Always Best Packet Switching: the Mobile VoIP Case Study

Abstract

<p class="MsoNormal" style="margin: 0cm 0cm 0pt; layout-grid-mode: char;"><span style="mso-bidi-font-weight: bold;"><span style="font-size: x-small;"><span style="font-family: Times New Roman;">Currently, a mobile device equipped with multiple heterogeneous wireless Network Interface Cards (NICs), cannot take fully advantage of its capabilities as the conventional mobility management approach allows it to select and use only one of its NICs at a time. In contrast to this approach, we propose the so-called Always Best Packet Switching (ABPS) model that allows applications to use simultaneously all the available NICs, and switch each given IP datagram through the most suitable NIC, depending on the characteristics of the datagram itself. Specifically, we show that the ABPS model enables mobile applications to create policies for load balancing and recovery purposes in order to support effectively mobile multimedia services. In particular, in this paper we describe a cross-layer mechanism, termed Robust Wireless Multi-Path Channel (RWMPC) that adopts the ABPS model in order to meet effectively interactivity and low packet loss Quality of Service (QoS) requirements of Voice over IP (VoIP) applications, running on mobile hosts equipped with multiple WLAN NICs. By Exploiting the RWMPC services, VoIP applications can establish and maintain separate wireless links with different access points providing access to, possibly independently managed, wireless networks, and select for each UDP datagram the best link to be used for communication purposes. In essence, the RWMPC mechanism monitors each link in use, and notifies the application if detects that a datagram has been lost. In this case, the application retransmits the datagram using an alternative link, available through one of the interfaces homed in the mobile host.</span></span></span></p><span style="mso-bidi-font-weight: bold;"><span style="font-size: x-small;"><span style="font-family: Times New Roman;"><p class="MsoNormal" style="margin: 0cm 0cm 0pt; layout-grid-mode: char;"><span style="mso-bidi-font-weight: bold;">We have carried out an experimental evaluation of our mechanism in a real wireless scenario through the emulation of a VoIP application. The results we have obtained from this evaluation are discussed in this paper and confirm the effectiveness of our approach.</span></p></span></span></span&gt

Analysis of packet switching in VoIP telephony at the command post of tactical level units

“…Subinterfaces must be assigned a VLAN tag. It is inserted into the Ethernet header to separate the associated VLAN (Ghini et al, 2009). The tags must match the VLAN number defined on the switch.…”

Mobile games through the nets: a cross-layer architecture for seamless playing

“…A characteristic of our approach is that it differs from the common Always Best Connected (ABC) model; in this model, the best available network is identified and used until its performance degrades [11]. In contrast, in our approach all the available Network Interface Cards (NICs) are used simultaneously, differentiating the choice of a network from datagram to datagram, and introducing the ability to switch to the most suitable path depending on the characteristics of the datagram [9]. This enables to create policies for load balancing and recovery in order to maximize the available bandwidth and decrease the loss rate.…”

“…In addition, our architecture can be exploited for other real-time multimedia applications, e.g. VoIP [9]. In this paper, we show how our architecture can proficiently manage mobile game traffic.…”

The “Always Best Packet Switching” architecture for SIP-based mobile multimedia services

“…2) The Transmission Error Detector (TED) operates across the MAC, network and transport layers of the Linux kernel [10]. Its principal responsibility is to monitor each single UDP datagram sent over an active WiFi link in order to detect whether that datagram has been successfully received by the access point or discarded by the MAC layer.…”