Dipl.-Ing. Hannes Tschofenig
+358 50 4871445
+49 551 39-14416
Georg-August-Universität Göttingen Institut für Informatik Computer Networks Group Goldschmidtstr. 7 37077 Göttingen
Hannes Tschofenig is a Senior Research Scientist at Nokia Siemens Networks and guest lecturer at the University of Goettingen. He currently serves as member of the Internet Architecture Board (IAB) and co-chair of IETF OAUTH and KEYPROV working groups, former co-chair of IETF DIME and ECRIT working groups, and a co-author of more than 40 RFCs, including: rfc3726, Requirements for Signaling Protocols rfc4081, Security Threats for Next Steps in Signaling (NSIS) rfc4230, RSVP Security Properties rfc4279, Pre-Shared Key Ciphersuites for Transport Layer Security (TLS) rfc4442, Bootstrapping Timed Efficient Stream Loss-Tolerant Authentication (TESLA) rfc4484, Trait-based Authorization Requirements for the Session Initiation Protocol (SIP) rfc4487, Mobile IPv6 and Firewalls: Problem Statement rfc4507, Transport Layer Security (TLS) Session Resumption without Server-Side State rfc4589, Location Type Registry rfc4621 , Design of the IKEv2 Mobility and Multihoming (MOBIKE) Protocol rfc4745, Common Policy: A Document Format for Expressing Privacy Preferences rfc4764, The EAP-PSK Protocol: A Pre-Shared Key Extensible Authentication Protocol (EAP) Method rfc4806, Online Certificate Status Protocol (OCSP) Extensions to IKEv2 rfc4891, Using IPsec to Secure IPv6-in-IPv4 Tunnels rfc5069, Security Threats and Requirements for Emergency Call Marking and Mapping rfc5077, Transport Layer Security (TLS) Session Resumption without Server-Side State rfc5106, The Extensible Authentication Protocol-Internet Key Exchange Protocol version 2 (EAP-IKEv2) Method rfc5191, Protocol for Carrying Authentication for Network Access (PANA) rfc5222, LoST: A Location-to-Service Translation Protocol rfc5223, Discovering Location-to-Service Translation (LoST) Servers Using the Dynamic Host Configuration Protocol (DHCP)
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Cloud-based Computation Offloading for Mobile Devices: State of the Art, Challenges and Opportunities,
Lei Jiao, Xiaoming Fu, Roy Friedman, Stefano Secci, Zbigniew Smoreda and Hannes Tschofenig, Future Network & Mobile Summit 2013, Lisbon, Portugal,
Mobile cloud computing is a new rapidly growing field. In addition to the conventional fashion that mobile clients access cloud services as in the well-known client/server model, existing work has proposed to explore cloud functionalities in another perspective — offloading part of the mobile codes to the cloud for remote execution in order to optimize the application performance and energy efficiency of the mobile device. In this position paper, we investigate the state of the art of code offloading for mobile devices, highlight the significant challenges towards a more efficient cloud-based offloading framework, and also point out how existing technologies can provide us opportunities to facilitate the framework implementation.
jiao_article13.pdf [221.4 kB]
NSIS Protocol Operation in Mobile Environments,
Takako Sanda, Xiaoming Fu, Seong-Ho Jeong, Jukka Manner, and Hannes Tschofenig, Internet Engineering Task Force, RFC 5980, Next Steps in Signaling (NSIS) Working Group,
ISSN: 2070-1721, March 2011.
Mobility of an IP-based node affects routing paths, and as a result, can have a significant effect on the protocol operation and state management. This document discusses the effects mobility can cause to the Next Steps in Signaling (NSIS) protocol suite, and shows how the NSIS protocols operate in different scenarios with mobility management protocols.
PDF [68.0 kB]
NAT/Firewall NSIS Signaling Layer Protocol (NSLP),
Martin Stiemerling, Hannes Tschofenig, Cedric Aoun, and Elwyn Davies, Internet Engineering Task Force, RFC 5973, Next Steps in Signaling (NSIS) Working Group,
This memo defines the NSIS Signaling Layer Protocol (NSLP) for Network Address Translators (NATs) and firewalls. This NSLP allows hosts to signal on the data path for NATs and firewalls to be configured according to the needs of the application data flows. For instance, it enables hosts behind NATs to obtain a publicly reachable address and hosts behind firewalls to receive data traffic. The overall architecture is given by the framework and requirements defined by the Next Steps in Signaling (NSIS) working group. The network scenarios, the protocol itself, and examples for path-coupled signaling are given in this memo.
PDF [135.9 kB]
General Internet Signaling Transport (GIST) State Machine,
Tseno Tsenov, Hannes Tschofenig, Xiaoming Fu, Cedric Aoun, and Elwyn Davies, Internet Engineering Task Force, Request for Comment (RFC) 5972, Next Steps in Signaling (NSIS) Working Group,
This document describes state machines for the General Internet Signaling Transport (GIST). The states of GIST nodes for a given flow and their transitions are presented in order to illustrate how GIST may be implemented.
PDF [34.5 kB]
How secure is the next generation of IP-based emergency services architecture?,
Hannes Tschofenig, Mayutan Arumaithurai, Henning Schulzrinne, Bernard Aboba, International Journal of Critical Infrastructure Protection, Volume 3, Issue 1, pages 41-50,
Elsevier, doi:10.1016/j.ijcip.2010.02.001, May 2010.
For some location-based applications, such as emergency calling or
roadside assistance, it appears that the identity of the requester is
less important than accurate and trustworthy location information for
accomplishing the main function. Accurate and genuine location is
important for these applications to avoid misuse.
In this paper we point to some ongoing efforts regarding transition
emergency service architectures that could introduce security
countermeasures are being developed. Furthermore, we summarize the
ongoing work in providing cryptographic assertions for location.
We argue that many of the currently proposed ideas are
difficult to deploy and to operate. Additionally, when used without
ensuring that the underlying assumptions are met these mechanisms
do not provide any additional benefit, but costs.
We conclude this article with a suggestion on what the research
community and industry should be investigating to avoid potential
problems with IP-based emergency services.
PDF [595.0 kB]
Traffic Classification and Quality of Service (QoS) Attributes for Diameter,
Jouni Korhonen, Hannes Tschofenig, Mayutan Arumaithurai, Mark Jones, and Avi Lior, Request For Comment (RFC) 5777 (Proposed Standard),
Internet Engineering Task Force, ISSN 2070-1721, February 2010.
This document defines a number of Diameter attribute-value pairs (AVPs) for traffic classification with actions for filtering and Quality of Service (QoS) treatment. These AVPs can be used in existing and future Diameter applications where permitted by the Augmented Backus-Naur Form (ABNF) specification of the respective Diameter command extension policy.
PDF [55.8 kB]
Overhead and Performance Study of the General Internet Signaling Transport (GIST) Protocol,
Xiaoming Fu, Henning Schulzrinne, Hannes Tschofenig, Christian Dickmann, and Dieter Hogrefe, ACM/IEEE Transactions on Networking, 17(1): 158-171,
The General Internet Signaling Transport (GIST) protocol is currently being developed as the base protocol component in the IETF Next Steps In Signaling (NSIS) protocol stack to support a variety of signaling applications. We present our study on the protocol overhead and performance aspects of GIST. We quantify network-layer protocol overhead and observe the effects of enhanced modularity and security in GIST. We developed a first open source GIST implementation at the University of Goettingen, and study its performance in a Linux testbed. A GIST node serving 45,000 signaling sessions is found to consume average only 1.1 ms for processing a signaling message and 2.4 KB of memory for managing a session. Individual routines in the GIST code are instrumented to obtain a detailed profile of their contributions to the overall system processing. Important factors in determining performance, such as the number of sessions, state management, refresh frequency, timer management and signaling message size are further discussed. We investigate several mechanisms to improve GIST performance so that it is comparable to an RSVP implementation.
PDF [210.7 kB]
Performance Study of the NSIS QoS-NSLP Protocol,
Mayutan Arumaithurai, Xiaoming Fu, Bernd Schloer, and Hannes Tschofenig, The 51th Annual IEEE Global Telecommunications Conference (GLOBECOM 2008), Next Generation Networks, Protocols, and Services Symposium, New Orleans, LA, USA,
IEEE, December 2008.
This paper presents an evaluation of the Quality of Service Signalling Layer Protocol (QoS-NSLP) of the NSIS (Next Steps In Signalling) protocol suite. The QoS-NSLP in combination with the NSIS Transport Layer Protocol (NTLP) is proposed by the Internet Engineering Task Force (IETF) as an alternative to the Resource reSerVation Protocol (RSVP). We describe our implementations of the software architecture, both on a network simulator and on a Linux implementation. Both implementations are used in a complimentary manner to illustrate the performance of the QoS-NSLP protocol. The results show the performance of QoS-NSLP with respect to resource consumption, packet processing time, session set up time, refresh interval and protocol overhead. Furthermore, we analyse the protocol performance during route change scenarios.
PDF [328.7 kB]
Spam Score for SIP,
D. Wing, S. Niccolini, Martin Stiemerling, and Hannes Tschofenig, Internet draft (work in progress),
IETF, February 2008.
This document defines a mechanism for SIP proxies to communicate a spam score to downstream SIP proxies and SIP user agents so they can provide alternate call routing or call handling.
TXT [14.5 kB]
An NSIS-based Approach for Firewall Traversal in Mobile IPv6 Networks,
Niklas Steinleitner, Xiaoming Fu, Dieter Hogrefe, Thomas Schreck, and Hannes Tschofenig, Third Annual International Wireless Internet Conference (WICON 2007), Austin, Texas, USA,
ACM Press, October 2007.
Firewalls have been successfully deployed in todays network infrastructure in various environments and will also be used in IPv6 networks. However, most of the current firewalls do not support Mobile IPv6, the best known standardized solution for mobility support in IPv6. As a result, Mobile IPv6 traffic will be most likely dropped when used without an appropriate firewall traversal solution.
This paper describes the problems and impacts of having firewalls in Mobile IPv6 environments and presents a firewall traversal solution based on the IETFs Next Steps In Signaling framework to address these issues. Compared with other candidates such as STUN, TURN, ICE, ALG, MIDCOM
and COPS, this approach does not rely on specific firewall placements and can be applied in various operational modes without additional introducing entities. In this paper we also explore security aspects since they are typically difficult to handle.
PDF [372.2 kB]
Beyond QoS Signaling: a Generic IP Signaling Framework,
Xiaoming Fu, Hannes Tschofenig, and Dieter Hogrefe, Computer Networks, Volume 50, Issue 17, pages 3416-3433,
Elsevier, December 2006.
This paper describes the design principles and an introduction of a framework and protocols for generic IP signaling, namely the Cross-Application Signaling Protocol (CASP) and its signaling applications. While reusing certain features of the existing RSVP protocol, CASP overcomes its shortcomings and may be deployed as a replacement technology to provide simpler, mobility-supported, more extensible and more secure signaling services in IP based networks. This paper discusses challenges of todays IP signaling protocols and addresses fundamentals and key aspects of CASP and its current signaling applications. In addition, a comparison with previous signaling protocol proposals and an outlook of future work in this area are also given.
PDF [602.3 kB]
Securing the Next Steps in Signalling (NSIS) Protocol Suite,
Hannes Tschofenig, and Xiaoming Fu, International Journal of Internet Protocol Technology, Volume 1, No. 4, pages 271-282,
InderScience Publishers, ISSN 1743-8209, August 2006.
The Next Steps In Signalling (NSIS) protocol suite represents an extensible framework for enabling various signalling applications over IP-based networks. The framework consists of two layers that need different types of security protection; the lower layer mainly deals with the discovery of adjacent peers and establishment of channel security to protect the delivery of signalling messages between two peers, while the upper layer provides the signalling application specific functionalities. Different security properties are required at the two layers with stronger authorisation functionality at the signalling application layer. In this paper we examine how various security vulnerabilities can be utilised by an adversary, including eavesdropping, Man-In-The-Middle (MITM) attacks, fraud and Denial of Service (DoS) attacks. Moreover, we describe how to protect against a number of selected security threats and highlight some security challenges that require further research.
PDF [431.5 kB]
Implementation and Performance Study of a New NAT/Firewall Signaling Protocol,
Niklas Steinleitner, Henning Peters, Xiaoming Fu, and Hannes Tschofenig, in Proceedings of the 26th International Conference on Distributed Computing Systems-Workshops (ICDCSW 2006), the 5th International Workshop on Assurance in Distributed Systems and Networks (ADSN2006), Lisboa, Portugal,
IEEE Computer Society, ISBN 0-7695-2541-5, July 2006.
The NAT/Firewall NSIS Signaling Layer Protocol (NAT/FW NSLP) is a path-coupled signaling protocol for explicit Network Address Translator and firewall configuration within an extensible IP signaling framework currently being developed by the IETF Next Steps in Signaling (NSIS) working group. This new protocol allows end hosts to signal along a path to configure NATs and firewalls according to the data flow needs. In this paper we present a first open source implementation and performance evaluation of the NAT/FW NSLP protocol. The implementation utilizes a generic state machine template and can automatically generate source code for message handling classes. The performance study shows that our implementation scales well and is able to support firewall signaling for up to tens of thousands of flows in parallel even in a low-end PC testbed environment. The overall performance bottleneck is found to lie in the utilized firewall implementation, not depending on the NAT/FW NSLP implementation.
PDF [394.6 kB]
Overhead and Performance Study of the General Internet Signaling Transport (GIST) Protocol,
Xiaoming Fu, Henning Schulzrinne, Hannes Tschofenig, Christian Dickmann, and Dieter Hogrefe, IEEE INFOCOM 2006, Bacelona, Spain,
IEEE, April 2006.
The General Internet Signaling Transport (GIST) protocol is currently being developed as the base protocol component in the IETF Next Steps In Signaling (NSIS) protocol stack to support a variety of signaling applications. In this paper we present our study on the protocol overhead and performance aspects of GIST. We quantify network-layer protocol overhead and observe the effects of enhanced modularity and security in GIST. We developed a first open source GIST implementation at the University of Göttingen, and study its performance in a Linux testbed. A GIST node serving 45,000 signaling sessions is found to consume small amounts of CPU and memory (on average 1.1ms for processing a signaling message and 2.4KB memory for a session). Individual routines in the GIST code are instrumented to obtain a detailed profile of their contributions to the overall system processing. Important factors in determining performance, such as the number of sessions, state management, refresh frequency, timer management and signaling message size are further discussed. We investigate several mechanisms to improve GIST performance so as to be comparable with an RSVP implementation.
PDF [181.9 kB]
Comparison Studies between Pre-Shared and Public Key Exchange Mechanisms for Transport Layer Security,
Fang-Chun Kuo, Hannes Tschofenig, Fabian Meyer, and Xiaoming Fu, Proceedings of the 9th IEEE Global Internet Symposium, in conjunction with IEEE INFOCOM 2006, Barcelona, Spain, pages 77-82,
IEEE, ISBN 3-937201-01-7, April 2006.
The pre-shared key based mechanisms for Transport Layer Security (TLS) were recently standardized by the IETF to extend the set of ciphersuites by utilizing existing key management infrastructures. The benefit of pre shared based mechanisms is the avoidance or reduction of the cryptographic operations used in public-key based mechanisms. However, so far there are no performance measurements for pre-shared key based ciphersuites available. In this paper, we present a systematic analysis and performance comparison between the pre-shared key exchange mechanisms and the standard public key exchange mechanisms in TLS. Our performance metrics are processing
time and transmitted amount of data for a handshake establishment. Furthermore, the interaction between the overall TLS handshake duration and the network environment is evaluated. The results for different key exchange mechanisms are comparatively studied and the design choices of pre-shared key based key exchange mechanisms have been validated. Experimental results give details about the performance improvement of the preshared key based mechanisms compared to the standard public key based mechanisms.
PDF [331.4 kB]
Comparison Studies between Pre-Shared Key and Public Key Exchange Mechanisms for Transport Layer Security (TLS),
Fang-Chun Kuo, Hannes Tschofenig, Fabian Meyer, and Xiaoming Fu, Technical Report No. IFI-TB-2006-01, Institute of Computer Science, University of Göttingen, Göttingen, Germany,
ISSN 1611-1044, 2006.
The public-key based handshake process of TLS is regarded as part of bottleneck that significantly degrades the performance. The pre-shared key based key exchange mechanisms for TLS were recently standardized by the IETF for avoiding or reducing the cryptographic operations in public-key based mechanisms. However, so far there is no performance measurement for pre-shared key based key exchange suites available. In this paper, we present a systematic analysis of performance comparison between the pre-shared key exchange mechanisms and the standard public key exchange mechanisms in TLS. Our performance metrics are the processing time in both slow and fast processor machines as well as the transmitted data amount for a handshake establishment. Furthermore, the interaction of the overall TLS handshake duration and the network environment is evaluated. The results for different key exchange mechanisms are comparatively studied and the design choices of pre-shared key based key exchange mechanisms have been validated. It has been observed that pre-shared key based mechanisms perform better than the standard public key based mechanisms.
PDF [357.6 kB]
A Quality-of-Service Resource Allocation Client for CASP,
Henning Schulzrinne, Hannes Tschofenig, Xiaoming Fu, and Jochen Eisl, Technical Report No. TB-IFI-2005-07, Institute of Computer Science, University of Goettingen, Germany,
ISSN 1611-1044, November 2005.
Signaling resource reservations is one of the possible applications of the Cross-Application Signaling Protocol (CASP). This document describes a client protocol that supports per-flow resource reservationin both sender- and receiver-directed modes operation.
PDF [99.8 kB]
Security Implications of the Session Identifier,
Hannes Tschofenig, Henning Schulzrinne, Robert Hancock, Andrew McDonald, and Xiaoming Fu, Technical Report No. TB-IFI-2005-08, Institute of Computer Science, University of Goettingen, Germany,
ISSN 1611-1044, November 2005.
As one result of the analysis activities in the NSIS group it was realized that mobility and the ability to change the flow identifier causes problems with existing QoS reservations. To be able to associate a signaling message with existing state an identifier other than the flow identifier had to be used. Such an abstraction is achieved with the session identifier which allows identification of established state independently of the flow characteristics.
Although the introduction of a session identifier sounds simple and beneficial, it introduces a problem which is subsequently referred to as the session ownership problem.
This document describes the session ownership problem, the implications for an NSIS protocol and summarizes already discussed solutions.
PDF [79.7 kB]
NSIS: A New Extensible IP Signaling Protocol Suite,
Xiaoming Fu, Henning Schulzrinne, Attila Bader, Dieter Hogrefe, Cornelia Kappler, Georgios Karagiannis, Hannes Tschofenig, and Sven Van den Bosch, IEEE Communications Magazine, Internet Technology Series, 43(10): 133-141,
IEEE, October 2005.
In the last few years, a number of applications have emerged that can benefit from network-layer signaling, i.e., the installation, maintenance and removal of control state in network elements. These applications include path-coupled and path-decoupled quality of service (QoS) management and resource allocation, as well as network debugging, NAT and firewall control. These applications call for an extensible and securable signaling protocol. This paper discusses some of the recent standardization efforts in the IETF for a new extensible IP signaling protocol suite (NSIS). We describe the design of the NSIS protocol suite, and compare them with RSVP, the current Internet QoS signaling protocol.
PDF [159.9 kB]
Towards Self-optimizing Protocol Stack for Autonomic Communication: Initial Experience,
Xiaoyuan Gu, Xiaoming Fu, Hannes Tschofenig, and Lars Wolf, In: Ioannis Stavrakakis and Michael Smirnov (eds), Proceedings of 2nd IFIP International Workshop on Autonomic Communication (WAC 2005), Athens, Greece, Lecture Notes in Computer Science, Volume 3854, pages 186-201,
Springer-Verlag, October 2005.
The Internet is facing ever-increasing complexity in the construction, configuration and management of heterogeneous networks. New communication paradigms are undermining its original design principles. The mobile Internet demands a level of optimum that is hard to achieve with a strictly-layered protocol stack. Questioning if layering is still an adequate foundation for autonomic protocol stack design, we study the state-of-the-art from both the layered camp and its counterpart. We then outline our vision on protocol stack design for autonomic communication with the POEM model and its internals. A novel cross-layer design approach that combines the advantages of layering and the benefits of holistic and systematic cross-layer optimization is at the core of this work. With inspirations from the natural ecosystem, we are working on the role-based Composable Functional System for self-optimization that features proactive monitoring and control. By doing so step-by-step, we envisage reaching the goal of self-tuning autonomic network with high level of autonomy and efficiency, with minimum human management complexity and user intervention.
PDF [296.8 kB]
Advanced Authentication and Authorization for Quality of Service Signaling,
Tseno Tsenov, Hannes Tschofenig, Xiaoming Fu, and Eckhart Koerner, 1st IEEE Workshop on Security and QoS in Communication Networks (SecQoS 2005), Athens, Greece (in conjunction with the first IEEE International Conference on Security and Privacy for Emerging Areas in Communication and Networks - SECURECOM 2005), Pages 224-235,
IEEE Computer Society Press, September 2005.
One of the key requirements of todays and future network infrastructures is to provide Quality of Service (QoS) support for end-to-end applications, by distinguishing the application flows and properly handling them in network nodes. As an important component to achieve Internet QoS, explicit signaling schemes for resource reservation have been proposed, which deal with admission, installation and refreshment of QoS reservation state information. To be useful, any QoS signaling protocol should provide a capability for authentication and authorization of the QoS requests, especially in environments where the end points are not trusted by the network nodes. However, existing protocols for QoS signaling encounter a number of authentication and authorization issues, which limit their application scenarios. The advent of NSIS QoS Signaling Layer Protocol (QoS-NSLP) offers the prospect to overcome some of these issues. After describing the overall design of QoSNSLP, we present an approach to support advanced authentication and authorization capabilities by using the Extensible Authentication Protocol (EAP). In comparison with existing approaches, this approach, combined with the support for effective interaction with the Authentication, Authorization and Accounting (AAA) infrastructure, provides flexible and extensible authentication and authorization methods for the QoS signaling.
PDF [959.2 kB]
Enabling Mobile IPv6 in Operational Environments,
Xiaoming Fu, Hannes Tschofenig, Srinath Thiruvengadam, and Wenbing Yao, in: Pascal Lorenz (ed), Proceedings of the 10th IFIP International Conference on Personal Wireless Communications (PWC 2005), Colmar, France, pp. 365-372,
Imperial College Press, ISBN 1-86094-582-1, August 2005.
Although Mobile IPv6 allows maintaining transport layer connections alive when an IPv6 node roams to different access networks, certain enabling mechanisms are needed for it to work in large scale network scenarios, including, most notably, issues with Mobile IPv6 bootstrapping and firewall traversal. This paper tries to address these problems by extending the IETF PANA and NSIS protocols to form an extensible framework for wide deployment of a secure, light-weight mobility service in operational IPv6 environments.
PDF [162.4 kB]
Mobility Support for Next-Generation Internet Signaling Protocols,
Xiaoming Fu, Henning Schulzrinne, and Hannes Tschofenig, Proceedings of the IEEE 58th Vehicular Technology Conference (VTC 2003-Fall), Orlando, Florida, USA, pp. 1979-1983, Symposium on IP Mobility,
IEEE, ISBN 0-7803-7954-3, October 2003.
Internet signaling protocols establish, maintain and remove state along the data path. Next-generation signaling protocols design must meet the scaling requirements imposed by the various tasks of the Internet signaling applications, such as resource reservation and middlebox configuration, and to meet the demand for general functionality in signaling protocols, including strong security, reliability, congestion control, support for various signaling purposes and message sizes, and efficient support for mobility. This paper presents a generic signaling architecture, the Cross-Application Signaling Protocol (CASP) and describes how it supports efficient and secure signaling in IP mobility scenarios. In this approach, the signaling functionality is splitted into two layers: a generic messaging layer which provides the generic functionality for message delivery, and a client layer consisting of a next-hop discovery client and any number of client protocols which perform the actual signaling tasks. The essential mechanisms required to support mobility are: (1) a session identifier uniquely selected by the initiator and effective discovery of the cross-over node; (2) a branch identifier incrementally assigned for the new branch and efficient release of state in the abandoned branch; (3) ensuring discovery messages are delivered exactly following the path that mobile IP packets are encapsulated; (4) effective hop-by-hop authentication and reauthorization provided by the messaging layer, non hop-by-hop security for signaling clients and denial-of-service protection in the discovery client.
PDF [75.9 kB]
CASP - Cross-Application Signaling Protocol,
Henning Schulzrinne, Hannes Tschofenig, Xiaoming Fu, and Andrew McDonald, Technische Berichte des Instituts für Informatik an der Georg-August-Universität Göttingen,
Institut für Informatik, Georg-August-Universität Göttingen, Germany, ISSN 1611-1044, IFI-TB-2003-01, (equivalent to the Internet draft), March 2003.
CASP is a modular potocol for establishing network control state along a data path between two nodes communicating on the Internet.
The signalling problem addressed by CASP is the same as the overall problem being addressed by the NSIS activities.
The CASP framework is defined as a modular protocol, which includes a general purpose messaging layer (M-layer), which supports a number of client layers for particular ignalling applications (e.g. QoS, MIDCOM). In addition there is distinct, special purpose client component for next-peer discovery.
PDF [103.1 kB]
Analysis on RSVP Regarding Multicast,
Xiaoming Fu, Cornelia Kappler, and Hannes Tschofenig, Technische Berichte des Instituts für Informatik an der Georg-August-Universität Göttingen,
Institut für Informatik, Georg-August-Universität Göttingen, Germany, ISSN 1611-1044, IFI-TB-2002-001, October 2002.
RSVP version 1 has been designed for optimum support multicast. However, in reality multicast is being used much less frequently than anticipated. Still, even for unicast (one sender, one receiver) full-fledged multicast-enabled RSVP signaling must be used. As pointed out in the NSIS requirement draft, multicast would not be necessarily required for an NSIS signaling protocol. This draft analyses ingredients of RSVP Version 1 which are affected by multicast, and derives how these ingredients may look like if multicast is not supported in the generic RSVP signaling protocol and adapt related functionalities accordingly - we call the resulting feature set "RSVP Lite", a potentially more light-weight version of RSVP.
PDF [335.7 kB]