- MPLS VPN Inter-AS with ASBRs Exchanging VPN-IPv4 Addresses
- MPLS VPN Inter-AS with ASBRs Exchanging IPv4 Routes and MPLS Labels
- MPLS VPN Multipath Support for Inter-AS VPNs
- MPLS VPN--Inter-AS Option AB
- MPLS VPN Carrier Supporting Carrier Using LDP and an IGP
- MPLS VPN Carrier Supporting Carrier with BGP
- MPLS VPN Load Balancing Support for Inter-AS and CSC VPNs
- MPLS VPN eBGP Multipath Support for CSC and Inter-AS MPLS VPNs
- MPLS VPN Explicit Null Label Support with BGP IPv4 Label Session
Contents
- MPLS VPN Multipath Support for Inter-AS VPNs
- Finding Feature Information
- Restrictions for MPLS VPN Multipath Support for Inter-AS VPNs
- Information About MPLS VPN Multipath Support for Inter-AS VPNs
- Load Sharing with MPLS VPN Inter-AS ASBRs
- How to Configure MPLS VPN Multipath Support for Inter-AS VPNs
- Configuring eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
- Example
- Verifying eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
- Configuration Examples for MPLS VPN Multipath Support for Inter-AS VPNs
- Example: Configuring eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 CE1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 PE1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 P1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 ASBR1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR3
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 P2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 PE2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 CE2
- Additional References
- Feature Information for MPLS VPN Multipath Support for Inter-AS VPNs
- Glossary
MPLS VPN Multipath Support for Inter-AS VPNs
The MPLS VPN Multipath Support for Inter-AS VPNs feature supports Virtual Private Network (VPN)v4 multipath for Autonomous System Boundary Routers (ASBRs) in the interautonomous system (Inter-AS) Multiprotocol Label Switching (MPLS) VPN environment. It allows load balancing of VPN traffic when you use the VPNv4 peering model for Inter-AS VPNs.
- Finding Feature Information
- Restrictions for MPLS VPN Multipath Support for Inter-AS VPNs
- Information About MPLS VPN Multipath Support for Inter-AS VPNs
- How to Configure MPLS VPN Multipath Support for Inter-AS VPNs
- Configuration Examples for MPLS VPN Multipath Support for Inter-AS VPNs
- Additional References
- Feature Information for MPLS VPN Multipath Support for Inter-AS VPNs
- Glossary
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Restrictions for MPLS VPN Multipath Support for Inter-AS VPNs
The following restrictions apply to configuring multipath load sharing for Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) interautonomous system (Inter-AS) Autonomous System Boundary Routers (ASBRs) exchanging VPN-IPv4 routes:
- Per-packet load balancing is not supported for this feature. Load balancing for this features works on the IP source and destination hash or on the bottom label in the label stack, depending on the platform and depth of the MPLS label stack.
- If MPLS scalability is an issue for you, we recommend that you do not enable VPNv4 multipath on ASBRs.
Information About MPLS VPN Multipath Support for Inter-AS VPNs
Load Sharing with MPLS VPN Inter-AS ASBRs
Before the MPLS VPN Interautonomous System Support feature, if multiple paths existed across Autonomous System Boundary Routers (ASBRs), the Border Gateway Protocol (BGP) executed the best path algorithm and marked only one of the paths as the best path. This path was added to the routing table and became the only path that was used for forwarding traffic between ASBRs.
The MPLS VPN Multipath Support for Inter-AS VPNs feature extends the functionality of BGP so that it can pick one path as the best path and mark the other legitimate paths between ASBRs as multipath. This allows the load sharing of traffic among the different multipaths and the best path to reach the destination. No Routing Information Base (RIB) or Cisco Express Forwarding entries are associated with the Virtual Private Network (VPN)-IPv4 prefixes.
The MPLS VPN Multipath Support for Inter-AS VPNs feature applies to ASBRs that do not have a VPN routing and forwarding (VRF) instance configuration. BGP installs a number of learned VPN-IPv4 prefixes into the Multiprotocol Label Switching (MPLS) forwarding table (LFIB). VPN-IPv4 entries in the LFIB consist of the Route Distinguisher (RD) and the IPv4 prefix and are called VPNv4 entries.
The MPLS VPN Multipath Support for Inter-AS VPNs feature requires that you configure the maximum-paths number-of-paths command in address family configuration mode. This command is used to set the number of parallel (equal-cost) routes that BGP installs in the routing table to configure multipath load sharing. The number of paths that can be configured is determined by the version of Cisco software.
 Note | The maximum-paths command cannot be configured with the maximum-paths eibgp command for the same BGP routing process. |
The figure below shows an example of VPNv4 load balancing for ASBRs in an Inter-AS network. In this example, ASBR1 load balances the traffic from the CE device CE1 to CE2 using the two available links—ASBR2 and ASBR3.
When you configure an ASBR for VPNv4 load balancing, you must configure the next-hop-self command for the iBGP peers. Without this command, the next hop that is propagated to the iBGP peer is the ASBR2 address or the ASBR3 address, depending on which one BGP selects as the best path. Configuring the next-hop-self command provides direct VPNv4 forwarding entries in the MPLS forwarding table for the VPNv4 prefixes learned from the remote ASBRs. VPNv4 forwarding entries are not created if you do not configure the next-hop-self command.
Note | If the number of forwarding entries in the MPLS forwarding table on the system or on a line card is a concern for your network, we recommend that you do not enable VPNv4 multipath on ASBRs. |
How to Configure MPLS VPN Multipath Support for Inter-AS VPNs
Configuring eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
Perform this task to configure the external Border Gateway Protocol (eBGP) multipath load sharing for MPLS VPN Inter-AS ASBRs exchanging Virtual Private Network (VPN)-IPv4 routes. This allows for more efficient use of the label switched paths (LSPs) in an interautonomous system network because you can set up the load sharing of traffic among the different multipaths and the best path to reach the destination.
1.
enable
2.
configure terminal
3.
router bgp
as-number
4.
no bgp default route-target filter
5.
neighbor {ip-address |
peer-group-name}
remote-as
as-number
6.
neighbor {ip-address |
peer-group-name}
update-source
interface-type
interface-number
7.
neighbor {ip-address |
peer-group-name}
next-hop-self
8.
neighbor {ip-address |
peer-group-name}
remote-as
as-number
9. Repeat Step 8 for each BGP neighbor.
10.
address-family vpnv4 [unicast]
11.
neighbor {ip-address |
peer-group-name}
activate
12.
neighbor {ip-address |
peer-group-name}
next-hop-self
13.
neighbor {ip-address |
peer-group-name}
send-community [both |
standard |
extended]
14.
neighbor {ip-address |
peer-group-name |
ipv6-address}
activate
15.
neighbor {ip-address |
peer-group-name}
send-community [both |
standard |
extended]
16. Repeat Steps 14 and 15 for each BGP neighbor.
17.
maximum-paths
number-paths
18.
exit-address-family
19.
end
DETAILED STEPS
Example
The following example shows the configuration for external Border Gateway Protocol (eBGP) multipath for VPNv4 sessions on the ASBR1 device:
configure terminal router bgp 1 no bgp default route-target filter neighbor 10.1.0.4 remote-as 1 neighbor 10.1.0.4 update-source Loopback 0 neighbor 10.1.0.4 next-hop-self neighbor 172.16.1.9 remote-as 2 neighbor 172.16.2.8 remote-as 2 ! address-family vpnv4 neighbor 10.1.0.4 activate neighbor 10.1.0.4 next-hop-self neighbor 10.1.0.4 send-community extended neighbor 172.16.1.9 activate neighbor 172.16.1.9 send-community extended neighbor 172.16.2.8 activate neighbor 172.16.2.8 send-community extended maximum-paths 2 exit-address-family end
Verifying eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
Perform the following task to verify that the external Border Gateway Protocol (eBGP) multipath load sharing for Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) interautonomous system (Inter-AS) Autonomous System Boundary Routers (ASBRs) is operating as you expect.
The configurations in the figure above are used as an example for the task that follows.
1.
enable
2.
show ip bgp vpnv4 all [summary]
3.
show ip bgp vpnv4 all
4.
show ip bgp vpnv4 [network]
5.
show mpls forwarding-table
6.
exit
DETAILED STEPS
Configuration Examples for MPLS VPN Multipath Support for Inter-AS VPNs
Example: Configuring eBGP Multipath Load Sharing for MPLS VPN Inter-AS ASBRs
This section includes examples that show how to configure the external Border Gateway Protocol (eBGP) multipath load sharing for Multiprotocol Label Switching (MPLS) Virtual Private Network (VPN) interautonomous system (Inter-AS) Autonomous System Boundary Routers (ASBRs) that exchange VPN-IPv4 routes.
The network topology in the figure below shows two autonomous systems, which are configured as follows:
- Autonomous system 1 contains PE1, P1, and ASBR1.
- Autonomous system 2 contains PE2, P2, ASBR2, and ASBR3.
- CE1 and CE2 belong to the same VPN, which is called VPN1.
- The P devices are route reflectors.
- ASBR1 and ASBR2 are configured with the neighbor next-hop-self command for the internal BGP (iBGP) neighbors.
- ASBR1 and ASBR2 are configured with the maximum paths commands to set up eBGP multipath load sharing.
The following examples shows how to configure eBGP multipath load sharing for MPLS VPN Inter-AS ASBRs that exchange VPN-IPv4 routes. This section includes sample configurations for P1, ASBR1, ASBR2, and P2 devices.
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 CE1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 PE1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 P1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 ASBR1
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR3
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 P2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 PE2
- Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 CE2
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 CE1
The following example shows how to configure CE1 in VPN1:
! hostname CE1 ! interface Loopback 1 ip address 192.168.0.1 255.255.255.255 ! interface Ethernet 1/0 description Link to PE1 ip address 192.168.1.1 255.255.255.0 ! router ospf 1 log-adjacency-changes network 192.168.0.0 0.0.255.255 area 0 ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 PE1
The following example shows how to configure PE1 in autonomous system 1:
! hostname PE1 ! ip cef ! ip vrf V1 rd 1:105 route-target export 1:100 route-target import 1:100 ! interface Loopback 0 ip address 10.1.0.3 255.255.255.255 ! interface Ethernet 0/0 description Link to CE1 ip vrf forwarding V1 ip address 192.168.1.2 255.255.255.0 ! interface Ethernet 1/0 description Link to P1 ip address 10.1.1.3 255.255.255.0 mpls ip ! router ospf 10 vrf V1 log-adjacency-changes redistribute bgp 1 metric 100 subnets network 192.168.0.0 0.0.255.255 area 0 ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 0 ! router bgp 1 no synchronization bgp log-neighbor-changes neighbor 10.1.0.4 remote-as 1 no neighbor 10.1.0.4 transport path-mtu-discovery neighbor 10.1.0.4 update-source Loopback 0 no auto-summary ! address-family vpnv4 neighbor 10.1.0.4 activate neighbor 10.1.0.4 send-community extended exit-address-family ! address-family ipv4 vrf V1 redistribute ospf 10 vrf V1 no auto-summary no synchronization exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 P1
The following example shows how to configure P1 in autonomous system 1:
! hostname P1 ! ip cef ! interface Loopback 0 ip address 10.1.0.4 255.255.255.255 ! interface Ethernet 0/0 description Link to PE1 ip address 10.1.1.4 255.255.255.0 mpls ip ! interface Ethernet 1/0 description Link to ASBR1 ip address 10.1.2.4 255.255.255.0 mpls ip ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 0 ! router bgp 1 no synchronization bgp log-neighbor-changes neighbor R peer-group neighbor R remote-as 1 no neighbor R transport path-mtu-discovery neighbor R update-source Loopback 0 neighbor R route-reflector-client neighbor 10.1.0.3 peer-group R neighbor 10.1.0.5 peer-group R no auto-summary ! address-family vpnv4 neighbor R send-community extended neighbor R route-reflector-client neighbor 10.1.0.3 activate neighbor 10.1.0.5 activate exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 1 ASBR1
The following example shows how to configure ASBR1 in autonomous system 1:
hostname ASBR1 ! ip cef ! interface Loopback 0 ip address 10.1.0.5 255.255.255.255 ! interface Ethernet 0/0 description Core link to P1 ip address 10.1.2.5 255.255.255.0 mpls ip ! interface Ethernet 1/0 description Link to ASBR2 ip address 172.16.2.5 255.255.255.0 mpls bgp forwarding ! interface Serial 3/0 description Link to ASBR3 ip address 172.16.1.5 255.255.255.0 mpls bgp forwarding serial restart-delay 0 ! ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 0 ! router bgp 1 no synchronization no bgp default route-target filter bgp log-neighbor-changes neighbor 10.1.0.4 remote-as 1 neighbor 172.16.1.9 remote-as 2 neighbor 172.16.2.8 remote-as 2 no auto-summary ! address-family vpnv4 neighbor 10.1.0.4 activate neighbor 10.1.0.4 send-community extended neighbor 10.1.0.4 next-hop-self neighbor 172.16.1.9 activate neighbor 172.16.1.9 send-community extended neighbor 172.16.2.8 activate neighbor 172.16.2.8 send-community extended maximum-paths 2 exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR2
The following example shows how to configure ASBR2 in autonomous system 2:
! hostname ASBR2 ! ip cef ! interface Loopback 0 ip address 10.2.0.8 255.255.255.255 ! interface Loopback 1 no ip address shutdown ! interface Ethernet 0/0 description Link to ASBR1 ip address 172.16.2.8 255.255.255.0 mpls bgp forwarding ! interface Serial 2/0 description Link to P2 ip address 10.2.2.8 255.255.255.0 mpls ip no fair-queue serial restart-delay 0 ! router ospf 1 log-adjacency-changes redistribute connected subnets network 10.0.0.0 0.255.255.255 area 0 ! router bgp 2 no synchronization no bgp default route-target filter bgp log-neighbor-changes neighbor 10.2.0.7 remote-as 2 neighbor 10.2.0.7 update-source Loopback 0 neighbor 10.2.0.7 next-hop-self neighbor 172.16.2.5 remote-as 1 no auto-summary ! address-family vpnv4 neighbor 10.2.0.7 activate neighbor 10.2.0.7 send-community extended neighbor 10.2.0.7 next-hop-self neighbor 172.16.2.5 activate neighbor 172.16.2.5 send-community extended exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 ASBR3
The following example shows how to configure ASBR3 in autonomous system 2:
! hostname ASBR3 ! ip cef ! interface Loopback 0 ip address 10.2.0.9 255.255.255.255 ! interface Ethernet 0/0 description Link to ASBR1 ip address 172.16.1.9 255.255.255.0 mpls bgp forwarding ! interface Serial 3/0 description Link to P2 ip address 10.2.3.9 255.255.255.0 mpls ip no fair-queue serial restart-delay 0 ! router ospf 1 log-adjacency-changes redistribute connected subnets network 10.0.0.0 0.255.255.255 area 0 ! router bgp 2 no synchronization no bgp default route-target filter bgp log-neighbor-changes neighbor 10.2.0.7 remote-as 2 neighbor 10.2.0.7 update-source Loopback 0 neighbor 10.2.0.7 next-hop-self neighbor 172.16.1.5 remote-as 1 no auto-summary ! address-family vpnv4 neighbor 10.2.0.7 activate neighbor 10.2.0.7 send-community extended neighbor 10.2.0.7 next-hop-self neighbor 172.16.1.5 activate neighbor 172.16.1.5 send-community extended exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 P2
The following example shows how to configure P2 in autonomous system 2:
! hostname P2 ! ip cef ! interface Loopback 0 ip address 10.2.0.7 255.255.255.255 ! interface Ethernet 1/0 description Link to PE2 ip address 10.2.1.7 255.255.255.0 mpls ip ! interface Serial 2/0 description Link to ASBR2 ip address 10.2.2.7 255.255.255.0 mpls ip no fair-queue serial restart-delay 0 ! interface Serial 3/0 description Link to ASBR3 ip address 10.2.3.7 255.255.255.0 mpls ip serial restart-delay 0 ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 0 ! router bgp 2 no synchronization bgp log-neighbor-changes neighbor R peer-group neighbor R remote-as 2 no neighbor R transport path-mtu-discovery neighbor R update-source Loopback 0 neighbor R route-reflector-client neighbor 10.2.0.6 peer-group R neighbor 10.2.0.8 peer-group R neighbor 10.2.0.9 peer-group R no auto-summary ! address-family vpnv4 neighbor R send-community extended neighbor R route-reflector-client neighbor 10.2.0.6 activate neighbor 10.2.0.8 activate neighbor 10.2.0.9 activate exit-address-family ! end !
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 PE2
The following example shows how to configure PE2 in autonomous system 2:
hostname PE2 ! ip cef ! ip vrf V1 rd 1:105 route-target export 1:100 route-target import 1:100 ! interface Loopback 0 ip address 10.2.0.6 255.255.255.255 ! interface Ethernet 0/0 description Link to P2 ip address 10.2.1.6 255.255.255.0 mpls ip ! interface Serial 2/0 description Link to CE2 ip vrf forwarding V1 ip address 192.168.2.2 255.255.255.0 no fair-queue serial restart-delay 0 ! router ospf 10 vrf V1 log-adjacency-changes redistribute bgp 2 subnets network 192.168.0.0 0.0.255.255 area 0 ! router ospf 1 log-adjacency-changes network 10.0.0.0 0.255.255.255 area 0 ! router bgp 2 no synchronization bgp log-neighbor-changes neighbor 10.2.0.7 remote-as 2 neighbor 10.2.0.7 update-source Loopback 0 no auto-summary ! address-family vpnv4 neighbor 10.2.0.7 activate neighbor 10.2.0.7 send-community extended exit-address-family ! address-family ipv4 vrf V1 redistribute connected redistribute ospf 10 vrf V1 no auto-summary no synchronization exit-address-family ! end
Example: Multipath Support for Inter-AS VPNs Configuration for Autonomous System 2 CE2
The following example shows how to configure CE2 in VPN1:
hostname CE2 ! interface Loopback 0 ip address 192.168.0.2 255.255.255.255 ! interface Serial 2/0 description Link to PE2 ip address 192.168.2.1 255.255.255.0 no fair-queue serial restart-delay 0 ! router ospf 1 log-adjacency-changes network 192.168.0.0 0.0.255.255 area 0 end
Additional References
Related Documents
Related Topic |
Document Title |
|---|---|
|
Cisco IOS commands |
|
|
MPLS commands |
|
|
Configuration tasks for basic MPLS VPNs |
“Configuring MPLS VPNs” module in the MPLS: Layer 3 VPNs Configuration Guide |
|
Configuration tasks for MPLS VPN Inter-AS system exchanging IPv4 routes and MPLS labels |
“MPLS VPN Inter-AS with ASBRs Exchanging IPv4 Routes and MPLS Labels” module in the MPLS: Layer 3 VPNs Inter-AS and CSC Configuration Guide |
|
Information about monitoring MPLS VPNs with MIBs |
“MPLS VPN SNMP MIB Notifications” module in the MPLS: Embedded Management and MIBs Configuration Guide |
RFCs
RFC |
Title |
|---|---|
|
RFC 1164 |
Application of the Border Gateway Protocol in the Internet |
|
RFC 1700 |
Assigned Numbers |
|
RFC 1771 |
A Border Gateway Protocol 4 |
|
RFC 1965 |
Autonomous System Confederation for BGP |
|
RFC 1966 |
BGP Route Reflection: An Alternative to Full Mesh iBGP |
|
RFC 2547 |
BGP/MPLS VPNs |
|
RFC 2842 |
Capabilities Advertisement with BGP-4 |
|
RFC 2858 |
Multiprotocol Extensions for BGP-4 |
|
RFC 3107 |
Carrying Label Information in BGP-4 |
Technical Assistance
Description |
Link |
|---|---|
|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for MPLS VPN Multipath Support for Inter-AS VPNs
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
|---|---|---|
|
MPLS VPN Multipath Support for Inter-AS VPNs |
12.2(30)S 12.2(33)SRA 12.2(33)SXH 12.4(20)T |
The MPLS VPN Multipath Support for Inter-AS VPNs feature supports Virtual Private Network (VPN)v4 multipath for Autonomous System Boundary Routers (ASBRs) in the interautonomous system (Inter-AS) Multiprotocol Label Switching (MPLS) VPN environment. It allows load balancing of VPN traffic when you use the VPNv4 peering model for Inter-AS VPNs. No commands were introduced or modified. |
Glossary
autonomous system—A collection of networks under a common administration sharing a common routing strategy.
BGP —Border Gateway Protocol. An interdomain routing protocol that exchanges network reachability information with other BGP systems (which may be within the same autonomous system or between multiple autonomous systems).
CE device—customer edge device. A device that is part of a customer network and that interfaces to a provider edge (PE) device. CE devices do not recognize associated MPLS VPNs.
eBGP —exterior Border Gateway Protocol. A BGP between devices located within different autonomous systems. When two devices, located in different autonomous systems, are more than one hop away from one another, the eBGP session between the two devices is considered a multihop BGP.
iBGP —interior Border Gateway Protocol. A BGP between devices within the same autonomous system.
LFIB —Label Forwarding Information Base. Data structure used in MPLS to hold information about incoming and outgoing labels and associated Forwarding Equivalence Class (FEC) packets.
MPLS —Multiprotocol Label Switching. The name of the IETF working group responsible for label switching, and the name of the label switching approach it has standardized.
PE device—provider edge device. A device that is part of a service provider’s network. It is connected to a customer edge (CE) device and all MPLS VPN processing occurs in the PE device.
RD —route distinguisher. An 8-byte value that is concatenated with an IPv4 prefix to create a unique VPN-IPv4 prefix.
VPN —Virtual Private Network. A secure MPLS-based network that shares resources on one or more physical networks (typically implemented by one or more service providers). A VPN contains geographically dispersed sites that can communicate securely over a shared backbone network.
VRF —VPN routing and forwarding instance. Routing information that defines a Virtual Private Network (VPN) site that is attached to a provider edge (PE) device. A VRF consists of an IP routing table, a derived forwarding table, a set of interfaces that use the forwarding table, and a set of rules and routing protocols that determine what goes into the forwarding table.