Consider the network in Figure $1.$ It represents a small corporate network. The IP addresses are shown

explicitly; M$1$ to M$12$ mean MAC addresses. B$1,$ B$2$ and B$3$ are bridges; R$1,$ R$2$ and R$3$ are routers.

Figure$1.$ A small corporate network. D$3$ is the DNS server for this network. The machines C$1,$ D$1,$ C$2,$ D$2,$ and C$3$ are configured with

DNS server address $=192\mathrm{.}168\mathrm{.}1\mathrm{.}52.$

All interfaces that have IP addresses of the form $192\mathrm{.}168.$x$.$y are configured with netmask $=$

$255\mathrm{.}255\mathrm{.}255\mathrm{.}240.$

The default gateways are configured as follows

$$ at C$1$ and D$1$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}17$

$$ at C$2$ and D$2$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}33$

$$ at C$3$ and D$3$: $192\mathrm{.}168\mathrm{.}1\mathrm{.}49$

$1.$ What IP address and netmask should we give to M$12?$

with reliable service.

connection$-$oriented or connectionless service?

Explain.

$2/5$

shown

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$2.$ In the following table, write the routing tables after RIP has stabilized. $($Give only

the entries for destination prefixes that are

$3.$ We reconfigure the network as shown in Figure $2.$ The interfaces at M$4,$ M$8$ and M$12$ are not

used. We change the network mask to $255\mathrm{.}255\mathrm{.}255\mathrm{.}0$ on all systems, the IP addresses remain the

same. We do a ping from C$1$ to C$2,$ C$2$ to C$3$ and C$3$ to C$1.$ Packet sniffers are placed at locations

labeled $1,2$ and $3$ on the figure.

Figure$2.$ A small corporate

In the table below, mark the values of the fields that are read in the ping packets

corresponding to each of the ping exchanges if the packet is visible at this location.

Consider only the ping packets themselves, not the replies.

not on$-$link with this router.$)$