Question $4$b

Figure Q$4($b$)$ shows a bridged network comprising four bridges B$1$ to B$4$ with B$1$ and B$4$ being the lowest and highest bridge ID numbers, respectively. The bridges interconnect five LAN segments LAN$1$ to LAN$5.$ It uses a spanning tree approach to develop its routing tables.

Figure Q$4($b$)$

Question $4$b$($i$)$

Explain how a spanning tree approach helps bridges in a network to develop its routing tables.

$(4$ marks$)$

Question $4$b$($ii$)$

Apply the spanning tree algorithm to construct a spanning tree for the network by identifying the following:

$-$ Root bridge $($RB$)$

$-$ Designated bridges $($DB$)$

$-$ Root port $($R$),$ designated port $($D$),$ and disabled port $($X$)$ on the appropriate bridges

$[$Hints: use the notation B$3-$p$2$ to indicate port number $2$ on a bridge B$3]$

$(7$ marks$)$