Consider three LANs interconnected by two routers, as shown in the Figure below.

Interfaces in Subnet $1$ have addresses of the form $192\mathrm{.}168\mathrm{.}101/24$; Interfaces in Subnet

$2$ uses addresses of the form $192\mathrm{.}168\mathrm{.}102/24$; Interfaces in Subnet $3$ use addresses of

the form $192\mathrm{.}168\mathrm{.}103/24.$ Each adapter has also a MAC address.

himee halva wimeticu by two ivuteis

a$.$ Show the appropriate IP and MAC addresses in the given network topology.

b$.$ Consider sending an IP datagram from Host E to Host B$.$ Suppose all of the ARP

tables are up to date. Enumerate all the steps.

c$.$ Repeat $($c$),$ now assuming that the ARP table in the sending host is empty $($and the

other tables are up to date$).$

d$.$ Replace the router between subnets $1$ and $2$ with a switch $S1,$ and label the router

between subnets $2$ and $3$ as R$1.$ Suppose E would like to send an IP datagram to B$,$ and

assume that E$\text{'}$s ARP cache does not contain B$\text{'}$s MAC address. Will E perform an

ARP query to find B$\text{'}$s MAC address? Why? In the Ethernet frame $($containing the IP

datagram destined to B$)$ that is delivered to router R$1,$ what are the source and

destination IP and MAC addresses?

e$.$ Suppose now that the leftmost router in Figure $1$ is replaced by a switch. Hosts A$,$

$B,C,$ and $D$ and the right router are all star$-$connected into this switch. Give the source

and destination MAC addresses in the frame encapsulating this IP datagram as the

frame is transmitted $($i$)$ from A to the switch, $($ii$)$ from the switch to the right router,

$($iii$)$ from the right router to F$.$ Also give the source and destination IP addresses in the

IP datagram encapsulated within the frame at each of these points in time.