Example for Configuring Prefix-based BGP ORF
Networking Requirements
As shown in Figure 9-36, PE1 and PE2 belong to AS 100. PE2 needs to advertise only the routes that match the import policy of PE1 without having to maintain export policies.
Configuration Roadmap
The configuration roadmap is as follows:
Configure prefix-based BGP ORF so that PE2 can advertise only the routes that match the import policy of PE1 without having to maintain export policies.
Procedure
- Establish an IPv4 unicast peer relationship between PE1
and PE2.
# Configure PE1.
<Huawei> system-view [Huawei] sysname PE1 [PE1] interface gigabitethernet 1/0/0 [PE1-GigabitEthernet1/0/0] ip address 111.1.1.1 255.255.255.0 [PE1-GigabitEthernet1/0/0] quit [PE1] bgp 100 [PE1-bgp] peer 111.1.1.2 as-number 100 [PE1-bgp] quit
# Configure PE2.
<Huawei> system-view [Huawei] sysname PE2 [PE2] interface gigabitethernet 1/0/0 [PE2-GigabitEthernet1/0/0] ip address 111.1.1.2 255.255.255.0 [PE2-GigabitEthernet1/0/0] quit [PE2] bgp 100 [PE2-bgp] peer 111.1.1.1 as-number 100 [PE2-bgp] quit
- Apply the prefix-based inbound policy on PE1.
# Configure PE1.
[PE1] ip ip-prefix 1 permit 4.4.4.0 24 greater-equal 32 [PE1] bgp 100 [PE1-bgp] peer 111.1.1.2 ip-prefix 1 import [PE1-bgp] quit
# Configure PE2.
[PE2] ip route-static 3.3.3.3 255.255.255.255 NULL0 [PE2] ip route-static 4.4.4.4 255.255.255.255 NULL0 [PE2] ip route-static 5.5.5.5 255.255.255.255 NULL0 [PE2] bgp 100 [PE2-bgp] import static [PE1-bgp] quit
# Check the routes sent by PE2 to PE1.
[PE2] display bgp routing peer 111.1.1.1 advertised-routes BGP Local router ID is 111.1.1.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 3 Network NextHop MED LocPrf PrefVal Path/Ogn *> 3.3.3.3/32 111.1.1.2 0 100 0 ? *> 4.4.4.4/32 111.1.1.2 0 100 0 ? *> 5.5.5.5/32 111.1.1.2 0 100 0 ?
# Check the routes received by PE1 from PE2.
[PE1] display bgp routing-table peer 111.1.1.2 received-routes BGP Local router ID is 111.1.1.1 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Path/Ogn *>i 4.4.4.4/32 111.1.1.2 0 100 0 ?
When prefix-based BGP ORF is not enabled, PE2 sends routes 3.3.3.3, 4.4.4.4, and 5.5.5.5 to PE1. Because the prefix-based inbound policy is applied on PE1, PE1 receives only route 4.4.4.4.
- Enable prefix-based BGP ORF.
# Enable prefix-based BGP ORF on PE1.
[PE1] bgp 100 [PE1-bgp] peer 111.1.1.2 capability-advertise orf ip-prefix both [PE1-bgp] quit
# Enable prefix-based BGP ORF on PE2.
[PE2] bgp 100 [PE2-bgp] peer 111.1.1.1 capability-advertise orf ip-prefix both [PE2-bgp] quit
- Verify the configuration.
# Check the negotiation of prefix-based BGP ORF.
[PE1] display bgp peer 111.1.1.2 verbose BGP Peer is 111.1.1.2, remote AS 100 Type: IBGP link BGP version 4, Remote router ID 111.1.1.2 Update-group ID: 2 BGP current state: Established, Up for 00h01m22s BGP current event: KATimerExpired BGP last state: OpenConfirm BGP Peer Up count: 8 Received total routes: 1 Received active routes total: 1 Received mac routes: 0 Advertised total routes: 0 Port: Local - 54845 Remote - 179 Configured: Connect-retry Time: 32 sec Configured: Active Hold Time: 180 sec Keepalive Time:60 sec Received : Active Hold Time: 180 sec Negotiated: Active Hold Time: 180 sec Keepalive Time:60 sec Peer optional capabilities: Peer supports bgp multi-protocol extension Peer supports bgp route refresh capability Peer supports bgp outbound route filter capability Support Address-Prefix: IPv4-UNC address-family, rfc-compatible, both Peer supports bgp 4-byte-as capability Address family IPv4 Unicast: advertised and received Received: Total 5 messages Update messages 1 Open messages 1 KeepAlive messages 2 Notification messages 0 Refresh messages 1 Sent: Total 4 messages Update messages 0 Open messages 1 KeepAlive messages 2 Notification messages 0 Refresh messages 1 Authentication type configured: None Last keepalive received: 2011/09/25 18:48:15 Last keepalive sent : 2011/09/25 18:48:19 Last update received: 2011/09/25 16:11:28 Minimum route advertisement interval is 15 seconds Optional capabilities: Route refresh capability has been enabled Outbound route filter capability has been enabled Enable Address-Prefix: IPv4-UNC address-family, rfc-compatible, both 4-byte-as capability has been enabled Peer Preferred Value: 0 Routing policy configured: No import update filter list No export update filter list Import prefix list is: 1 No export prefix list No import route policy No export route policy No import distribute policy No export distribute policy
# Check the routes sent by PE2 to PE1.
[PE2] display bgp routing peer 111.1.1.1 advertised-routes BGP Local router ID is 111.1.1.2 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Path/Ogn *> 4.4.4.4/32 111.1.1.2 0 100 0 ?
# Check the routes received by PE1 from PE2.
[PE1] display bgp routing-table peer 111.1.1.2 received-routes BGP Local router ID is 111.1.1.1 Status codes: * - valid, > - best, d - damped, h - history, i - internal, s - suppressed, S - Stale Origin : i - IGP, e - EGP, ? - incomplete Total Number of Routes: 1 Network NextHop MED LocPrf PrefVal Path/Ogn *>i 4.4.4.4/32 111.1.1.2 0 100 0 ?
After being enabled with prefix-based BGP ORF, PE2 sends only route 4.4.4.4 matching the inbound policy of PE1.
Configuration Files
Configuration file of PE1
# sysname PE1 # interface GigabitEthernet1/0/0 ip address 111.1.1.1 255.255.255.0 # bgp 100 peer 111.1.1.2 as-number 100 # ipv4-family unicast undo synchronization peer 111.1.1.2 enable peer 111.1.1.2 ip-prefix 1 import peer 111.1.1.2 capability-advertise orf ip-prefix both # ip ip-prefix 1 index 10 permit 4.4.4.0 24 greater-equal 32 less-equal 32 # return
Configuration file of PE2
# sysname PE2 # interface GigabitEthernet1/0/0 ip address 111.1.1.2 255.255.255.0 # bgp 100 peer 111.1.1.1 as-number 100 # ipv4-family unicast undo synchronization import-route static peer 111.1.1.1 enable peer 111.1.1.1 capability-advertise orf ip-prefix both # ip route-static 3.3.3.3 255.255.255.255 NULL0 ip route-static 4.4.4.4 255.255.255.255 NULL0 ip route-static 5.5.5.5 255.255.255.255 NULL0 # return