Suppose P, Q, and R are network service providers, with respective CIDR address allocations C1.0.0.0/8, C2.0.0.0/8, and C3.0.0.0/8. Each provider’s customers initially receive address allocations that are a subset of the provider’s. P has the following customers:

PA, with allocation C1.A3.0.0/16, and PB, with allocation C1.B0.0.0/12.

Q has the following customers:

QA, with allocation C2.0A.10.0/20, and QB, with allocation C2.0B.0.0/16.

Assume there are no other providers or customers.

(a) Give routing tables for P, Q, and R assuming each provider connects to both of the others.

(b) Now assume P is connected to Q and Q is connected to R, but P and R are not directly connected. Give tables for P and R.

(c) Suppose customer PA acquires a direct link to Q, and QA acquires a direct link to P, in addition to existing links. Give tables for P and Q, ignoring R.