If a router needs to advertise 50 routes, it will need 50 specific lines in its update packet. As these routes increase, the number of lines required also increases, expanding packet size and the amount of bandwidth used. That means there will be less bandwidth available for actual data transfer.
Route summarization enables multiple routes to be advertised with only one line in an update packet, reducing the packet size and leaving more bandwidth for data transfer.
Also, each time a new data flow enters a router, it must identify which interface the traffic must be sent out to. For this, it must perform a lookup in its routing table. This process takes longer for large routing tables and requires more router central processing unit (CPU) cycles to route traffic.
Route summarization can eliminate this problem by minimizing both the time required to perform lookup and reducing the number of CPU cycles.
