Cisco WS-C6506 Software Manual page 95

Chapter 5 Configuring Ethernet VLAN Trunks
Table 5-2 Ethernet Trunk Encapsulation Types
Encapsulation Function
isl Specifies ISL encapsulation on the trunk link.
dot1q Specifies 802.1Q encapsulation on the trunk link.
negotiate Specifies that the port negotiate with the neighboring port to become an ISL (preferred) or 802.1Q trunk,
depending on the configuration and capabilities of the neighboring port.
The trunking mode, the trunk encapsulation type, and the hardware capabilities of the two connected
ports determine whether a trunk link comes up and the type of trunk the link becomes.
the result of the possible trunking configurations.
Table 5-3 Results of Possible Fast Gigabit Ethernet, and 10-Gigabit Ethernet Trunk Configurations
Local Port Trunk Mode and Trunk Encapsulation
Neighbor Port
Trunk Mode off
and Trunk isl or
Encapsulation dot1q
off Local:
isl or dot1q Nontrunk
Neighbor:
Nontrunk
on Local:
isl Nontrunk
Neighbor:
ISL trunk
desirable Local:
isl Nontrunk
Neighbor:
Nontrunk
auto Local:
isl Nontrunk
Neighbor:
Nontrunk
on Local:
dot1q Nontrunk
Neighbor:
1Q trunk
desirable Local:
dot1q Nontrunk
Neighbor:
Nontrunk
OL-8978-04
on desirable auto
isl isl isl
Local: Local: Local:
ISL trunk Nontrunk Nontrunk
Neighbor: Neighbor: Neighbor:
Nontrunk Nontrunk Nontrunk
Local: Local: Local:
ISL trunk ISL trunk ISL trunk
Neighbor: Neighbor: Neighbor:
ISL trunk ISL trunk ISL trunk
Local: Local: Local:
ISL trunk ISL trunk ISL trunk
Neighbor: Neighbor: Neighbor:
ISL trunk ISL trunk ISL trunk
Local: Local: Local:
ISL trunk ISL trunk Nontrunk
Neighbor: Neighbor: Neighbor:
ISL trunk ISL trunk Nontrunk
Local: Local: Local:
1
ISL trunk Nontrunk Nontrunk
Neighbor: Neighbor: Neighbor:
1
1Q trunk 1Q trunk 1Q trunk
Local: Local: Local:
ISL trunk Nontrunk Nontrunk
Neighbor: Neighbor: Neighbor:
Nontrunk Nontrunk Nontrunk
on desirable
dot1q dot1q
Local: Local:
1Q trunk Nontrunk
Neighbor: Neighbor:
Nontrunk Nontrunk
Local: Local:
1
1Q trunk Nontrunk
Neighbor: Neighbor:
1
ISL trunk ISL trunk
Local: Local:
1Q trunk Nontrunk
Neighbor: Neighbor:
Nontrunk Nontrunk
Local: Local:
1Q trunk Nontrunk
Neighbor: Neighbor:
Nontrunk Nontrunk
Local: Local:
1Q trunk 1Q trunk
Neighbor: Neighbor:
1Q trunk 1Q trunk
Local: Local:
1Q trunk 1Q trunk
Neighbor: Neighbor:
1Q trunk 1Q trunk
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
Understanding How VLAN Trunks Work
Table 5-3
auto desirable auto
dot1q negotiate negotiate
Local: Local: Local:
Nontrunk Nontrunk Nontrunk
Neighbor: Neighbor: Neighbor:
Nontrunk Nontrunk Nontrunk
Local: Local: Local:
Nontrunk ISL trunk ISL trunk
Neighbor: Neighbor: Neighbor:
ISL trunk ISL trunk ISL trunk
Local: Local: Local:
Nontrunk ISL trunk ISL trunk
Neighbor: Neighbor: Neighbor:
Nontrunk ISL trunk ISL trunk
Local: Local: Local:
Nontrunk ISL trunk Nontrunk
Neighbor: Neighbor: Neighbor:
Nontrunk ISL trunk Nontrunk
Local: Local: Local:
1Q trunk 1Q trunk 1Q trunk
Neighbor: Neighbor: Neighbor:
1Q trunk 1Q trunk 1Q trunk
Local: Local: Local:
1Q trunk 1Q trunk 1Q trunk
Neighbor: Neighbor: Neighbor:
1Q trunk 1Q trunk 1Q trunk
shows
5-3