1.1

1. [50 points] Consider a three layer protocol in which Layer 3 encapsulates Layer 2 and Layer 2 encapsulates Layer 1. Assume minimalist headers with fixed length packets. Assume the following characteristics of the layers: Layer 1, 6 octet address length, 512 octet payload; Layer 2, 4 octet address length , 256 octet payload; Layer 3, 8 octet address length, 1024 octet payload. Note that in the minimalist header arrangement, no error detection or correction will be used; however, there must be a scheme (that you must devise) to allow a multipacket datagram at each separate layer. You may assume that there is some sort of routing or other address translation protocol that will identify which addresses are to be used. Assume that the data communications channel in use do form a data communications network. (Hint: do recall what is needed for a data communications network as contrasted with an arbitrary graph.) 1.1. For each of the three layers, separately calculated, how many items (nodes) can be addressed? Do not simply show an answer, but ex- plain your reasoning (hint: combinatorics). 1.2. We have discussed functors as a formal, theoretical description be- tween layers of a network. In terms of these three layers, illustrate the functors between the layers, and explain how functors addres:s the differences in topology and relevant information content at the different layers 1.3. Assume that the datagram has 5 layer 1 packets. How does this datagram encapsulate in layer 2