BGP Routing Table

Table 1 lists all the common route attributes that affect route selection and the commands that are used to check them.

**Table 1** Commands used to check route attributes
Route Attribute	Command Used to Check the Route Attribute
PrefVal	display bgp routing-table [ network ]
Local_Pref	display bgp routing-table [ network ]
Route type	display bgp routing-table network
AS_Path	display bgp routing-table [ network ]
Origin	display bgp routing-table [ network ]
MED	display bgp routing-table [ network ]
Peer type	display bgp routing-table network
IGP cost	display bgp routing-table network display ip routing-table ip-address [ mask \| mask-length ] [ verbose ], in which ip-address is the next hop IP address of a BGP route
Cluster_List	display bgp routing-table network
Originator_ID	display bgp routing-table network
Router ID	display bgp routing-table network
Peer IP address	display bgp routing-table network

The following example describes how to check BGP route attributes in the display bgp routing-table command output.

<HUAWEI> display bgp routing-table

 BGP Local router ID is 192.168.2.2
 Status codes: * - valid, > - best, d - damped,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete


 Total Number of Routes: 9
      Network            NextHop        MED        LocPrf    PrefVal Path/Ogn

 *>   1.1.1.9/32         0.0.0.0         0                     0      i
 *>i  2.2.2.7/32         10.1.1.2        0          100        0      (65001)i
 * i                     10.1.3.1        0          100        0      (65011 65001)i
 *>i  2.2.2.8/32         10.1.2.2        0          100        0      (65011)i
 * i                     10.1.3.2        0          100        0      (65001 65011)i
 *>i  2.2.2.9/32         10.1.4.2        0          100        0      (65001 65101)i
 * i                     10.1.5.2        0          100        0      (65011 65101)i
   i  3.3.3.9/32         10.1.6.2        0          100        0      (65001 65101) 300i
   i                     10.1.6.2        0          100        0      (65011 65001 65101) 300i

**Table 2** Description of the **display bgp routing-table** command output
Item	Description
BGP Local router ID is 1.1.1.2	Router ID: 1.1.1.2, in the same format as an IPv4 address
Status codes	Route status code, displayed in front of each route entry: *: indicates a valid route with a reachable next hop address. >: indicates an optimal route selected by BGP. d: indicates a dampened route. h: indicates a History route. i: indicates a route learned from an IBGP peer. s: indicates a suppressed route. If specific routes for route summarization are suppressed, s is displayed in front of each specific route. S: indicates a route in Stale status, and the route is being deleted. Such routes may occur during a BGP GR process. BGP dampening measures route stability using a penalty value. The greater the penalty value, the less stable a route. Each time route flapping occurs (a device receives a Withdraw or an Update packet), BGP adds a penalty value to the route carried in the packet. When the penalty value of a route exceeds the Suppress value, BGP suppresses the route by replacing the > sign of the route with the d or h sign. The route is ignored and its Update packets are not advertised to other BGP peers until the penalty value of the route decreases to the Reuse value. If d is displayed in front of a route, the route is carried in an Update packet. If h is displayed in front of a route, the route is carried in a Withdraw packet. The penalty value is not increased after it reaches the suppression threshold. The penalty value of a suppressed route reduces by half after a half-life period. When the penalty value of a route with the d sign decreases to the Reuse value, the route becomes reusable, and BGP removes the d sign, adds the route to the IP routing table, and advertises an Update packet carrying the route to BGP peers. When the penalty value of a route with the h sign decreases to 0, BGP deletes this route from the BGP routing table.
Origin	Route origin code, displayed in front of each route entry: IGP: indicates that routes are added to the BGP routing table using the network (BGP) command. EGP: indicates that routes are learned through the EGP protocol. Incomplete: indicates that routes are added to the BGP routing table using the import-route (BGP) command.
Network	Network address in the BGP routing table
NextHop	Next hop address
MED	MED value of a BGP route, similar to the cost of IGP routes
LocPrf	Local_Pref
PrefVal	PrefVal
Path/Ogn	AS_Path and Origin attributes

Information about Next_Hop, MED, Local_Pref, PrefVal, AS_Path, and Origin can be displayed using the display bgp routing-table command. To check information about the route type, peer type, IGP cost, Cluster_List, router ID, and peer IP address, run the display bgp routing-table network command.

<HUAWEI> display bgp routing-table 10.1.1.1

 BGP local router ID : 192.168.2.2
 Local AS number : 65001
 Paths:   1 available, 1 best, 1 select
 BGP routing table entry information of 10.1.1.1/32:
 From: 10.1.3.1 (192.168.2.3)
 Route Duration: 05h35m04s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface: GigabitEthernet1/0/4
 Original nexthop: 10.1.3.1
 Qos information : 0x0
 AS-path Nil, origin incomplete, MED 1234, localpref 100, pref-val 0, valid, internal, best, select, active, pre 255, IGP cost 1
 Not advertised to any peer yet

**Table 3** Description of the **display bgp routing-table** command output
Item	Description
BGP local router ID	Router ID of the local device, in the same format as an IPv4 address.
Local AS number	Local AS number.
Paths	BGP route information.
BGP routing table entry information of 10.1.1.1/32	Information about the BGP route 10.1.1.1/32:
From	IP address of the device that advertised the route. In this example, 10.1.3.1 is the IP address of the interface used by the peer to establish the BGP peer relationship (peer IP address), and 192.168.2.3 is the router ID of the peer.
Route Duration	Duration of a route.
Relay IP Nexthop	IP address of the route to which the BGP route is iterated.
Relay IP Out-Interface	Outbound interface of the route to which the BGP route is iterated.
Original nexthop	Original next hop IP address.
Qos information	QoS information.
AS-path	AS_Path attribute. If Nil is displayed, the AS_Path attribute is null.
origin incomplete	Origin attribute: IGP: indicates that routes are added to the BGP routing table using the network (BGP) command. EGP: indicates that routes are learned through the EGP protocol. Incomplete: indicates that routes are imported using the import-route (BGP) command.
MED	MED value of a BGP route, similar to the cost of IGP routes.
localpref	Local_Pref
pref-val	PrefVal
valid	Valid route with a reachable next hop address.
internal	Type of the peer from which the route is learned. external: indicates that the route is learned from an EBGP peer. internal: indicates that the route is learned from an IBGP peer.
best	Optimal route.
select	Selected route to be delivered to the IP routing table. NOTE: According to BGP selection rules, BGP selects only one optimal route, and this route is marked with best. In load balancing or FRR scenarios, more than one route needs to be added to the IP routing table, and each of the route is marked with select. Therefore, the number of the route marked with best is 1, and the number of the routes marked with select is the actual number of routes added to the IP routing table.
active	Active route.
pre 255	Protocol priority of the route: 255
Not advertised to any peer yet	The route has not advertised to any peer yet.

The display bgp routing-table network [ { mask | mask-length } [ longer-prefixes ] ] command output varies with the route generation mode and transmission mode, and not all BGP attributes are necessarily displayed. In the preceding example, the route type is not displayed because the route 10.1.1.1/32 is an IBGP route. For example:

<HUAWEI> display bgp routing-table 10.0.0.0

 BGP local router ID : 192.168.2.4
 Local AS number : 200
 Paths:   1 available, 1 best, 1 select
 BGP routing table entry information of 10.0.0.0/8:
 Aggregated route.
 Route Duration: 04h50m46s
 Direct Out-interface: NULL0
 Original nexthop: 127.0.0.1
 Qos information : 0x0
 AS-path {65001 10 100}, origin incomplete, pref-val 0, valid, local, best, select, active, pre 255
 Aggregator: AS 200, Aggregator ID 192.168.2.4, Atomic-aggregate
 Advertised to such 3 peers:
    10.1.7.2
    172.16.1.2
    192.168.1.2

The route 10.0.0.0/8 was manually summarized using the aggregate command. Therefore, Aggregated route is displayed in the command output. The route type varies as follows:

If the route is automatically summarized using the summary automatic command, Summary automatic route will be displayed.
If the route is imported using the network command, Network route will be displayed.
If the route is imported using the import-route command, Imported route will be displayed.

In the following example, an RR and a cluster are configured. Therefore, the Cluster_List attribute is displayed in the display bgp routing-table network [ { mask | mask-length } [ longer-prefixes ] ] command output.

<HUAWEI> display bgp routing-table 10.2.1.0

BGP local router ID : 4.4.4.4
 Local AS number : 65010
 Paths:   1 available, 0 best, 0 select
 BGP routing table entry information of 10.2.1.0/24:
 From: 10.1.4.1 (2.2.2.2)
 Route Duration: 00h00m14s
 Relay IP Nexthop: 0.0.0.0
 Relay IP Out-Interface:
 Original nexthop: 10.1.1.2
 Qos information : 0x0
 AS-path Nil, origin igp, MED 0, localpref 100, pref-val 0, internal, pre 255
 Originator:  1.1.1.1
 Cluster list: 0.0.0.1
 Not advertised to any peer yet