StonyBrook is a Tier 3 ISP that is a customer of a Tier 2 ISP Comcast. SUNY Buffalo is a Tier 3 ISP, which is a customer of a different Tier 2 ISP Level3. Both Comcast and Level3 are customers of Tier 1 ISP AT&T.

There are two other Tier 1 ISPs Verizon and Sprint. There may be other relationships that we don't know about.

(i) First, draw the customer, provider, and peer relationship among StonyBrook, Suny Buffalo, Comcast, Level3, AT&T, Verizon, and Sprint. Clearly mark the peer links and show who the customer is and who the provider is

(ii) Comcast generates a route advertisement (to reach Stony Brook) and sends it to AT&T. Which ISPs will AT&T forward this advertisement to and why?

(iii) Level3 receives a route advertisement to reach Verizon, from a different ISP not in this picture. Will Level3 send this route to AT&T. Explain why?

(iv) What are the advantages of StonyBrook and SUNY Buffalo peering with each other?