1. 1 NSIS: A New Extensible IP Signaling Protocol Suite Myungchul Kim mckim@icu.ac.kr Tel: 042-866-6127

2. 2 by X. Fu, H. Schulzrinne, et al., IEEE Communications Magazine, Oct. 2005. Introduction –Signaling in communication networks is defined as the exchange of information between nodes to establish, maintain, and remove control state in network nodes. –Signaling System 7 (SS7) –Examples Reserving resources for QoS guarantees Configuring firewall pinholes and network address translator (NAT) binding Diagnosing path status –RSVP –NSIS (Next Steps in Signaling) The lower layer provides a generic transport service for different signaling applications (General Internet Signaling Transport, GIST) The upper layers: QoS signaling, firewall and NAT control.

3. 3 Soft state signaling and the RSVP signaling protocol –Hard state: installed upon receipt of a setup message and removed only upon receipt of an explicit tear down message. –Soft state: nonpermanet control state will expire unless refreshed. –Fig 1

4. 4 –RSVP Many-to-many multicast QoS reservation Per-flow-based Periodic refreshes –RSVP key problems Not support mobile nodes UDP for transport mechanism Discovery and signaling message delivery are combined into a single protocol step. -> not provide a solid security framework. Design principles of NSIS –NSIS initiator (NI), NSIS forwarder (NF), NSIS responder (NR) –Fig 2

5. 5 –All NSIS nodes necessarily do not support all signaling applications. –Separating signaling message transport from signaling applications NSIS Transport Layer Protocol (NTLP) NSIS Signaling Layer Protocols (NSLPs) See Figure 3 –Decoupling of discovery and transport of signaling messages –Introduction of a session identifier Flow identifier vs session identifier Mobility Multihoming Tunneling and IPv4/v6 traversal –Support for signaling to hosts, networks, and proxies

6. 6 Fig 3

7. 7 GIST: General Internet Signaling Transport Protocol –NSIS Transport Layer Protocol: NTLP –Datagram mode (UDP), Connection mode (TCP) –IPsec, TLS The QoS signaling application protocol in NSIS –QoS NSLP can signal for any QoS model (e.g., IntServ or DiffServ) –QSPEC -> RMF -> policy control and admission control

8. 8 –Fig 4

9. 9 –Sender-initiated and receiver-initiated –Fig 5

10. 10 Security consideration for NSIS –Security protection for GIST in connection mode 1.Authentication of the two neighboring protocol peers 2.Security association establishment to provide integrity, confidentiality, and replay protection for signaling message exchanged between these entities. 3.Denial of service protection 4.Authorization of the signaling peers 5.Some security protection for the discovery mechanism

11. 11 Comparison between RSVP and NSIS signaling –Table 1