Consider a planet where everyone belongs to a family of six, every family lives in its own house, each house has a unique address, and each person in a given house has a unique name. Suppose this planet has a mail service that delivers letters from source house to destination house. The mail service requires that (1) the letter is in an envelope, and that (2) the address of the destination house (and nothing more) be clearly written on the envelope. Suppose each family has a delegate family member who collects and distributes letters for the other family members. The letters do not necessarily provide any indication of the recipients of the letters.

(a) (15 points) Please describe a protocol that the delegates can use to deliver letters from a sending family member to a receiving family member.

(b) (10 points) In your protocol, does the mail service ever have to open the envelope and examine the letter in order to provide its service? Please give details by considering the routing protocols learned in the course.