609 research outputs found
Efficient hardware architecture for fast IP address lookup
A multigigabit IP router may receive several millions packets per second from each input link. For each packet, the router needs to find the longest matching prefix in the forwarding table in order to determine the packet's next-hop. In this paper, we present an efficient hardware solution for the IP address lookup problem. We model the address lookup problem as a searching problem on a binary-trie. The binary-trie is partitioned into four levels of fixed size 255-node subtrees. We employ a hierarchical indexing structure to facilitate direct access to subtrees in a given level. It is estimated that a forwarding table with 40K prefixes will consume 2.5Mbytes of memory. The searching is implemented using a hardware pipeline with a minimum cycle of 12.5ns if the memory modules are implemented using SRAM. A distinguishing feature of our design is that forwarding table entries are not replicated in the data structure. Hence, table updates can be done in constant time with only a few memory accesses.published_or_final_versio
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Blueswitch: Enabling provably consistent configuration of network switches
Previous research on consistent updates for distributed network
configurations has focused on solutions for centralized networkconfiguration
controllers. However, such work does not address
the complexity of modern switch datapaths. Modern commodity
switches expose opaque configuration mechanisms, with minimal
guarantees for datapath consistency and with unclear configuration
semantics. Furthermore, would-be solutions for distributed consistent
updates must take into account the configuration guarantees
provided by each individual switch – plus the compositional problems
of distributed control and multi-switch configurations that
considerably transcend the single-switch problems. In this paper,
we focus on the behavior of individual switches, and demonstrate
that even simple rule updates result in inconsistent packet switching
in multi-table datapaths. We demonstrate that consistent configuration
updates require guarantees of strong switch-level atomicity
from both hardware and software layers of switches – even in a
single switch. In short, the multiple-switch problems cannot be
reasonably approached until single-switch consistency can be resolved.
We present a hardware design that supports a transactional configuration
mechanism, and provides packet-consistent configuration:
all packets traversing the datapath will encounter either the
old configuration or the new one, and never an inconsistent mix of
the two. Unlike previous work, our design does not require modifications
to network packets. We precisely specify the hardwaresoftware
protocol for switch configuration; this enables us to prove
the correctness of the design, and to provide well-specified invariants
that the software driver must maintain for correctness. We
implement our prototype switch design using the NetFPGA-10G
hardware platform, and evaluate our prototype against commercial
off-the-shelf switches.This work was jointly supported by the Defense Advanced Research
Projects Agency (DARPA) and the Air Force Research Laboratory
(AFRL), under contract FA8750-11-C-0249. The views,
opinions, and/or findings contained in this article/presentation are
those of the author/ presenter and should not be interpreted as representing
the official views or policies, either expressed or implied,
of the Department of Defense or the U.S. Government. We also acknowledge
the support of the UK EPSRC for contributing to parts
of our work, through grant EP/H040536/1. Additional data related
to this publication is available at the http://www.cl.cam.ac.
uk/research/srg/netfpga/blueswitch/ data repository.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ANCS.2015.711011
MLET: A Power Efficient Approach for TCAM Based, IP Lookup Engines in Internet Routers
Routers are one of the important entities in computer networks specially the
Internet. Forwarding IP packets is a valuable and vital function in Internet
routers. Routers extract destination IP address from packets and lookup those
addresses in their own routing table. This task is called IP lookup. Internet
address lookup is a challenging problem due to the increasing routing table
sizes. Ternary Content-Addressable Memories (TCAMs) are becoming very popular
for designing high-throughput address lookup-engines on routers: they are fast,
cost-effective and simple to manage. Despite the TCAMs speed, their high power
consumption is their major drawback. In this paper, Multilevel Enabling
Technique (MLET), a power efficient TCAM based hardware architecture has been
proposed. This scheme is employed after an Espresso-II minimization algorithm
to achieve lower power consumption. The performance evaluation of the proposed
approach shows that it can save considerable amount of routing table's power
consumption.Comment: 14 Pages, IJCNC 201
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Internet Infrastructures for Large Scale Emulation with Efficient HW/SW Co-design
Connected systems are becoming more ingrained in our daily lives with the advent of cloud computing, the Internet of Things (IoT), and artificial intelligence. As technology progresses, we expect the number of networked systems to rise along with their complexity. As these systems become abstruse, it becomes paramount to understand their interactions and nuances. In particular, Mobile Ad hoc Networks (MANET) and swarm communication systems exhibit added complexity due to a multitude of environmental and physical conditions. Testing these types of systems is challenging and incurs high engineering and deployment costs. In this work, we propose a scalable MANET emulation framework using virtualized internet infrastructures that generalizes an assortment of application spaces with diverse attributes. We then quantify the architecture using various evaluation techniques to determine both feasibility and scalability. Finally, we developed a hardware offload engine for virtualized network systems that builds upon recent work in the field
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