Origin Attribute

- network command

- Redistributed from EGP

- Redistributed from IGP or static

The origin attribute informs all autonomous systems in the internetwork how the prefixes were introduced into BGP.

The origin attribute is well-known, mandatory.

The origin attribute defines the origin of the path information. The origin attribute can be one of these three values:

■ IGP: The route is interior to the originating AS. This value normally results when the network command is used to advertise the route via BGP. An origin of IGP is indicated with an "i" in the BGP table.

■ Exterior Gateway Protocol (EGP): The route has been learned via EGP. This value is indicated with an "e" in the BGP table. EGP is considered a historical routing protocol and is not supported on the Internet because it performs only classful routing and does not support classless interdomain routing (CIDR).

■ Incomplete: The origin of the route is unknown or has been learned by some other means. This value usually results when a route is redistributed into BGP. An incomplete origin is indicated with a question mark (?) in the BGP table.

6-92 Building Scalable Cisco Internetworks (BSCI) v3.0 © 2006 Cisco Systems, Inc.

RouterA# show ip

bgp

BGP table version is 14

, local router

ID is 172

.31.11

1

Status codes: s

suppressed,

d damped,

h history

, * valid, > best,

i -

internal, r RIB-

failure

, S

Stale

Origin codes: i

- IGP,

e -

EGP, ? - incomplete

Network

Next Hop

Metric

LocPrf

Weight

Path

*> 10.1.0.0/24

0.0

.0.0

0

32768

i

* i

10.

1.0.

2

0

100

0

i

*> 10.1.1.0/24

0.0

.0.0

0

32768

i

*>i10.1.2.0/24

10.

1.0.

2

0

100

0

i

*> 10.97.97.0/24

172

.31.

1.3

0

64998

64997

i

*

172

.31.

11.4

0

64999

64997

i

* i

172

.31.

11.4

0

100

0

64999

64997

i

*> 10.254.0.0/24

172

.31.

1.3

0

0

64998

i

*

172

.31.

11.4

0

64999

64998

i

* i

172

.31.

1.3

0

100

0

64998

i

r> 172.31.1.0/24

172

.31.

1.3

0

0

64998

i

r

172

.31.

11.4

0

64999

64998

i

r i

172

.31.

1.3

0

100

0

64998

i

*> 172.31.2.0/24

172

.31.

1.3

0

0

64998

i

<output omitted>

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