Example for Configuring Static BGP VPNv4 Flow Specification

This section provides an example for configuring static BGP VPNv4 Flow Specification to allow BGP VPNv4 Flow Specification routes to be transmitted and traffic filtering policies to be generated. The policies improve security of devices in VPNs.

Networking Requirements

As shown in Figure 1, in a VPN, CE1 belongs to AS 100, while PE1, and PE2 belong to AS 200. PE1 is an ingress of AS 200. AS 200 communicates with AS 100 through PE1.

The attack source in AS 100 may flow into AS 200 through PE1, severely affecting network performance of AS 200.

In this situation, configure static BGP VPN Flow Specification to address this problem. Specifically, create a BGP VPN Flow Specification route on PE2, and enable the BGP-Flow VPNv4 address family so that a BGP VPNv4 Flow Specification route is generated automatically. Then establish a BGP VPNv4 Flow Specification peer relationship between PE1 and PE2 to transmit the BGP VPNv4 Flow Specification route. The BGP VPNv4 Flow Specification route is used to generate a traffic filtering policy for traffic filtering and control.

Figure 1 Configuring static BGP VPNv4 Flow Specification

Interfaces 1 and 2 in this example represent GE 0/1/0 and GE 0/1/8, respectively.

Configuration Roadmap

The configuration roadmap is as follows:

Configure an IP address for each involved interface.
Create a VPN instance on PE1 and PE2 and bind the VPN instance to the PE1's interface that is connected to CE1.
On PE2, configure a BGP VPN Flow Specification route (FlowSpec1) to discard the attack traffic whose source port number is 159.
Establish a BGP VPNv4 Flow Specification peer relationship between PE1 and PE2 so that the configured BGP VPNv4 Flow Specification route can be sent to PE1 and be used by PE1 as a traffic filtering policy.

Data Preparation

To complete the configuration, you need the following data:

AS number of CE1 (100) and AS number of PE1, and PE2 (200)
Name of a VPN instance (vpna)

Procedure

Configure an IP address for each interface.
For detailed configurations, see the configuration files in this example.

Create a VPN instance and bind the VPN instance to the PE1's interface that is connected to CE1.

# Configure PE1.

[~PE1] ip vpn-instance vpna
[*PE1-vpn-instance-vpna] ipv4-family
[*PE1-vpn-instance-vpna-af-ipv4] route-distinguisher 100:1
[*PE1-vpn-instance-vpna-af-ipv4] vpn-target 111:1 export-extcommunity
[*PE1-vpn-instance-vpna-af-ipv4] vpn-target 111:1 import-extcommunity
[*PE1-vpn-instance-vpna-af-ipv4] commit
[~PE1-vpn-instance-vpna-af-ipv4] quit
[~PE1-vpn-instance-vpna] quit
[~PE1] interface GigabitEthernet0/1/0
[~PE1-GigabitEthernet0/1/0] undo shutdown
[*PE1-GigabitEthernet0/1/0] ip binding vpn-instance vpna
[*PE1-GigabitEthernet0/1/0] ip address 10.1.1.2 255.255.255.0
[*PE1-GigabitEthernet0/1/0] commit
[~PE1-GigabitEthernet0/1/0] quit
[~PE1] interface GigabitEthernet0/1/8
[~PE1-GigabitEthernet0/1/8] undo shutdown
[*PE1-GigabitEthernet0/1/8] ip address 10.2.1.1 255.255.255.0
[*PE1-GigabitEthernet0/1/8] commit
[~PE1-GigabitEthernet0/1/8] quit

# Configure PE2.

[~PE2] ip vpn-instance vpna
[*PE2-vpn-instance-vpna] ipv4-family
[*PE2-vpn-instance-vpna-af-ipv4] route-distinguisher 200:1
[*PE2-vpn-instance-vpna-af-ipv4] vpn-target 111:1 export-extcommunity
[*PE2-vpn-instance-vpna-af-ipv4] vpn-target 111:1 import-extcommunity
[*PE2-vpn-instance-vpna-af-ipv4] commit
[~PE2-vpn-instance-vpna-af-ipv4] quit
[~PE2-vpn-instance-vpna] quit
[~PE2] interface GigabitEthernet0/1/0
[~PE2-GigabitEthernet0/1/0] undo shutdown
[*PE2-GigabitEthernet0/1/0] ip address 10.2.1.2 255.255.255.0
[*PE2-GigabitEthernet0/1/0] commit
[~PE2-GigabitEthernet0/1/0] quit

Configure a BGP VPN Flow Specification route.

# Configure PE2.

[~PE2] flow-route FlowSpec1 vpn-instance vpna
[*PE2-flow-route-vpna] if-match source-port equal 159
[*PE2-flow-route-vpna] apply deny
[*PE2-flow-route-vpna] commit
[~PE2-flow-route-vpna] quit

Configure BGP VPNv4 Flow Specification peer relationships.

# Configure PE1.

[~PE1]bgp 200
[*PE1-bgp] peer 10.2.1.2 as-number 200
[*PE1-bgp] vpn-instance vpna
[*PE1-bgp-instance-vpna] quit
[*PE1-bgp] ipv4-flow vpn-instance vpna
[*PE1-bgp-flow-vpna] quit
[*PE1-bgp] ipv4-flow vpnv4
[*PE1-bgp-af-flow-vpnv4] peer 10.2.1.2 enable
[*PE1-bgp-af-flow-vpnv4] commit
[~PE1-bgp-af-flow-vpnv4] quit
[~PE1-bgp] quit

# Configure PE2.

[~PE2]bgp 200
[*PE2-bgp] peer 10.2.1.1 as-number 200
[*PE2-bgp] vpn-instance vpna
[*PE2-bgp-instance-vpna] quit
[*PE2-bgp] ipv4-flow vpn-instance vpna
[*PE2-bgp-flow-vpna] quit
[*PE2-bgp] ipv4-flow vpnv4
[*PE2-bgp-af-flow-vpnv4] peer 10.2.1.1 enable
[*PE2-bgp-af-flow-vpnv4] commit
[~PE2-bgp-af-flow-vpnv4] quit
[~PE2-bgp] quit

Verify the configuration.

# Check whether BGP VPNv4 Flow Specification peer relationships are established on PE2. The command output shows that BGP VPNv4 Flow Specification peer relationships are established.

<PE2> display bgp flow vpnv4 all peer
 
 BGP local router ID : 10.2.1.2
 Local AS number : 200
 Total number of peers : 1                 Peers in established state : 1

  Peer            V          AS  MsgRcvd  MsgSent  OutQ  Up/Down       State  PrefRcv
  10.2.1.1        4         200     1042     1051     0 15:07:49 Established        0

# Check information about the BGP VPNv4 Flow Specification routes received by PE1.

<PE1> display bgp flow vpnv4 route-distinguisher 200:1 routing-table
 
 BGP Local router ID is 10.1.1.2
 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
 RPKI validation codes: V - valid, I - invalid, N - not-found


 Route Distinguisher: 200:1
 
 Total Number of Routes: 1
 * >  ReIndex : 536870913
      Dissemination Rules:
       Src. Port      : eq 159
       MED      : 0                   PrefVal  : 0                   
       LocalPref: 100                       
       Path/Ogn :  i

# Check the traffic filtering rule carried in the BGP VPNv4 Flow Specification route by specifying ReIndex of the route.

<PE1> display bgp flow vpnv4 all routing-table 536870913
 
 BGP local router ID : 10.1.1.2
 Local AS number : 200
 ReIndex : 536870913
 Order   : 0
 Dissemination Rules :
   Src. Port      : eq 159
 
 BGP flow-vpnv4 routing table entry information of 536870913:
 Route Distinguisher: 200:1
 Match action :
   apply deny
 From: 10.2.1.2 (10.2.1.2) 
 Route Duration: 0d13h59m46s
 Ext-Community: RT <111 : 1>
 AS-path Nil, origin igp, MED 0, localpref 100, pref-val 0, valid, internal, best, pre 255
 Not advertised to any peer yet

Configuration Files

CE1 configuration file

#
sysname CE1
#               
interface GigabitEthernet0/1/0
 undo shutdown  
 ip address 10.1.1.1 255.255.255.0
#               
return

PE1 configuration file

#
sysname PE1
#
ip vpn-instance vpna
 ipv4-family
  route-distinguisher 100:1
  apply-label per-instance
  vpn-target 111:1 export-extcommunity
  vpn-target 111:1 import-extcommunity
#               
interface GigabitEthernet0/1/0
 undo shutdown  
 ip binding vpn-instance vpna
 ip address 10.1.1.2 255.255.255.0
#               
interface GigabitEthernet0/1/8
 undo shutdown  
 ip address 10.2.1.1 255.255.255.0
#               
bgp 200         
 peer 10.2.1.2 as-number 200
 #              
 ipv4-family unicast
  undo synchronization 
  peer 10.2.1.2 enable
 #              
 vpn-instance vpna
 #              
 ipv4-flow vpn-instance vpna
 #              
 ipv4-flow vpnv4
  policy vpn-target
  peer 10.2.1.2 enable
#               
return

PE2 configuration file

#
sysname PE2
#
ip vpn-instance vpna
 ipv4-family
  route-distinguisher 200:1
  apply-label per-instance
  vpn-target 111:1 export-extcommunity
  vpn-target 111:1 import-extcommunity
#               
interface GigabitEthernet0/1/0
 undo shutdown  
 ip address 10.2.1.2 255.255.255.0
#               
bgp 200         
 peer 10.2.1.1 as-number 200
 #              
 ipv4-family unicast
  undo synchronization 
  peer 10.2.1.1 enable
 #              
 vpn-instance vpna
 #              
 ipv4-flow vpn-instance vpna
 #              
 ipv4-flow vpnv4
  policy vpn-target
  peer 10.2.1.1 enable
#               
flow-route FlowSpec1 vpn-instance vpna
 if-match source-port equal 159
 apply deny     
#               
return