Packet switching vs Circuit switching Flashcards
Describe packet switching
This is where a system could use one communication link to communicate with more than one machine by assembling data into packets. The link can be shared and each packet could be routed independently of other packets.
Describe circuit switching
This is seen in the old typical telephone circuit, a dedicated circuit is tied up for the duration of the call and communication is only possible with the single party on the other end of the circuit
What is an important property of circuit switching?
It is the need to set up an end-to-end path before any data is transmitted.
What is occurring during the end of dialing and the start of ringing?
The telephone system is hunting for a path. The call request signal must propagate all the way to the destination and be acknowledge
Are dedicated paths set up in advance for packet switching?
No each packet has to find its own way to its destination
By placing a tight upper limit on block size what does packet switching networks allow?
It allows packets to be buffered in the router’s main memory
What are 5 differences between circuit switching and packet switching?
Circuit switching is less fault tolerant and packet switching is more fault tolerant.
Circuit switching requires that a circuit be set up end to end before communication begins whereas packet does not require any advance setup
Circuit switching the bits flow through the wire continuously, meanwhile packet switching is store and forward hence a packet is accumulated in the router’s memory then sent onto the next router
In circuit switching charging is based on distance and time whereas in packet switching the connect time is not an issue but the volume of traffic sometimes is (this determines charge in backbone carriers)
In circuit switching the bandwidth is reserved all the way from the sender to the receiver. All packets follow this and hence can’t arrive out of order. However in packet switching there is no bandwidth reservation, packets can follow different paths and hence may arrive out of order.
In client switching if a circuit has been reserved for a particular user and there is no traffic to send, the bandwidth of that circuit is wasted. It can’t be used for other traffic. On the other hand packet switching doesn’t reserve the bandwidth and hence doesn’t waste bandwidth
In client switching congestion can occur at setup time so when trying to establish a circuit, meanwhile in packet switching congestion can occur when a packet shows up.
Which switching needs call setup?
Circuit switched
Which switching needs a dedicated physical path?
Circuit switched
Which packet needs each packet to follow the same route?
Circuit switched
Which switch is fatally affected by a crash?
Circuit switched
How is bandwidth available in circuit and packet switching?
It is fixed in circuit switched and dynamic in packet switching
When does congestion occur in packet and circuit switching?
At setup time in circuit switched and on every packet in packet switching
Which switching potentially wastes bandwidth?
Circuit switched
Which switching has store and forward transmission?
Packet switched
