mpls l2 vpn

Question 1

What are the 3 types of L2 VPN models?

Answer 1

Local Switching, VPWS and VPLS

Question 2

VPWS type that can be implemented over IP backbone

Answer 2

L2TPv3

Question 3

What are the 3 elements of L2VPN architecture

Answer 3

Attachment Circuit - It is the circuit or element that is mapped into the PW • Ethernet port or VLAN • Frame-Relay port or just a DLCI • PPP port • ATM Virtual Path Identifier – VPI or Virtual Channel Identifier – VCI o Pseudowires  P2P connection over the packet network  Emulates operation of a “Transparent Cable” o Transport Technologies  MPLS packet network (supports P2P and PMP)  IP packet network (supports only P2P)

Question 4

What are the transport technology options for circuits

Answer 4

Transport technology: MPLS or IP

Question 5

Do VPWS circuits learn MACs

Answer 5

False, VPLS does

Question 6

________ _________ ________ is the ability to process and classify multiple Ethernet frames and their attributes

Answer 6

Flexible ethernet mapping

Question 7

______ _______ is the MAC learning domain regardless of which VLANs are mapped to it

Answer 7

The Bridge Domain

Question 8

An _______ _______ is a Layer 2 logical subinterface used to classify traffic under a physical or a bundle interface. A physical interface can be an Ethernet interface and has ports on the line card.

Answer 8

Ethernet Flow Point (EFP) Subinterface that is mapped to a PW

Question 9

Some fields are not transmitted in the PW

Answer 9

True: • Encapsulates frame without transmission fields that offer no benefit, such as synchronization data preamble Start Frame Delimiter – SFD  Marks the beginning of the frame FCS

Question 10

In IOS XR an ACL is required for BPDUS filters, this is necessary to prevent the port from entering err-disable for receiving BPDUs from inconsistent VLANs

Answer 10

True

Question 11

Does VPWS emulate a LAN using PW or VCs

Answer 11

False, VPLS does

Question 12

In VPLS an unknown unicast, multicast and broadcast frame is propagated to all PEs in a common VPLS, upon reaching these PEs the frame is forwarded to all client ports but NOT forwarded to ANY OTHER PE

Answer 12

True. Split horizon • VPLS Split horizon is similar to iBGP mesh

Question 13

Is VPLS composed of N individual PWs

Answer 13

True

Question 14

Does H-VPLS operate independently of Split Horizon

Answer 14

False, split horizon must be disabled.

Question 15

_________ __________ _______ • The Virtual Switching Instance, implemented as VFI is a virtual L2 entity that defines the VPLS domain • VFI functions o Connects ACs to PWs

Answer 15

Virtual Forwarding Instance

Question 16

Is a _ _ _ used to connect a VPLS to a bridge domain to create a routed VPLS

Answer 16

True

Question 17

Are MAC learning and aging processes handled by IGP extensions

Answer 17

False, it is the responsibility of LDP extensions

Question 18

Can BGP and LDP be used for discovery

Answer 18

False, only BGP

Question 19

In BGP configuration are RD and RT used the same way as in L3VPN

Answer 19

True

Question 20

Is the VPLS Edge Identifier - VE ID announced by BGP

Answer 20

True

Question 21

What are the 3 steps of VPLS configuration

Answer 21

Service instance configuration on the interface Configuration of the l2vpn vrf context NAME – manually add peers Configuration of the bridge domain – add the interface in its service instance – add the VFI Name

Question 22

In H-VPLS is the N-PE like a Route Reflector in BGP

Answer 22

True, basically U-PEs will establish PWs only with N-PE

Question 23

ELAN = H-VPLS and ETREE = VPLS

Answer 23

False, the reverse

Question 24

Should split Horizon be disabled on U-PE > N-PE uplinks and enabled on N-PE > N-PE uplinks

Answer 24

True

Question 25

What is the framework created to unify and standardize Ethernet service configurations called

Answer 25

Ethernet Virtual Circuit

Question 26

What is the purpose of the EVC framework

Answer 26

facilitate the abstraction of a physical interface through the multiplexing of services

Question 27

In EVC what is the name of the abstraction entity where interesting traffic is associated with the service

Answer 27

Ethernet Flow Point

Question 28

What is the difference between EFP, BVI and BD

Answer 28

Ethernet Flow Point (EFP) Abstraction of an Ethernet service on an interface. ‘service instance instance_number ethernet’ under the interface ­ this ‘binds’ an EFP to an interface. Bridge Domain (BD) Ethernet Broadcast domain. A single VLAN can have multiple BDs. Bridge Domain Interface (BDI) Layer 3 interface associated with a BD to perform Integrated Routing and Bridging (IRB). Gateway between a Layer 2 domain within a Bridge Domain and the Layer 3 domain, similar to an SVI.

Question 29

Can COS or ethertype be used to match traffic to an EFP

Answer 29

Yes

Question 30

Does BVI allow VLAN significance by port

Answer 30

False, it is BD, bridge domain

Question 31

The ___ can be used to provide an “exit point” out of the Bridge Domain and into a routed segment, and uses the standard ARP mechanism to resolve addresses.

Answer 31

BDI

Question 32

What are the 3 operations of Advanced Frame Manipulation or VLAN Acrobatics

Answer 32

Push, pop and translate

Question 33

What is the effect of the command below: rewrite ingress tag translate 1­to­1 dot1q 20 symmetric

Answer 33

translates the outer tag to 20, regardless of what it is