CST3607 Class Notes 2018-10-30

News & Tools

Loop Prevention (Routers)

  • Split horizon in distance-vector Routing Protocols
    • When using split horizon, a routing protocol tries to prevent a routing loop. It does this by not advertising a route from an interface from which it received an advertisement for that route. Simply: The split horizon rule prohibits a router from advertising a route through an interface that the router itself uses to reach that destination network.
  • Poison Reverse
    • Distance-vector routing protocols in computer networks use route poisoning to indicate to other routers that a route is no longer reachable and should be removed from their routing tables.

Routing Tables

  • The minimum fields needed in a routing table:
FieldDescription
MaskThe network prefix (in CIDR notation) of the destination network
Network addressThe network address of the destination network

Interface
The network interface used to get to the next hop router. 
a.k.a. “Exit Interface” 
Think… From the router you’re on, which interface do I have to send the packet out of, to get it to the Next Hop router?
Next Hop IP addressThe IP address of the next neighbor router to the destination network. 
Think… From the router I am on, what is the IP address of the closest router I can forward the packet to, to get that packet to the destination network?

Lab-03: Building Routing Tables

  • Lab-03: Network Diagram (PDF)
  • Lab-03: Worksheet with Router A Complete (rtf)
  • Lab-03: Empty Worksheet (rtf)
  • You must be in class to get credit for this lab.
  • You must complete the routing table for all routers and hand in the completed worksheet at the beginning of the next class, to get full credit for this lab.

Read / Do

  • CCNA Routing and Switching Study Guide, 2nd Ed.: Chapter 18: OSPF
    • Do the Chapter: Written Lab, Review Questions, AND Hands-on Labs
  • Note: Until further notice, bring your text book to every class, so that you’ll have access to the instructions for the Hands-on Labs.

Study for Exam #2

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