Question:
I have configured 2 C2951-VSEC sub-interface on same physical interface. And the physical interface is connected to a Managed switch on trunk port. Both sub-interface is pppoe-client and dial to the DSL network. Both modem in bridge mode an connected to respective VLAN on switch. The problem is that at a given time, only one PPPOE session can be established. I believe this could be ISP denying multiple pppoe session from single MAC -address as all the sub-interface is using physical interface mac-address. Anyway to trick this? change mac-address of sub-interface?
Answer:
It may be possible that your ISP is actually imposing the number of concurrent connections based on your PPP login name, and not based on your MAC address. Are you using two different usernames, unique for each PPPoE client?
Sadly, I do not see any immediate solution if your ISP is indeed performing a session limiting based on MAC addresses. It is, to my best knowledge, not possible to change the MAC address of a 802.1Q subinterface. All subinterfaces necessarily inherit the same MAC address from the physical interface. C2921-VSEC