It then explains which types of SIP calls in the IMS network can benefit from the co-location of IMS servers and shows how to design the IMS network to maximize IMS server co-location. Finally, it introduces Lucent Technologies' SIPia BUS software architecture, which implements the co-location capability by introducing a new SIP transport in a way that is both natural and non-disruptive for the SIP stack and the SIP user agent. © 2006 Lucent Technologies Inc.that at least seven Session Initiation Protocol (SIP) nodes must talk to each other. In this paper, we will show in the first section that having so many different nodes involved has many adverse effects on the performance, reliability, and security of the system. Although this kind of arrangement does not cause any challenges that could not be resolved, it results in an expensive deployment. The first section of this paper will show that having the different nodes running on the same host, as far as possible, would

As the deployment of Session Initiation Protocol (SIP) accelerates of a firewall in protecting the IP Multimedia Subsystem (IMS) or SIP-based core network, distinguish it from an SBC, and characterize the specific threats to SIP messages at the L2 (data link layer), L3 (network layer), L4 (transport layer), and L5 (session layer).We show how a SIP firewall can thwart these attacks and we propose an implementation based on a simplified, but fully hardware accelerated SIP proxy as a front end SIP firewall. Such a system naturally blocks most attacks and implements many defense mechanisms. © 2011 Alcatel-Lucent. make sense of the SIP message and qualify it as normal or anomalous. Clearly, burdening a conventional firewall with these capabilities while also expecting that it will perform its canonical firewall duties is a difficult undertaking. In order to deal with SIP-specific attacks, a SIP firewall must have enough knowledge of SIP grammar to allow some parsing, and enough cognizance of SIP state to be state-aware in order to stop the large variety of attacks that are possible.

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in the world was 314 million in second quarter 2007. We believe that there is a real need for those millions of broadband subscribers to call each other "over IP," even when between different operators, IMS or non-IMS, and using all the benefits of high speed Internet (i.e., better voice quality, video, instant messaging). We also believe that there is a strong need for a standard authentication and encryption for those calls. This will not only provide call participants on both ends with reliable information about who the other party really is-similar to what the PSTN provides more or less today-it will also provide