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EtherChannel port bundles allow you to increase the bandwidth of connections between devices by grouping multiple physical ports into a single virtual port.
VLAN trunks are point-to-point links that carry the traffic of multiple VLANs. Trunk ports are useful in the network backbone, where traffic from many VLANs is handled.
You can configure EtherChannel links as VLAN trunks, providing high-bandwidth connections to the network backbone.
To configure EtherChannel VLAN trunks on the switch, perform these tasks:
Step 2 Configure VLAN Trunks---Configure the EtherChannel link as a trunk port to transport traffic for multiple VLANs.
EtherChannel port bundles provide increased bandwidth between network devices by grouping multiple Fast or Gigabit Ethernet ports into a single logical transmission path.
An EtherChannel bundle contains two or more Fast or Gigabit EtherChannel-capable ports. EtherChannel capabilities and flexibility vary depending on your hardware and software. Use the show port capabilities command to determine the supported channeling capabilities on your switch.
You can configure ports to negotiate an EtherChannel bundle with the neighboring device automatically (using the auto and desirable modes), or you can place the ports in on mode on both ends of the link. Ports in on mode will not form a channel with ports in auto or desirable mode. By default, Fast and Gigabit Ethernet ports are in auto mode.
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Note There are additional configuration restrictions associated with EtherChannel port bundles. For complete information, see the Software Configuration Guide for your switch. |
| Task | Command | |
|---|---|---|
Step 1 | If you are unsure which ports support EtherChannel or how the ports are grouped, verify the port groups for the module or switch you are configuring. | show port capabilities [mod_num[/port_num]] |
Step 2 | Create a channel on the desired ports. | set port channel port_list {on | off | auto | desirable} |
Step 3 | Verify the channeling configuration. | show port channel [mod_num[/port_num]] |
This example shows how to configure a two-port Gigabit EtherChannel bundle and how to verify the EtherChannel configuration (this example assumes that there are no configuration mismatches between the local and neighboring ports, and that the ports on the other end of the link are in auto or desirable mode):
Console> (enable) set port channel 2/1-2 desirable
Port(s) 2/1-2 are assigned to admin group 21.
Port(s) 2/1-2 channel mode set to desirable.
Console> (enable) show port channel
Port Status Channel Admin Ch
Mode Group Id
----- ---------- -------------------- ----- -----
2/1 connected desirable silent 21 833
2/2 connected desirable silent 21 833
----- ---------- -------------------- ----- -----
Port Device-ID Port-ID Platform
----- ------------------------------- ------------------------- ----------------
2/1 003812064 1/1 WS-C5509
2/2 003812064 1/2 WS-C5509
----- ------------------------------- ------------------------- ----------------
Console> (enable)
VLAN trunks carry the traffic of multiple VLANs. Fast Ethernet and Gigabit Ethernet ports (including EtherChannel port bundles) can use Inter-Switch Link (ISL) or IEEE 802.1Q encapsulation for VLAN trunking. Other media use other encapsulation schemes (for example, LAN Emulation on ATM).
By default, Fast Ethernet and Gigabit Ethernet ports are in auto mode. If the port on the other end of the link is in desirable mode or on, a port in auto mode automatically becomes a trunk port.
The default trunk encapsulation depends on which encapsulation the hardware supports:
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Note For complete information on the various trunk modes and encapsulation types, refer to the Software Configuration Guide for your switch. |
To configure a Fast Ethernet or Gigabit Ethernet port as a trunk, perform this task in privileged mode:
| Task | Command | |
|---|---|---|
Step 1 | If you are unsure which encapsulation types a port supports, verify the port capabilities. | show port capabilities [mod_num[/port_num]] |
Step 2 | Configure a Fast or a Gigabit Ethernet port as a trunk. If you are configuring an EtherChannel port bundle as a trunk, specify any one of the ports in the channel. | set trunk mod_num/port_num {on | desirable | auto} {isl | dot1q | negotiate} |
Step 3 | Verify that the trunk configuration is correct. |
This example shows how to configure a port to become a trunk and how to verify the trunk configuration (this example assumes that the port on the other end of the link is in auto, desirable, or on mode and supports IEEE 802.1Q encapsulation):
Console> (enable) set trunk 2/1 desirable dot1q Port(s) 2/1-2 trunk mode set to desirable. Port(s) 2/1-2 trunk type set to dot1q. Console> (enable) show trunk Port Mode Encapsulation Status Native vlan -------- ----------- ------------- ------------ ----------- 2/1 desirable dot1q trunking 1 2/2 desirable dot1q trunking 1 Port Vlans allowed on trunk -------- --------------------------------------------------------------------- 2/1 1-1005 2/2 1-1005 Port Vlans allowed and active in management domain -------- --------------------------------------------------------------------- 2/1 1,10,20,30,40,50,60 2/2 1,10,20,30,40,50,60 Port Vlans in spanning tree forwarding state and not pruned -------- --------------------------------------------------------------------- 2/1 1,10,20,30,40,50,60 2/2 1,10,20,30,40,50,60 Console> (enable)
Posted: Sun Jun 11 11:29:18 PDT 2000
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