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.

Answer DescriptionExplanation:

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. A BGP peer does not require any configuration changes to become a route reflector client.

A. Routers with receivers send join messages to their upstream neighbors.

D. Traffic is only forwarded to routers that request to join the distribution tree.

Answer DescriptionExplanation:

PIM sparse mode (PIM-SM) is a multicast routing protocol that uses a pull model to deliver multicast traffic. In PIM-SM, routers with receivers send join messages to their upstream neighbors toward a rendezvous point (RP) or a source-specific tree (SPT). The RP or SPT acts as the root of a shared distribution tree for a multicast group. Traffic is only forwarded to routers that request to join the distribution tree by sending join messages. PIM-SM does not flood traffic to all routers or prune routers without receivers, as PIM dense mode does.

B. Behavior aggregate classifiers

D. Fixed classifiers

E. Multifield Classifiers

Answer DescriptionExplanation:

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.

C. When the encapsulation is vLan-ccc or extended-vlan-ccc, the configured VLAN tag is included in the control plane LDP advertisement

D. When the encapsulation is ethemet-ccc, tagged and untagged frames are both accepted in the data plane.

Answer DescriptionExplanation:

The customer interface in an LDP-signaled pseudowire is the interface on the PE router that connects to the CE device. An LDP-signaled pseudowire is a type of Layer 2 circuit that uses LDP to establish a point-to-point connection between two PE routers over an MPLS network. The customer interface can have different encapsulation types depending on the type of traffic that is carried over the pseudowire. The encapsulation types are ethernet-ccc, vlan-ccc, extended-vlan-ccc, atm-ccc, frame-relay-ccc, ppp-ccc, cisco-hdlc-ccc, and tcc-ccc. Depending on the encapsulation type, the customer interface can accept or reject tagged or untagged frames in the data plane, and include or exclude VLAN tags in the control plane LDP advertisement. The following table summarizes the behavior of different encapsulation types:

D. By default on PE-2, the remote site IDs are automatically assigned based on the order that you add the interfaces to the site configuration.

B. It uses dynamically created routing policies to protect a network from denial-of-service attacks

A. A router with a priority of 10 wins the DIS election over a router with a priority of 1.
D. On the multi-access network, each router only forms an adjacency to the DIS.