Describe the different types of delays at each node along the path the packet traverses. State an expression to represent the total node delay with a diagram.

There are four main types of delays at each node along the path a packet traverses:

1. Processing Delay: This is the time it takes for a router to process the packet header. It includes the time taken to check for bit-level errors and to determine where to direct the packet next.

2. Queuing Delay: This is the time a packet spends in routing queues. It depends on how much traffic the router is dealing with. If the router is busy handling other packets, the queuing delay will be longer.

3. Transmission Delay: This is the time it takes to push (that is, transmit) all of the packet’s bits into the link. The transmission delay is a function of the packet’s length and has nothing to do with the distance between the source and destination.

4. Propagation Delay: This is the time it takes for a bit to travel from the sender to the receiver, and it's a function of the distance between the source and destination.

The total node delay can be represented by the following expression:

Total Node Delay = Processing Delay + Queuing Delay + Transmission Delay + Propagation Delay

Here is a simple diagram to represent this:

[Packet] --> [Processing Delay] --> [Queuing Delay] --> [Transmission Delay] --> [Propagation Delay] --> [Next Node]

In this diagram, the packet first experiences a processing delay at the node. It then may be queued, adding a queuing delay. The packet is then transmitted, adding a transmission delay. Finally, the packet propagates over the link to the next node, adding a propagation delay. This process is repeated at each node along the packet's path.