Network+ 1 Flashcards
converged network : a network transporting multiple types of traffic (ex : voice, video, and data), and might offer cost savings to organizations and reduces staffing costs.
*** switch : inspects traffic and sends to specific port not all ports (layer 2 device) and makes routing decisions based on MAC address on NIC.
converged network etc …
forwards traffic based on logical network addresses (IP), it examines destination IP address of traffic and sends based on routing table.
*** WAN Link : connects one or more networks together
*** MPLS and ATM are WAN technologies /// Metro Ethernet is example of MAN
router
logical toplogy : what the user sees not the full map of what happens (the actual traffic flow)
physical topology : is the actual map of what is happening within the topology (way components are physically interconnected)
logical/physical topology
a single network segment is a single collision domain, which means that all devices connected to the bus might try to gain access to the bus at the same time, resulting in an error condition known as a collision.
*** a partial-mesh topology can be designed to offer an optimal route between selected sites while avoiding the expense of interconnecting every site to every other site.
single network
Fiber Distributed Data Interface (FDDI) was another variant of a ring-based topology. Most FDDI networks (which, as the name suggests, have fiber optics as the media) used not just one ring, but two. These two rings sent data in opposite directions, resulting in counter-rotating rings. One benefit of counter-rotating rings was that if a fiber broke, the stations on each side of the break could interconnect their two rings, resulting in a single ring capable of reaching all stations on the ring.
*** example of ad hoc technology is Apple’s Airdrop (send files between smart phones)
FDDI
With the infrastructure topology, you have specialized wireless equipment for permitting the wireless communications to take place. (WLAN, WAP)
specific type of ad hoc wireless topology is the mesh, specialized nodes help move the traffic throughout the topology.
*** A NAS device is a mass storage device that attaches directly to a network.
*** both laptop and web server use IP (layer 3)
infrastructure topology
At the physical layer, binary expressions (that is, a series of 1s and 0s) represent data. A binary expression is created using bits, where a bit is a single 1 or a single 0. At upper layers, however, bits are grouped together, into what is known as a protocol data unit (PDU) or a data service unit.
physical layer = how bits are represented on the medium, wiring standards for connectors and jacks, physical topology, synchronizing bits, bandwidth usage, multiplexing strategy
*** (transport = segments) — (network = packets) — (data link = frames) — (physical = bits)
physical layer
Asynchronous: With this approach, a sender states that it is about to start transmitting by sending a start bit to the receiver. When the receiver sees this, it starts its own internal clock to measure the next bits. After the sender transmits its data, it sends a stop bit to say that it has finished its transmission.
Synchronous: This approach synchronizes the internal clocks of both the sender and the receiver to ensure that they agree on when bits begin and end. A common approach to make this synchronization happen is to use an external clock (for example, a clock given by a service provider). The sender and receiver then reference this external clock.
asynchronous/synchronous
Broadband: Broadband technologies divide the bandwidth available on a medium (for example, copper or fiber-optic cabling) into different channels. A sender can then transmit different communication streams over the various channels.
Baseband: Baseband technologies, in contrast, use all the available frequencies on a medium to send data. Ethernet is an example of a networking technology that uses baseband.
*** Multiplexing allows multiple communications sessions to share the same physical medium.
broadband/baseband
NAT is a feature available on routers that allows private IP addresses used within an organization to be translated into a pool of one or more publicly routable IP addresses.
*** DHCP relay agent. The device takes the discover packet from the client (broadcast) and routes it to where the DHCP server is (unicast).
Link-Local IP address is only usable on local subnet and nonroutable in nature.
NAT
