Chapter Objectives After completing this chapter you will
Chapter Objectives After completing this chapter you will be able to: l. Describe why SCSP is needed l. Describe three phases of SCSP and how they are implemented l. Define the sub-protocols of SCSP l. Describe how the SCSP protocol is used with MARS and NHRP
SCSP Topology Model Server Group A Server Group B RS DCS DCS RS LS Local Server (LS) Directly Connected Server (DCS) Remote Server (RS) LS
SCSP Phases
Hello Protocol DCS Hello LS • Sender ID • Receiver ID • Hello Interval • Dead. Factor
Hello Protocol States Down Waiting Bidirectional Connection Unidirectional Connection
Cache Alignment Protocol DCS 2 DCS 1 CSAS Records DCS 2 CSAS Records DCS 1 Cache State Advertisement Summary Records (CSAS records) LS LS
Cache Alignment Protocol States Down Master/Slave Negotiation Cache Summarise Update Cache Aligned
Cache State Update Protocol Changes of State in the Cache of the LS DCS • Add an entry to your cache • Remove an entry from your cache Cache entry has been modified Cache entry has timed out LS
Applications of SCSP l MARS l NHRP l ATMARP
MARS Servers Cache synchronised with Sub Cache B Cache synchronised with Sub Cache A
NHRP Servers l All NHRP servers in the same LIS are in the same server group l An NHRP client registers with only one NHRP server but may use any NHRP server within the server group
- Slides: 11