Category: Arch

SONET / SDH

Sonet ( Synchronous Optical Networking)

• American National Standards Institute (ANSI)
• Used in US / Canada
• Synchronous transport signals (STS) used for speed

Synchronous Digital Hierarchy

• International Telecommunications union (ITU)
• Used everywhere expect US / Canada
• Synchronoous transport Modules (STM) used for speed)

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EIGRP design principles

• EIGRP works for arbitrary topologies for small to medium networks.
• A flat EIGRP network doesn’t really scale beyond 400 routers and will lead to performance issuse
  • How to solve this?
    • Stub areas, summerization, route filtering limits the query scope
• If EIGRP doesn’t have a feasible successor it will query all it’s neighbours.
  • “I don’t have a route anymore, don’t route through me, give me a viable route”.
• BFD to optimize convergence (100ms wtih 1000 routes).
• 2 second hello timer, 6 second hold timer ( recommended )

Multiple EIGRP design principles

• Used to merge two networks ( Acquisitions )
• Different administrative groups in a company
• a way to devide large networks ( and control queries )
• Routes are distributed between AS ( don’t loop! )

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