JN0-664 Practice Test

B.   This value is used to identify BGP routes learned from the remote PE device.


D.   This value is used to add a target community to BGP routes advertised to the remote PE device.

Explanation:

The `vrf-target` statement in a Layer 3 VPN configuration is used to control the import and export of VPN routes by attaching a target community to the routes. This helps in defining which VPN routes should be imported into or exported from a particular VRF (Virtual Routing and Forwarding) instance.

1. Understanding VRF Target

• The `vrf-target` statement specifies the extended community attributes (route targets) that are used to control the import and export of routes in a VRF.
• These attributes help in identifying which routes should be shared between different VRFs, particularly across different PE (Provider Edge) devices.

2. Statements Analysis

• This value is used to identify BGP routes learned from the local CE device incorrect. The `vrf-target` attribute is not used to identify routes learned from the local CE device. It is used to manage routes between PE devices and within the provider's MPLS network.
• This value is used to identify BGP routes learned from the remote PE device.
• Correct. The `vrf-target` value helps in identifying which routes from remote PE devices should be imported into the local VRF. It essentially acts as a filter for importing BGP routes with matching target communities.
• This value is used to add a target community to BGP routes advertised to the local CE device.
• Incorrect. Routes advertised to the local CE device do not use the `vrf-target` attribute. Instead, these routes are typically managed within the local VRF routing table.
• This value is used to add a target community to BGP routes advertised to the remote PE device.
• Correct. When advertising routes from the local PE to remote PE devices, the `vrf-target` value is added to these routes. This target community ensures that the correct routes are shared across the VPN.

Conclusion:

The correct statements about the `vrf-target` configuration in a Layer 3 VPN scenario are:

This value is used to identify BGP routes learned from the remote PE device.

This value is used to add a target community to BGP routes advertised to the remote PE device.

B.   Behavior aggregate classifiers


D.   Fixed classifiers


E.   Multifield Classifiers

Explanation:

Junos platforms use different mechanisms to evaluate incoming traffic for CoS purposes, such as: Behavior aggregate classifiers: These classifiers use a single field in a packet header to classify traffic into different forwarding classes and loss priorities based on predefined or user-defined values.

Fixed classifiers: These classifiers use a fixed field in a packet header to classify traffic into different forwarding classes and loss priorities based on predefined values.

Multifield classifiers: These classifiers use multiple fields in a packet header to classify traffic into different forwarding classes and loss priorities based on user-defined values and filters. Rewrite rules and traffic shapers are not used to evaluate incoming traffic for CoS purposes, but rather to modify or shape outgoing traffic based on CoS policies.

A.   It creates an OSPF multihop neighborship between two PE routers.


C.   The PEs exchange Type 1 OSPF LSAs instead of Type 3 OSPF LSAs for the L3VPN routes

Explanation:

A sham link is a logical link between two PE routers that belong to the same OSPF area but are connected through an L3VPN. A sham link makes the PE routers appear as if they are directly connected, and prevents OSPF from preferring an intra-area back door link over the VPN backbone. A sham link creates an OSPF multihop neighborship between the PE routers using TCP port 646. The PEs exchange Type 1 OSPF LSAs instead of Type 3 OSPF LSAs for the L3VPN routes, which allows OSPF to use the correct metric for route selection1.

A.   LDP-signaled VPLS tunnels only support control bit 0.


C.   BGP-signaled VPLS tunnels can use either RSVP or LDP between the PE routers.

Explanation:

https://www.juniper.net/documentation/us/en/software/nce/feature-guide-virtual-private-lan-service/topics/task/vpls-ldp-signaling-solutions.html

https://www.juniper.net/documentation/us/en/software/junos/vpn-l2/topics/concept/vpns-configuring-vpls-routing-instances.html#id-11510150__id-11568648

D.   OSPFv3 supports IPv4 only on interfaces with family inet6 defined