We revisit the question of how much buffer an IP router should allocate for its Droptail FIFO link. For a long time, setting the buffer size to the bitrate-delay product has been regarded as reasonable. Recent studies of interaction between queueing at IP routers and TCP congestion control offered alternative guidelines. First, we explore and reconcile contradictions between the existing rules. Then, we argue that the problem of link buffer sizing needs a new formulation: design a buffer sizing algorithm that accommodates needs of all Internet applications without engaging IP routers in any additional signaling. Our solution keeps network queues short: set the buffer size to ¾Ä datagrams, where Ä is the number of input links. We also explain how end systems can utilize the network effectively despite such small buffering at routers.
Instantaneous Fair Sharing (IFS) is a traditional network ideal prescribing to share the network capacity among competing applications fairly during any infinitesimal time interval. In this paper, we argue that IFS is an inappropriate ideal for the application of massive data transfers where the primary goal is to minimize message transfer times. We propose an alternative paradigm of Virtual Finish Time First (ViFi) scheduling that dedicates the entire capacity to one message at a time in the order of message finish times under IFS. Unlike Shortest Remaining Time First and other earlier algorithms for dedicated scheduling, ViFi provides a remarkable guarantee of delivering each message no later than under IFS. Our analysis and simulations show the dedicated ViFi scheduling offers significant reductions in the average transfer time. The above properties make ViFi a promising approach for resource allocation in emerging dedicated-channel networks that enable advance reservation of end-to-end channels between hosts.
A majority of ISPs (Internet Service Providers) support connectivity to the entire Internet by transiting their traffic via other providers. Although the transit prices per M bps 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 of 264 ISPs 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.
Categories and Subject DescriptorsC.2.3 [Computer-communications networks]: Network operations; network management * Tuangou (pronounced "twangoo"), a term originating in China, loosely translates as team buying or group buying, http://en.wikipedia.org/wiki/Tuangou.
Group subscription is a useful mechanism for multicast congestion control: RLM, RLC, FLID-DL, and WEBRC form a promising line of multi-group protocols where receivers provide no feedback to the sender but control congestion via group membership regulation. Unfortunately, the group subscription mechanism also offers receivers an opportunity to elicit self-beneficial bandwidth allocations. In particular, a misbehaving receiver can ignore guidelines for group subscription and choose an unfairly high subscription level in a multi-group multicast session. This poses a serious threat to fairness of bandwidth allocation. In this paper, we present the first solution for the problem of inflated subscription. Our design guards access to multicast groups with dynamic keys and consists of two independent components: DELTA (Distribution of ELigibility To Access) -a novel method for in-band distribution of group keys to receivers that are eligible to access the groups according to the congestion control protocol, and SIGMA (Secure Internet Group Management Architecture) -a generic architecture for key-based group access at edge routers.
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