13.6.5 Checking the route refresh function

<Structure of this section>

(1) List of operation commands

The following table lists the operation commands related to the route refresh facility.

Table 13-29: List of operation commands
Command name	Description
clear ip bgp	Clears BGP4 sessions or BGP4-related information, or filters inbound or outbound routes using new BGP filter information.
show ip route	Displays routing information stored in the routing table.
show ip bgp	Shows information related to the BGP4 protocol.

(2) Confirm route refresh capability negotiation

First, make sure that route refresh capability has been successfully negotiated with the BGP4 peer that will be requested to re-advertise its BGP4 routes. To do so, use the show ip bgp operation command with the neighbors parameter specified. If route refresh capability has not been negotiated, route refresh requests to relearn changed routes will not be sent to the remote peer.

Figure 13-41: Result of executing show ip bgp command (specifying neighbors parameter)
> show ip bgp neighbors 172.16.2.2 Date 20XX/10/17 15:52:14 UTC BGP Peer: 172.16.2.2 , Remote AS: 65532 Remote Router ID: 172.16.1.102 BGP Status: Established HoldTime: 180 , Keepalive: 60 Established Transitions: 1 Established Date: 20XX/10/17 15:49:35 BGP Version: 4 Type: External Local Address: 172.16.2.1 Local AS: 65531 Local Router ID: 192.168.1.100 Next Connect Retry: - Connect Retry Timer: - Last Keep Alive Sent: 15:51:35 Last Keep Alive Received: 15:51:35 BGP Message UpdateIn UpdateOut TotalIn TotalOut 1 1 4 6 BGP Capability Negotiation: <IPv4-Uni Refresh Refresh(v)> ..1 Send : <IPv4-Uni Refresh Refresh(v)> Receive: <IPv4-Uni Refresh Refresh(v)> Password: UnConfigured BFD Name: -, BFD ID: -, BFD State: -

Figure 13-41: Result of executing show ip bgp command (specifying neighbors parameter)

> show ip bgp neighbors 172.16.2.2
Date 20XX/10/17 15:52:14 UTC
BGP Peer: 172.16.2.2     , Remote AS: 65532
Remote Router ID: 172.16.1.102
    BGP Status: Established         HoldTime: 180  , Keepalive: 60
    Established Transitions: 1      Established Date: 20XX/10/17 15:49:35
    BGP Version: 4                  Type: External
    Local Address: 172.16.2.1       Local AS: 65531
    Local Router ID: 192.168.1.100
    Next Connect Retry: -           Connect Retry Timer: -
    Last Keep Alive Sent: 15:51:35  Last Keep Alive Received: 15:51:35
    BGP Message  UpdateIn   UpdateOut  TotalIn    TotalOut
                 1          1          4          6
    BGP Capability Negotiation: <IPv4-Uni Refresh Refresh(v)>             ..1
      Send   : <IPv4-Uni Refresh Refresh(v)>
      Receive: <IPv4-Uni Refresh Refresh(v)>
    Password: UnConfigured
    BFD Name: -, BFD ID: -, BFD State: -

Route refresh capability with the remote peer was successfully negotiated.

(3) Re-advertisement requests and re-advertisements of BGP4 routes

To request that all BGP4 peers re-advertise their BGP4 routes, and to re-advertise the routes to all BGP4 peers, use the clear ip bgp operation command with the * both parameter specified.

Figure 13-42: Result of executing clear ip bgp command
#clear ip bgp * both

(4) Checking BGP4 route relearning and re-advertisement

To check that BGP4 routes have been re-advertised and relearned by using the route refresh functionality, use the show ip bgp command with the neighbors parameter specified.

Figure 13-43: Result of executing show ip bgp command (specifying neighbors parameter)
> show ip bgp neighbors 172.16.2.2 Date 20XX/10/17 15:58:12 UTC BGP Peer: 172.16.2.2 , Remote AS: 65532 Remote Router ID: 172.16.1.102 BGP Status: Established HoldTime: 180 , Keepalive: 60 Established Transitions: 1 Established Date: 20XX/10/17 15:49:35 BGP Version: 4 Type: External Local Address: 172.16.2.1 Local AS: 65531 Local Router ID: 192.168.1.100 Next Connect Retry: - Connect Retry Timer: - Last Keep Alive Sent: 15:57:35 Last Keep Alive Received: 15:57:35 BGP Message UpdateIn UpdateOut TotalIn TotalOut 2 2 11 14 ..1 BGP Capability Negotiation: <IPv4-Uni Refresh Refresh(v)> Send : <IPv4-Uni Refresh Refresh(v)> Receive: <IPv4-Uni Refresh Refresh(v)> Password: UnConfigured BFD Name: -, BFD ID: -, BFD State: -

Figure 13-43: Result of executing show ip bgp command (specifying neighbors parameter)

> show ip bgp neighbors 172.16.2.2
Date 20XX/10/17 15:58:12 UTC
BGP Peer: 172.16.2.2     , Remote AS: 65532
Remote Router ID: 172.16.1.102
    BGP Status: Established         HoldTime: 180  , Keepalive: 60
    Established Transitions: 1      Established Date: 20XX/10/17 15:49:35
    BGP Version: 4                  Type: External
    Local Address: 172.16.2.1       Local AS: 65531
    Local Router ID: 192.168.1.100
    Next Connect Retry: -           Connect Retry Timer: -
    Last Keep Alive Sent: 15:57:35  Last Keep Alive Received: 15:57:35
    BGP Message  UpdateIn   UpdateOut  TotalIn    TotalOut
                 2          2          11         14                    ..1
    BGP Capability Negotiation: <IPv4-Uni Refresh Refresh(v)> 
      Send   : <IPv4-Uni Refresh Refresh(v)>
      Receive: <IPv4-Uni Refresh Refresh(v)>
    Password: UnConfigured
    BFD Name: -, BFD ID: -, BFD State: -

There has been an increase in the numbers of received UPDATE messages and sent UPDATE messages.

Notes: The operation-command clear ip bgp(* in,* out,* both specification applies both route filtering changes and route refresh functionality (see 13.4.5 Route refresh). If route refresh capability has not been negotiated, no route refresh requests are made in order to relearn changed routes, although the route filter changes are applied.