Users Guide

NOTE: The MEDs are advertised across both links, so if a link goes down, AS 1 still has connectivity to AS300 and AS400.
Figure 23. Multi-Exit Discriminators
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 the 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.
The AS path is shown in the following example. The origin attribute is shown following the AS path information (shown in bold).
Border Gateway Protocol IPv4 (BGPv4) 172