Traditionally, a cell phone remains on a single primary mobile network operator (MNO) as long as it is available, and uses another MNO only when the primary is unavailable and a roaming agreement exists. Multi-network access (MNA), where a cell phone can use any one of multiple MNOs at any point in space and time, can greatly increase cellular network capacity. This paper investigates how much MNA can improve cellular network capacity in the context of a multi-operator mobile virtual network operator (MO-MVNO), such as Google's Project Fi, and explores how the capacity gain varies with the MNOs' resource allocation scheme, and the MO-MVNO's market share and MNO selection algorithm. Simulations show that MNA can expand cellular network capacity by as much as 80% without additional spectrum or infrastructure. Resource allocation schemes affect both total capacity gain and how the gain is shared among operators. We also show that an MNO selection algorithm that is rational for an individual MO- MVNO subscriber can hurt the overall performance of both the MO-MVNO and MNOs.

Mobility and multihoming have become the norm in Internet access, e.g. smartphones with Wi-Fi and LTE, and connected vehicles with LTE and DSRC links that change rapidly. Mobility creates challenges for active session continuity when provider-aggregatable locators are used, while multihoming brings opportunities for improving resiliency and allocative efficiency. This paper proposes a novel migration protocol, in the context of the eXpressive Internet Architecture (XIA), the XIA Migration Protocol. We compare it with Mobile IPv6, with respect to handoff latency and overhead, flow migration support, and defense against spoofing and replay of protocol messages. Handoff latencies of the XIA Migration Protocol and Mobile IPv6 Enhanced Route Optimization are comparable and neither protocol opens up avenues for spoofing or replay attacks. However, XIA requires no mobility anchor point to support client mobility while Mobile IPv6 always depends on a home agent. We show that XIA has significant advantage over IPv6 for multihomed hosts and networks in terms of resiliency, scalability, load balancing and allocative efficiency. IPv6 multihoming solutions either forgo scalability (BGP-based) or sacrifice resiliency (NAT-based), while XIA's fallback-based multihoming provides fault tolerance without a heavy-weight protocol. XIA also allows fine-grained incoming load-balancing and QoS-matching by supporting flow migration. Flow migration is not possible using Mobile IPv6 when a single IPv6 address is associated with multiple flows. From a protocol design and architectural perspective, the key enablers of these benefits are flow-level migration, XIA's DAG-based locators and self-certifying identifiers.

We model the Internet as a collection of Internet Service Providers (ISPs) that transit and peer to meet an exogenous demand for the transport of IP traffic among an arbitrary set of cities. The prices of bandwidth and of transit are also exogenous. ISPs are assumed to behave rationally and selfishly and therefore they provision the network that maximizes their own profit regardless of how expensive the overall network becomes. We call optimal to a network that ISPs would build if they cooperated to reduce overall provisioning costs; and we call inefficiency cost the additional cost to provision a network at Nash equilibrium relative to the provisioning cost of an optimal network. We show that inefficiency cost is primarily related to transit agreements. In fact, in a world where only peering agreements exist there is no inefficiency cost. However, networks with only peering agreements forgo the efficiencies of traffic aggregation. Transit agreements help reduce provisioning costs by realizing benefits from economies of scale. We show, by example, that there exist Nash networks that are strictly more expensive than optimal networks even when ISPs choose transit prices and therefore the market to provision communication networks with interconnection agreements designed they way the are today is inefficient. We show that inefficiency cost may be reduced, for example, by enforcing side payments between ISPs. We conclude with an analysis of the difficulties a regulator would face in endeavoring to move a market from am inefficient Nash equilibrium to optimality.

As our economy and critical infrastructure increasingly relies on the Internet, the insecurity of the underlying border gateway routing protocol (BGP) stands out as the Achilles heel. Recent misconfigurations and attacks have demonstrated the brittleness of BGP. Securing BGP has become a priority.In this paper, we focus on a viable deployment path to secure BGP. We analyze security requirements, and consider tradeoffs of mechanisms that achieve the requirements. In particular, we study how to secure BGP update messages against attacks. We design an efficient cryptographic mechanism that relies only on symmetric cryptographic primitives to guard an ASPATH from alteration, and propose the Secure Path Vector (SPV) protocol. In contrast to the previously proposed S-BGP protocol, SPV is around 22 times faster. With the current effort to secure BGP, we anticipate that SPV will contribute several alternative mechanisms to secure BGP, especially for the case of incremental deployments.

The authors describe a method for fully distributed authentication using public key cryptography within the Kerberos ticket framework. By distributing most of the authentication workload away from the trusted intermediary and to the communicating parties, significant enhancements to security and scalability can be achieved as compared to Kerberos V5. Privacy of Kerberos clients is also enhanced. A working implementation of this extended protocol has been developed, and a migration plan is proposed for a transition from traditional to public key based Kerberos.