Please provide me with a simple example for creating a trunk from a 6506 to a 3750

[lamarmac]

An simple config example would be perfect
 

[Richard Burts]

Here is an example drawn from a working trunk on a 6500

interface GigabitEthernet2/48
 description example of a trunk
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 105
 switchport trunk allowed vlan 105,123,127
 switchport mode trunk

HTH

Rick

[chinpohpang851]

I'm using Packet Tracer but I don't see this line exist

Switch(config-if)#switchport trunk encapsulation dot1q   

What is this line for?

[shine pothen]

Encapsulation dot1q

To correctly deliver the traffic on a trunk port with several VLANs, the device uses the IEEE 802.1Q encapsulation (tagging) method that uses a tag that is inserted into the frame header. This tag carries information about the specific VLAN to which the frame and packet belong. This method allows packets that are encapsulated for several different VLANs to traverse the same port and maintain traffic separation between the VLANs. The encapsulated VLAN tag also allows the trunk to move traffic end-to-end through the network on the same VLAN.

A trunk is a point-to-point link between the device and another networking device. Trunks carry the traffic of multiple VLANs over a single link and allow you to extend VLANs across an entire network.

you will get more understanding from the URL 

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli_rel_4_0_1a/CLIConfigurationGuide/AccessTrunk.html#wp1206629

[Jon Marshall]

Some switches support multiple encapsulation types.

If the command is not available then don't worry about it. It simply means that the switch only supports that encapsulation so there is no need for the command.

Jon

[shine pothen]

Here is the link were you will get sample configuration.

http://apacketslife.com/blog/2013/07/22/vlan-trunk-configuration/

[shine pothen]

Here goes the configuration 

3560 – example
Switch(config)#int fa0/2
Switch(config-if)#switchport

Switch(config-if)#switchport trunk encapsulation ?
dot1q Interface uses only 802.1q trunking encapsulation when trunking
Switch(config-if)#switchport trunk encapsulation dot1q

Switch(config-if)#switchport trunk native vlan ?
<1-1005> VLAN ID of the native VLAN when this port is in trunking mode
Switch(config-if)#switchport trunk native vlan 3

Switch(config-if)#switchport trunk allowed vlan ?
WORD VLAN IDs of the allowed VLANs when this port is in trunking mode
add add VLANs to the current list
all all VLANs
except all VLANs except the following
none no VLANs
remove remove VLANs from the current list
Switch(config-if)#switchport trunk allowed vlan 1 – 5 , 23 , 34

Switch(config-if)#switchport mode ?
access Set trunking mode to ACCESS unconditionally
dynamic Set trunking mode to dynamically negotiate access or trunk mode
trunk Set trunking mode to TRUNK unconditionally
Switch(config-if)#switchport mode trunk

Ok so now let’s confirm the port by using the show interface trunk command….
sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/2 on 802.1q trunking 3

Port Vlans allowed on trunk
Fa0/2 1-1005