 ity, maintenance or operational reasons, and for resiliency. This requires flexibility and scalability in how access reaches the edge service functions. It also needs to be able to move dynamically with the movement of a VNF instance. Network Edge 12.5.1 ACCESS SCALE AND RESILIENCY Current access wireline access technologies use an Ethernet link layer and aggregate or separate customers using VLAN tagging. For large networks such as AT&Ts, the scale can be enormous. For example, at AT&T, for enterprise and infrastructure, there are about 400,000 point-to-point and multipoint Ethernet access connections used for mobile cell site backhaul, enterprise inter- site connectivity and connectivity to IP-edge services. There are roughly 16 million broadband connections from DSL and PON aggregation nodes and these are groomed using VLANs. These access connections are spread across almost 5000 access offices and points of presence domes- tically and internationally. They need to be groomed and connected to the edge service VNFs residing in hundreds of AIC zones (see Chapter 4) that could potentially grow over time to thousands. There is also a need to groom these connections into bundles rather than signal each one sepa- rately through the control plane. For example, carrying the 16 million broadband connections as individually signaled MPLS psuedowires would increase the existing MPLS signaled state in the network by about a factor of 50. In addition to scale, the connectivity into the cloud needs to be resilient. Interoffice rerouting over a diverse transport topology is provided by distributed MPLS routing protocols (see Chapter 13). However, the new generation of merchant leaf edge switches are fixed form factor chasses. To overcome the time to repair these potential single points of failure, access nodes (e.g., optical line terminals [OLTs] and digital subscriber line access multiplexers [DSLAMs]; see Chapter 11) will be connected to two edge switches, with the pair of links acting a single logical link from the persp