Suppose a router has built up the routing table shown in the Table shown above. The router can

deliver packets directly over interfaces $0$ and $1,$ or it can forward packets to routers R$2$ and R$3.$

Assume the router does the longest prefix match. Describe what the router does with a packet

addressed to each of the following destinations:

$255\mathrm{.}255\mathrm{.}254\mathrm{.}0=11111111\mathrm{.}11111111\mathrm{.}11111110\mathrm{.}00000000$

$255\mathrm{.}255\mathrm{.}252\mathrm{.}0=11111111\mathrm{.}11111111\mathrm{.}11111100\mathrm{.}00000000$

$1-128\mathrm{.}96\mathrm{.}171\mathrm{.}92(10000000\mathrm{.}01100000\mathrm{.}10101011\mathrm{.}01011100)$

Applying the subnet mask $255\mathrm{.}255\mathrm{.}254\mathrm{.}0,$ we get $128\mathrm{.}96\mathrm{.}170\mathrm{.}0.$ Use

nterface $0$ as the next hop.

$2-128\mathrm{.}96\mathrm{.}167\mathrm{.}151(10000000\mathrm{.}01100000\mathrm{.}10100111\mathrm{.}10010111)$

Ranter $2).$ Applying subnet mask $255\mathrm{.}755\mathrm{.}252\mathrm{.}0,$ we get $128\mathrm{.}96.164\mathrm{.}0$

$($uex hop is Router $3).$ Howevel, $255\mathrm{.}255\mathrm{.}254\mathrm{.}0$ is a longer prefis. Use

Ratiter $?$ as the next hop.

$3-128\mathrm{.}96\mathrm{.}169\mathrm{.}192(10000000\mathrm{.}01100000\mathrm{.}10101001\mathrm{.}11000000)$

Applying subnet mask $255\mathrm{.}255\mathrm{.}254\mathrm{.}0,$ we get $128\mathrm{.}96\mathrm{.}168\mathrm{.}0.$ Use inter$-$

lace $1$ as the acxt lop.

$4-128\mathrm{.}96\mathrm{.}165\mathrm{.}121(10000000\mathrm{.}01100000\mathrm{.}10100101\mathrm{.}01111001)$

Applying subnet mask $255\mathrm{.}255\mathrm{.}252\mathrm{.}0,$ we get $128\mathrm{.}96\mathrm{.}164\mathrm{.}0.$ Use Router $3$

as the next hop.