Admission control is a critical networking function in home networks developed to address diverse QoS requirements and accommodate user preferences. Home networks have evolved considerably with the advent of wireless networking. This paper describes a method for prioritized admission control in a wireless network with variable channel data rates to optimize policy-based provisioned services.

Mission-critical networks show great potential in emergency response and/or recovery, health care, critical infrastructure monitoring, etc. Such mission-critical applications demand that security service be ldquoanywhere,rdquo ldquoanytime,rdquo and ldquoanyhow.rdquo However, it is challenging to design a key management scheme in current mission-critical networks to fulfill the required attributes of secure communications, such as data integrity, authentication, confidentiality, nonrepudiation, and service availability. In this paper, we present a self-contained public key-management scheme, a scalable method of cryptographic key management (SMOCK), which achieves almost zero communication overhead for authentication, and offers high service availability. In our scheme, a small number of cryptographic keys are stored offline at individual nodes before they are deployed in the network. To provide good scalability in terms of the number of nodes and storage space, we utilize a combinatorial design of public-private key pairs, which means nodes combine more than one key pair to encrypt and decrypt messages. We also show that SMOCK provides controllable resilience when malicious nodes compromise a limited number of nodes before key revocation and renewal.

In this paper, we study a problem of deploying wireless ad hoc relay devices in real time by public safety first responders at an incident scene without pre-planning so that a wireless communication backbone network can be rapidly established at the scene. A collaborative deployment method is proposed to enable mobile devices carried by first responders to exchange control information and make deployment decisions based on such information. Simulation results show that the proposed method efficiently establishes a reliable ad hoc backbone network at an incident scene.

Mobile ad hoc networks show great potential in emergency response and/or recovery. Such mission-critical applications demand security service be "anywhere", "anytime" and "anyhow". However, it is challenging to design a key management scheme in current wireless ad hoc networks to fulfill the required attributes of secure communications, such as data integrity, authentication, confidentiality, non-repudiation and service availability, when Sybil attacks are present. In this paper, we present a self-contained public key management scheme, called SMOCK, which is able to resist the Sybil attack, achieves zero communication overhead for authentication, and offers high service availability. In oar scheme, small number of cryptographic keys are stored off-line at individual nodes before they are deployed in the network. To provide good scalability in terms of number of nodes and storage space, we utilize a combinatorial design of public-private key pairs, which means nodes combine more than one key pair to encrypt and decrypt messages. We also show that SMOCK provides controllable resilience when malicious nodes break into a limited number of nodes before key revocation and renewal

In this paper, we define architecture of a system for managing network resources in a hierarchical OSPF routing domain supporting DiffServ, wherein resources in terms of bandwidth are dynamically allocated among data flows, each traversing the domain from an ingress edge router to an egress edge router. Specifically, we consider a bandwidth management system in a hierarchical routing domain, wherein each level of the hierarchy comprises a number of areas defined for that level. We propose two alternative approaches for bandwidth management in such a routing domain. In the first approach, the admission control function is centralized at a domain-level bandwidth management agent. In the second approach, bandwidth management functions are distributed among a number of bandwidth managers, and edge-to-edge session admission control is executed on an area-by-area basis.

In this paper, we investigate and propose a method to address the problem of estimating channel quality at the medium access control (MAC) layer for a CSMA/CA type of wireless LAN that is subject to time-varying impairments. A key step in solving this problem is to distinguish the packet loss caused by channel impairments from that caused by collisions. Our proposed method estimates packet loss due to the channel impairments alone from the overall packet loss statistics at the MAC layer of a transmitter by exploiting the benefits of the bandwidth manager in such a wireless LAN. The state of each wireless channel can be estimated by deriving a channel quality factor from the estimated packet loss probability due to channel impairments.

With increasing demand for multimedia and real-time applications, local area network (LAN) technologies are rapidly being upgraded to support quality-of-service (QoS). Many QoS-enabled LANs are making use of resource allocation mechanisms that can discriminate among traffic classes of different priorities. When such LANs are interconnected by bridges to form an extended LAN, it is necessary to upgrade the bridges so that they are QoS-enabled as well. For example, the IEEE 802.1p standard defines a framework for priority queuing in bridges. Alternatively, frame forwarding decisions at the link later may be modified to recognize frame priorities and alternate paths may be used for differentiating QoS. In this paper, we describe a novel bridge protocol that can forward frames of different priorities using different paths. Our protocol ensures that the forwarding path of a higher priority frame is never longer than the forwarding path of a lower priority frame.

The problem of traffic load estimation in a shared-medium contention-based network is investigated and applied to a hybrid fiber coaxial (HFC) cable network. In particular, an estimator that utilizes channel feedback to estimate network traffic load is presented. The performance of this estimator is investigated and is enhanced by introducing modifications which provide for a better reaction to load variations.

We consider a communication network in which dynamic routing is used for establishing connections that support information transfer between end-users. Link state information is exchanged and maintained up-to-date among network nodes for path computation and network resource allocation. When the population of users is large, the amount of link state information can be overwhelming. A common solution is to use a hierarchical structure. In this paper, we present a method for aggregating link state information in a hierarchical network. We assume that each link state parameter associated with a link is symmetrical in both directions of the link. The key idea for the method is to first reduce the original subnetwork topology to a full-mesh representation that consists of a logical link for each pair of border nodes in the subnetwork, and then encode the link state information associated with the full-mesh representation with an appropriate spanning tree.

Studies the space-time characteristics of ALOHA multiple-access protocols in bidirectional bus networks where transmissions are in the form of packets of constant length. For point-to-point communications, the maximum throughput of unslotted ALOHA is known to be 1/(2e), independent of station configuration. The authors show that, with a uniform probabilistic station configuration, the maximum throughput of slotted ALOHA tends to a nonzero constant that is less than 1/(2e), when a, the end-to-end propagation delay normalized with respect to the packet transmission time, tends to infinity. However, when N stations are evenly spaced on the bus, the maximum throughput of slotted ALOHA vanishes as a tends to infinity. For broadcast communications, the maximum throughput of slotted ALOHA is well known to be 1.>

Buffer allocation for frame reassembly and queueing in the destination node of an ATM subnetwork supporting multiple frame relay connections is examined. The finite peak rate of a frame relay connection is explicitly modeled and shown to be an important factor in buffer sizing. Specifically, the average number of buffers required is shown to be large when many low-peak-rate frame relay connections are multiplexed for delivery to a single high-speed frame relay interface port, but the tail of the distribution is determined only by aggregate traffic statistics.>

Conventional allocation of network resources for connection management is by and large static. For each performance parameter that is negotiated during a call setup, its agreed value must be maintained throughout the duration of the call. Due to a dynamic networking environment, the result of quality of service (QOS) negotiation during call establishment may not remain ideal throughout the duration of a call. The authors propose a method for managing connections, in a connection-oriented integrated communication network, to maintain acceptable QOS for the entire duration of each connection, to make QOS improvements whenever possible, to recover from connection failures and call preemption, as well as to partially retrieve allocated resources to relieve network overload.>

Routing subject to multiple quality-of-service (QOS) constraints is considered. Such a problem arises in both private corporate backbone networks and public switched networks, and will become even more prevalent in the future with the emergence of asynchronous transfer mode (ATM) networks. A rule-based call-by-call source routing strategy that makes use of routing fallbacks to accommodate users with diverse QOS requirements is proposed.>

The performance of the slotted ALOHA multiple access protocol in a high-speed bidirectional passive bus network, where transmissions are in the form of packets of constant length, is studied. Slotted ALOHA is generally considered to have better throughput performance than unslotted ALOHA, whose maximum throughput is known to be 1/(2e), independent of station configuration. It is shown that, with a probabilistic station configuration, the throughput of slotted ALOHA can degrade to 1/(3e) when the end-to-end propagation delay is significantly larger than the packet transmission time. Nevertheless, in some very high speed bidirectional bus networks with a deterministic station configuration, the throughput of slotted ALOHA can be as high as 1/2.>