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Trunking between 3550 switch and 7200 routers

I attempting to trunk between a 3550 switch and 7200 router. There are several vlans that I want going over the trunk. But some devices on certain vlans are not reachable from the router or even the switch...Could someone help me out with the 3550(port-channel) configurations and the 7200 router configurations...An example would help a great deal....Thanks
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Menace212
Asked:
Menace212
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1 Solution
 
lrmooreCommented:
On your switch, apply this to the port that connects to the router:
!
interface FastEthernet0/23
 description 7200 router trunk uplink
 switchport trunk encapsulation dot1q
 switchport mode trunk
!


On the router:
interface fast 0/0
 ip address <vlan1 IP> 255.255.255.0
!
interface fast 0/0.2
 encapsulation dot1q 2  <== VLAN #
 ip address <vlan 2 IP> <mask>
!
interface fast 0/0.3
 encapsulation dot1q 3  
 ip address <vlan 2 IP> <mask>
!
interface fast 0/0.4
 encapsulation dot1q 4  
 ip address <vlan 2 IP> <mask>

<etc>


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lrmooreCommented:
Oops. router config should be:
 !
interface fast 0/0.2
 encapsulation dot1q 2  <== VLAN #
 ip address <vlan 2 IP> <mask>
!
interface fast 0/0.3
 encapsulation dot1q 3  
 ip address <vlan 3 IP> <mask>
!
interface fast 0/0.4
 encapsulation dot1q 4  
 ip address <vlan 4 IP> <mask>
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Menace212Author Commented:
Should the corresponding ports on the switches be configured with the access command or desirable command.

fast0/3
swichport mode access
switchport access vlan 2


Do I need a port-channel for the switch configuration, or is that optional....

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Menace212Author Commented:
Oh yea, what about the configuratin for the router connection to the switch. You have the switch trunking but I don't see and config's for the router connection to the switch...Or do you need any...
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lrmooreCommented:
Host ports on the switch should be set to access as you have in your post.

Router config is shown in my post above.
In my above example, router 7200 Fast0/0 is connected to 3550 Fast0/23
These are live, working examples
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Dr-IPCommented:
Issue the command below on the switch with the Ethernet port number you have the router attached to it to see if those VLAN’s are allowed on that trunk. You will get all, or a list of the allowed VLAN’s.

show interface Ethernet0/23 switchport allowed-vlan
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Dr-IPCommented:
Opps forgot the fast.

show interface FastEthernet0/23 switchport allowed-vlan
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Menace212Author Commented:
So my configurations should look like  this and this will allow my vlans to be trunked...


router config's
interface fast0/0
no ip address
!
interface fast 0/0.2
 encapsulation dot1q 2
 ip address 10.1.1.41 255.255.255.248
!
interface fast 0/0.3
 encapsulation dot1q 3  
 ip address 10.1.1.49 255.255.255.248
!
interface fast 0/0.4
 encapsulation dot1q 4  
 ip address 10.1.1.57 255.255.255.248

switch

interface FastEthernet0/23
 description 7200 router trunk uplink
 switchport trunk encapsulation dot1q
 switchport mode trunk


interface fasteth0/2
switchport mode access
switchport access vlan 2

interface fasteth0/3
swithport mode access
switchport access vlan 2

interface fasteth0/4
switchport mode access
switchport access vlan 3

interface fast0/5
switchport mode access
switchport access vlan 4

and so on

And these are the configurations I need...I attempted the configurations, but I was unsuccessful...I'll try again to see if I made a mistake...




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lrmooreCommented:
That's exactly what you need to do.
Keep in mind that the sub-interface for the VLAN won't be "up" unless and until there is at least one port active in that VLAN. So, you need something connected to each of those access ports in order for the router to be able to route between them.
For example, if you have only a single host connected to the switch on fast 0/5 on VLAN 4, it won't be able to ping the router on any IP except 10.1.1.57 (vlan4)
Once you enable a host on say, vlan3, then you can ping between the vlans, but only between 3 and 4
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Dr-IPCommented:
Try switching the encapsulation to ISL instead of dot1q, I have had issues with some Cisco router IOS not working when trunking to a switch using dot1q encapsulation, but they worked fine with ISL.
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