1) If a network middleware device can be described as 'transparent to the endpoints', why might it still violate the end-to-end principle?

2) Which part(s) of a packet header is/are used by a router to determine the next hop when it receives a packet for retransmission?

3) You have a small business. You are planning on opening up a new field office. What ISP service can you use to have a secure connection between the main office and the new field office? Note: we are looking for the name of the generic type of service, not a vendor name or a vendor's product name.