 Protocol (TWAMP) RFC 5357. MPLS-TP defines an extensive set of performance monitoring functions (RFC 6374 and RFC 6375). 6.6.5.4.8 Security 5G presents several new security challenges related to the transport network. The most obvi- ous one is the radical change in trust model due to openness of the core toward third-party applications. Related to this are the new use cases and novel network architecture based on distributed telco cloud. Higher number of cells, higher data rates, and lower latencies all further impact security solutions. Focusing on the transport network we find that performance issues lurk behind many of these challenges. Denial of service based on overloading physical bit per second rates, forwarding packet per second rate, cryptographic algorithm resources, or RAN-situated virtualization or computation infrastructure all need to be addressed in order to avoid bot- tlenecking the RAN or 5GC resources such as UPF. This involves both upgrading raw per- formance to handle worst case scenarios, and detecting and blocking threats at the edge. However, traditional Distributed Denial-of-Service (DDoS) mitigation approaches may be powerless against truly large-scale infected massive MTC attacks, and the conventional approach of redirecting suspicious packets to scrubbing centers may be irrelevant because of latency constraints. RAN transport protocols play a part here as well. In the forwarding plane it should be noted that while IP and Ethernet packets have SAs, and thus allow for packet-by-packet source authentication, MPLS label stacks contain neither destination nor SAs, and hence necessarily rely on lower or higher layers for this function. In the control plane IP and vanilla MPLS conventionally rely on distributed routing protocols, which facilitate certain 6.6 Transport Network attack vectors, while Carrier Ethernet and MPLS-TE traffic steering are configured from a central site in SDN fashion, which exposes them to different threats. Attacks involving undermining virtualized RAN infrastructure