SNMP Management Window

This window appears when you choose Administration > SNMP on the menu bar. You can also click here to launch it.

This window has these tabs:

Begin by:

When you have finished entering settings on the tabs, click OK.

System Options

Although SNMP allows a maximum of 255 characters for each field on this tab, CMS truncates this information to shorter lengths. For this reason, shorter entries are recommended. (See individual steps in the following procedure for guidelines.)

To assign system options:

  1. In the Host Name field, enter the host name of the switch.
    Host names must be unique. The maximum length of the host name on a command switch is 28 characters, and the maximum length of the host name on member switches is 31 characters.
    Note: Do not use -n (where n is a number) as the last characters in host names for any switch.
  2. In the System Location field, enter the physical location of the switch.
    The maximum length of an entry in the System Location field is 129 characters.
  3. In the System Contact field, enter the name or organization responsible for the switch.
    The maximum length of an entry in the Contact field is 129 characters.

Community Strings

Community strings serve as passwords to authenticate SNMP messages. Each community string is either read-only (RO), which allows MIB-object information to be displayed, or read-write (RW), which allows MIB-object information to be displayed and modified. When a switch joins a cluster, the first read-only and first read-write community string from the command switch are propagated to the new member, and an @esN notation is appended to each propagated string. The N in this notation is a numeric identifier that is unique for each switch, and it can be up to two digits long.

On 2900 XL and 3500 XL switches, the propagated strings are the first read-only and first read-write community strings listed on the SNMP Management window. On Catalyst 1900 and 2820 switches, the propagated strings are the last read-only and last read-write community strings listed on this window. Because they are necessary for SNMP packet routing, these strings should not be removed on any switch.

In addition to the propagated strings, the SNMP configuration can also contain user-defined community strings.

Adding Community Strings

The command switch uses community strings to route SNMP packets to member switches. Catalyst 2900 and 3500 XL switches support an unlimited number of community strings of any length. Catalyst 1900 and 2820 switches support a maximum of four read-only and four read-write community strings that are up to 32 characters long. When you assign community strings to these switches, limit their length to 27 characters to accommodate the @esN identifier that will be appended (strings longer than 27 characters are truncated to 27 characters).

To add a new community string to a switch:

  1. In the New String field, enter a character string.
    Note: Limit the string length to 27 characters if the switch is a Catalyst 1900 or 2820 switch.
  2. Select RO (read only) or RW (read-write) to specify the string type.
  3. Click Add to move the new community string to the Current Strings list.
    Note: If your access mode is read-only, you do not see community strings in this list.

Removing Community Strings

When you remove a switch from a cluster, all @esN strings on the switch are removed. If the switch rejoins the cluster, the first read-only and first read-write string from the command switch are propagated to the member switch, and the @esN identifier is appended to each string.

Note: Do not remove the first read-only or the first read-write community string from a 2900 XL or 3500 XL switch; do not remove the last read-only or the last read-write community string from a Catalyst 1900 or 2820 switch. These strings are required for SNMP functions.

To remove an existing community string from the cluster:

  1. In the Current Strings list, select the community strings to be deleted.
    To remove all community strings, click Select All.
  2. Click Remove.

If you remove a community string and enter a new one, click the Refresh button on your browser to put the change into effect (click Reload on Netscape Navigator).

Trap Managers

A trap manager is a management station that receives traps, the system alerts generated by a switch. If a cluster member switch has no IP address, the command switch receives the SNMP traps and relays them to the trap manager. By default, no trap manager is defined, and no traps are issued.

Catalyst 2900 and 3500 XL switches support an unlimited number of trap managers, and community strings for the trap managers can be any length. On these switches, you can enable specific trap types for specific trap managers. Catalyst 1900 and 2820 switches support up to four trap managers, and community string length is limited to 32 characters. You cannot configure specific trap types for specific trap managers on these switches.

To enable the selected device to send traps, check the Enable Traps box. Then check the boxes for the trap types you want to enable for each IP destination.

To add a new trap manager:

  1. In the IP Address field, enter the IP address of the new trap manager.
  2. In the Community String field, enter the community string for the new trap manager.
  3. Check the boxes for the trap types you want to enable. Trap Types shows the type of trap that each check box allows, and on what devices.
  4. Click Add to move your entry to the Current Managers list.
    Note: If your access mode is read-only, you do not see trap managers and their community strings in this list.

To remove a trap manager:

  1. In the Current Managers list, select the trap managers to be deleted.
    To remove all existing trap managers, click Select All.
  2. Click Remove.

Trap Types

This table lists the trap check boxes, shows what type of trap each allows, and shows the devices that the trap is allowed on.

Check Box Type of Trap Allowed Devices Trap Is Allowed On
address violation Address violation trap 1900, 2820
authentication Authentication failure trap 1900, 2820
bsc Broadcast storm trap 1900, 2820
c2900 SNMP C2900 trap 2900, 2950, 3500
cluster Cluster member status trap 2900, 2950, 3500, 3550
config SNMP configuration trap 2900, 2950, 3500, 3550
entity SNMP entity trap 2900, 2950, 3500, 3550
hsrp SNMP HSRP trap 2900, 2950, 3500, 3550
link-up-down Link up and link down trap 1900, 2820
rtr SNMP Response Time Reporter trap 2950, 3550
snmp SNMP-type notifications 2900, 2950, 3500, 3550
tty TCP connection trap 2900, 3500, 3550
vlan VLAN membership trap 2900, 3500
vtp SNMP VTP trap 1900, 2820, 2950, 3550

To receive udp-port traps, enter the number in the udp-port field of a software port that is used by the new trap manager.