Origin

The Origin attribute indicates how routes become BGP routes.

Three types of Origin attributes are available:

IGP: indicates that routes are added to the BGP routing table using the network command. IGP has the highest priority.
EGP: indicates that routes are learned through the EGP protocol. EGP has the second highest priority.

The NetEngine 8000 F can receive and send BGP routes with EGP as the Origin. However, the NetEngine 8000 F does not support the EGP protocol; therefore, to set the Origin of routes to EGP, you need to run the apply origin { egp { as-number-plain | as-number-dot } | igp | incomplete } command to configure an apply clause for a route-policy.
Incomplete: indicates that routes are added to the BGP routing table using the import-route command. Incomplete has the lowest priority.

The routes imported using the network command are more specific than those imported using the import-route command. Therefore, IGP takes precedence over Incomplete in route selection. In Figure 1, Device A and Device B are EBGP peers, and Device B, Device C, and Device D are IBGP peers.

Figure 1 Networking diagram with Origin configurations

The configurations on Device D are as follows:

#
bgp 65001
 #
 ipv4-family unicast
  network 10.1.4.0 255.255.255.252                       //Advertise the route 10.1.4.0/30.
#

The configurations on Device C are as follows:

#
bgp 65001
 #
 ipv4-family unicast
  import-route direct                                   //Import direct routes.
#

Run the display bgp routing-table [ ip-address ] command to check the configurations.

# Display the routing table of Device B.

[~DeviceB] display bgp routing-table
 BGP Local router ID is 10.1.1.2
 Status codes: * - valid, > - best, d - damped, x - best external, a - add path,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 RPKI validation codes: V - valid, I - invalid, N - not-found

 Total Number of Routes: 3
      Network            NextHop        MED        LocPrf    PrefVal Path/Ogn

   i  10.1.2.0/30        10.1.2.2        0          100        0      ?
 *>i  10.1.4.0/30        10.1.3.2        0          100        0      i
 * i                     10.1.2.2        0          100        0      ?

The preceding command output shows that two active routes 10.1.4.0/30 are available in the routing table.

[~DeviceB] display bgp routing-table 10.1.4.0
 
 BGP local router ID : 10.1.1.2
 Local AS number : 65001
 Paths:   2 available, 1 best, 1 select
 BGP routing table entry information of 10.1.4.0/30:
 From: 10.1.3.2 (10.1.3.2)
 Route Duration: 01h14m48s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: GigabitEthernet0/1/0
 Original nexthop: 10.1.3.2
 Qos information : 0x0
 AS-path Nil, origin igp, MED 0, localpref 100, pref-val 0, valid, internal, best, select, active, pre 255
 Advertised to such 1 peers:
    10.1.1.1
 BGP routing table entry information of 10.1.4.0/30:
 From: 10.1.2.2 (10.1.2.2)
 Route Duration: 01h13m20s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: GigabitEthernet0/1/8
 Original nexthop: 10.1.2.2
 Qos information : 0x0
 AS-path Nil, origin incomplete, MED 0, localpref 100, pref-val 0, valid, internal, pre 255, not preferred for Origin
 Not advertised to any peer yet

The preceding command output shows that the route learned from Device D is selected because it is imported using the network command and its Origin priority is higher than that of the route learned from Device C. Table 1 describes the attribute comparison of the routes learned from Device C and Device D.

**Table 1** Attribute comparison of the routes learned from Device C and Device D
Route Attribute	Route Learned from Device C	Route Learned from Device D	Comparison
PrefVal	0	0	The same.
Local_Pref	100	100	The same.
Route type	Learned from a peer	Learned from a peer	The same.
AIGP	-	-	The same.
AS_Path	-	-	The same length.
Origin	Incomplete	IGP	The route learned from Device D is optimal.

The Origin attribute can be modified using a route-policy. In the following example, a route-policy is configured on Device B to modify the Origin attribute, and the detailed configurations are as follows:

#
bgp 65001
 #
 ipv4-family unicast
  peer 10.1.3.2 route-policy for_d import              //Apply import policy named for_d to the routes learned from 10.1.3.2 and use for_d to modify the Origin value.
#
route-policy for_d permit node 10                      //Define the route-policy named for_d.
 apply origin incomplete                               //Set the Origin type to Incomplete.

Run the display bgp routing-table [ ip-address ] command to check the configurations.

# Display the routing table of Device B.

[~DeviceB] display bgp routing-table
 BGP Local router ID is 10.1.1.2
 Status codes: * - valid, > - best, d - damped, x - best external, a - add path,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 RPKI validation codes: V - valid, I - invalid, N - not-found

 Total Number of Routes: 3
      Network            NextHop        MED        LocPrf    PrefVal Path/Ogn

   i  10.1.2.0/30        10.1.2.2        0          100        0      ?
 *>i  10.1.4.0/30        10.1.2.2        0          100        0      ?
 * i                     10.1.3.2        0          100        0      ?

The preceding command output shows that the route learned from Device C becomes the optimal route.

[~DeviceB] display bgp routing-table 10.1.4.0
 BGP local router ID : 10.1.1.2
 Local AS number : 65001
 Paths:   2 available, 1 best, 1 select
 BGP routing table entry information of 10.1.4.0/30:
 From: 10.1.2.2 (10.1.2.2)
 Route Duration: 01h28m19s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: GigabitEthernet0/1/0
 Original nexthop: 10.1.2.2
 Qos information : 0x0
 AS-path Nil, origin incomplete, MED 0, localpref 100, pref-val 0, valid, internal, best, select, active, pre 255
 Advertised to such 1 peers:
    10.1.1.1
 BGP routing table entry information of 10.1.4.0/30:
 From: 10.1.3.2 (10.1.3.2)
 Route Duration: 00h03m18s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: GigabitEthernet0/1/8
 Original nexthop: 10.1.3.2
 Qos information : 0x0
 AS-path Nil, origin incomplete, MED 0, localpref 100, pref-val 0, valid, internal, pre 255, not preferred for router ID
 Not advertised to any peer yet

The preceding command output shows that the route learned from Device C becomes the optimal route because it has a smaller router ID than the route learned from Device D. Table 2 describes the attribute comparison of the routes learned from Device C and Device D.

**Table 2** Attribute comparison of the routes learned from Device C and Device D
Route Attribute	Route Learned from Device C	Route Learned from Device D	Comparison
PrefVal	0	0	The same.
Local_Pref	100	100	The same.
Route type	Learned from a peer	Learned from a peer	The same.
AIGP	-	-	The same.
AS_Path	-	-	The same.
Origin	Incomplete	Incomplete	The same.
MED	0	0	The same.
Peer type	IBGP	IBGP	The same.
IGP cost	-	-	The same.
Cluster_List	-	-	The same.
Router ID	10.1.2.2	10.1.3.2	The route learned from Device C is optimal.