To compare the efficiencies of "sliding-window" and "slow-start", I built a virtual network environment with 8 nodes and 3 traffics which are 2 CBRs, and 1 for each aimed protocol, and run both protocols in the same condition such as queue limit, bandwidth, delay, etc.  I compared two protocols in two different situation; one is in normal condition which means there is no packet loss ; the other is in congested condition which means there are some packet loss. If you want to see the parameter values, please refer to the ns scripts which attached below.

2. How these 2 protocols work in normal condition..?
 

1. sliding window protocol ( window size = 8 )	2. slow start protocol
Black packets are for "sliding window" traffic while red packets are for CBR traffic.	Black packets are for "slow start" traffic while red packets are for CBR traffic.
With nam graph, we could see the total packets and ACKs sent and received. In "sliding window", totally  58 packets are transmitted and 54 ACKs are received.	With nam graph, we could see the total packets and ACKs sent and received. In "slow start", totally  53 packets are transmitted and 53 ACKs are received.
Here is ns script for the above simulation. You can also download ns script and nam file.	Here is ns script for the above simulation. You can also download ns script and nam file.

3. How these 2 protocols work in the Internet..?

   In the Internet environment, the network parameters cannot be fixed nor forecasted. To establish those environment, I put more nodes, traffics, and also change the parameters several times.

1. sliding window protocol ( window size = 8 )	2. slow start protocol
Black packets are for "sliding window" traffic while red packets are for CBR traffics.	Black packets are for "slow start" traffic while red packets are for CBR traffics.
In "sliding window", totally 27 packets are transmitted successfully in congested condition.	In "slow start", totally 40 packets are transmitted successfully in congested condition.
Here is ns script for the above simulation. You can also download ns script and nam file.	Here is ns script for the above simulation. You can also download ns script and nam file.

4. Result

    In those environment where the network parameters such as delay, bandwidth, etc are fixed, "sliding window" could have better performance than "slow start" if its window size is properly setted as shown in #2. Otherwise, especially in the Internet environment where the network parameters are changing variously, "slow start" shows better performance as shown in #3.