Volume 2 - Chapter 19: WAN Architecture

Question 1

What type of service is provided by a Metro Ethernet WAN?

Answer 1

A layer 2 service.

Question 2

The following example below is what type of WAN service?

Answer 2

Metro Ethernet

Question 3

What type of User Network Interface (UNI) is used to connect to a Metro Ethernet service?

Answer 3

An ethernet access link. For example:
* 1000BASE-LX
* 1000BASE-ZX
* 10GBASE-LR

Question 4

True or False:

When connecting to a Metro Ethernet WAN service, the WAN provider (SP) will look at a frame’s header and 802.1Q fields for VLAN tags.

Answer 4

True, the SP’s network acts if you had your remote site routers connected to a switch.

Question 5

What are the 3 types of MetroE services?

Answer 5

• E-Line
• E-LAN
• E-Tree

Question 6

The following example below is what type of MetroE service?

Answer 6

This is an example of an E-Line service.

Question 7

Describe the following characteristics of a Metro Ethernet E-Line service:
* WAN Uplink
* WAN Subnet
* Routing Relationship

Answer 7

The WAN uplink will use a physical ethernet interface

The WAN subnet uses a point to point link, so a single subnet is created for each Ethernet Virtual Circuit. 10 E-Lines would require 10 subnets.

Each remote site forms a routing neighbor relationship with only the central site; not each other.

Question 8

True or False:

When connecting a central site to multiple remote sites using an E-Line service, only a single E-Line is required to connect the remote sites?

Answer 8

False, for every remote site that you add to the E-Line service, an additional E-Line is required.

Question 9

What type of topology is created by an E-Line service?

Answer 9

Point-to-Point

Question 10

The following example below is what type of MetroE service?

Answer 10

This is an example of an E-LAN service.

Question 11

What is it better to use an E-LAN service over an E-Line service?

Answer 11

When you have multiple remote sites that need to directly communicate with each other.

Question 12

Describe the following characteristics of a Metro Ethernet E-LAN service:
* WAN Uplink
* WAN Subnet
* Routing Relationship

Answer 12

The WAN uplink will use a physical ethernet interface

The WAN subnet uses a full mesh topology, so a single subnet is created for the entire E-LAN

Each remote site forms a routing neighbor relationship with all other remote site routers.

Question 13

The following example below is what type of WAN service?

Answer 13

This is an example of an MPLS (Multiprotocol Label Switching)

Question 14

An MPLS WAN is an example of a layer ____ service.

Answer 14

Layer 3

Question 15

With a MPLS service, the Customer Edge (CE) connects the ____ to the ____

The Provider Edge (PE) connects the ____ to the ____

Answer 15

• CE: Connects to the customer’s LAN to the customer’s edge
• PE: Connects to the Customer’s Edge to the Provider’s network

Question 16

In the following example, the red dots indicate the ____ and the green dots represent the ____

Answer 16

Red: Customer Edge
Green: Provider Edge

Question 17

What are examples of access links that are supported by an MPLS from the CE to the PE?

Answer 17

• Serial TDM
• 4G/5G
• Metro Ethernet
• CATV

Question 18

True or False:

When using a MPLS service, the MPLS must know the clients IP addressing.

Answer 18

True, the CE and PE must form a routing neighbor relationship.

Question 19

What type of routing protocols available to be used in the following areas of the MPLS?:
* Between the Customer and the Provider networks
* Within the Provider’s network

Answer 19

Between the CE and PE multiple routing protocols are supported. For example: OSPF, EIGRP, RIP, eBGP, etc….

However, the service provider will typically use Multiprotocol BGP (MP-BGP).

Question 20

How does an MPLS service provider provide services to multiple customers using an MPLS while keeping traffic seperated?

Answer 20

The MPLS SP uses MP-BGP, which allows multiple VRF instances to keep customer traffic seperate.

Question 21

With the CE to PE using OSPF and the provider network using a different protocol such as MP-BGP, how can one remote site learn a route to another?

Answer 21

Routes from the customer edge are redistributed into the WAN provider edge using a process called route redistribution.

Question 22

When a customer uses a DSL line for both internet and phone services, how is the traffic to each distinguished and seperated from each other?

Answer 22

Both services will use the same telephone line back to the service provider, where the DSLAM (DSL Access Multiplexer) will seperate out the traffic.

Question 23

When a customer uses a cable line for both internet and TV services, how is the traffic to each distinguished and seperated from each other?

Answer 23

The internet services use a different channel (frequency) than the other channels reserved from television.

Question 24

CATV stands for?

Answer 24

Cable Television

Question 25

Describe the difference between 5G NSA and 5G SA wireless

Answer 25

5G Non-standalone (NSA) uses the same infrastructure and network as 4G services. It is faster speed than 4G

5G Standalone (SA) offers higher perform than NSA, it uses more antennas and provides better service than 4G.

Question 26

Describe how IPSec uses a pair of encryption algorithms with VPN tunnels.

Answer 26

One encryption algorithm is used to encrypted the data, and another is used decrypt.

Question 27

What are the 2 most common security protocols used with remote-to-site VPNs?

Answer 27

IPsec or Transport Layer Security (TLS).

Question 28

Describe the difference between IPsec Tunnel mode and IPsec Transport mode.

Answer 28

IPSec Tunnel Mode is used for site-to-site VPNs; the entire original packet is encrypted.

IPSec Transport Mode is used for remote-to-site VPNs; everything in the packet is encrypted except for the original IP header.