How to trunk multiple vlans off of one port (See Diagram Inside !!!!) 1

[pctechnician]

Diagram Below !!!

running a 24 port cisco 2950 switch (0nly using first 8 ports) which is directly connected to a 2600 router. the router ip address is 10.10.21.1 ports 1-4 on the switch are associated w/ VLAN10. ports 5-7 w/ VLAN11. I want to set port 8 to be the trunking port for both of the VLANS. I put a test pc on vlan 10 to see if it can ping the router. didn't ping. then i put port 8 inside vlan 10 and pinged the router successfully.

I know its a trunking issue, but i cant figure it out.

basically i want to know How i can set port 8 to be the trunking port for two different vlans.

Basically i want FA 0/8 to be the trunk for vlan 10 and 11. FA 0/8 is directly connected to the cisco 2600 FA 0/0.

FA 0/8
[] [] [] [] [] [] [] []
|
| Trunk Line to
| Cisco 2600
| FA 0/0
|


A+,Network+,MCP

 

[rcasta]

Did you configured 8021q in the router?

For example:

interface Fastethernet 0/0
no ip address
no shutdown

interface Fastethernet 0/0.1
ip address 10.10.21.1 255.255.255.0
encapsulation dot1q vlan 10

interface Fastethernet 0/0.2
ip address 10.10.22.1 255.255.255.0
encapsulation dot1q vlan 11


Try the following configuration:

interface fastethernet 0/8
switchport trunk encapsulation dot1q
switchport mode trunk

I guess the rest of your interfaces look like this:

interface FastEthernet0/1-4
switchport access vlan 10
switchport mode access

interface FastEthernet0/5-7
switchport access vlan 10
switchport mode access

Hope it helps.

 

[pctechnician]

thanks rcasta i'll try this

the only thing i didnt understand from your posting is why you didnt give FA 0/0 an IP address ? Is it because when you set vlan trunking you have to set it on sub ints?

A+,Network+,MCP

 

[dmickovic]

when setting sub-interfaces, you assign the IP on the sub interface, you don't touch the main int (fast 0/0 in this case). Only configs that will be global for all interfaces will on the main interface.

 

[rcasta]

And that is why when pinging from vlan 11 the router didn't reply back. Perhaps the router took vlan 10 as native. As dmickovic said, when configuring trunking on routers, do not assign any ip address to the main interface but rather create subinterfaces. Unless of course, the interface has no trunking configured.

tell me if it helped or need more input.

cheers,

 

[pctechnician]

Thanks for your imput rcasta. I'm working on a school Capstone Project and slowly but surely im becoming good at router and switch configs, but i was just stumped. When i get to school on monday i'll try the configs out and let you know. I'm sure they'll work.

Please try to reply to my posts if i have some more questions.

A+,Network+,MCP

 

[rcasta]

Sure I will, let me know how did it go.

cheers,

CCNA