Plugga CCNP Route--BGP

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hej

BGP

Hallå

Tough Questions

  1. "aggregate-address" does not need to be synchronized, bute there *must* be at least one subnet of it, that exists in the routing table
  2. Split-horizon rule states that iBGP routes are never propagated to other iBGP peers (conclusion: use full mesh to solve this)
  3. "Always-compare-med" forces the router to compare MEDs from different AS'es
  4. BGP uses TCP port 179. Notifications are always bad [and (sometimes?) breaks the connection??]
  5. State table:
    • Idle -- BGP not enabled
    • Connect -- Waits for TCP connection
    • Active -- Open is Sent but connection still *not* established. Waiting for a connection
    • OpenSent -- OpenSent message is sent
    • OpenConfirm
    • Established
  6. A static route is preferred method (over IGP), when finding eBGP-neighbor
  7. Path selection
    1. highest Weight
    2. highest Local pref
    3. origin local router (0.0.0.0) (network command etc)
    4. shortest AS-path
    5. prefer IGP over EGP origin
    6. prefer lowest med
    7. ...
    8. Lowest Router ID
    9. LAST: lowest neighbor IP-address
  8. "neighbor x.x.x.x send-community"  ???
  9. BGP features:
    Enable feature with (memory intensive) "neighbor x.x.x.x soft-reconfiguration-inbound"
    show ip bgp neighbor x.x.x.x | include [Rr]oute [Rr]efresh
    Above two is mutually exclusive !! (ena eller andra)
    HUR KÖR JAG KOMMANDOT ??
  10. Kom ihåg att läsa ordet "not" !! (:-)
  11. Kom ihåg att alltid dubbelkolla Route-Maps om det är implicit deny vid route redistribution
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