Cisco Systems EA6500 Benutzerhandbuch

For information about VLANs, see 

A trunk is a point-to-point link between the switch and another networking device. Trunks carry the 
traffic of multiple VLANs over a single link and allow you to extend VLANs across an entire network.

Two trunking encapsulations are available on all Ethernet ports:

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

The following switching modules do not support ISL encapsulation:

 

 

• WS-X6501-10GEX4

 

• WS-X6502-10GE 

 

• WS-X6548-GE-TX

 

• WS-X6548V-GE-TX

 

• WS-X6148-GE-TX

 

• WS-X6148V-GE-TX 

802.1Q—802.1Q is an industry-standard trunking encapsulation.

You can configure a trunk on a single Ethernet port or on an EtherChannel. For more information about 
EtherChannel, see 

Ethernet trunk ports support several trunking modes (see 

). You can specify 

whether the trunk uses ISL or 802.1Q encapsulation, and if the encapsulation type is autonegotiated.

You can configure LAN ports to negotiate the encapsulation type. You cannot configure WAN interfaces 
to negotiate the encapsulation type.

The Dynamic Trunking Protocol (DTP) manages trunk autonegotiation on LAN ports. DTP supports 
autonegotiation of both ISL and 802.1Q trunks.

To autonegotiate trunking, the LAN ports must be in the same VTP domain. Use the trunk or 
nonegotiate keywords to force LAN ports in different domains to trunk. For more information on VTP 
domains, see