g, EVPN, etc.) that can be exploited for xHaul packet transport. The choice between these is often influenced more by the transport provider and equipment vendor histories than by the true pros and cons of the technologies. Generally, there are a number of different kinds of transport providers offering xHaul services: The first kind is a metro connectivity provider, who was originally PDH/SDH-based, then perhaps moved to asynchronous transfer mode (ATM), but has now overwhelm- ingly adopted Ethernet. Such service providers have enthusiastically embraced Carrier Ethernet, as espoused by the MEF forum, in order to provide SLA-based services. A second type of service provider covers large geographic regions, such as whole coun- tries, or even worldwide service. Such service providers are traditionally MPLS-based, more specifically supporting the L3VPN (RFC 4364) variety of MPLS, perhaps supple- mented with pseudowire services (RFC 3985). A third kind of provider is typified by electric utilities, who, having excess fiber plant, are willing to lease it at reasonable prices. Since these service providers are actually not networking experts, they tend to offer wavelength service, or piggybacking over whatever mechanisms they already have in place, e.g. flat IP or vanilla MPLS. Finally, there are those operators with an in-house transport division, whose technology toolkits vary according to their history. Accordingly, there are two traditionally opposing worlds of backhauling based on Carrier Ethernet and MPLS, with a newer possibility of pure IP networks. MPLS networks, with their local labels rather than network-unique addresses, tend to scale better, and thus second aggregation networks are most often MPLS-based. Ethernet technologies can be scaled up using Provider Backbone Bridge Network (PBBN) techniques ((III) gl JNB/eNB gNB DU gNB CU gNB DU gNB(v)CU Access Access Mobile ((III)) IP-TNL network IP-TNL Agg Node Aggregation gNB DU Pop/CO network Mobile IP-TNL P-TNL gNB(v)CU Network Agg Node S1-C/U gNB(v)CU IP-TNL 