5-3
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 5 Configuring Ethernet VLAN Trunks
Understanding How VLAN Trunks Work
Table 5-3
Results of Possible Fast Ethernet and Gigabit Ethernet Trunk Configurations
Neighbor Port
Trunk Mode
and Trunk
Encapsulation
Local Port Trunk Mode and Trunk Encapsulation
off
isl or
dot1q
on
isl
desirable
isl
auto
isl
on
dot1q
desirable
dot1q
auto
dot1q
desirable
negotiate
auto
negotiate
off
isl or dot1q
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
on
isl
Local:
Nontrunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
1Q trunk
1
Neighbor:
ISL trunk
1
1.
Using this configuration can result in spanning tree loops and is not recommended.
Local:
Nontrunk
Neighbor:
ISL trunk
Local:
Nontrunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
desirable
isl
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
1Q trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
auto
isl
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
Nontrunk
Neighbor:
Nontrunk
on
dot1q
Local:
Nontrunk
Neighbor:
1Q trunk
Local:
ISL trunk
1
Neighbor:
1Q trunk
1
Local:
Nontrunk
Neighbor:
1Q trunk
Local:
Nontrunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
desirable
dot1q
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
auto
dot1q
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
Nontrunk
Neighbor:
Nontrunk
desirable
negotiate
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
auto
negotiate
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
1Q trunk
Neighbor:
1Q trunk
Local:
Nontrunk
Neighbor:
Nontrunk
Local:
ISL trunk
Neighbor:
ISL trunk
Local:
Nontrunk
Neighbor:
Nontrunk