Benefit of Multipoint Design

typeshtypesh Posts: 168Member
Hey guys...

I've been thinking about Frame Relay quite a bit. The more I think about it, I don't understand why an organization would choose a Multipoint Design rather than a Point To Point.

In a 3 router hub-and-spoke scenario where R1 is the hub, R1 would need to disable split horizon in order to advertise R2s subnets to R3, and also to advertise R3s subnets to R2. While turning off split-horizon will allow full reachability, it still will allow routing loops to occur (for instance if one of R2s subnets goes down just before R1 advertises a 2 hop route back to R2 for the same subnet that went down).

I can't really find a benefit in a multipoint design...why not just make it point to point and avoid any issues...?

Comments

  • alan2308alan2308 Senior Member Ann Arbor, MIPosts: 1,854Member ■■■■■■■■□□
    The real benefit is cost. Multiple point to point links between each site would be ideal, but its not always economical.

    And there are other mechanisms besides split horizon to prevent routing loops, such as the hold-down timer.
  • notgoing2failnotgoing2fail Posts: 1,138Member
    IP addressing scheme and what routing protocol you use comes into play.
  • typeshtypesh Posts: 168Member
    Thanks guys. I forgot about hold-down! icon_pale.gif
  • alan2308alan2308 Senior Member Ann Arbor, MIPosts: 1,854Member ■■■■■■■■□□
    IP addressing scheme and what routing protocol you use comes into play.

    True. When I saw split horizon, I just assumed RIP. :)
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