MPLS (Multiprotocol Label Switching) and SR-MPLS (Segment Routing MPLS) are both technologies used for packet forwarding in computer networks.

MPLS is a widely used protocol that uses labels to forward packets along a network path. The labels are assigned to each packet when it enters the MPLS network and are used to determine the forwarding path. The forwarding path is determined by the label stack, which is a series of labels that the packet carries.

SR-MPLS, on the other hand, is an extension of MPLS that uses a source-based routing approach. It assigns a segment identifier to each packet, which is used to determine the forwarding path. This approach allows for greater flexibility and scalability compared to traditional MPLS.

One of the key differences between MPLS and SR-MPLS is the way they handle traffic engineering. MPLS uses a set of protocols called RSVP-TE (Resource Reservation Protocol – Traffic Engineering) to manage traffic flow and ensure efficient use of network resources. In contrast, SR-MPLS uses the segment routing approach to dynamically steer traffic along a network path that meets specific traffic engineering requirements.

Another difference between the two technologies is the way they handle label stacks. MPLS uses a hierarchical label stack, which can lead to label exhaustion in large networks. SR-MPLS uses a flat label stack, which simplifies network design and management.

In summary, while MPLS and SR-MPLS both use label switching for packet forwarding, SR-MPLS offers greater flexibility and scalability by using a source-based routing approach and a flat label stack.

source: ChatGPT