With UM, all of the various messaging systems are rolled into one ...

[lracut11]

With UM, all of the various messaging systems are rolled into one system, with one access pointthe user's e-mail inbox, which means that the system cannot be hacked into.
 
  Indicate whether the statement is true or false

Question 2

Explain why virtual circuits are less flexible than datagrams.
 
  What will be an ideal response?

[mcabuhat]

Answer to Question 1

FALSE

Answer to Question 2

Virtual circuits are less flexible than datagrams in that if a problem occurs along the route, the packets cannot simply be routed around the problem area. Instead, a new virtual circuit must be established. Recall that with a datagram, if a link is bad or congested, the datagram can simply take a different route. In order to use a single route, virtual circuits also require that packets carry, besides sequence numbers, additional identification information. This identification information includes the address of the virtual circuit being used as well as the address of the specific communication on the virtual circuit. An address for the specific communication is required because multiple communications share the virtual circuit links and the packet-switching cloud needs a way to differentiate one communication from another.

[lracut11]

Excellent

[Zebsrer]

Thanks for the timely response, appreciate it