It is yet unclear how to deal with changes in technology descriptions over time. New technologies are easy: just add a 
new encoding or schema. For existing adaptation stacks this is harder.

Imagine that IP over Ethernet is defined as an adaptation that ignores the EtherType or the QoS bits in the VLAN header,
 but due to some changes in Ethernet or IP it is deemed necessary to describe it at a stack of two adaptations: 
EtherType over VLAN and IP over EtherType. It is likely that during such transition two schemas will be used at the same
 time. This makes it necessary to be able to say that one adaptation stack is really the same as another adaptation 
stack.

We need a proposal to define how this is done.