What is the role of a Label Edge Router (LER) in MPLS?

What is the role of a Label Edge Router (LER) in MPLS?

• A. It establishes BGP sessions
• B. It handles label distribution
• C. It forwards packets within the core network
• D. It aggregates multiple data flows

Answer: (B)

The role of a Label Edge Router (LER) in Multiprotocol Label Switching (MPLS) is primarily to handle label distribution. In an MPLS network, the LER serves as a crucial point where packets enter or exit the MPLS domain. When a packet arrives at an LER, it encodes the necessary information into labels, which are used to facilitate faster forwarding through the network by enabling the routers to make forwarding decisions based on the label rather than looking up long network addresses. The LER is responsible for assigning labels to incoming packets, which it does by examining the packet's headers and determining the appropriate label according to the specified forwarding equivalence class (FEC). It also manages the distribution of these labels to upstream Label Switch Routers (LSRs). This process ensures that packets can be quickly and efficiently routed through the MPLS network without needing to analyze complex routing tables at each hop, significantly increasing performance and reducing latency in the transfer of data. The other options indicate different functions that do not align with the specific responsibilities of an LER. For instance, establishing BGP sessions pertains more to the role of border routers exchanging routing information rather than label distribution. Likewise, forwarding packets within the core network is typically the role of

The role of a Label Edge Router (LER) in Multiprotocol Label Switching (MPLS) is primarily to handle label distribution. In an MPLS network, the LER serves as a crucial point where packets enter or exit the MPLS domain. When a packet arrives at an LER, it encodes the necessary information into labels, which are used to facilitate faster forwarding through the network by enabling the routers to make forwarding decisions based on the label rather than looking up long network addresses.

The LER is responsible for assigning labels to incoming packets, which it does by examining the packet's headers and determining the appropriate label according to the specified forwarding equivalence class (FEC). It also manages the distribution of these labels to upstream Label Switch Routers (LSRs). This process ensures that packets can be quickly and efficiently routed through the MPLS network without needing to analyze complex routing tables at each hop, significantly increasing performance and reducing latency in the transfer of data.

The other options indicate different functions that do not align with the specific responsibilities of an LER. For instance, establishing BGP sessions pertains more to the role of border routers exchanging routing information rather than label distribution. Likewise, forwarding packets within the core network is typically the role of