No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

Configuration Guide - IP Unicast Routing

S1720, S2700, S5700, and S6720 V200R011C10

This document describes IP Unicast Routing configurations supported by the switch, including the principle and configuration procedures of IP Routing Overview, Static Route, RIP, RIPng, OSPF, OSPFv3, IS-IS(IPv4), IS-IS(IPv6), BGP, Routing Policy ,and PBR, and provides configuration examples.
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
BGP Routing Table

BGP Routing Table

Table 10-5 lists all the common route attributes that affect route selection and the commands that are used to check them.

Table 10-5  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 10-6  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 10-7  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

IGP cost

IGP cost.

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
Translation
Download
Updated: 2019-10-21

Document ID: EDOC1000178171

Views: 310733

Downloads: 1092

Average rating:
This Document Applies to these Products
Related Documents
Related Version
Share
Previous Next