Question | Answer |
computers bus | is the circuit or signaling pathway used by the motherboard to transmit data to the pc components ,including its memory ,processor,hard disk and nic |
computers bus | system bus main bus |
a data path size | equals the number of bits that it can transmit in parallel at any given rate |
PCIe bus | most popular expansion board NIC today |
PCIe slot | can support up to 32 lanes |
device driver | software that enables an attached device to communicate with the computers operating system |
GBIC | gigabit interface converter |
sfp | small form factor pluggable transceviers |
gbic | standard type of modular interface |
small form factor pluggable | provide the same function as a gbic but allow more ports per inch |
sfp standards | enable these transceivers to send and receive data at rates up to 10 Gbps |
gbic | standard type of modular interface designed in the 1990s for gigabit ethernet connections |
repeaters | simplest type of connectivity devices that regenerate a digital signal |
repeaters | do not interpret the data they retransmit |
repeaters | suited only to bus topologies |
repeaters | extend a network inexpensively |
hub | repeater with more then one output port |
gbic | ability to transmit at gigabit speed if it is not a gigabit switch |
hub | repeater with more then one output port |
uplink port | allows the hub to connect to another hub or connectivity device |
repeaters | operate at the physical layer of the osi model |
bridges | devices that connect two network segments by analyzing incoming frames and making decisions about where to direct them based on each frames MAC address |
bridges | operate at the data link layer of the osi model |
bridges | one input one output port but can interpret physical addressing information |
bridges | protocol independent |
bridges | analyze incoming frames and decides where to direct them |
bridges | contains known mac addresses and network location |
bridges | extend a network without further extending a collision domain or segment |
filtering database | a collection of known MAC address and their locations on a network |
switches | connectivity devices that subdivide a network into smaller logical pieces or segments |
switches | interpret MAC address information |
switch | interprets mac address info to determine whether to filter,discard,or forward packets it receives |
switches | multiple ports which can make better use of bandwidth than bridges |
common switch components | internal processor,operating system,memory,ports |
two advantages of switches | better security better performance |
switch | turns a shared channel into several channels |
each port on a switch acts like a bridge | each device connected to a switch effectively receives its own dedicated channel |
each dedicated channel | represents a collision domain |
switching methods | cut thru mode store and forward mode |
cut thru mode | reads a frames header and decides where to forward the data before it receives the entire packet |
on most switches the uplink port | is directly wired to its adjacent port inside the device |
runts | erroneously shortened packets |
cut thu switches | cannot detect corrupt packets |
switches | give each node a dedicated channel |
cut thu mode | runt detected,wait for integrity check |
cut thru mode most significant advantage | speed because it does not stop to read the entire packet just the first fourteen bytes |
runts | erroneously shortened packets |
cut thu switches | cannot detect corrupt packets |
switches | give each node a dedicated channel |
cut thu mode | runt detected,wait for integrity check |
cut thru mode most significant advantage | speed because it does not stop to read the entire packet just the frame header |
cut thru mode disadvantage | data buffering,switch flooded with traffic |
cut thru switches | best suited to small workgroups with a low number of devices in which speed is important |
store and forward mode | switch reads entire data frame into memory |
store and forward mode | checks for accurancy before transmitting |
store and forward mode | transmits data more accurately but more slowly |
store and forward mode | can transfer data between segments running different transmission speeds |
vlan | virtual local area network |
vlans | logically separate networks within networks by grouping a number of ports into a broadcast domain |
vlans | group ports into broadcast domains |
broadcast domain | port combination making a layer 2 segment |
broadcast domain | ports rely on layer two devicess to forward broadcast frames |
collision domain | ports in same broadcast domain |
collision domain | do not share a single channel |
reasons for using vlans | separating groups of users who need special security or network functions |
reasons for using vlans | connect multiple nodes across my network but have them logically function on one network |
reasons for using vlans | flexible |
reasons for using vlans | isolating connections with heavy or unpredictable traffic patterns |
reasons for using vlans | identifying priority device groups |
reasons for using vlans | grouping legacy protocol devices |
reasons for using vlans | separating large network into smaller subnets |
reasons for using vlans | allows visitors access to minimal network functions |
a switch is typically preconfigured | with one default vlan that includes all its ports |
broadcast domain | subnet |
802.1q | specifies how vlan information appears in frames and how switches interpret that information |
switches | seperate collision domains |
once you create a vlan | you also maintain it via the switch's software |
potential problem in creating vlans | by grouping certain nodes you are not merely including those nodes-you are excluding another group |
trunk | physical connection between switches |
to keep the data belonging to each vlan separate | each frame is identified with a vlan identifier,or tag. |
critical step in creating vlans | indicate which vlan each port belongs to |
vlan trunking protocol | allows one switch on a network to centrally manage all vlans |
access port | used for connecting nodes that can only exchange information with the switch |
vlan disadvantage | cutting off the group from the rest of the network |
trunking | switchs interface carries traffic of multiple vlans |
vlan data separation | frame contains vlan identifier in header |
in the context of switching a trunk is a | single physical connection between switches thru which many logical vlans can transmit and receive data |
spanning tree protocol | iee standard 802.1d and function sin the data layer |
stp | prevents traffic loops by calculating paths that avoid potential loops and by artificially blocking the links that would complete a loop |
stp | can adapt to changes in the network |
root bridge | will provide the basis for all subsequent path calculations |
one root bridge exits on a network | from it a series of logical branches,data paths,emanate |
bridge ID | combination o a 2-byte priority field and the bridges mac address |
stp | disables links that are not part of the
shortest path |
rapid spanning tree protocol | ieee 802.1w |
stp | operates in data link layer |
rstp | can detect and correct for link failures |
switches | operate in layer two of the osi |
routers | operate in layer three |
stp | prevents traffic loops |
stp | artifically blocking links completeing loops |
hubs | operate in layer one |
stp three steps | select root bridge based on bridge id |
stp three steps | examine possible paths between network and root bridge |
stp three steps | disable links not part of the shortest path |
layer three switch | routing switch |
switches that operate anywhere between layer four and layer seven | content switches |
application switches | the ability to interpret higher layer data enables switches to perform advanced filtering,statistics keeping and security functions |
router | multiport connectivity device that directs data between nodes on a network |
when a router receives an incoming packet | it reads the packets logical addressing in formation |
network layer protocols | direct data from one segment or type of network to another |
content switch | interprets layer four thru layer seven data |
content and multilayer switches advantages | advanced filtering, keeping statistics, security function |
routers are slower than switches and bridges | because they take time to interprt information in layer three and higher |
routers | determine the shortest fastest path between two nodes |
vlans | connect different subnets |
router | directs data between network nodes |
routers | protocol dependent,designed to recognize a protocol before they can use it |
switches | protocol independent |
routers | reroute traffic if a primary path is down but anoher path is available |
interior router | directs data between nodes on an autonomous lan,a single network,interior traffic |
exterior router | directs data between nodes outside a given autonomous lan,for example routers used on the internets backbone |
border routers | connects an autonomous lan with an exterior network,for example the router that connects a business to its isp |
gateway routers | border router |
static routing | technique in which a router is programmed to use a specific path between nodes |
dynamic routing | automatically calculates the best path between two nodes and accumulates the info in a routing table |
dynamic routing | if congestion or failure affects the network a router can detect the problems and reroute data thru a different path |
router capabilities | reroute traffic,interpret layer three addressing,connect dissimiliar networks |
best path | the most efficient route from one node on a network to another |
routing tables | identify which routers serve which hosts |
routing protocols | the means by which routers communicate with each other about network status |
routing protocols | determine the best path to take between nodes |
routing metric | determines the best path for data to follow over a network |
convergence time | the time it takes for a router to recognize a best path in the event of a change or a network outage |
distance vector routing protocol | determine the best route for data based on the distance to a destination |
routing information protocol | oldest routing protocol,only factors in number of hops between nodes |
interior gateway protocol | routing protocol that can only route data within an autonomous internal network |
routing information protocol version two | generates less broadcast traffic and functions more securely cannot exceed fifteen hops |
border gateway protocol | a distance vector routing protocol capable of considering many factors in its routing metrics.routing protocol used on internet backbones |
exterior gateway protocol | routing protocol that can span multiple,autonomous networks |
enhanced interior gateway protocol | routing protocol that has a fast convergence time and a low network overhead,but it is easier to configure and less CPU intensive that ospf |
link state routing protocol | enables routers across a network to share information,after which each router can independently map the network and determine the best path between itself and a packets destination node |
ospf | open shortest path first |
routing protocols dependent on | hops between nodes |
routing protocols dependent on | current network activity |
routing protocols dependent on | unavailable link |
routing protocols dependent on | network transmission speed |
routing protocols dependent on | topology |
rip | distance vector protocol that uses hop count as its routing metric and allows up to fifteen hops |
ospf | a link state routing protocol used on interior or border routers,no hop limit |
bgp | communicates using bgp specific messages, many factors determine best paths |
link state routing protocol | one that enables routers across a network to share information |
link state protocol | routers share information |
link state protocol | open shortest path first |
border gateway protocol | distance vector protocol suited to wans |
IS IS | intermediate system to intermediate system |
is is | link state routing protocol |
is is | type of igp |
hybrid routing protocols | combined link state and distance vector protocols |
eigrp | fast convergence time,low network overhead |
eigrp | supports multiple protocols |
gateways | combinations of networking hardware and software that connect two dissimilar kinds of networks |
gateways | resides on servers,microcomputers,connectivity devices or mainframes |
gateways | they may connect two systems that use different formatting,communication protocols, or architecture |
firewalls | gateway that selectively blocks or filters traffic between networks |