Page Comparison

Open Msg
Notification Msg
Open
Keep Alive
Update Message

Well Known/ WK:

       Mandatory: Origin , AS-Path , Next-Hop
       Discretionary: Local-pref

Optional: 

  
Transitive: Community , Aggr
None-Transitive: MED, Origin-ID , Cluster list

RR: Originator ID, Cluster List ( Cluster ID )

Idle
Connected
Active
Opensent
Openconfirm
Establish

path Selection
add-paths
fast reroute

iBGP to iBGP : NOK Split Horizon ( uless Route Reflection)

eBGP to iBGP, eBGP to eBGP and iBGP to eBGP: OK

remove private AS:  remove-private

company buy another one,

old company change AS : local-as 1

old company change AS but not advertised : local-as 1 private