2,295 research outputs found
Language Assistant Capability Exchange Protocol
This disclosure describes techniques to support language assistance services for communication between devices. Per techniques of this disclosure, language assistant capabilities are exchanged between participating devices during call setup. A call protocol such as session initiation protocol (SIP) is suitably modified to exchange language assistant parameters during call set up. The SIP header fields are extended to add a parameter to indicate language assistant capabilities by indicating a suitable language code. An INVITE request is transmitted from an originating device that includes a language identifier that indicates the language assistant capabilities of the originating device. A corresponding language identifier of the terminating device is requested. A language identifier for the terminating device is obtained from and transmitted to the originating device along with a RING message. When the call is answered at the terminating device, an updated language identifier may be provided along with an OK message
ALEX: Improving SIP Support in Systems with Multiple Network Addresses
The successful and increasingly adopted session initiation protocol (SIP) does not adequately support hosts with multiple network addresses, such as dual-stack (IPv4-IPv6) or IPv6 multi-homed devices. This paper presents the Address List Extension (ALEX) to SIP that adds effective support to systems with multiple addresses, such as dual-stack hosts or multi-homed IPv6 hosts. ALEX enables IPv6 transport to be used for SIP messages, as well as for communication sessions between SIP user agents (UAs), whenever possible and without compromising compatibility with ALEX-unaware UAs and SIP servers
A Survey on Handover Management in Mobility Architectures
This work presents a comprehensive and structured taxonomy of available
techniques for managing the handover process in mobility architectures.
Representative works from the existing literature have been divided into
appropriate categories, based on their ability to support horizontal handovers,
vertical handovers and multihoming. We describe approaches designed to work on
the current Internet (i.e. IPv4-based networks), as well as those that have
been devised for the "future" Internet (e.g. IPv6-based networks and
extensions). Quantitative measures and qualitative indicators are also
presented and used to evaluate and compare the examined approaches. This
critical review provides some valuable guidelines and suggestions for designing
and developing mobility architectures, including some practical expedients
(e.g. those required in the current Internet environment), aimed to cope with
the presence of NAT/firewalls and to provide support to legacy systems and
several communication protocols working at the application layer
Covert Channels in SIP for VoIP signalling
In this paper, we evaluate available steganographic techniques for SIP
(Session Initiation Protocol) that can be used for creating covert channels
during signaling phase of VoIP (Voice over IP) call. Apart from characterizing
existing steganographic methods we provide new insights by introducing new
techniques. We also estimate amount of data that can be transferred in
signalling messages for typical IP telephony call.Comment: 8 pages, 4 figure
SecSip: A Stateful Firewall for SIP-based Networks
SIP-based networks are becoming the de-facto standard for voice, video and
instant messaging services. Being exposed to many threats while playing an
major role in the operation of essential services, the need for dedicated
security management approaches is rapidly increasing. In this paper we present
an original security management approach based on a specific vulnerability
aware SIP stateful firewall. Through known attack descriptions, we illustrate
the power of the configuration language of the firewall which uses the
capability to specify stateful objects that track data from multiple SIP
elements within their lifetime. We demonstrate through measurements on a real
implementation of the firewall its efficiency and performance
Session Initiation Protocol Attacks and Challenges
In recent years, Session Initiation Protocol (SIP) has become widely used in
current internet protocols. It is a text-based protocol much like Hyper Text
Transport Protocol (HTTP) and Simple Mail Transport Protocol (SMTP). SIP is a
strong enough signaling protocol on the internet for establishing, maintaining,
and terminating session. In this paper the areas of security and attacks in SIP
are discussed. We consider attacks from diverse related perspectives. The
authentication schemes are compared, the representative existing solutions are
highlighted, and several remaining research challenges are identified. Finally,
the taxonomy of SIP threat will be presented
Providing End-to-End Connectivity to SIP User Agents Behind NATs
The widespread diffusion of private networks in SOHO scenarios is fostering an increased deployment of Network Address Translators (NATs). The presence of NATs seriously limits end-to-end connectivity and prevents protocols like the Session Initiation Protocol (SIP) from working properly. This document shows how the Address List Extension (ALEX), which was originally developed to provide dual-stack and multi-homing support to SIP, can be used, with minor modifications, to ensure end-to-end connectivity for both media and signaling flows, without relying on intermediate relay nodes whenever it is possibl
Options for Securing RTP Sessions
The Real-time Transport Protocol (RTP) is used in a large number of
different application domains and environments. This heterogeneity
implies that different security mechanisms are needed to provide
services such as confidentiality, integrity, and source
authentication of RTP and RTP Control Protocol (RTCP) packets
suitable for the various environments. The range of solutions makes
it difficult for RTP-based application developers to pick the most
suitable mechanism. This document provides an overview of a number
of security solutions for RTP and gives guidance for developers on
how to choose the appropriate security mechanism
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