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14.1.2 Changing the Origin Type
When using the BGP network command, the origin should show up as IGP on each of the remote peers.
In some cases, you may wish to change the origin to a lower priority origin type such as INC to influence
the route decision at a remote peer. A path with the lowest origin type will be selected, where IGP is lower
than EGP and EGP is lower than INComplete.
For example, let's assume we wish to take the path from 9001 to ERS8000-E to get to network
200.1.40.0/24. To do so, we will configure a route policy on 8008 to advertise network 200.1.40.0/24 with
an origin of INC and apply this to the BGP peer containing neighbor 10.1.1.13 or ERS8000-D.
If we look at the BGP route table on ERS8000-D, you will notice the path to 200.1.40.0/24 has two paths
both with an origin of IGP with the preferred route via 10.1.1.14.
ERS8000-D# show ip bgp route 200.1.40.0/24
The total number of routes is 22
Network/Mask
------------------ --------------- --------------- --- ----------
200.1.40.0/24
200.1.40.0/24
ERS8000-D# show ip route -s 200.1.40.0/24
=================================================================================
=================================================================================
DST
---------------------------------------------------------------------------------
200.1.40.0
1 out of 14 Total Num of Route Entries, 14 Total Num of Dest Networks displayed.
---------------------------------------------------------------------------------
TYPE Legend:
I=Indirect Route, D=Direct Route, A=Alternative Route, B=Best Route, E=Ecmp Route
, U=Unresolved Route, N=Not in HW
In the configuration steps that follow, we will configure a route policy to advertise from 8008 to ERS8000-
D the route to 200.1.40.0/24 with an origin of INC. This will result in ERS8000-D using the next-hop of
10.1.1.61 (via ERS8000-E) to get to network 200.1.40.0/24.
January 2016
Peer Rem Addr
NextHop Address Org Loc Pref
10.1.1.14
10.1.1.14
AS_PATH: (1)
10.1.1.61
10.1.1.42
AS_PATH: (1)
MASK
255.255.255.0
10.1.1.14
Avaya Inc. – External Distribution
IGP 100
IGP 100
Ip Route
NEXT COST VLAN
PORT PROT AGE TYPE PRF
1 2171
4/6
avaya.com
BGP
0 IB
45
76
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