Four categories of attributes exist are as follows:-
- Well-known mandatory
- Well-known discretionary
- Optional transitive
- Optional non-transitive
AS_Path attribute- this particular path attribute lists the autonomous system numbers in the end-to-end path. BGP uses AS_Path as its primary loop-prevention tool.
AS_Path attribute is a well-known mandatory attribute. its list of AS through which updates are coming. The shortest AS_PATH list is more desirable.
Next_hop is a well-known, mandatory attribute next hop means IP address to reach next autonomous system because BGP is AS by AS routing protocol.
Origin attributeorigin informs all AS in internetwork how network got introduced into BGP.
Weight Attribute is a cisco's attribute. its tell how to exit the AS, path with the highest weight is more desirable. weight is partial attribute, by default weight 0 learn route 32,769 for locally injected routes. its local to the router not advertise to any BGP peers.
Local Preference Attribute
Local preference define how to data traffic should exit from an Autonomous system. path with highest preference value is more desirable by default is 100, and the range 0 through 232 local preference is well known, discretionary attribute it is advertise only to iBGP neighbor within an Autonomous system.
Here is the lists of all BGP labs and theories CCNA to CCIE
1.Introduction of BGP
3.BGP Peer Group
5.BGP Weight Attribute
6.BGP Local Preference (Local_Pref)
7.BGP Multi Exit Discriminator (MED)
8.BGP AS Path Prepending
9.BGP Route Reflectors (RR)
10.BGP Communities_No-advertise configuration
11.BGP community Local-AS
12.BGP Confederations and configuration
13.BGP Route filtering methods