Determining a Path in SR-TE with Limited Network Topology Knowledge

B.

When implementing SR-TE (Segment Routing - Traffic Engineering) with a head-end, a path computation engine can be used to determine the path from the head-end to a tail-end router, even with little information on the network topology. Therefore, the correct answer is B, path computation engine.

SR-TE is a technology that allows the network operator to specify the path that traffic should follow through the network. It is based on the concept of segment routing, which uses a source routing paradigm to steer packets through the network. In SR-TE, the path that a packet takes through the network is determined by a set of segment identifiers (SIDs) that are encoded in the packet header.

To determine the path from the head-end to a tail-end router, a path computation engine (PCE) is used. A PCE is a network element that computes paths through the network based on various constraints, such as bandwidth, latency, or route diversity. The PCE receives information about the network topology and the available resources from various sources, such as link-state routing protocols or network management systems.

The PCE uses this information to compute a path that satisfies the constraints specified by the operator. The path is then encoded as a set of SIDs, which are programmed into the packet header by the head-end router. As the packet traverses the network, each router uses the SIDs to forward the packet along the path specified by the PCE.

In summary, a path computation engine is used to determine the path from the head-end to a tail-end router when implementing SR-TE with a head-end, with little information on the network topology. The PCE computes a path that satisfies the operator's constraints and encodes it as a set of SIDs in the packet header.