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Encapsulation dot1q

ghtmoha153
Level 1
Level 1

I have router 2921 with 3 layer 3 interfaces i need to configure one of them as access interface encapsulation in bidirectional (not subinterface solutions)

9 Replies 9

marce1000
VIP
VIP

 

 - The question is confusing , layer 3 interface, can not be access ports ,

 M.



-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

.

My question is layer3  interface can encapsulation packets and send it out from router or no t

in the router and in SW must not use native vlan, native vlan is send untag frame
for config you need 
in SW config trunk and allow vlan <vlan id>
and in Router config subinterface with encapsulation dot1q <vlan id>

In my case i want to configure two interfaces in same router one is physical and second one is subinterface with vlan 3090 in another physical interface and physical one i need connect it to end device 

sorry can you more elaborate more?
router interface f0/0 without subinterface 
router interface f0/1 with subinterface 
and then what?

 So in R1 i configure bridge group (interface fa0/0 and fa0/1.3090)  fa0/0 is connected to switch 3750 with vlan 1 

Fa0/1.3090 connect to sw 3750 with vlan 3090 i do ping between int vlan 3090 and int vlan 1 so no reply what can i do to connect vlan 1 and 3090

R1
bridge irb
bridge-group 1
!
interface FastEthernet2/0.999
encapsulation dot1Q 999
bridge-group 1
!
interface BVI1
ip address 10.0.0.10 255.255.255.0
!
bridge 1 protocol ieee
bridge 1 route ip

IOU1
interface Vlan1
ip address 10.0.0.1 255.255.255.0
no ip route-cache
!
ip default-gateway 10.0.0.10

IOU2
interface Vlan999
ip address 10.0.0.2 255.255.255.0
no ip route-cache
!
ip default-gateway 10.0.0.10
!
interface Ethernet2/0
switchport trunk allowed vlan 999
switchport trunk encapsulation dot1q
switchport mode trunkScreenshot (185).png


Hello


@ghtmoha153 wrote:

My question is layer3  interface can encapsulation packets and send it out from router or no t


Yes it can.
The physical port of the interface will connect to the switch at layer 2 and then the logical sub-interfaces provids the Layer 3 addressing that relates to the specific vlan ids using dot1q trunking.

By default if you use the parent physical interface as L3 also then this is the native vlan 1

example:
int x/x
description vlan 1
ip address 10.1.1.1 255.255.255.0

or

int x/x

int x/x.1
description vlan 1
encapsulation dot1q 1 native
ip address 10.1.1.1 255.255.255.0


 
int x/x.2
description vlan 2
encapsulation dot1q 2
ip address 10.1.2.1 255.255.255.0

int x/x.3
description vlan 3
encapsulation dot1q 3
ip address 10.1.3.1 255.255.255.0


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul
Review Cisco Networking for a $25 gift card