A tagged Ethernet packet has extra data in the packet that defines the vlan it is a member of. The different port modes (Trunk, Access, General) define how tagged and untagged packets are handled.
Ingress means packets entering a port. Egress means traffic exiting a port.
Access mode VLAN: by default sets egress to untagged, supports single VLAN configuration only, automatically sets PVID (native VLAN, ingress untagged) to configured VLAN. Will accept untagged packets or tagged packets with VLAN ID to which the port is a member - in this case the port is a member of only one VLAN.
Trunk mode VLAN: by default sets egress to tagged, supports multiple VLANs, does not set PVID (native VLAN, ingress untagged), native VLAN cannot be a configured Trunk VLAN or 4095 (discard VLAN).
General mode VLAN: by default sets egress to tagged, supports multiple VLANs, does not set PVID (native VLAN, ingress untagged), native VLAN can be any defined VLAN. Setting the PVID removes default vlan (VID=1) for that port.. PVID can be 4095 (discard VLAN). General mode allows mix of tagged and untagged VLANs in the egress direction.
Here is an example config you can use on 2 switches connected via port g24. Port 1 on each switch can communicate to eachother. Port 2 on each switch can communicate with eachother. Port 3 on each switch can communicate with eachother.
console(config)# vlan database
console(config-vlan)# vlan 101,102,310
console(config-vlan)# exit
console(config)# interface Ethernet g1
console(config-if)# switchport access vlan 101
console(config-if)# exit
console(config)# interface Ethernet g2
console(config-if)# switchport access vlan 102
console(config-if)# exit
console(config)# interface Ethernet g3
console(config-if)# switchport access vlan 310
console(config-if)# exit
console(config)# interface Ethernet g24
console(config-if)# switchport mode general
console(config-if)# switchport general allowed vlan add 101,102,310 tagged
bh1633
909 Posts
1
April 10th, 2007 17:00
A tagged Ethernet packet has extra data in the packet that defines the vlan it is a member of. The different port modes (Trunk, Access, General) define how tagged and untagged packets are handled.
Ingress means packets entering a port. Egress means traffic exiting a port.
console(config)# vlan database
console(config-vlan)# vlan 101,102,310
console(config-vlan)# exit
console(config)# interface Ethernet g1
console(config-if)# switchport access vlan 101
console(config-if)# exit
console(config)# interface Ethernet g2
console(config-if)# switchport access vlan 102
console(config-if)# exit
console(config)# interface Ethernet g3
console(config-if)# switchport access vlan 310
console(config-if)# exit
console(config)# interface Ethernet g24
console(config-if)# switchport mode general
console(config-if)# switchport general allowed vlan add 101,102,310 tagged
console(config-if)# switchport general pvid 4095
console(config-if)# exit
Rumhy
36 Posts
0
April 11th, 2007 07:00