Motivated by our experiences operating a global WAN, we argue that SDN's reliance on infrastructure external to the data plane has substantially complicated the challenge of maintaining high availability. We propose a new decentralized SDN (dSDN) architecture in which SDN control logic instead runs within routers, eliminating the control plane's reliance on external infrastructure and restoring fate-sharing between control and data planes. We present dSDN as a simpler approach to realizing the benefits of SDN in the WAN. Despite its much simpler design, we show that dSDN is practical from an implementation viewpoint, and outperforms centralized SDN in terms of routing convergence and SLO impact.

We present the design of Espresso, Google's SDN-based Internet peering edge routing infrastructure. This architecture grew out of a need to exponentially scale the Internet edge cost-effectively and to enable application-aware routing at Internet-peering scale. Espresso utilizes commodity switches and host-based routing/packet processing to implement a novel fine-grained traffic engineering capability. Overall, Espresso provides Google a scalable peering edge that is programmable, reliable, and integrated with global traffic systems. Espresso also greatly accelerated deployment of new networking features at our peering edge. Espresso has been in production for two years and serves over 22% of Google's total traffic to the Internet.

Content-Centric Networking (CCN) is a communication paradigm that emphasizes content distribution. Named-Data Networking (NDN) is an instantiation of CCN, a candidate Future Internet Architecture. NDN supports human-readable content naming and router-based content caching which lends itself to efficient, secure, and scalable content distribution. Because of NDN's fundamental requirement that each content object must be signed by its producer, fragmentation has been considered incompatible with NDN since it precludes authentication of individual content fragments by routers. The alternative is to perform hop-by-hop reassembly, which incurs prohibitive delays. In this paper, we show that secure and efficient content fragmentation is both possible and even advantageous in NDN and similar content-centric network architectures that involve signed content. We design a concrete technique that facilitates efficient and secure content fragmentation in NDN, discuss its security guarantees and assess performance. We also describe a prototype implementation and compare performance of cut-through with hop-by-hop fragmentation and reassembly.

Named data networking (NDN) is a new networking paradigm using named data instead of named hosts for communication. Implementation of scalable NDN packet forwarding remains a challenge because NDN requires fast variable-length hierarchical name-based lookup, per-packet data plane state update, and large-scale forwarding tables. In this paper, we review various design options for a hash table-based NDN forwarding engine and propose a design that enables fast forwarding while achieving DoS (Denial-of-Service) resistance. Our forwarding engine features (1) name lookup via hash tables with fast collision-resistant hash computation, (2) an efficient FIB lookup algorithm that provides good average and bounded worst-case FIB lookup time, (3) PIT partitioning that enables linear multicore speedup, and (4) an optimized data structure and software prefetching to maximize data cache utilization. We have implemented an NDN data plane with a software forwarding engine on an Intel Xeon-based line card in the Cisco ASR 9000 router. By simulation with names extracted from the IR-Cache traces, we demonstrate that our forwarding engine achieves a promising performance of 8.8 MPPS and our NDN router can forward the NDN traffic at 20 Gbps or higher.

Named data networking (NDN) is a new networking paradigm using named data instead of named hosts for communication. Implementation of scalable NDN packet forwarding remains a challenge because NDN requires fast variable-length hierarchical name-based lookup, per-packet data plane state update, and large-scale forwarding tables. We have designed and implemented an NDN data plane with a software forwarding engine on an Intel Xeon-based line card in a Cisco ASR9000 router. In order to achieve high-speed forwarding, our design features (1) name lookup via hash tables with fast collision-resistant hash computation, (2) an efficient and secure FIB lookup algorithm that provides good average and bounded worst-case FIB lookup time, (3) PIT partitioning that enables linear multi-core speedup, and (4) an optimized data structure and software prefetching to maximize data cache utilization. In this demonstration, we showcase our NDN router implementation on the ASR9000 and demonstrate that it can forward real NDN traffic at 20Gbps or higher.

In Named Data Networking (NDN), forwarding lookup is based on tokenized variable-length names instead of fixed-length host addresses, and therefore it requires a new approach for designing a fast packet forwarding lookup engine. In this paper, we propose a design of an NDN software forwarding lookup engine based on hash tables and evaluate its performance with different design options. With a good hash function and table design combined with Bloom filters and data prefetching, we demonstrate that our design reaches about 1.5MPPS with a single thread on an Intel 2.0GHz Xeon processor.

We present and evaluate an optimal scheduling algorithm for inserting secondary content for improving resource utilization in VoD systems. The algorithm runs in polynomial time, and is optimal with respect to the total bandwidth usage over the merging interval. We present constraints on content insertion which make the overall QoS of the delivered stream acceptable, and show how our algorithm can satisfy these constraints. We discuss dynamic scenarios with user arrivals and interactions, and show by simulations that content insertion reduces the channel bandwidth requirement to almost half.