I have a L2 scenerio on cisco switches 4507 like.
RAS Router-->Cisco 4507 Switch A(Trunk Port)--->Cisco 4507 Switch A(trunk port) with another 4507 switch B---> Access Port on 4507 Switch B (from where one IP DSLAM connected).
Problem is that we are not getting PPPoEd packet from this IP dslam on Switch B access port, i.e it is dropping in between DSLAM to Cisco Acess port Switch B.
But when we are giving command "switchport trunk native vlan XX" on the cisco switch B access port that PPPOed packet on coming on the port. But as we can't give this Switchport trunk native command on backend trunk link as all other / many vlans also allowed.
Wht is the reasn for PPPoed packet not coming on acess port. Where may be the problem.
Note :- We have some othe IPDLSAM also which are connected on the same switch with same backend configs (but with other Vlan) are responfding fine. i.e PPPoED packet coming properly with any additional configs or command line Switchport trunk native".