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What Is a MAC Address?
Answer
MAC (Media Access Control) addresses are globally unique addressed that are
written into hardware at the time of manufacture. The MAC address is a unique
value associated with a network adapter. MAC addresses are also known as
hardware addresses or physical addresses. They uniquely identify an adapter on
a LAN. MAC addresses are 12-digit hexadecimal numbers (48 bits in
length).
MAC vs. IP Addressing
Answer
Whereas MAC addressing works at the data link layer, IP addressing functions at
the network layer (layer 3). It's a slight oversimplification, but one can
think of IP addressing as supporting the software implementation and MAC
addresses as supporting the hardware implementation of the network stack. The
MAC address generally remains fixed and follows the network device, but the IP
address changes as the network device moves from one network to another.
Define Spanning-Tree Protocol (STP)
Answer
Spanning-Tree Protocol (STP) as defined in the IEEE 802.1D is a link management
protocol that provides path redundancy while preventing undesirable loops in
the network. For an Ethernet network to function properly, only one active path
can exist between two stations. Loops occur in networks for a variety of
reasons. The most common reason you find loops in networks is the result of a
deliberate attempt to provide redundancy - in case one link or switch fails,
another link or switch can take over.
What is VPN?
Answer
A VPN is a service that offers secure, reliable connectivity over a shared
public network infrastructure such as the Internet. VPNs maintain the same
security and management policies as a private network. They are the most cost
effective method of establishing a virtual point-to-point connection between
remote users and an enterprise customer's network.
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