Difference between revisions of "VLANs"
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r1-basic#show interfaces trunk | r1-basic#show interfaces trunk | ||
= Access port configuration = | |||
interface GigabitEthernet1/0/2 | interface GigabitEthernet1/0/2 | ||
description Access Port to Cisco Access Point | description Access Port to Cisco Access Point | ||
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interface range gi 0/1/0 - 3 | interface range gi 0/1/0 - 3 | ||
= Trunk port configuration = | |||
For 802.1Q trunking, one VLAN is not tagged. This VLAN is called native VLAN. The native VLAN is used for untagged traffic when the port is in 802.1Q trunking mode. While configuring 802.1Q trunking, it is very important to keep in mind that the native VLAN must be configured the same on each side of the trunk link. It is a common mistake not to match the native VLANs while configuring 802.1Q trunking between the router and the switch. | |||
In this example 802.1Q encapsulation is used | |||
interface GigabitEthernet1/0/1 | interface GigabitEthernet1/0/1 | ||
description Trunk Port to Cisco WLC | description Trunk Port to Cisco WLC | ||
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switchport nonegotiate | switchport nonegotiate | ||
no shutdown | no shutdown | ||
The following list shows options for the <code>switchport mode</code> command. | |||
:'''trunk''' - configures the port into permanent 802.1Q trunk mode and negotiates with the connected device to convert the link to trunk mode. | |||
:'''access''' - disables port trunk mode and negotiates with the connected device to convert the link to nontrunk. | |||
:'''nonegotiate''' - the port is a trunk and does not do DTP negotiation with the other side of the link. | |||
:'''dynamic desirable''' - triggers the port to negotiate the link from nontrunk to trunk mode. The port negotiates to a trunk port if the connected device is in trunk state, desirable state, or auto state. Otherwise, the port becomes a nontrunk port. | |||
:'''dynamic auto''' - enables a port to become a trunk only if the connected device has the state set to ''trunk'' or ''desirable''. Otherwise, the port becomes a nontrunk port. | |||
== Verifying a Trunk == | |||
******* (requires live capture) ************ | |||
Switch#'''show interfaces GigabitEthernet1/0/1 switchport''' | |||
Switch#'''show interfaces GigabitEthernet1/0/1 trunk''' | |||
[[Category:cisco]] | [[Category:cisco]] | ||
Revision as of 13:53, 4 May 2014
Basic VLANs info. Cisco series 1900 routers support up to 16 VLANs.
- Create
#vlan vlan_id
- Deleting a VLAN
#no vlan vlan_id
- Show all VLANs summary and port assignment
r1-basic#sh vlan-switch
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi0/1/0, Gi0/1/1, Gi0/1/2
Gi0/1/3
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 1002 1003
1002 fddi 101002 1500 - - - - - 1 1003
1003 tr 101003 1500 1005 0 - - srb 1 1002
1004 fdnet 101004 1500 - - 1 ibm - 0 0
1005 trnet 101005 1500 - - 1 ibm - 0 0
- Verify trunk interfaces
r1-basic#show interfaces trunk
Access port configuration
interface GigabitEthernet1/0/2 description Access Port to Cisco Access Point switchport access vlan 10 no ip address end
interface range
interface range gi 0/1/0 - 3
Trunk port configuration
For 802.1Q trunking, one VLAN is not tagged. This VLAN is called native VLAN. The native VLAN is used for untagged traffic when the port is in 802.1Q trunking mode. While configuring 802.1Q trunking, it is very important to keep in mind that the native VLAN must be configured the same on each side of the trunk link. It is a common mistake not to match the native VLANs while configuring 802.1Q trunking between the router and the switch.
In this example 802.1Q encapsulation is used
interface GigabitEthernet1/0/1 description Trunk Port to Cisco WLC switchport trunk encapsulation dot1q switchport trunk native vlan 99 switchport trunk allowed vlan add 10,20,99 switchport mode trunk switchport nonegotiate no shutdown
The following list shows options for the switchport mode command.
- trunk - configures the port into permanent 802.1Q trunk mode and negotiates with the connected device to convert the link to trunk mode.
- access - disables port trunk mode and negotiates with the connected device to convert the link to nontrunk.
- nonegotiate - the port is a trunk and does not do DTP negotiation with the other side of the link.
- dynamic desirable - triggers the port to negotiate the link from nontrunk to trunk mode. The port negotiates to a trunk port if the connected device is in trunk state, desirable state, or auto state. Otherwise, the port becomes a nontrunk port.
- dynamic auto - enables a port to become a trunk only if the connected device has the state set to trunk or desirable. Otherwise, the port becomes a nontrunk port.
Verifying a Trunk
******* (requires live capture) ************
Switch#show interfaces GigabitEthernet1/0/1 switchport
Switch#show interfaces GigabitEthernet1/0/1 trunk