WANs

Question 1

Is a WAN a public or private link?

Answer 1

WANs can be private links via leased lines.

Question 2

Common types of VPN protocols for site to site connections? (x4)

Answer 2

• IPsec - Open standard. Doesnt support Multicast which is used by routers to share routes
• GRE (Generic Routing Encapsulation) over IPsec - adds support for multicast
• IPsec VTI (Virtual Tunnel Interface) - Cisco proprietary simplified configuration, supports multicast.
• DMVPN (Dynamic Multipoint VPN) - Cisco proprietary. Enables full mesh connectivity between all offices although the config steps act like configuring a hub and spoke VPN model.

Question 3

Common type of VPN encryption for end-user to site connections?

Answer 3

SSL but sometimes also IPsec

Question 4

Primary WAN connectivity options?

Answer 4

• Leased Line
• MPLS
• Satellite

Question 5

Secondary WAN connectivity options?

(can be primary options for small offices)

Answer 5

• DSL
• Cable Modem
• Wireless 4G or LTE

Question 6

What will a SLA include?

Answer 6

• Uptime
• Loss
• Delay
• Maybe Jitter

Question 7

What is a Leased Line to Cisco?

Answer 7

A point-to-point connection using a serial port.

Question 8

What is PPP?

Answer 8

Point-to-Point Protocol

Question 9

What is HDLC?
cHDLC?

Answer 9

Protocol used over serial connections
cHDLC is the Cisco proprietary version of HDLC

Question 10

What OSI layer is HDLC

Answer 10

Layer 2

Question 11

What OSI layer is PPP for leased line serial connections?

Answer 11

Layer 2

Question 12

What side of a link is the clock rate set?
DCE or DTE

Answer 12

DCE.

on the Data Communications Equipment (providor),
not on the DTE - Date Termination Equipment (customer)

Question 13

Difference between serial Clock Rate and Interface Bandwidth setting?

Answer 13

The bandwidth statement doesn’t affect the physical clocking of the line. The bandwidth statement only effects software policies such as routing protocol metrics and QoS shaping.

Question 14

Default bandwidth of a serial interface?

Answer 14

1.544 Mbps (T1)

Question 15

HDLC confg steps:

Answer 15

Question 16

PPP config steps:

Answer 16

Question 17

Command to view PPP settings:

Answer 17

R1# show ppp all

Question 18

What is the default username for CHAP in one-way PPP authentication

Answer 18

The remote device’s hostname

Question 19

Command to configure CHAP authentication

Answer 19

R1(config-if)# ppp chap password Presto1

Question 20

What is MLPPP

Answer 20

MultiLink PPP - Using multiple parallel serial links as one single logical link.

Question 21

MLPPP Config steps:

Answer 21

Question 22

Define PPPoE

Answer 22

Point-to-Point Protocol over Ethernet

Question 23

Would you configure PPPoE on the router or the DSL model?

Answer 23

Either are standard things that are done.

Question 24

PPPoE Config steps:

Answer 24

Question 25

What is a ‘Virtual Access’ interface on a Router?

Answer 25

A product of a PPPoE dialer configured on the router.

Question 26

Define GRE

Answer 26

Generic Routing Encapsulation

Does not support encryption but does support multicast for routing protocol traffic.

Can be paired with IPsec for a full end to end tunnel.

Question 27

GRE Tunnell config steps:

Answer 27