Datagram switching and Virtual circuit

Question

I. Datagram switching does not have set up and tear down phases. hence it is faster than virtual circuit approach
II. Virtual circuit approach uses simple VC ID to decide next hope rather than complete addressing information. hence it is faster than datagram switching

Which of the given statements are TRUE?
a) I only
b) II only
c) I is correct but reason is wrong
d) II is correct, but reason is wrong

Answer 1

Data gram switching does not have a set up and tear phases , but here each data gram is independent of each other , so it may happen one data gram may follow route 1 and reaches there with a shortest distance, Other 1 may follow a longest distance . Hence delay are not variable so we cant really say it is faster . However  this should be used when data is small enough to have  min delay .

Hence we cant say it is faster Than virtual circuit.

Considering statement 2 ,, this seem to be correct. Here virtual circuit do have set up and tear , Here first packet has a global header , and rest all one follows that only . They do consider  next hop by making use of VC ID rather than complete addressing information . here they reserve channel , BW and all one of them follow same path .

However this scheme is used when large data need to be transmitted .It is faster as compared to Datagram one. :)

Hence option b

Comments

@ Arjun sir can you verify this :)

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but how is virtual circuits faster than datagrams switiching??

virtual circuits are reliable then datagrams swithcing for sure as they are connection oriented.