is the same as the forward-delay parameter value when STP reconfigures.
Because each VLAN is a separate instance of STP, the switch accelerates aging on a per-VLAN basis. A reconfiguration of STP on one VLAN can cause the dynamic addresses learned on that VLAN to be subject to accelerated aging. Dynamic addresses on other VLANs can be unaffected and remain subject to the aging interval entered for the switch.
Disabling STP Protocol
STP is enabled by default. Disable STP only if you are sure there are no loops in the network topology. With STP disabled and loops present in the topology, network performance is degraded by excessive traffic and indefinite packet duplication.
CLI Procedure for Disabling STP Protocol
Beginning in privileged EXEC mode, follow these steps to disable STP protocol:
Changing STP Parameters for a VLAN
To change STP parameters for a VLAN, select Device>Spanning-Tree Protocol from the menu bar, select the VLAN ID of the STP instance to change, and click Modify STP Parameters.
In Figure 3-27, the parameters under the heading Current Spanning-Tree Root are read-only and could be defined on another switch. The MAC Address field shows the MAC address of the switch currently acting as the root; the remaining parameters show the other STP settings for the root switch. The root switch is the switch with the highest priority and transmits topology frames to other switches in the spanning tree.
The parameters under the heading Spanning-Tree Options are the values that this switch would use as the root switch. The following fields (Figure 3-27) define how your switch responds when STP reconfigures itself.
Figure 3-27 Spanning-Tree Protocol (Part 1)
CLI Procedure for Changing the STP Implementation
Beginning in privileged EXEC mode, follow these steps to change the STP implementation. The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the Switch Priority
Beginning in privileged EXEC mode, follow these steps to change the switch priority and effect which switch is the root switch. The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the BPDU Message Interval
Beginning in privileged EXEC mode, follow these steps to change the BPDU message interval (max age time). The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the Hello BPDU Interval
Beginning in privileged EXEC mode, follow these steps to change the hello BPDU interval (hello time). The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the Forwarding Delay Time
Beginning in privileged EXEC mode, follow these steps to change the forwarding delay time. The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Changing STP Port Parameters
The ports listed on this page (Figure 3-28) belong to the VLAN selected at the top of the page.
To change STP port options, select Device>Spanning-Tree Protocol from the menu bar, select the VLAN ID, and click Modify STP Parameters.
Use the following fields (Figure 3-28) to check the status of ports that are not forwarding due to STP:
Figure 3-28 Spanning-Tree Protocol (Part 2)
Enabling the Port Fast Feature
The Port Fast feature brings a port directly from a blocking state into a forwarding state. The only time a port with the Port Fast feature enabled goes through the normal cycle of STP status changes is when the switch is restarted. Use this feature when a port is connected to a workstation or server and cannot contribute to bridging loops.
Caution
CLI Procedure for Enabling STP Port Fast
Enabling this feature on a port connected to a switch or hub could prevent STP from detecting and disabling loops in your network. Beginning in privileged EXEC mode, follow these steps to enable the Port Fast feature:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the Path Cost
Beginning in privileged EXEC mode, follow these steps to change the path cost for STP calculations. The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
CLI Procedure for Changing the Port Priority
Beginning in privileged EXEC mode, follow these steps to change the port priority, which is used when two switches tie for position as the root switch. The stp-list is the list of VLANs to which the STP command applies.
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Creating and Maintaining VLANs
Use the VLAN Membership page (Figure 3-29) to perform the following tasks:
•
•
To display this page, select VLAN>VLAN Membership from the menu bar.
For the restrictions that apply to multi-VLAN ports, see the "Managing Configuration Conflicts" section.
Figure 3-29 VLAN Membership
Understanding VLANs
A VLAN is a switched network that is logically segmented by function, project team, or application, without regard to the physical locations of the users. Any switch port can belong to a VLAN, and unicast, broadcast, and multicast packets are forwarded and flooded only to stations in the VLAN. Each VLAN is considered a logical network, and packets destined for stations that do not belong to the VLAN must be forwarded through a router or bridge.
Because a VLAN is considered a separate logical network, it contains its own bridge MIB information and can support its own implementation of the Spanning-Tree Protocol (STP).
You can configure up to 250 VLANs on all 3500 XL switches and on the following 2900 XL switches:
•
•
•
The remaining 2900 XL switches support up to 64 VLANs. Regardless of the switch model, only 64 possible instances of STP are supported.
All other switches supported by this IOS release can support 64 VLANs. VLANs are identified with a number between 1 and 1001.
Note
When a port belongs to a VLAN, the switch learns and manages the addresses associated with the port on a per-VLAN basis. See the "Managing the MAC Address Tables" section for more information.
VLAN Membership for an ATM Port
Using the ATM module CLI, you can map the LAN emulation (LANE) client to a VLAN or bind one or more permanent virtual connections (PVCs) to a VLAN. The VLAN ID is then displayed in the Assigned VLANs column of the VLAN Membership page. Using standard edition software, an ATM port can only be a static-access port. Using Enterprise Edition Software, an ATM port can only be a trunk port. An ATM port can never be a multi-VLAN port.
Assigning Ports to VLANs
By default, all ports are static-access ports assigned to VLAN 1, which is the default management VLAN. The management VLAN interface is configurable and is also the interface to the switch itself. If you are using SNMP or CVSM to manage the switch, ensure that the port through which you are connected to the switch is in management VLAN. Links among a command switch, cluster members, and candidate switches must be through ports that belong to the management VLAN interface. For information on configuring the management VLAN, see the "Configuring the Management VLAN Interface" section.
A port can be in one of these modes:
•
•
When you assign a port to a VLAN, you define the port as a multi-VLAN or a static-access port and enter a VLAN ID for it. If you change the VLAN ID on a port that belongs to a port group, the VLAN ID for all the ports in that group is also changed.
CLI Procedure for Assigning Static-Access Ports to a VLAN
Beginning in privileged EXEC mode, follow these steps to assign a port for static-access VLAN membership:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Overlapping VLANs
A multi-VLAN port connected to a router can link two or more VLANs. Intra-VLAN traffic stays within the boundaries of the respective VLANs as shown in . Connectivity between VLANs is accomplished by using the router connected to the multi-VLAN port.
A multi-VLAN port performs normal switching functions in all its assigned VLANs. For example, when a multi-VLAN port receives an unknown MAC address, all the VLANs to which the port belongs learn the address. Multi-VLAN ports also respond to the STP messages generated by the different instances of STP in each VLAN.
Figure 3-30 Two VLANs Sharing a Port Connected to a Router
Caution
CLI Procedure for Assigning Ports for Multi-VLAN Membership
Caution
Beginning in privileged EXEC mode, follow these steps to assign ports for multi-VLAN membership:
For more information on these commands, see the Cisco IOS Desktop Switching Command Reference (online only). The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Switch to Log Information
Use the Logging Configuration page (Figure 3-31 and Figure 3-32) to define the logging type and the severity level of information that the switch logs. The switch can generate log messages when the configuration changes and when certain network or switch events occur.
To display this page, select Fault>Logging Config from the menu bar.
Figure 3-31 Logging Configuration (Part 1)
Selecting a Logging Option
You can select one of the following options for recording log information:
Defining a Severity Level
The switch can log eight levels of messages. When you select a logging level, the switch logs all syslog messages of that level and above. The default level is "Errors." In all cases, the severity level defines the amount of detail to be logged.
Select a level from one of the following choices on the Logging Level drop-down list:
Figure 3-32 Logging Configuration (Part 2)
CLI Procedure for Configuring Logging
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
Configuring the Switch for Remote Monitoring
The Remote Monitoring (RMON) feature, which is used with the SNMP agent in the switch, allows you to monitor all the traffic flowing among switches on all connected LAN segments.
You can configure your switch for RMON, which is disabled by default, by using the CLI or an SNMP-compatible network management station. You cannot configure it using CVSM. In addition, a generic RMON console application is recommended on the NMS to take advantage of RMON's network management capabilities. You must also configure SNMP on the switch to access RMON MIB objects.
RMON data is usually placed in the high-priority queue for the processor and can render the switch unusable; however, because the 2900 and 3500 XL switches use hardware counters, the monitoring is more efficient and little processing power is required.
The switch supports the following four RMON groups:
•
•
•
•
You configure RMON alarms and events in global configuration mode by using the rmon alarms and rmon events commands. You can collect group history or group Ethernet statistics in interface configuration mode by using the rmon collection history or rmon collection stats commands.
This guide describes the use of IOS commands that have been created or changed for use with switches that support IOS Release 12.0(5)XP. The complete IOS Release 12.0 documentation is available through CCO by selecting Service and Support>Technical Documents>Documentation Home Page>Cisco IOS Software Configuration>Cisco IOS Release 12.0.
