Example for Configuring BGP RPD

BGP RPD ensures that route-policies are distributed dynamically.

Networking Requirements

In a MAN ingress or IGW scenario, uneven link resource usage or link faults may cause link congestion. To make full use of network bandwidth, you can deploy an inbound traffic optimization solution to adjust route priorities so that traffic is diverted to idle links. In such a scenario, the router functions as a forwarder, and RPD needs to be deployed on it.

In Figure 1, BGP runs on all routers. Device A and Device B reside in AS 100, Device C in AS 200, and NCE in AS 300. The traffic that Device C in AS 200 sends to the destination IP address 192.168.1.0 can enter AS 100 through Device A or Device B. However, NCE finds that the link between Device A and Device C is congested. In this case, a traffic optimization policy can be configured so that an RPD route is delivered to divert the traffic from Device C to Device B when the traffic enters AS 100.

Figure 1 Networking for configuring BGP RPD

Interface 1 and interface 2 in this example stand for GE 0/1/0 and GE 0/1/1, respectively.

Precautions

None

Configuration Roadmap

The configuration roadmap is as follows:

Configure EBGP connections between Device A and Device C, and between Device B and Device C.
On Device A and Device B, enable RPD and establish RPD peer relationships with the NCE.
Configure IPv4 unicast on Device A, Device B, and Device C so that IPv4 unicast peer relationships are established between Device A and Device C, and between Device B and Device C.

This section provides only the configurations and procedures for forwarders. For details about NCE's configurations, such as the BGP, RPD address family, and traffic optimization policy configurations, see the NCE manual.

Data Preparation

To complete the configuration, you need the following data:

Router ID 4.1.1.1 of Device A, router ID 2.2.2.2 of Device B, and their AS number 100
Router ID 3.3.3.3 of Device C and its AS number 200

Procedure

Assign an IP address to each interface. For configuration details, see Configuration Files in this section.

Configure BGP connections.

# Configure Device A.

[~DeviceA] bgp 100
[*DeviceA-bgp] router-id 4.1.1.1
[*DeviceA-bgp] peer 10.2.1.2 as-number 200
[*DeviceB-bgp] peer 1.1.1.1 as-number 300
[*DeviceA-bgp] ipv4-family unicast
[*DeviceA-bgp-af-ipv4] network 192.168.1.0 255.255.255.0
[*DeviceA-bgp-af-ipv4] commit
[~DeviceA-bgp-af-ipv4] quit
[~DeviceA-bgp] quit

# Configure Device B.

[~DeviceB] bgp 100
[*DeviceB-bgp] router-id 2.2.2.2
[*DeviceB-bgp] peer 10.3.1.2 as-number 200
[*DeviceB-bgp] peer 2.1.1.1 as-number 300
[*DeviceB-bgp] ipv4-family unicast
[*DeviceB-bgp-af-ipv4] network 192.168.1.0 255.255.255.0
[*DeviceB-bgp-af-ipv4] commit
[~DeviceB-bgp-af-ipv4] quit
[~DeviceB-bgp] quit

# Configure Device C.

[~DeviceC] bgp 200
[*DeviceC-bgp] router-id 3.3.3.3
[*DeviceC-bgp] peer 10.2.1.1 as-number 100
[*DeviceC-bgp] peer 10.3.1.1 as-number 100
[*DeviceC-bgp] ipv4-family unicast
[*DeviceC-bgp-af-ipv4] commit
[~DeviceC-bgp-af-ipv4] quit
[~DeviceC-bgp] quit

# Check the routing table of Device C.

[~DeviceC] display bgp routing-table 192.168.1.0 24

 BGP local router ID : 3.3.3.3
 Local AS number : 200
 Paths:   2 available, 1 best, 1 select
 BGP routing table entry information of 192.168.1.0/24:
 From: 10.2.1.1 (1.1.1.1)
 Route Duration: 0d00h00m56s
 Direct Out-interface: GigabitEthernet0/1/0
 Original nexthop: 10.2.1.1
 Qos information : 0x0
 AS-path 100, origin igp, MED 0, pref-val 0, valid, external, best, select, pre 255
 Advertised to such 2 peers:
    10.2.1.1
    10.3.1.1

 BGP routing table entry information of 192.168.1.0/24:
 From: 10.3.1.1 (2.2.2.2)
 Route Duration: 0d00h00m06s
 Direct Out-interface: GigabitEthernet0/1/1
 Original nexthop: 10.3.1.1
 Qos information : 0x0
 AS-path 100, origin igp, MED 0, pref-val 0, valid, external, pre 255, not preferred for router ID
 Not advertised to any peers yet

The preceding command output shows that there are two valid routes to 192.168.1.0/24. The route with the next-hop address of 10.2.1.1 is the optimal route because the router ID of Device A is smaller. In this case, traffic enters AS 100 through Device A.

Configure BGP RPD functions on forwarders so that the forwarders receive RPD routes delivered by the NCE and execute corresponding route-policies.

# Configure Device A.

[~DeviceA] bgp 100
[*DeviceA-bgp] peer 1.1.1.1 as-number 300
[*DeviceA-bgp] rpd-family
[*DeviceA-bgp-af-rpd] peer 1.1.1.1 enable
[*DeviceA-bgp-af-rpd] quit
[*DeviceA-bgp] ipv4-family unicast
[*DeviceA-bgp-af-ipv4] peer 10.2.1.2 rpd-policy export enable
[*DeviceA-bgp-af-ipv4] commit
[~DeviceA-bgp-af-ipv4] quit
[~DeviceA-bgp] quit

# Configure Device B.

[~DeviceB] bgp 100
[*DeviceB-bgp] peer 2.1.1.1 as-number 300
[*DeviceB-bgp] rpd-family
[*DeviceB-bgp-af-rpd] peer 2.1.1.1 enable
[*DeviceB-bgp-af-rpd] quit
[*DeviceB-bgp] ipv4-family unicast
[*DeviceB-bgp-af-ipv4] peer 10.3.1.2 rpd-policy export enable
[*DeviceB-bgp-af-ipv4] commit
[~DeviceB-bgp-af-ipv4] quit
[~DeviceB-bgp] quit

# Check information about RPD routes on Device A.

[~DeviceA] display bgp rpd routing-table

 Total number of Routes : 1
 BGP Local router ID is 4.1.1.1
 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
        Network                        Peer           MED        LocPrf    PrefVal Path/Ogn 
 *>     1/10.2.1.2/1                   1.1.1.1        50                   0       100?

# Check the routing table of Device C.

[~DeviceC] display bgp routing-table 192.168.1.0 24

 BGP local router ID : 3.3.3.3
 Local AS number : 200
 Paths:   2 available, 1 best, 1 select
 BGP routing table entry information of 192.168.1.0/24:
 From: 10.3.1.1 (2.2.2.2)
 Route Duration: 0d00h00m06s
 Direct Out-interface: GigabitEthernet1/0/1
 Original nexthop: 10.3.1.1
 Qos information : 0x0
 AS-path 100, origin igp, MED 0, pref-val 0, valid, external, best, select, pre 255
 Advertised to such 2 peers:
    10.2.1.1
    10.3.1.1

 BGP routing table entry information of 192.168.1.0/24:
 From: 10.2.1.1 (1.1.1.1)
 Route Duration: 0d00h00m56s
 Direct Out-interface: GigabitEthernet1/0/0
 Original nexthop: 10.2.1.1
 Qos information : 0x0
 AS-path 100, origin igp, MED 50, pref-val 0, valid, external, pre 255, not preferred for MED
 Not advertised to any peers yet

The preceding command output shows that DeviceC selects the route with the next hop of 10.3.1.1 (Device B) as the optimal route because the MED value (0) of this route is smaller than that (50) of the route with the next hop of 10.2.1.1 (Device A). In this case, the traffic bypasses the congested link.

Configuration Files

Device A configuration file

#
sysname DeviceA
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.2.1.1 255.255.255.0
#
interface GigabitEthernet0/1/1
 undo shutdown
 ip address 1.1.1.2 255.255.255.0
#
bgp 100
 router-id 1.1.1.1
 peer 1.1.1.1 as-number 300
 peer 10.2.1.2 as-number 200
 #
 ipv4-family unicast
  network 192.168.1.0 255.255.255.0
  peer 10.2.1.2 enable
  peer 10.2.1.2 rpd-policy export enable
 #
 rpd-family
  peer 1.1.1.1 enable
#
return

Device B configuration file

#
sysname DeviceB
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.3.1.1 255.255.255.0
#
interface GigabitEthernet0/1/1
 undo shutdown
 ip address 2.1.1.2 255.255.255.0
#
bgp 100
 router-id 2.2.2.2
 peer 2.1.1.1 as-number 300
 peer 10.3.1.2 as-number 200
 #
 ipv4-family unicast
  network 192.168.1.0 255.255.255.0
  peer 10.3.1.2 enable
  peer 10.3.1.2 rpd-policy export enable
 #
 rpd-family
  peer 2.1.1.1 enable
#
return

Device C configuration file

#
sysname DeviceC
#
interface GigabitEthernet0/1/0
 undo shutdown
 ip address 10.2.1.2 255.255.255.0
#
interface GigabitEthernet0/1/1
 undo shutdown
 ip address 10.3.1.2 255.255.255.0
#
bgp 200
 router-id 3.3.3.3
 peer 10.2.1.1 as-number 100
 peer 10.3.1.1 as-number 100
 #
 ipv4-family unicast
  peer 10.2.1.1 enable
  peer 10.3.1.1 enable
#
return