Accommodating the recent changes that cisco
(MPLS is described in more detail in a later section.) Based upon Cisco's proprietary tag-switching protocol, the IETF is defining MPLS as a vendor-independent protocol.
(At the time of this writing, the MPLS definitions were not quite complete.) Although the two protocols have much in common, differences between them prevent tag-switching devices from interacting directly with MPLS devices. However, this article starts with a comparison of terms involved with tag switching and MPLS.
Because each of the routers between Stations A and B could switch the frame based upon content in the LFIB and did not need to perform usual routing operation, the frame was handled more quickly.
MPLS relies on two principal components: forwarding and control.
Table: Equivalency Table for Cisco Tag Switching and IETF MPLS Terms compares tag switching with MPLS terminology. Cisco TDP and MPLS Label Distribution Protocol (LDP) are nearly identical in function, but they use incompatible message formats and some different procedures.
Cisco is changing from TDP to a fully compliant LDP.
Each of the subsequent routers handles the frame in a similar manner until the frame reaches the egress LSR.
The frame generated by Station A follows the standard Ethernet format with a normal Layer 2 header followed by a Layer 3 header.Details about MPLS's forwarding and control mechanisms follow.The forwarding paradigm employed by MPLS is based on the notion of label swapping.When a packet with a label is received by an LSR, the switch uses the label as an index in its label information base (LFIB).Each entry in the LFIB consists of an incoming label and one or more subentries (of the form outgoing label, outgoing interface, outgoing link-level information).