This read-create INTEGER selects the encapsulation carried over the PVC, such as pppoA(1), pppoE(2), router2684(3), or bridge2684PlusIp(5). An admin sets this to match what the ISP's aggregation equipment expects, since a mismatched encapsulation prevents any traffic from passing even though the ADSL line itself trains fine. For example, migrating a customer from PPPoE to routed IP over ATM requires changing this value from pppoE(2) to router2684(3) and reconfiguring the IP table accordingly.