IOS Switch Commands

The standard Cisco IOS was used as the basis for the commands for the 2900XL switches. Some of those commands are still the same, and where I have not described a command you should assume that the regular IOS command does the job.

I have arranged the commands to resemble similar commands (on other switches) that appear in the main part of the book.

Management and Administrative Commands

This first section deals with commands that can be grouped together as management and administration, such as setting global values for the switch.

mac-address-table dynamic  This command adds a dynamic address entry to the address table.

mac-address-table static  This command adds a static address entry to the address table.

Interface Mode and Trunk Commands

The following commands are entered from the privileged interface configuration mode.

duplex {full | half | auto} and no duplex  These commands set the interface duplex mode (the default mode is auto).

port block {unicast | multicast} and no port block {unicast | multicast} These commands block the flooding of unknown unicast or multicast packets to a port. (The default is to unknown unicast and multicast packets to all ports.)

switchport access vlan {vlan-id | dynamic} and no switchport access vlan {vlan-id | dynamic}  These commands configure a port as a static-access or dynamic-access port. Access mode makes the port a member of the configured VLAN. Dynamic mode makes the port discover the VLAN assignment based on received incoming packets.

switchport mode {access | multi | trunk} and no switchport mode {access | multi | trunk}  These commands set the port to become a trunk. (This operation is supported only in Enterprise Edition Software.)

switchport trunk encapsulation {isl | dot1q} and no switchport trunk encapsulation  These commands set the encapsulation format on the trunk port. (This operation is supported only in Enterprise Edition Software.)

switchport trunk allowed vlan {add vlan-list | all | except vlan-list | remove vlan-list} and no switchport trunk allowed vlan  These commands control which VLANs can receive and transmit traffic on the trunk. (This operation is supported only in Enterprise Edition Software.)

VLAN and VTP Commands

As with some other switches, the VLAN information is contained inside a different database, so you have to enter the VLAN database configuration mode to alter VTP and VLAN information. This section shows some of the most useful commands.

VLAN Database Mode

You must enter the VLAN database mode first. Once in this mode, the remainder of the commands in this section can be entered.

vlan database  To enter the VLAN database, allowing advanced configuration of VLAN and VTP parameters, use the global command vlan database.

vlan 1  This command configures a VLAN by its ID.

vtp  This command configures the VTP mode.

vtp domain  This command configures the VTP domain.

reset  This command abandons the changes, but remains in VLAN database mode.

apply  This command implements the changes, propagates them throughout the administrative domain, and remains in VLAN database mode.

exit  This command implements the changes, propagates them throughout the administrative domain, and exits the VLAN database mode to return to the privileged mode.

Spanning Tree Commands

The spanning tree commands are pretty unusual. In the first instance, only a single VLAN was supported on the switch (or if you like, no VLANs were supported), so all of the spanning tree commands applied to the whole switch. With the current support for up to 64 VLANs, new commands were created to allow spanning tree to be configured on a per-VLAN basis.

The negating of these commands is also pretty unusual, so I have added the commands for that as well.

Global Commands

The following commands are entered from the privileged global command prompt.

spanning-tree vlan 1 and no spanning-tree vlan 1  This command enables spanning tree on the stated VLAN.

vlan 1 {ieee | dec | ibm} and no vlan 1 (reverts to default)  This command determines which version of spanning tree will be implemented.

spanning-tree vlan 1 forward-time seconds and no spanning-tree vlan 1 forward-time (reverts to default)   This command determines the spanning tree forward timer.

spanning-tree vlan 1 hello-time secondsand no spanning-tree vlan 1 hello-time (reverts to default)  This command determines the spanning tree hello timer settings.

spanning-tree vlan 1 max-age seconds and no spanning-tree vlan 1 max-age (reverts to default)  This command determines the spanning tree aging timer settings.

spanning-tree vlan 1 priority bridge-priority and no spanning-tree vlan 1 priority (reverts to default)  This command determines the spanning tree priority.

Interface Commands

The following commands are entered from the privileged interface command prompt.

vlan 1 cost cost and no vlan 1 cost (reverts to default)  This command determines the port spanning tree cost.

vlan 1 port-priority port-priority and no vlan 1 priority (reverts to default)  This command determines the port spanning tree priority.

vlan 1 portfast interface and no spanning-tree vlan 1 portfast interface  This command determines that the port will run in the spanning tree portfast mode.

show Commands

This final section deals with a few of the more useful show commands. These commands are used to query the condition of general tables and specific ports on the switch.

show mac-address-table  This command displays the MAC address table.

show port block This command displays the multicast and unicast filtering on the port.

show port group  This command displays the assignation of ports to groups.

show port monitor  This command displays the ports where monitoring is enabled.

show port security  This command displays the ports where security is enabled.



CCNP. Building Cisco Multilayer Switched Networks Study Guide (642-811)
CCNP: Building Cisco Multilayer Switched Networks Study Guide (642-811)
ISBN: 078214294X
EAN: 2147483647
Year: 2002
Pages: 174
Authors: Terry Jack

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