Planning Network Architectures

1. Planning Network Architectures Hierarchical Network Design – a Review RD-CSY3021

2. Objectives • Internetworking • Campus Networks • Issues - nonhierarchical network • multilayer switches in nonhierarchical network • Enterprise Composite module (ECNM) • benefits of the ECNM • Campus Infrastructure module of the ECNM RD-CSY3021

3. Internetworking • Internetworking is the communication between two or more networks • Requires many protocols and features to • permit scalability • manageability without constant manual intervention • Large internetworks can consist of the three distinct components: • Campus networks, which consist of locally connected users in a building or group of buildings • Wide-area networks (WANs), which connect campuses together • Remote connections, which link branch offices and single users (mobile users and/or telecommuters) to a local campus or the Internet Typical Enterprise Network RD-CSY3021

4. Campus Networks • A campus is a building or group of buildings all connected into one enterprise network that consists of many local area networks (LANs). • A large campus with groups of buildings can also use WAN technology to connect the buildings • Campus network generally optimized for the fastest functional architecture that runs on existing physical wire. • Scalable to requirements of emerging applications Campus Network RD-CSY3021

5. Cisco Enterprise Architecture RD-CSY3021

6. Trends in Campus Design Past: • Limited hardware options • routers or hubs when purchasing a technology for their campus networks Recent: • deploying LAN switches to replace shared concentrator hubs and give higher bandwidth connections to the end user Trends: Past and Present Trends in campus design RD-CSY3021

7. Nonhierarchical Network Devices • Large collision domain • Large broadcast domain • High latency • Difficult to troubleshoot Disadvantages Flat Network RD-CSY3021

8. Layer 2 Switching • Features • Hardware-based bridging • Wire-speed performance • Collision domain per port • Traffic containment based on MAC address Issues • No traffic between VLANs • Unbounded broadcast domain • Servers not centrally located Features and Issues Switched Network RD-CSY3021

9. Layer 3 Routing • Single broadcast domain per interface • ACLs can be applied between segments Issues • High per-port cost • Layer 3 processing required • High latency over Layer 2 switching Features and Issues Routed Network RD-CSY3021

10. Multilayer Switching • Combined functionality • Layer 2 switching • Layer 3 switching • Layer 4 switching • Low latency • High-speed scalability RD-CSY3021

11. Issues with Multilayer Switchesin a Nonhierarchical Network • Single point of failure for Layers 2 and Layers 3 • Underutilization of hardware • Spanning tree complexity • Servers not centrally located RD-CSY3021

12. Hierarchical Campus Model RD-CSY3021

13. Enterprise Composite Network Model RD-CSY3021

14. Campus Infrastructure Module RD-CSY3021

15. Modules in the Enterprise Campus RD-CSY3021

16. Summary • Multilayer switches combine both Layer 2 and Layer 3 functionality to support the modern campus network topology. • Multilayer switches can be used in nonhierarchical networks; however, they will not perform at the optimal level. • The enterprise composite model identifies the key components and logical design for a modern topology. • Implementation of an ECNM provides a secure, robust network with high availability. • The Campus infrastructure, as part of an ECNM, provides additional security and high availability at all levels of the campus. RD-CSY3021

17. Resources • Cisco Service-Oriented Network Architecture • http://cisco.com/en/US/partner/netsol/ns629/networking_solutions_market_segment_solutions_home.html • Cisco Intelligent Information Network • http://cisco.com/en/US/partner/netsol/ns650/networking_solutions_market_segment_solution.html RD-CSY3021

18. Next Week • Designing LANs • Routed Network • Compatibility, • conformance, and • Interoperability RD-CSY3021