13.6.2 Checking the Community

<Structure of this section>

(1) List of operation commands

The following table lists the operation commands related to communities.

Table 13-26: List of operation commands
Command name	Description
show ip route	Displays routing information stored in the routing table.
show ip bgp	Shows information related to the BGP4 protocol.

(2) Displaying the community of learned routes

To display routes that have a specific community, use the show ip bgp command with the community parameter specified.

Figure 13-35: Result of executing show ip bgp command (specifying community parameter)
> show ip bgp community 1000:1002 Date 20XX/10/20 21:07:32 UTC Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, * valid, > active, S Stale, r RIB failure Origin Codes: i - IGP, e - EGP, ? - incomplete Network Next Hop MED LocalPref Weight Path > 10.10/16 172.16.2.2 0 - 0 65532 i > 10.20/16 172.16.2.2 0 - 0 65532 i

Figure 13-35: Result of executing show ip bgp command (specifying community parameter)

> show ip bgp community 1000:1002
Date 20XX/10/20 21:07:32 UTC
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Origin Codes: i - IGP, e - EGP, ? - incomplete
   Network             Next Hop        MED    LocalPref Weight Path
*> 10.10/16            172.16.2.2      0      -         0      65532 i
*> 10.20/16            172.16.2.2      0      -         0      65532 i

To display the communities that a route belongs to, use the show ip bgp command with the route parameter specified.

Figure 13-36: Result of executing show ip bgp command (specifying route parameter)
> show ip bgp route 10.10/16 Date 20XX/10/20 21:09:12 UTC BGP Peer: 172.16.2.2 , Remote AS: 65532 Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, * valid, > active, S Stale, r RIB failure Route 10.10/16 *> Next Hop 172.16.2.2 MED: -, LocalPref: 100, Weight: 0, Type: External route Origin: IGP, IGP Metric: 0 Path: 65532 Communities: 1000:1002

Figure 13-36: Result of executing show ip bgp command (specifying route parameter)

> show ip bgp route 10.10/16
Date 20XX/10/20 21:09:12 UTC
BGP Peer: 172.16.2.2   , Remote AS: 65532
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Route 10.10/16
*> Next Hop 172.16.2.2
     MED: -, LocalPref: 100, Weight: 0, Type: External route
     Origin: IGP, IGP Metric: 0
     Path: 65532
     Communities: 1000:1002

(3) Displaying learned route filtering results

To display the result of learned route filtering based on the COMMUNITIES attribute, use the show ip bgp operation command.

Figure 13-37: Result of executing show ip bgp command
> show ip bgp Date 20XX/10/20 21:10:09 UTC Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, * valid, > active, S Stale, r RIB failure Origin Codes: i - IGP, e - EGP, ? - incomplete Network Next Hop MED LocalPref Weight Path > 10.10/16 172.16.2.2 - 120 0 65532 i 10.10/16 10.2.2.2 - 80 0 65533 i > 10.20/16 172.16.2.2 - 120 0 65532 i 10.20/16 10.2.2.2 - 80 0 65533 i > 192.169.10/24 192.168.2.2 - 100 0 i > 192.169.20/24 192.168.2.2 - 100 0 i

Figure 13-37: Result of executing show ip bgp command

> show ip bgp
Date 20XX/10/20 21:10:09 UTC
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Origin Codes: i - IGP, e - EGP, ? - incomplete
   Network             Next Hop        MED    LocalPref Weight Path
*> 10.10/16            172.16.2.2      -      120       0      65532 i
*  10.10/16            10.2.2.2        -       80       0      65533 i
*> 10.20/16            172.16.2.2      -      120       0      65532 i
*  10.20/16            10.2.2.2        -       80       0      65533 i
*> 192.169.10/24       192.168.2.2     -      100       0      i
*> 192.169.20/24       192.168.2.2     -      100       0      i

(4) Displaying communities for advertised routes

To display the COMMUNITIES attribute of advertised BGP4 routes, use the show ip bgp operation command with the advertised-routes parameter specified.

Figure 13-38: Result of executing show ip bgp command (specifying advertised-routes parameter)
> show ip bgp advertised-routes 192.169.10/24 Date 20XX/10/20 21:10:25 UTC BGP Peer: 172.16.2.2 , Remote AS: 65532 Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, * valid, > active, S Stale, r RIB failure Route 192.169.10/24 > Next Hop 192.168.2.2 MED: -, LocalPref: -, Type: Internal route Origin: IGP Path: 65531 Next Hop Attribute: 172.16.2.1 Communities: 1000:1001 BGP Peer: 10.2.2.2 , Remote AS: 65533 Local AS: 65531, Local Router ID: 192.168.1.100 Status Codes: d dampened, valid, > active, S Stale, r RIB failure Route 192.169.10/24 *> Next Hop 192.168.2.2 MED: -, LocalPref: -, Type: Internal route Origin: IGP Path: 65531 Next Hop Attribute: 10.1.2.1 Communities: 1000:1001

Figure 13-38: Result of executing show ip bgp command (specifying advertised-routes parameter)

> show ip bgp advertised-routes 192.169.10/24
Date 20XX/10/20 21:10:25 UTC
BGP Peer: 172.16.2.2    , Remote AS: 65532
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Route 192.169.10/24
*> Next Hop 192.168.2.2
     MED: -, LocalPref: -,  Type: Internal route
     Origin: IGP
     Path: 65531
     Next Hop Attribute: 172.16.2.1
     Communities: 1000:1001
 
BGP Peer: 10.2.2.2     , Remote AS: 65533
Local AS: 65531, Local Router ID: 192.168.1.100
Status Codes: d dampened, * valid, > active, S Stale, r RIB failure
Route 192.169.10/24
*> Next Hop 192.168.2.2
     MED: -, LocalPref: -, Type: Internal route
     Origin: IGP
     Path: 65531
     Next Hop Attribute: 10.1.2.1
     Communities: 1000:1001