The same upstream LSR attached to Interface 2 might also send MPLS packets with labels of 18 or 105, for example, and those packets would be switched differently than the packets with a label of 1434.
Mar 21, 2018 · Picture 3: MPLS Forwarding Table of PE1 Router The label 21 is the inner (VPN) label, added by the PE1 router. It is used to identify the correct next-hop (10.0.0.18) on the PE2 router for Customer A data traffic. The inner label is kept untouched by the P router. MPLS VPN is a family of methods for using multiprotocol label switching (MPLS) to create virtual private networks (VPNs). MPLS VPN is a flexible method to transport and route several types of network traffic using an MPLS backbone. There are three types of MPLS VPNs deployed in networks today: 1. Point-to-point (Pseudowire) 2. The same upstream LSR attached to Interface 2 might also send MPLS packets with labels of 18 or 105, for example, and those packets would be switched differently than the packets with a label of 1434. Apr 23, 2020 · The MPLS label is between the link layer header and the network layer header, and allows use of any link layer protocol. Figure 2-3 shows position of an MPLS label and fields in the MPLS label. Figure 2-3 MPLS label encapsulation format An MPLS label contains the following fields: As packets are forwarded in a label-switching framework, MPLS routers encapsulate the packets with special headers called labels. A label basically tells the router which LSP it belongs to. The router can then use the ingress port and the LSP information to determine where the next hop in the LSP is. You can actually add …
the label mappings at each LSR on the path using some form of management such as SNMP control of the MIBs. 2.1.2 Tunnels and Label Stacks A key feature of MPLS, especially when considering VPNs, is that once the labels required for an LSP have been exchanged between the LSRs that support the LSP,
MPLS VPNs use an IGP and LDP to learn routes and labels, specifically to learn the label values to use in the outer label. To link the concepts together, it can be helpful to think of the full control plane process related to the LSP used for the outer label, particularly Step 4 onward:
• MPLS labels can also be stacked multiple times. • The top label is used to control the delivery of the packet. • When destination is reached, the top label is removed (or “popped”), and the second label takes over to direct the packet further. • Some common stacking applications are: • VPN/Transport services, which use an inner
May 17, 2013 · This label is the only label that is being looked at by the receiving PE router. In theory, you only need a single label to identify the VRF for the destination prefix, and then you can do an IP lookup to further process the packet. This is what the “MPLS VPN Per VRF Label” does.