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45 Cards in this Set
- Front
- Back
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what does wic stand for? |
wireless interface card |
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what cable connects serial interface to csu/du's? |
serial cable |
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what do csu/dsu's provide? |
a bridge between the serial standards and the telco t-carrier system, acting as the DCE for the serial interface |
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what type of wire connects csu/du to telco? |
4wire rj-48 |
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are serial links synchronous or asynchronous? |
synchronous |
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does ethernet do synchronous or asynchronous? |
synchronous |
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are serial lines full or half duplex? |
full |
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what are the two roles for serial interfaces? |
DTE (Data-terminal equipment) or DCE (data circuit-terminating equipment) |
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what does the dce provide? |
clocking. dte will only attempt to send/recieve on the clock |
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on serial-to-serial connections what cords are used? |
dte/dce crossover, crossover being on the dce side |
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what speeds do the t-carrier systems support? |
multiples of 64kbps |
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what speed is a ds0? |
64kbps |
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what is fractional t1? |
multiples of 64kbps up to t1(ds1) speeds |
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how fast is t1? |
1.544mbps |
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what are the two major l2 standards for p2p links? |
HLDC & PPP |
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what does HLDC stand for? |
high data link control |
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how large are hldc headers? |
5bytes |
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how large are hldc trailers? |
2bytes |
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what does cisco add to hldc header? |
2byte type field |
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what does ios default to for serial? |
hldc |
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what command changes the encapsulation? |
encapsulation |
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how does one set the clock rate on DCE's? |
clock rate *speed* |
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how can you see if a serial interface has a dce cable? |
show controllers serial |
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what are the two authentication options provided by ppp?
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PAP (password authentication protocol) and CHAP (challenge handshake authentication protocol) |
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how many bytes is the PPP header? |
5 bytes |
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how many bytes is FC? |
2 |
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What does PPP use for data-link related messages? |
LCP (link control protocol) |
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what does ppp use for l3 related messages? |
1 NCP (network control protocol) for each network layer protocol |
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How does LCP provide looped link detection? |
magic numbers |
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how does lcp handle error detection? |
LQM (link quality monitoring) disables interfaces with too many errors, allowing rerouting over other interfaces
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how does ppp handle traffice balancing? |
multilink PPP, behaves similar to etherchannels |
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what are the two steps of the PAP process? |
Text and password are sent to authenticating device and authenticating device returns an ack |
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what are the 3 steps of teh chap process? |
authenticating router sends a challenge, authenticated router returns with hased password and authenticting router returns an accepted |
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what kinda hash i the password has |
md5 |
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what does the challenge include? |
a random number to run against the password, changing each challenge |
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what happens if authentication fails? |
up/down status |
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what else causes up/down status? |
authentication mismatch |
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how do you configure chap? |
ppp authentication chap |
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how do you set up the username/passwords to be used? |
on opposing routers, their login database must have a username with the opposite routers hostname and share the same password |
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which cp exchanges chap message and handles interface statuses? |
lcp |
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what are keepalive messages |
messaqges sent via lcp to alert the other that they're still up, if one is set not to send them and the other is, it will believe it to have failed |
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what does up/down on one and up/up on the other hint at? |
keepalive mismatch |
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what speed does t3 run at? |
44.736 |
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good way to check authentication failure |
debug ppp authenticate |
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good way to kook for keepalive prablems |
show interfaces |
