Cannot configure dot1Q encapsulation on a trunk port in the WS-X6148-GE-TX module

[TCC_2]

Core issue

The encapsulation option does not show up when trunking is configured on a trunk port in the WS-X6148-GE-TX module. This is because the encapsulation option is enabled by default.

Two trunking encapsulations are available on all Ethernet ports:

• Inter-Switch Link (ISL) is a Cisco-proprietary trunking encapsulation.

  Note: The WS-X6148-GE-TX switching module does not support ISL encapsulation.

     
• 802.1Q (or dot1Q) is an industry-standard trunking encapsulation. 

A trunk can be configured on a single Ethernet port or on an EtherChannel.

Resolution

The trunking mode, the trunk encapsulation type, and the hardware capabilities of the two connected LAN ports determine whether a link becomes an ISL or 802.1Q trunk.

Ethernet trunk ports support several trunking modes. As the WS-X6148-GE-TX switching module does not support ISL encapsulation, the 802.1Q encapsulation is configured by default. So the dot1Q encapsulation is not available when trunking is configured on a trunk port in the WS-X6148-GE-TX module.

To display the administrative and operational status of a switching (nonrouting) port, issue the show interfaces switchport command.

For more information, refer to the Release Notes for Cisco IOS Release 12.2(33)SXH and Later Releases.