Cisco Catalyst 3850 Manual page 55

Uplink Interface Connectivity
interface
description
switchport mode trunk
switchport trunk native vlan
switchport trunk allowed vlan
channel-protocol lacp
channel-group
!
interface
description
switchport mode trunk
switchport trunk native vlan
switchport trunk allowed vlan
channel-protocol lacp
channel-group 1 mode active
!
interface
description
switchport mode trunk
switchport trunk native vlan
switchport trunk allowed vlan
channel-protocol lacp
channel-group
!
interface
description
switchport mode trunk
switchport trunk native vlan
switchport trunk allowed vlan
channel-protocol lacp
channel-group 1 mode active
Configure an Uplink Interface to Connect to a Distribution Router (or Standalone Distribution
Switch)
Note Use this configuration when connecting the switch stack to two standalone distribution switches (not
configured as a VSS or VPC pair). However, do not use the spanning-tree portfast trunk command for
switch configuration.
•
•
•
Figure 7
EtherChannel is configured as a trunk with VLANs 10, 11, 12, 100, 200, and 999, with the native VLAN
set to 999.
GigabitEthernet 1/1/1
connection to Distribution VSS or VPC switch 1
1 mode active
GigabitEthernet 2/1/1
connection to Distribution VSS or VPC switch 1
GigabitEthernet 1/1/2
connection to Distribution VSS or VPC switch 2
1 mode active
GigabitEthernet 2/1/2
connection to Distribution VSS or VPC switch 2
Ensure that the distribution VSS or VPC router side of the connections are configured the same and
that the EtherChannel is configured with the LACP active mode.
For additional resilience, the configured uplink interfaces should be located on different switches in
the switch stack.
Use the spanning-tree portfast trunk command to allow the switch side of the uplink to
immediately transition to a spanning-tree forwarding state when the link becomes available, because
routers do not participate in a spanning tree.
shows a switch stack having a separate EtherChannel to each distribution router. Each
Best Practice User Guide for the Catalyst 3850 and Catalyst 3650 Switch Series
999
10,11,12,100,200
999
10,11,12,100,200
999
10,11,12,100,200
999
10,11,12,100,200
Configure Uplink Interface Connectivity
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