1. What is the function of external oscillator in 8051 microcontroller?

The 8051 uses the crystal for precisely that: to synchronize
it's operation. Effectively, the 8051 operates using what
are called "machine cycles." A single machine cycle is the
minimum amount of time in which a single 8051 instruction
can be executed. although many instructions take multiple

4. Which of the following is true regarding 2 switches? (Choose two)?

1. A switch is a a hub with more ports

2. A switch is a multi-port bridge

3. Switches learn IP addresses from each frame and filter
the network using these addresses

4. Switches learn MAC addresses by examining the source
address of each frame

Answers No. 1 & 4 are true. As a switch is a hub to connect
devices and unicast while Hub is multicast.
Switch is use to deliver packets systems to systems
(identify MAC)

5. Which of the following is true regarding trunked links?

1. They are configured by default on all switch ports

2. They only work with a type of Ethernet network-not with
Token Ring, FDDI

3. You can set trunk links to any 10-, 100-, and 1000 Mbps ports

4. You must clear the unwanted VLANs by hand

6. If you network is currently congested and you are using hubs in you network, what would be the best solution to decrease congestion on your network?

1. Cascade your hubs

2. Replace your hubs with switches

3. Replace your hubs with routers

4. Add faster hubs

7. What is the broadcast address of the subnet address



8. Which of the following is a true statement?

1. MAC address broadcast are all zeros
2. MAC address are defined at the Physical layer
3. MAC address are used by bridges and switches to make
forwarding / filtering decisions
4. IP addresses allow a flat address scheme,
whereas MAC addresses are hierarchical

9. What is the broadcast address of the subnet address