a) (10 points) Show the layered protocol architecture (i.e., how you would represent them using OSI layers) of both the Voice over IP (VoIP) phone and the router. Note the following Assume the VoIP phone is a regular host, just like a desktop computer. Make sure to show the peer interfaces between router and VoIP phone. VoIP Phone Internet Router EO b) (10 points) Assume the information is a 20-byte audio sample (Application Layer) generated by the audio codec located at the VolP phone. It is carried by a Real-Time Transport Protocol (RTP) packet (RTP is implemented at an intermediate layer, between Application Layer and Transport Layer - you may consider it as Session Layer). How does the Layer 2 frame look like at the router's E0 interface? Please draw the frame showing all the sizes. Assume the following protocol headers are used: RTP header = 12 bytes UDP header = 8 bytes IP header = 20 bytes