In your original post, answer the following: Describe routing. How does a router decide when and where to forward a packet? How does a device know when to send a packet to the default router? What takes place at the data-link and network layers of the TCP/IP model? Briefly describe an IPV4 header. Be sure to include the fields, size, etc. Briefly describe DNS, ARP, and ICMP. Give a brief example of how each "work."