CISCO Mpls Quiz Questions And Answers

LDP refers to Label Distribution Protocol, which is used in MPLS networks to establish label-switched paths. The three steps of LDP include discovery, session establishment, and label distribution/exchange. During the discovery phase, LDP routers exchange Hello messages to discover neighboring LDP routers. In the session establishment phase, LDP routers establish TCP connections to form LDP sessions with their neighbors. Finally, in the label distribution/exchange phase, LDP routers exchange label mapping information to distribute labels and establish label-switched paths.

The actions of adding and removing labels with MPLS are referred to as "push and pop". When a packet enters an MPLS network, a new label is pushed onto the packet header. This label is used to determine the forwarding path. When the packet reaches its destination, the label is popped off, and the original IP header is revealed. This push and pop mechanism allows for efficient routing and forwarding of packets within an MPLS network.

The device that adds or strips labels for frames entering or exiting the provider MPLS network is called an Edge Label Switch Router. This device is responsible for applying MPLS labels to incoming packets and removing them from outgoing packets, allowing for efficient routing within the MPLS network. Core routers are responsible for forwarding packets within the network, while edge switches are responsible for connecting devices within a local network. None of these devices perform the specific task of adding or stripping labels in the MPLS network.

The correct answer is Label, Experimental, BS (last label in stack), TTL. In MPLS (Multiprotocol Label Switching), the label is the key component that identifies the forwarding path for the data frame. The experimental field is used for Quality of Service (QoS) purposes. The BS (Bottom of Stack) indicates whether the label is the last one in the stack. The TTL (Time to Live) field is used to prevent data frames from circulating indefinitely in the network.

MPLS (Multiprotocol Label Switching) is based on Cisco's proprietary technology called CEF (Cisco Express Forwarding). CEF is a high-speed switching technology used in Cisco routers to forward packets efficiently. It uses a forwarding information base (FIB) and an adjacency table to make forwarding decisions based on labels. By using CEF as the underlying technology, MPLS is able to provide efficient and scalable packet forwarding, traffic engineering, and quality of service (QoS) capabilities.

CEF (Cisco Express Forwarding) is a forwarding technology used in Cisco routers. It creates a Forwarding Information Base (FIB) table, which is used for making forwarding decisions. The FIB table contains the next-hop information for destination IP addresses and is used to determine the best path for packet forwarding. Therefore, the correct answer is FIB.

The given question involves combining the words "LIB" and "FIB" to form a new word. By analyzing the options, we can see that the correct answer is "LFIB". This is because the first two letters of the first word, "LI", are combined with the last two letters of the second word, "FB", to create the new word "LFIB".

The correct answer is LDP (Label Distribution Protocol). LDP is the official routing protocol used in MPLS (Multiprotocol Label Switching) networks. It is responsible for distributing labels that are used to forward packets through the MPLS network. LDP establishes label-switched paths (LSPs) between routers, allowing efficient and scalable forwarding of traffic. RIPv2 and FIB are not specific to MPLS and do not serve as the official routing protocol for MPLS networks. Therefore, the correct answer is LDP.

An MPLS label consists of 20 bits. The MPLS label is used to identify the forwarding equivalence class (FEC) for a packet, allowing routers to make forwarding decisions based on the label rather than the packet's network layer header. The 20-bit label provides a large number of possible labels, allowing for efficient routing and traffic engineering in MPLS networks.

The MPLS label lives between the IP and MAC layers in a data frame. MPLS (Multiprotocol Label Switching) is a technique used in packet-switched networks to efficiently route data packets. It adds a label to the IP packet, which is used to determine the forwarding path. This label is inserted between the IP and MAC headers in the data frame. By placing the MPLS label at this position, the network devices can quickly and accurately identify the appropriate forwarding path for the packet based on the label, improving network efficiency and performance.

LDP (Label Distribution Protocol) is a protocol used in MPLS networks to distribute labels between routers. It operates on UDP port 646.

The control plane in MPLS is responsible for establishing and maintaining the label-switched paths (LSPs) in the network. It handles tasks such as label distribution, routing, and signaling between routers. Therefore, it is in the control plane where the routing protocols and label exchange protocols exist in MPLS. The transport plane is responsible for forwarding the actual data packets based on the established LSPs, while the data plane is where the actual data packets are encapsulated with MPLS labels. The Sarengeti plane is not a recognized plane in MPLS.

An ISP router adds labels to routes learned by BGP using LSR (Label Switching Router). LSR is responsible for the implementation of label switching in a network. It assigns labels to incoming packets and forwards them based on these labels, enabling efficient and fast routing. The other options, FIB Forwarding Information Base router and LDP Label Discovery Protocol router, do not specifically deal with adding labels to routes learned by BGP. Therefore, the correct answer is LSR Label Switching Router.

LDP hellos are sent to the multicast address 224.0.0.2. Multicast addresses are used to send data packets to multiple destinations simultaneously. In this case, LDP hellos are sent to this specific multicast address to discover and establish LDP sessions with neighboring routers. The other multicast addresses mentioned (224.0.0.10 and 224.0.0.5) are not used for LDP hellos.

The data plane is responsible for sending data based on L3 or L2 information and takes care of label swapping. It is the component of a network that handles the actual transmission of data packets. It forwards the packets from one network node to another, making routing decisions based on the information contained in the packet headers. The data plane operates independently of the control plane, which is responsible for managing and configuring the network.

The correct answer is that the FIB forwards IP packets while the LFIB forwards *labelled* IP packets. This means that the FIB is responsible for forwarding regular IP packets based on routing information, while the LFIB is used for forwarding IP packets that have been labeled for specific paths. The LFIB is used in MPLS (Multiprotocol Label Switching) networks, where labels are added to IP packets to improve routing efficiency and speed.

When labels are exchanged via LDP (Label Distribution Protocol) between two routers, the LIB (Label Information Base) is built. The LIB is a table that stores the mapping between the incoming labels and the corresponding outgoing interfaces and labels. It is used by the routers to make forwarding decisions based on the received labels.