L2 VPN Fr, ATM, Ethernet, Vpls

Multiple VPLS services can be provisioned over the same set of provider MPLS tunnels. This means that a single set of MPLS tunnels can be used to support multiple VPLS services, allowing for efficient use of network resources. This can be achieved by using different Virtual Private LAN Service (VPLS) instances, which are isolated from each other and can be configured to provide separate Layer 2 connectivity for different customers or applications. By utilizing the same set of provider MPLS tunnels, organizations can simplify their network architecture and reduce costs.

Spanning-tree is a network protocol used to prevent loops in Ethernet networks. However, one disadvantage of spanning-tree is that it does not always choose the optimal path for data transmission. Instead, it selects a path that avoids loops but may not be the most efficient or shortest path. This can result in suboptimal network performance and slower data transmission times. Therefore, the statement that the path chosen by spanning-tree is not necessarily the optimal one is true.

A 16-port switch running spanning-tree can have a maximum of 1 root port because in a spanning-tree protocol, there can only be one root bridge in a network. The root bridge is the bridge with the lowest bridge ID and all other switches in the network will have a single root port that connects them to the root bridge. Therefore, regardless of the number of ports on the switch, there can only be one root port.

VPLS is not a point-to-point service. It is a bridged service that provides VPN connectivity to CE devices. VPLS allows for broadcast communication between CE devices, which means that multiple devices can communicate with each other simultaneously.

A PE device in a VPLS network must support MAC Learning, flooding packets sent to an unknown MAC address, and packet forwarding. Proxy-ARP is not a required operation for a PE device in a VPLS network.

The correct answer is 1 because MPLS LSP's (Label Switched Paths) are used to establish connections between Provider Edge (PE) routers in a VPLS (Virtual Private LAN Service) network. In this case, only one MPLS LSP is required in each direction between PE1 and PE2 to support 100 VPLS domains across the network. This means that a single path can be used to carry traffic for all 100 VPLS domains, making it more efficient and reducing the number of LSP's needed.

The TCP/IP Port number is not a method for differentiating between logical layer-2 connections across a shared physical media. Layer-2 connections are typically differentiated using methods such as Ethernet VLAN's, ATM VPI/VCI, and Frame-relay DLCI. TCP/IP Port numbers are used at the layer-4 (transport layer) of the TCP/IP protocol stack to differentiate between different applications or services running on a device.

All of the given statements are true. Frames should be switched based on the destination MAC address to ensure that they reach the intended recipient. Frames should also be sent only to the Provider Edge (PE) attached to the destination when possible, as this helps in efficient routing and reduces unnecessary network traffic. Finally, frames should be flooded as little as possible to minimize network congestion and optimize the use of network resources. Therefore, all of the statements are correct.

Both RSVP and LDP signalled LSP's will support VPLS transport. RSVP (Resource Reservation Protocol) and LDP (Label Distribution Protocol) are both used in MPLS (Multiprotocol Label Switching) networks to establish and maintain Label Switched Paths (LSP's). VPLS (Virtual Private LAN Service) is a technology that allows the extension of a LAN over a wide area network using MPLS. Therefore, both RSVP and LDP signalled LSP's can be used to support VPLS transport.

Duplex mismatch refers to a situation where two devices connected by an ethernet link have different settings for their duplex mode. This can lead to poor performance, collisions, and connectivity issues because one device may be transmitting data while the other is receiving, causing data to be lost or corrupted. It is a common problem that occurs when one device is set to full duplex mode while the other is set to half duplex mode.

VPLS (Virtual Private LAN Service) operates in a point-to-multipoint mode, which means it allows multiple sites to be connected together in a single bridged domain. On the other hand, L2VPN (Layer 2 Virtual Private Network) functions only as point-to-point, meaning it can only establish a connection between two sites. This key difference makes VPLS more suitable for scenarios where multiple sites need to communicate with each other as if they were on the same LAN, while L2VPN is more appropriate for connecting two specific sites together.

The spanning-tree protocol is used in a network to prevent routing loops in networks with redundant switched paths. This protocol helps to create a loop-free logical topology by selecting a root bridge and blocking certain redundant paths. By doing so, it ensures that packets are not endlessly forwarded in a loop, which can cause network congestion and instability. Instead, it establishes a single active path between network devices, improving network efficiency and reliability.

Rapid Spanning Tree Protocol (RSTP) is an improvement over the original Spanning Tree Protocol (STP) which aims to provide faster convergence in network topologies. While RSTP does choose a valid path between nodes, it does not necessarily choose the optimal path. The main goal of RSTP is to eliminate unnecessary blocking of ports and reduce the convergence time, rather than finding the absolute shortest path. Therefore, the statement that RSTP chooses the optimal path is false.

The root-bridge in a network is elected based on the Bridge Priority value. In this case, both R1 and R3 have the same priority of 32768. However, the tiebreaker is the MAC Address, and R3 has the lowest MAC Address among all the routers. Therefore, R3 would be elected as the root-bridge.

To achieve fully meshed connectivity between 5 customer sites, each site needs to be connected to every other site. In a fully meshed network, each site has a direct connection to every other site, resulting in a total of (n * (n-1))/2 connections, where n is the number of sites. In this case, with 5 customer sites, the calculation would be (5 * (5-1))/2 = 10 connections. Therefore, 10 L2VPN's are required to achieve fully meshed connectivity between the 5 customer sites.

The Spanning Tree Protocol calculates the path cost based on the link bandwidth. This means that it considers the capacity or speed of the links when determining the best path for data transmission. By taking into account the link bandwidth, the protocol aims to ensure efficient and optimal utilization of the network resources. It prioritizes paths with higher link bandwidth, as they can handle more traffic and provide faster data transmission.

If Port A is configured for 100m, Full Duplex and Port B is configured for Auto-detect, it will result in a duplex mismatch on the ethernet link. This is because Port A is set to operate at a specific speed and in full duplex mode, while Port B is set to automatically detect the speed and duplex mode. This mismatch in configuration can lead to communication issues and performance degradation on the link.

VPLS, or Virtual Private LAN Service, supports only Ethernet connections. This means that it can be used to connect Ethernet-based devices or networks together, providing a virtual LAN over a wide area network. VPLS does not support ATM or Serial connections, limiting its compatibility to Ethernet-based systems only.

The correct answer is 802.3ad. This specification, also known as Link Aggregation Control Protocol (LACP), defines the method for combining multiple physical network links into a single logical link. It allows for increased bandwidth, redundancy, and load balancing across the aggregated links, improving network performance and reliability.

The priority value determines the likelihood of a switch becoming the root bridge in a spanning tree network. The switch with the lowest priority value will be elected as the root bridge. In this case, R4 has the highest priority value of 32768, which means it has the lowest priority compared to the other switches. Therefore, R4 would be elected as the root bridge.

The Hello Timer affects how often the Spanning Tree Root Bridge will send configuration BPDU's. The Hello Timer is a timer used in the Spanning Tree Protocol (STP) to determine how often the Root Bridge should send Hello BPDUs to other switches in the network. These Hello BPDUs are used to establish and maintain the network topology and elect the Root Bridge. By sending Hello BPDUs at regular intervals, the Root Bridge ensures that all switches in the network are aware of its presence and can make necessary adjustments to the network topology if needed.

Kompella style L2VPN's use BGP as the signalling protocol because it is a Layer 3 VPN technology that uses BGP to distribute VPN routes between the PE routers. On the other hand, Martini style L2VPN's use LDP as the signalling protocol because it is a Layer 2 VPN technology that uses LDP to establish the pseudowires between the PE routers.