Difference between Early and Delayed Token Release

Prerequisite – Token Ring

1. Early Token Release :

• Sender does not wait for the data packet to complete revolution before releasing the token. Token is released as soon as the data is transmitted.
• Multiple packets present in the ring.
• Less reliable than Delayed Token Release.

2. Delayed Token Release :

• In this, the sender transmit the data packet and waits till the time the whole packet takes the round trip of the ring and return to it. When the whole packet is received by the sender, then it releases the token.
• There is only one packet in the ring at an instance.
• More reliable than Early Token Release.

Difference between Early and Delayed Token Release :

Early Token Release	Delayed Token Release
Sender does not wait for the data packet to complete revolution before releasing the token.	In this, the sender transmit the data packet and waits till the time the whole packet takes the round trip of the ring and return to it.
Token is released as soon as the data is transmitted.	When the whole packet is received by the sender, then it releases the token.
At an instance, Multiple packets are present in the ring.	There is only one packet in the ring at any instance.
Less Reliable as compared to Delayed Token Release.	More Reliable as compared to Early Token Release.
Token Holding Time (THT) = Tt where, Tt = transmission delay	Token Holding Time (THT) = Tt + Tp where, Tt = transmission delay, Tp = propagation delay
Collision is possible as multiple packets are present in the ring.	Collision is not possible as there is only one packet in the ring at any instance.
Cycle Time = Tp + N * (Tt) where, Tt = transmission delay Tp = propagation delay N = No. of stations in ring	Cycle Time = Tp + N*(Tt + Tp) where, Tt = transmission delay Tp = propagation delay N = No. of stations in ring
Efficiency = (N * Tt) / (Tp + N * (Tt)) where, Tt = transmission delay Tp = propagation delay N = No. of stations in ring	Efficiency = (N * Tt)/(Tp + N*(Tt + Tp)) where, Tt = transmission delay Tp = propagation delay N = No. of stations in ring