Latest revision as of 12:21, 15 April 2014

hej

[edit] BGP

Hallå

[edit] 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