7-2 - Layer 2 Service Architecture and Carrier Ethernet Services

Question 1

What is the acronym for Cisco’s Metro Ethernet Services lifecycle?

Answer 1

PPDIOO:
Prepare
Plan
Design
Implement
Operate
Optimize

Question 2

Ethernet Virtual Circuit (EVC)

Answer 2

virtualized service carrying customer Ethernet traffic

Question 3

User-to-Network Interface (UNI)

Answer 3

physical interface that marks the boundary between service provider, cable operator, or carrier and the subscriber.

Question 4

Ethernet Flow Point (EFP)

Answer 4

A Layer 2 logical subinterface that you use to classify traffic under a physical or bundle interface

Question 5

E-Line

Answer 5

• point-to-point ethernet EVC
• two UNIs are logically cross-connected by a “virtual wire” (e.g. pseudowire)
• the service provider is a “wire”

Question 6

E-LAN

Answer 6

• multipoint-to-multipoint EVC
• multiple UNIs are reachable within the same Ethernet broadcast domain where MAC learning and forwarding behaviors are performed
• The service provider is a “switch”

Question 7

E-Tree

Answer 7

• rooted multipoint EVC
• each UNI is designated as a root or a leaf. A root can communicate with any leaf. A leaf can communicate only with a root.

Question 8

The EVC solution defines these aspects of Ethernet-based attachment circuits and virtual circuits:

Answer 8

• Frame matching is based on one or more VLAN tags.
• Optional VLAN tag manipulation.
• Traffic forwarding.
• Additional services, such as QoS policies.

Question 9

What is this an example configuration of?

interface GigabitEthernet 0/0/0/1.4 l2transport
encapsulation dot1q 4
rewrite ingress tag pop 1 symmetric

Answer 9

Cisco IOS-XR Ethernet Flow Points Configuration Example.

• l2transport: This command identifies a subinterface (or a physical port or bundle-port parent interface) as an EFP.
• encapsulation: Use this command to specify matching criteria.
• rewrite: Use this command to specify the VLAN tag rewrite criteria.

Question 10

T/F: Because Bridged Virtual Interfaces (BVIs) do not support VLAN tags, the VLAN tag must pop on ingress and add on egress for the BVI to handle the ingress traffic on the EFP. Use the rewrite command for this purpose.

Answer 10

True

Question 11

Bridge Domain

Answer 11

an L2 broadcast domain that L2 EFPs and virtual L3 routed interfaces can be placed in

Question 12

T/F: The use of 802.1Q VLAN tags in the context of EFPs differs from legacy L2 switching in that the incoming VLAN tag doesn’t inherently represent what the outgoing VLAN tag must be. The incoming VLAN is strictly used for matching criteria, and the EFP is then applied to the bridge-domain for forwarding. Matching and forwarding are decoupled.

Answer 12

True

Question 13

What is this a configuration example of?

interface GigabitEthernet0/0/1
no ip address
negotiation auto
service instance 1 ethernet
encapsulation dot1q 201
rewrite ingress tag translate 1-to-1 dot1q 300 symmetric
bridge-domain 1
!

Answer 13

Cisco IOS-XE Ethernet Flow Point (Service Instance) Configuration Example

Question 14

Which of the following statements is true?

A. You can provision Layer 2 VPNs between switches, hosts, or routers and allow Layer 3 connectivity between separate sites.
B. An EVC is a Layer 2 logical subinterface that you use to classify traffic under a physical or a bundle interface.
C. On Cisco devices, you use the EFP to represent Cisco Software architecture to address Carrier Ethernet services.
D. Cisco Carrier Ethernet services help the service provider offer Ethernet services.

Answer 14

D