13 - Implementing Pt to Pt WANS Flashcards Preview

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Flashcards in 13 - Implementing Pt to Pt WANS Deck (48)
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1
Q

What is CPE?

A

Customer Premise Equipment

2
Q

What does CSU/DSU stand for?

A

Channel Service Unit / Data Service Unit

3
Q

What does a CSU/DSU do?

A

Provides clocking on the line controlling the speed and timing that the router can send each bit over the line

4
Q

What is the bit rate for a DS0?

A

64 Kbps

5
Q

What is another name for DS1?

A

T1

6
Q

What is the bit rate for a T1?

A

1.544 Mbps

7
Q

What multiples make up a Fractional T1?

A

Multiples of 64 Kbps

8
Q

What multiples make up a Fractional T3?

A

Multiples of 1.536 Mbps

9
Q

What is the bit rate for a T3?

A

44.736 Mbps

10
Q

What does DCE stand for?

A

Data Circuit-terminating Equipment

11
Q

What does the DCE funtion do?

A

Controls the speed of the router’s serial interface

12
Q

What does DTE stand for?

A

Data Terminal Equipment

13
Q

What does the DTE do?

A

DTE is the router that is controlled by the DCE

14
Q

How is Cisco’s HDLC protocol different that ISO’s HDLC?

A

Cisco adds a Type field that allows the serial line to support multiple types of network layer packets

15
Q

What are the 6 fields in a Cisco HDLC frame?

A
  • Flag
  • Address
  • Control
  • Type
  • Data
  • FCS
16
Q

What are 2 ways to enable HDLC encapsulation on an interface?

A
  • ‘no encapsulation’ cmd to return to default HDLC or
  • encapsulation HDLC
17
Q

What 2 ‘show’ commands that confirm a serial link has been successfully installed?

A
  • show controllers s0/0/0
  • show interfaces s0/0/0
18
Q

What 5 things does PPP provide?

A
  • defines a header and trailer
  • supports both synchronous and asynchronous
  • Protocol Type field allowing multiple layer 3 protocols
  • Built-in authentication tools
  • control protocols for each higher-layer protocol riding over PPP
19
Q

In PPP frame what does the Type field do?

A

Identifies which L3 protocol is in the frame

20
Q

in PPP what are the 2 categories of Control Protocols?

A
  • Link Control Protocols (LCP)
  • Network Control Protocols (NCP)
21
Q

What are 3 examples of NCPs?

A
  • IPCP
  • IPv6CP
  • CDPCP
22
Q

What are 4 LCPs?

A
  • Looped Link Detection
  • Error Detection
  • Multilink Support
  • Authentication
23
Q

In PPP what are the 2 Authentication protocols?

A
  • PAP
  • CHAP
24
Q

How does the PAP authentication process work?

A
  • The router wanting to be authenticated - R2 - starts the conversation
  • R2 tells R1 username and password in clear text
  • R1 Acknowledges auth successful
25
Q

How does the CHAP process work?

A
  • The router doing the authenticating - R1 - initiates
  • R1 sends challenge that includes a Random Number to R2
  • R2 replies with a MD5 Hash created from the Random Number and the Password
  • R1 acknowledges auth successful
26
Q

In PPP CHAP what does the Challenging router do if authentication fails?

A

Leaves interface in Up/Down state

27
Q

What kind of Hash does PPP CHAP use?

A

MD5

28
Q

What is the command to enable PPP on an interface?

A

encapsulation ppp

29
Q

What show command verifies that PPP has been enabled?

A
  • show interfaces s0/0/0
    • will show encapsulation ppp
    • also LCP Open
    • also Open: IPCP, CDPCP
30
Q

What configuration steps are needed on router1 to configure CHAP?

A
  • encapsulation ppp
  • hostname router1
  • username router2 password letmein
  • interface s0/0/0
    • ppp authentication chap
31
Q

What configuration steps are needed on router2 to configure CHAP?

A
  • encapsulation ppp
  • hostname router2
  • username router1 password letmein
  • interface s0/0/0
    • ppp authentication chap
32
Q

When configuring PPP CHAP which two parameters need to match?

A
  • username on local router must match hostname on remote router
  • passwords must be the same
33
Q

What show command confirms authentication succeeded?

A
  • show ppp all
  • should show ‘+’ for every protocol that succeeded
34
Q

When configuring PPP PAP which parameters need to match?

A
  • interface s0/0
  • ppp pap sent-username r1 password test
    • must match username r1 password test on remote router
35
Q

What ‘show’ command will show if PAP authentication worked?

A

* show ppp all * should show ‘+’ for every protocol that succeeded

36
Q

What configuration steps are needed to configure PAP?

A

* interface subcommands * encapsulation ppp * ppp authentication pap * ppp pap sent-username r1 password test * then on remote router username r1 password test

37
Q

What command will tell a router to try CHAP first and if that doesn’t succeed try PAP

A

* ppp authentication chap pap

38
Q

Which layer does MLPPP load balance at?

A

Layer 2

39
Q

Which 2 ‘show’ commands verify MLPPP is working?

A

* show interfaces multilink 1 * show ppp multilink

40
Q

What does an interface state of down/down indicate?

A

a problem at layer 1

41
Q

What does an interface state of up/down indicate?

A

a problem at layer 2

42
Q

What does an interface state of up/up indicate?

A

layer 3 is working

43
Q

What are some possible causes of interfaces in down/down state?

A

* cable unplugged * bad cable * broken CSU * problem at telco

44
Q

What could be the problem when interfaces are up/down flapping on both ends?

A

Mismatched encapsulation commands

45
Q

What could be the problem if one side is up/down and the other side is up/up?

A

Keepalives disabled on the up/up side

46
Q

What could be the problem when interfaces are up/down on both ends but NO Flapping?

A

PAP or CHAP Authentication Failure

47
Q

How often are keepalives sent to the remote router by default?

A

once every 10 seconds

48
Q

What debug command will help diagnose a PPP Authentication Failure?

A

debug ppp authentication