Connecting switches with two or more Ethernet cables is a piece of cake
All you need to do is create/configure a port-channel on both switches and plug in the cables.
The following setup should work on Cisco Catalyst switches. Three different VLANs are used:
Access ports for clients (vlan2) and server/admin network (vlan1) and voip (vlan3).
Step 1:
Define port-channel (Switch A)
interface Port-channel2
description ### Uplink-Channel to switch B ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
Step 2:
Assign port-channel to physical interfaces (Switch A)
interface GigabitEthernet0/1
description ### Uplink-Channel to switch B ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
channel-group 2 mode active
interface GigabitEthernet0/2
description ### Uplink-Channel to switch B ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
channel-group 2 mode active
Please note that [id] in “channel-group [id] mode active” must match [id] in “interface Port-channel[id]”
Step 3:
Create a port-channel and assign it to physical interfaces the same way as on Switch A now on Switch B
interface Port-channel2
description ### Uplink-Channel to switch A ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
interface GigabitEthernet0/1
description ### Uplink-Channel to switch A ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
channel-group 2 mode active
interface GigabitEthernet0/2
description ### Uplink-Channel to switch a ###
switchport trunk allowed vlan 1,2,3
switchport mode trunk
switchport nonegotiate
channel-group 2 mode active
Step 4:
Get yourself two Ethernet cables and plug them in