Origin Attribute
The origin is a mandatory attribute that defines the origin of the path information. The origin attribute can assume three values:
IGP: Network Layer Reachability Information (NLRI) is interior to the originating AS. This normally happens when we use the bgp network command or when IGP is redistributed into BGP, then the origin of the path info will be IGP. This is indicated with an "i" in the BGP table.
EGP: NLRI is learned via EGP (Exterior Gateway Protocol). This is indicated with an "e" in the BGP table.
INCOMPLETE: NLRI is unknown or learned via some other means. This usually occurs when we redistribute a static route into BGP and the origin of the route will be incomplete. This is indicated with an "?" in the BGP table.
RTA will reach 170.10.0.0 via: 300 i (which means the next AS path is 300 and the origin of the route is IGP).The origin is a mandatory attribute that defines the origin of the path information. The origin attribute can assume three values:
IGP: Network Layer Reachability Information (NLRI) is interior to the originating AS. This normally happens when we use the bgp network command or when IGP is redistributed into BGP, then the origin of the path info will be IGP. This is indicated with an "i" in the BGP table.
EGP: NLRI is learned via EGP (Exterior Gateway Protocol). This is indicated with an "e" in the BGP table.
INCOMPLETE: NLRI is unknown or learned via some other means. This usually occurs when we redistribute a static route into BGP and the origin of the route will be incomplete. This is indicated with an "?" in the BGP table.
RTA#
router bgp 100
neighbor 190.10.50.1 remote−as 100
neighbor 170.10.20.2 remote−as 300
network 150.10.0.0
redistribute static
ip route 190.10.0.0 255.255.0.0 null0
RTB#
router bgp 100
neighbor 150.10.30.1 remote−as 100
network 190.10.50.0
RTE#
router bgp 300
neighbor 170.10.20.1 remote−as 100
network 170.10.0.0
RTA will also reach 190.10.50.0 via: i (which means, the entry is in the same AS and the origin is IGP).
RTE will reach 150.10.0.0 via: 100 i (the next AS is 100 and the origin is IGP).
RTE will also reach 190.10.0.0 via: 100 ? (the next AS is 100 and the origin is incomplete "?", coming from a static route).
