Dell S4048T, Configuration Manual

Page: 217 / 1277

Origin
The origin indicates the origin of the prefix, or how the prefix came into BGP. There are three origin codes:
IGP, EGP, INCOMPLETE.
Origin Type Description
IGP Indicates the prefix originated from information learned through an interior gateway
protocol.
EGP Indicates the prefix originated from information learned from an EGP protocol, which
NGP replaced.
INCOMPLETE Indicates that the prefix originated from an unknown source.
Generally, an IGP indicator means that the route was derived inside the originating AS. EGP generally means
that a route was learned from an external gateway protocol. An INCOMPLETE origin code generally results
from aggregation, redistribution, or other indirect ways of installing routes into BGP.
In Dell Networking OS, these origin codes appear as shown in the following example. The question mark (?)
indicates an origin code of INCOMPLETE (shown in bold). The lower case letter (i) indicates an origin code of
IGP (shown in bold).
Example of Viewing Origin Codes
Dell#show ip bgp
BGP table version is 0, local router ID is 10.101.15.13
Status codes: s suppressed, d damped, h history, * valid, > best
Path source: I - internal, a - aggregate, c - confed-external, r - redistributed,
n - network
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 7.0.0.0/29 10.114.8.33 0 0 18508 ?
*> 7.0.0.0/30 10.114.8.33 0 0 18508 ?
*> 9.2.0.0/16 10.114.8.33 10 0 18508 701 i
AS Path
The AS path is the list of all ASs that all the prefixes listed in the update have passed through.
The local AS number is added by the BGP speaker when advertising to a eBGP neighbor.
NOTE: Any update that contains the AS path number 0 is valid.
The AS path is shown in the following example. The origin attribute is shown following the AS path
information (shown in bold).
Example of Viewing AS Paths
Dell#show ip bgp paths
Total 30655 Paths
Address Hash Refcount Metric Path
0x4014154 0 3 18508 701 3549 19421 i
0x4013914 0 3 18508 701 7018 14990 i
0x5166d6c 0 3 18508 209 4637 1221 9249 9249 i
Border Gateway Protocol IPv4 (BGPv4) 217