Switchport Trunk - Cisco Catalyst 3750 Metro Command Reference Manual

Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands

switchport trunk

Use the switchport trunk interface configuration command to set the trunk characteristics when the
interface is in trunking mode. Use the no form of this command to reset a trunking characteristic to the
default.
Syntax Description allowed vlan vlan-list
dot1q ethertype value
encapsulation
dot1q
isl
negotiate
native vlan vlan-id
pruning vlan vlan-list
The vlan-list format is all | none | [add | remove | except] vlan-atom [,vlan-atom...] where:
•
•
•
OL-9645-10
switchport trunk {allowed vlan vlan-list| dot1q ethertype value | encapsulation {dot1q | isl |
negotiate} | native vlan vlan-id | pruning vlan vlan-list}
no switchport trunk {allowed vlan | dot1q ethertype value | encapsulation | native vlan |
{pruning vlan}
Set the list of allowed VLANs that can receive and send traffic on this
interface in tagged format when in trunking mode. See the following vlan-list
format. The none keyword is not valid. The default is all.
Sets the ethertype value on an enhanced-services (ES) port for 802.1Q
encapsulation. Used to select a nonstandard (nondefault) 2-byte ethertype to
identify 802.1Q tagged frames. The default ethertype value is 0x8100.
Note
Set the encapsulation format on the trunk port. The default is to negotiate.
Note
Set the encapsulation format on the trunk port to 802.1Q. With this format,
the switch supports simultaneous tagged and untagged traffic on a port.
Set the encapsulation format on the trunk port to Inter-Switch Link (ISL).
The switch encapsulates all received and sent packets with an ISL header and
filters native frames received from an ISL trunk port.
Specify that the interface negotiate encapsulation with the neighboring
interface. This is the default. If Dynamic Inter-Switch Link (DISL) and
Dynamic Trunking Protocol (DTP) negotiation do not resolve the
encapsulation format, ISL is the selected format.
Set the native VLAN for sending and receiving untagged traffic when the
interface is in 802.1Q trunking mode. The range is 1 to 4094.
Set the list of VLANs that are eligible for VTP pruning when in trunking
mode. The all keyword is not valid.
all specifies all VLANs from 1 to 4094. This keyword is not allowed on commands that do not
permit all VLANs in the list to be set at the same time.
none means an empty list. This keyword is not allowed on commands that require certain VLANs
to be set or at least one VLAN to be set.
add adds the defined list of VLANs to those currently set instead of replacing the list. Valid IDs are
from 1 to 1005; extended-range VLANs (VLAN IDs greater than 1005) are valid in some cases.
This keyword is supported only on ES ports.
Starting with release 12.2(25)EY, this keyword is not supported on
ES ports. ES ports support only 802.1Q encapsulation.
Catalyst 3750 Metro Switch Command Reference
switchport trunk
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