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Switch-Off Transients in Cellular Access Networks with Sleep Modes
Get PDFThe introduction of sleep modes in the operations
of base stations is today considered one of the most promising
approaches to reduce the energy consumption of cellular access
networks. Several papers have considered this option, assuming
that the switch-on and switch-off transients are of negligible
duration. In this paper we study the switch-off transients for one
cell, investigating the amount of time necessary to implement the
switch-off, while allowing terminals to handover to a new BS
without overloading the signaling channels, and we show that
the switch-off durations have a marginal impact on the energy
savings achievable with the sleep mode scheme.TRUEpu
Reaching approximate Wardrop equilibrium at reduced costs of link state updates
Get PDFSeveral routing protocols have been proposed to
take advantage of the dynamic metrics on links such as link
delays, queueing lengths, and available link bandwidths. Wardrop
routing, QOS routing are few such example routing protocols.
Even when these protocols can be shown to offer convergence
properties without oscillations, the protocols have not been widely
adopted for a number of reasons. The expected cost of keeping
the link metrics updated at various nodes in the network being
one of them.
In this paper, we study the problem of reducing the cost of
propagating dynamic link metrics while keeping the quality of
paths within a margin of error. We propose a simple technique
of threshold-based metric propagation that is shown, through
analysis and simulations, to offer bounded guarantees on path
quality while significantly reducing the cost of propagating
the dynamic link metric information. Our results indicate that
threshold based updates can reduce the number of link updates
by up to 90-95% in some cases.TRUEpu
LFA Applicability in Service Provider Networks
No full textThe standardization topics related to Pierre Francois’s activities for the period September-December 2011 in the Routing Area relate to «IP Fast Reroute». An IETF working group document («LFA applicability in SP networks», draft-ietf-rtgwg-lfa-applicability-04) co-authored with Clarence Filsfils, distinguished engineer at Cisco Systems, underwent working group last call in the RTGWG working group. This draft presents an analysis of the applicability of an IP Fast Reroute technique called «Loop-free alternates» in Internet Service Provider Networks. This work has been performed in collaboration with Cisco Systems, France Telecom - Orange, AT&T, and Deutsche Telekom.In this draft, we analyze the applicability of LoopFree Alternates in both core and access parts of Service Provider networks. We provide design guides to favor their applicability where relevant, typically in the access part of the network.Network Working GroupInternet Engineering Task Force (IETF)pu
Power save analysis of cellular networks with continuous connectivity
Get PDFIn this paper, we analyze the power save and its
impact on web traffic performance when customers adopt the
continuous connectivity paradigm. To this aim, we provide
a model for packet transmission and cost. We model each
mobile user’s traffic with a realistic web traffic profile, and study the aggregate behavior of the users attached to a
base station by means of a processor-shared queueing system.
In particular, we evaluate user access delay, download time
and expected economy of energy in the cell. The model is
validated through packet-level simulations. Our model shows
that dramatic energy save can be achieved by both mobile users and base stations, e.g., as much as 70% of the energy cost due to packet transmission at the base station.TRUEpu
B-Neck – A Distributed and Quiescent Max-min Fair Algorithm
Get PDFIn this brief announcement we propose B-Neck, a max-min
fair distributed algorithm that is also quiescent. As far as we
know, B-Neck is the �rst max-min fair distributed algorithm
that does not require a continuous injection of control tra�c
to compute the rates. When changes occur, a�ected sessions
are asynchronously informed, so they can start the process
of computing their new rate (i.e., sessions do not need to
poll the network for changes). The correctness of B-Neck is
formally proved, and extensive simulations are conducted.
In them it is shown that B-Neck converges relatively fast
and behaves nicely in presence of sessions arriving and de-
parting.TRUEpu
An FTP Application Layer Gateway (ALG) for IPv6-to-IPv4 Translation
Get PDFFTP64 was adopted by the BEHAVE working group for an application layer gateway that makes it possible for an IPv6 FTP client to connect and exchange files with an IPv4 FTP server. It has been published as RFC 6384 in October 2011. This RFC specifies an application layer gateway (ALG) that works together with NAT64 to allow the FTP protocol to work when FTP clients that only have IPv6 connectivity connect to FTP servers that only have IPv4 connectivity and don’t understand the newer commands that are used with IPv6. The FTP64 ALG modifies the commands that the FTP client sends to the FTP server and the responses from the server to the client.The File Transfer Protocol (FTP) has a very long history, and despite the fact that today other options exist to perform file transfers, FTP is still in common use. As such, in situations where some client computers only have IPv6 connectivity while many servers are still IPv4-only and IPv6-to-IPv4 translators are used to bridge that gap, it is important that FTP is made to work through these translators to the best possible extent. FTP has an active and a passive mode, both as original commands that are IPv4-specific and as extended, IP version agnostic commands. The only FTP mode that works without changes through an IPv6-to-IPv4 translator is extended passive. However, many existing FTP servers do not support this mode, and some clients do not ask for it. This document specifies a middlebox that may solve this mismatch.Internet Engineering Task Force (IETF)pu
CIPT: Using Tuangou to Reduce IP Transit Costs
Get PDFA majority of ISPs (Internet Service Providers) support connectivity to the entireInternet by transiting their traffic via other providers. Although the transit prices per Mbps decline steadily, the overall transit costs of these ISPs remain high or even increase, due to the traffic growth. The discontent of the ISPs with the high transit costs has yielded notable innovations such as peering, content distribution networks, multicast, and peer-to-peer localization. While the above solutions tackle the problem by reducing the transit traffic, this paper explores a novel approach that reduces the transit costs without altering the traffic. In the proposed CIPT (Cooperative IP Transit), multiple ISPs cooperate to jointly purchase IP (Internet Protocol) transit in bulk. The aggregate transit costs decrease due to the economies-of-scale effect of typical subadditive pricing as well as burstable billing: not all ISPs transit their peak traffic during the same period. To distribute the aggregate savings among the CIPT partners, we propose Shapley-value sharing of the CIPT transit costs. Using public data about IP traffic and transit prices, we quantitatively evaluate CIPT and show that significant savings can be achieved, both in relative and absolute terms. We also discuss the organizational embodiment, relationship with transit providers, traffic confidentiality, and other aspects of CIPT.Institute IMDEA Networkspu
Green Wireless Networking: Three Questions
Get PDFIn this short note we briefly discuss three issues
related to the relevance and the possible impact of research in the field of green networking, with special attention to the wireless case, since this is the context where energy efficiency is needed most.TRUEpu
Leveraging the Rate-Delay Trade-off for Service Differentiation in Multi-Provider Networks
Get PDFThe single best-effort service of the Internet struggles to accommodate divergent needs of different distributed applications. Numerous alternative network architectures have been proposed to offer diversified network services. These innovative solutions failed to gain wide deployment primarily due to economic and legacy issues rather than technical shortcomings. Our paper presents a new simple paradigm for network service differentiation that accounts explicitly for the multiplicity of Internet service providers and users as well as their economic interests in environments with partly deployed new services. Our key idea is to base the service differentiation on performance itself, rather than price. We design RD (RateDelay) network services that give a user an opportunity to choose between a higher transmission rate or low queuing delay at a congested network link. To support the two services, an RD router maintains two queues per output link and achieves the intended rate-delay differentiation through simple link scheduling and dynamic buffer sizing. We evaluate the performance, deployment, and security properties of the RD network services in various network topologies and traffic scenarios including delay-sensitive VoIP (Voice over Internet Protocol) applications.TRUEpu
Bounds on QoS-Constrained Energy Savings in Cellular Access Networks with Sleep Mode
Get PDFBest Paper AwardSleep modes are emerging as a promising technique
for energy-efficient networking: by adequately putting to sleep and waking up network resources according to traffic demands, a proportionality between energy consumption and network utilization can be approached, with important reductions in energy consumption. Previous studies have investigated and evaluated sleep modes for wireless access networks, computing variable percentages of energy savings. In this paper we characterize the maximum energy saving that can be achieved in a cellular wireless access network under a given performance constraint. In particular, our approach allows the derivation of realistic estimates of the energy-optimal density of base stations corresponding
to a given user density, under a fixed performance constraint. Our results allow different proposals to be measured against the maximum theoretically achievable improvement. We show, through numerical evaluation and simulation, the possible energy savings in today’s networks, and we further demonstrate that even with the development of highly energy-efficient hardware, a holistic approach incorporating system level techniques is essential to achieving maximum energy efficiency.TRUEpu