One way layer 2 traffic

[tkachour]

Hello everyone,

I have a problem that i tried to schematize below. 

Except IP adresses my 2 routers have exactly the same configuration and have the same version and model. All my links are functionning properly and all my VLANs are configured the same way.

The problem is that the Ping or any kind of traffic is passing between R1 and Sw A on a set of VLAN only when it's generated from R1

When i run a continuous Ping on the vlan 10 from Sw A to R1 i don't receive any reply until i generate a Ping or any kind of traffic from R1 to Sw A.

Do you have any idea what the causes can be ?

Thank you,

[balaji.bandi]

It is too hard to say what is configured, can you post the config of all the devices.

[tkachour]

The configuration is very simple, i deleted all the routing and vpn part and left interfaces configuration to focus on my issue. In the routers i have sub interfaces configured as below :
interface GigabitEthernet0/0.10
encapsulation dot1Q 10
ip address 192.168.10.X 255.255.255.0
!
interface GigabitEthernet0/0.20
encapsulation dot1Q 20
ip address 192.168.20.X 255.255.255.0
!
interface GigabitEthernet0/0.30
encapsulation dot1Q 30
ip address 192.168.30.X 255.255.255.0
!
interface GigabitEthernet0/0.40
encapsulation dot1Q 40
ip address 192.168.40.X 255.255.255.0
!
Between the switchs and the routers i have a trunk and on the Switch A i have vlan interfaces. I'm sorry buy i can't post any configuration due to some restriction but anyway there isn't any subtil configuration that should be taken into consideration.