4A0-106 Sample Questions Answers

The customer carrier network can be a pure IP network.

The customer carrier can provide Layer 2 and Layer 3 services to its end-customers.

If the customer carrier offers VPRN services, PE routers residing in different customer carrier sites must run iBGP between them to exchange IPv4 routes.

If the customer carrier offers VPRN services, the network provider stores the end-customer routes in its CSC VPRN.

It is best used when a single VPN is required to provide Internet access, as well as to maintain VPN connectivity between different customer sites.

If there is no requirement for the VRF to contain the full Internet routing table, a default route to the Internet gateway router is sufficient.

Only one interface on the CE is required for both VPN and Internet connectivity.

The Nokia 7750 SR supports route leaking in full mesh and extranet VPRN topologies only.

show service id base

show router Idp bindings

show service id sdp detail

show service id vc-mtu

It forwards the packet based on the label signaled by MP-BGP.

It decrements the TTL and forwards the packet based on the inner label.

It swaps the outer label then forwards the packet.

The P router does not perform any operations on labeled packets.

An MP-eBGP session between route reflectors in different autonomous systems to exchange IPv4 routes.

An MP-eBGP session between ASBRs to exchange labeled IPv4 routes.

An eBGP session between ASBRs to exchange IPv4 routes.

An MP-eBGP session between ASBRs to exchange VPN-IPv4 routes.

On the PE facing the CE neighbor

On the CE facing the PE neighbor

On the P facing the PE neighbor

On the PE facing the PE neighbor

PE1 and PE2 advertise the same VPN route to the route reflector.

The route reflector receives two routes for prefix 10.1.1.0/24; one from PE1 and one from PE2.

The route reflector reflects two routes for prefix 10.1.1.0/24.

PE3 receives two routes and is able to load balance traffic across PE1 and PE2.

PE1 pushes three labels on the IP packet: a VPN label, a BGP label, and an LDP transport label.

ASBR1 pops the LDP label, swaps the BGP label and forwards the IP packet to ASBR2.

ASBR2 swaps the BGP label and pushes an LDP transport label.

PE2 pops all labels and forwards the unlabeled packet to its destination.

CE2 forwards an unlabeled IP packet to PE2 via the VPRN interface.

PE2 pushes one label on the IP packet and label-switches it to ASBR2.

ASBR2 forwards an unlabeled IP packet to ASBR1.

ASBR1 pushes two labels on the IP packet and label-switches the packet to PE1.

MP-BGP for exchanging customer routes with other PEs.

A routing protocol for exchanging customer routes with the CE.

A label signaling protocol for defining transport tunnels between the PE and CE.

MPLS for exchanging labels with other provider core devices.

The route with the shortest AS path.

The route with the lowest route or tunnel table cost to the NEXT_HOP.

The route with the highest local preference.

The route with the lowest originator ID or BGP identifier.

The ability to offer Internet connectivity and a variety of services over a single CSC VPRN interface.

The ability to maintain its own backbone.

The ability to learn system addresses of network provider PEs.

There is no need to manage end-customer services.

Red VRF imports only "Internet"

Internet VRF imports only "Red-Only"

Red VRF imports "Internet" and "Red-Only"

Internet VRF imports only "Red-Only"

Red VRF imports only "Red-Only"

Internet VRF imports "Red-Only" and "Internet"

Red VRF imports "Internet" and "Red-Only"

Internet VRF imports only "Internet"

The customer carrier does not learn any network provider routes.

The network provider must learn the customer carrier PE and CE system addresses.

Routes exchanged between CSC-CE and CSC-PE are labeled.

The customer carrier PE system addresses are populated in the CSC VRF.

Each PE must implement a policy to apply a unique SoO attribute to the set of routes received from each customer site.

A different BGP extended community is used on each PE that connects to a single site.

An import policy on the PE rejects a route if the attached SoO matches the configured value.

Import and export policies are applied on the PEs under the global BGP context.

"Spoke.Sites" and "Hub_Site"

"Hub_Site"

"Spoke_Sites"

No communities should be imported

"Spoke.Sites" and "Hub_Site"

"Spoke_Sites"

"Hub_Site"

No communities should be exported

The protocol is configured under the config>service context

The protocol is configured under the global router context

The interface leading to the PE is defined as a protocol neighbor

The routing protocol used must be the same as the routing protocol used at other CE-PE locations in the same VPN.

A routing policy may or may not be required depending on the routing requirements and routing protocol

Show service all

Show service id detail

Show service id base

Show service id bindings

Show service sap-using

PE1 sends the data packet with three labels: the bottom label is a service label, the middle label is a BGP label, and the top label is an LDP label.

ASBR1 sends the data packet with one label: the BGP label.

ASBR1 sends the data packet with one label: the service label.

ASBR2 sends the data packet with three labels: the bottom label is a service label, the middle label is a BGP label, and the top label is an LDP label.

Global, router

Router, router

Service, router

Router, service

Service, service

Router, global

Identify the egress PE in the MPLS domain

Signal the egress VPRN ID

Identify the ingress PE in the MPLS domain

Transport route updates between PEs

CE1

CE2

PE1

PE2

The policy should be applied as an import policy on the PE connected to the main site of Customer 1.

The policy should be applied as an import policy on all the PEs connected to the sites of Customer 1.

The policy should be applied as an export policy on the PE connected to the main site of Customer 1.

The policy should be applied as an export policy on all the PEs connected to the sites of Customer 1.

Full mesh between all CE, PE and P devices

Full mesh between PE and P devices

Full mesh of P devices

Full mesh of PE devices

Full mesh between PE and CE devices

This configuration is correct and complete.

This configuration is correct, but the interfaces must also be configured in the "configure router mpls" context.

There is no configuration required for LDP in the core network.

This configuration is correct but Targeted-LDP is also required.

CE1 forwards the data packet to PE1 via the VPRN 20 interface.

PE1 pushes two labels on the IP packet: a BGP label and an LDP transport label.

CSC-CE1 pops the LDP label and swaps the BGP label.

CSC-PE1 pops the BGP label and pushes a VPN label and an MPLS transport label.

In the routing updates exchanged from CE to PE

In the routing updates exchanged from PE to PE

In the routing updates exchanged from P to PE

In customer packets as they traverse the provider core

In all route tables of the VPRN control plane

Model B does not require the configuration of VPRN instances on the ASBRs.

The ASBRs exchange data packets that are encapsulated with a transport label and a service label.

The route target advertised in one AS is maintained and used in the remote AS.

The CLI command "configure router bgp enable-inter-as-vpn" is required on the ASBRs.