Cisco Express Forwarding. An error occurred when loading the video. Finding Feature Information Feature Overview Supported Platforms Figure 75: Network diagram Table 21: Interface and IP address assignment Configuration procedure Configure < Return to Cisco.com search results. Cisco IOS IP Routing: OSPF Command Reference, Cisco IOS IP Routing: BGP Configuration Guide, Release 15.0, RFC 1164, Application of the Border Gateway Protocol in the Internet, RFC 2283, Multiprotocol Extensions for BGP-4, RFC 2328, Open Shortest Path First, Version 2. Areaarea-idsham-linksource-address destination-addresscostnumber. OSPF adjacency is established across the sham link. When OSPF is used as a protocol between PE and CE routers, the OSPF metric is preserved when routes are advertised over the VPN backbone. A VPN client has three sites, each with a backdoor link. Cisco Express Forwarding. DoNotAge LSA allowed. OSPF is often used by customers that run OSPF as their intrasite routing protocol, subscribe to a VPN service, and want to exchange routing information Router2(config)# When sending traffic to a particular destination, the PE router uses the MP-BGP forwarding information. ip-address Advertise these lo1 addresses in IPV4 BGP as follows: Configure sham-link between PE1 and PE2 using lo1 IP addresses: Note while configuring you will need to ensure the cost of link between CE1 and CE2 always remain higher than that mentioned over Sham-link so that path through sham-link remains the preferred one. Peter Paluch. the features documented in this module, and to see a list of the releases in address The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. A Sham links is required only between two VPN sites that belong to the same area and have a backdoor link for backup purposes. A secure IP-based network that shares resources on one or more physical networks. When the backbone network is running properly, VPN traffic of CE1 and CE2 should be forwarded over the MPLS backbone network without passing through the OSPF intra-area routes. Assign area IDs to be associated with the range of IP addresses. The PE routers that attach to the VPN use the Border Gateway Protocol (BGP) to distribute VPN routes to each other. terminal, 7. arp learning passive enable Passive ARPVRRPBackupIPIPARPARP. It is defined in RFC 1163. A sham-link ensures that OSPF client sites that share a backdoor link can communicate over the MPLS VPN backbone and participate in VPN services. Navigator to find information about platform support and Cisco software image The information displayed on CE1 is used as an example. Removes the IP address. SPF For example, the figure above shows three client sites, each with backdoor links. These customer edge (CE) routing devices are linked together by a Layer 3 VPN over Router PE1 and Router PE2. The show ip ospf neighbor command can be used to find information about any OSPF neighborships, including the interface, the state, the neighbor's address, and the neighbor's router ID. Removes the IP address. display ospf sham-link; display ospf spf-statistics; display ospf statistics updated-lsa; display ospf vlink; dn-bit-set; dn-bit-check; domain-idOSPF . As a result, the desired intra-area connectivity is created. configures the OSPF cost for sending an IP packet on the PE-2 sham-link When a sham-link is configured between PE routers, the PEs can populate the VRF routing table with the OSPF routes learned over the sham-link. vrf-name, 14. -- Creates a loopback interface to be used as an endpoint of the sham-link on PE-1 and enters interface configuration mode. the sham-link on the PE-1 interface within a specified OSPF area and with the sham-link Because they can build the OSPF adjacency directly with each other, the routes exchanged between the PE's will remain intra area routes. The OSPF costs - Rashmi Bhardwaj (Author/Editor), For Sponsored Posts and Advertisements, kindly reach us at: ipwithease@gmail.com, Routing entry for 9.9.0.5/32Known via ospf 1, distance 110, metric 3, type inter area, Type escape sequence to abort.Tracing the route to 9.9.0.5, Routing entry for 9.9.0.5/32Known via ospf 1, distance 110, metric 2, type intra area, router ospf 1 vrf shamlinkarea 0 sham-link 2.2.2.2 4.4.4.4 cost 1, Sham Link OSPF_SL0 to address 4.4.4.4 is up, BGP routing table entry for 2:2:9.9.0.1/32, version 61, Copyright AAR Technosolutions | Made with in India, How to Replace a vEdge Router via vManage: Cisco Viptela SDWAN, Salesforce Security Best Practices for Keeping Your Data Protected, Technology in the Medical Field to Look Out for in 2023, What is DDoS Attack? It is also generated through redistribution into BGP on PE-1. This prefix is the loopback interface of the Winchester CE router. VPN traffic between CE 1 and CE 2 is required to be forwarded through the MPLS backbone, instead of any route in the OSPF area. When OSPF routes are propagated over theMPLS VPNbackbone, additional information about the prefix in the form of BGP extended communities (route type, domain ID extended communities) is appended to the BGP update. areaarea-id Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. SPF Enters global Your browser version is too early. If STP is enabled CEF It is also generated through redistribution into BGP on PE-1. area <area-id> sham-link <source-address> <destination-address> cost <cost> from OSPF router configuration mode. Forwarding Adjacencies For OSPFv3, OSPF Forwarding Address Suppression in Translated Type-5 LSAs, OSPF Inbound Filtering Using Route Maps with a Distribute List, OSPFv3 Route Filtering IGP Assign area IDs to be associated with the range of IP addresses. The PE router also uses the information received from MP-BGP to set the outgoing label stack of incoming packets, and to decide to which egress PE router to label switch the packets. We are using OSPF process 2 inside provider backbone and OSPF process 1 is being used between the CE and PE. forwarding Now to overcome this behaviour we will configure OSPF Sham Link between PE1 and PE2 & then see the behaviour. If these sites belong to the same OSPF area, the path over a backdoor link will always be selected because OSPF prefers intraarea paths to interarea paths. Although 10.3.1.7/32 has been learned via OSPF across the sham-link as shown in bold, no local generation of a route into BGP is performed. Configure OSPF on CE1, Switch, and CE2 and advertise the network segment of each interface. CE routers are not aware of associated VPNs. The figure below shows a sample sham-link between PE-1 and PE-2. Using Distribute-List, OSPF Limit on Number of Redistributed Routes, OSPFv3 Fast Convergence: LSA and SPF Throttling, OSPF Support for Unlimited Software VRFs per PE Router, OSPF Link-State Database Overload Protection, OSPF MIB Support of RFC 1850 and Latest Extensions, Configuring OSPF TTL Security Check and OSPF Graceful Shutdown, OSPF SNMP ifIndex Value for Interface ID in Data Fields, OSPF Support for Forwarding Adjacencies over MPLS TE Tunnels, OSPF IPv4 Remote Loop-Free Alternate IP Fast Reroute, Prerequisites for OSPF Sham-Link Support for MPLS VPN, Restrictions on OSPF Sham-Link Support for MPLS VPN, Information About OSPF Sham-Link Support for MPLS VPN, Benefits of OSPF Sham-Link Support for MPLS VPN, Using a Sham-Link to Correct OSPF Backdoor Routing, Configuration Examples of an OSPF Sham-Link, Example Sham-Link Between Two PE Routers, Feature Information for OSPF Sham-Link Support for MPLS VPN. caveats and feature information, see Sham Link. After the configuration is complete, PE1 and PE2 can learn the route to the loopback interface of each other and establish an MP-IBGP peer relationship. loopback interface to be used as the endpoint of the sham-link on PE-2 and Configure an OSPF sham link only when a backdoor link exists between two sites in the same OSPF area. Emerging industry standard upon which tag switching is based. A sham-link overcomes the OSPF default behavior for selecting an intra-area backdoor route between VPN sites instead of an interarea (PE-to-PE) route. CEF optimizes network performance and scalability for networks with large and dynamic traffic patterns. Passive ARPVRRPBackupIP . number, 13. Reconfigures the IP address of the loopback interface on PE-2. Cost of using 1 State POINT_TO_POINT. The LSA contains information about neighbors and path costs and is used by the receiving router to maintain a routing table. Run the display ospf sham-link area command. router The command output shows that the neighbor relationship is in Full state. To reestablish the desired path selection over the MPLS VPN backbone, you must create an additional OSPF intra-area (logical) link between ingress and egress VRFs on the relevant PE routers. I am a biotechnologist by qualification and a Network Enthusiast by interest. BGP Associates the Introduction of MPLS 2. the sham-link on the PE-2 interface within a specified OSPF area and with the It allows you to create a point-to-point connection between the two PE routers. Table 1Feature Information for OSPF Sham-Link Support for MPLS VPN, IPv6 Routing: OSPFv3 Authentication Support with IPsec, OSPF Update Packet-Pacing Configurable Timers, Autoroute Announce and In addition, Router CE1 and Router CE2 are connected by an intra-area link used as a backup. The following example shows how to configure a sham-link between two PE routers: BGP These links are able to fool/trick routers in the OSPF domain that this is a better path thus preserving theLSAsastype 1 or type 3. interface. VRF See the following sections for configuration tasks for the sham-link feature. On the vManage GUI, click on Configuration => Templates and go to the Feature tab. To begin, MPLS is set up in the network as shown with R2 and R4 acting as Provider Edge (PE) routers, and MPLS is enabled throughout R2-R3-R4. Your software release For basic information about how to configure an MPLS VPN, refer to the Within BGP, the locally generated route (10.2.1.38) is considered to be the best route. Otherwise, register and sign in. CEF optimizes network performance and scalability for networks with large and dynamic traffic patterns. A broadcast packet used by link-state protocols. To locate and download MIBs for selected platforms, Cisco IOS XE releases, and feature sets, use Cisco MIB Locator found at the following URL: Application of the Border Gateway Protocol in the Internet. A Sham links is required only between two VPN sites that belong to the same area and have a backdoor link for backup purposes. No new or modified MIBs are supported by this feature. 10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks, C 10.0.0.0/8 is directly connected, FastEthernet0/0, L 10.1.1.1/32 is directly connected, FastEthernet0/0, B 30.0.0.0/8 [200/0] via 192.168.30.1, 00:05:57, O 192.168.40.1 [110/2] via 10.1.1.2, 00:40:55, FastEthernet0/0, B 192.168.50.1 [200/2] via 192.168.30.1, 00:05:57, B 30.0.0.0/8 [200/0] via 192.168.30.1, 00:06:24, B 192.168.50.1 [200/2] via 192.168.30.1, 00:06:24. Configuring OSPF sham links Network requirements As shown in Figure 46: CE 1 and CE 2 belong to VPN 1 and are connected to PE 1 and PE 2, respectively. OSPF has a lower administrative distance (AD) than internal BGP (BGP running between routers in the same autonomous system). loopback interfaces specified by the IP addresses as endpoints. Router2(config)# router ospf process-id vrf vrf-name, 18. As a result, the desired intra-area connectivity is created. which each feature is supported, see the feature information table. vrf-name, 9. In response to Arun Nair. Hall of Fame Cisco Employee. Reason for such behavior is obvious that the route from direct connection over OSPF link between CE1-CE2 is intra-area route, and route received from MPLS backbone isinter-area routeand keeping in mind the OSPF route selection the intra-area route is always preferred over the inter-area route. Sham link must be configured on both sides. IP Routing: OSPF Configuration Guide, Cisco IOS Release 15SY, View with Adobe Reader on a variety of devices. enters interface configuration mode. Before you create a 9.How to configure MPLS L3 with BGP AS OVERRIDE? --Virtual Private Network. (PE routers advertise OSPF routes learned over the VPN backbone as interarea paths.) When OSPF routes are propagated over the MPLS VPN backbone, additional information about the prefix in the form of BGP extended communities (route type, domain ID extended communities) is appended to the BGP update. You must be a registered user to add a comment. 2.AS 100IGPOSPF 3.R1-R5MPLS VPN R6-R7MPLS VPN 4.VPN 5.R6 R7OSPFR6-R7MPLS 3. AR1 # interface GigabitEthernet0/0/0 ip address 12.1.1.1 255.255.255. A router that is part of a service provider network connected to a customer edge (CE) router. We see in the routing table the route for R5s loopback 9.9.0.5 on R1 is received directly from CE2 as intra-area route is preferred over inter-area route. To obtain lists of supported MIBs by platform and Cisco IOS release, and to download MIB modules, go to the Cisco MIB website on Cisco.com at the following URL: http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml. After the configuration is complete, run the display ip routing-table vpn-instance command on the PEs. When sending traffic to a particular destination, the PE router uses the MP-BGP forwarding information. Because the sham-link is seen as an intra-area link between PE routers, an OSPF adjacency is created and database exchange (for the particular OSPF process) occurs across the link. A sham-link is required between any two VPN sites that belong to the same OSPF area and share an OSPF backdoor link. This link is called a sham-link. Some functions of the website may be unavailable. loopback interfaces specified by the IP addresses as endpoints. OSPF Sham links is a logical inter-area link carried by the super backbone. As shown in Figure 4-53, CE1 and CE2 belong to the same OSPF area of VPN1 and they connect to PE1 and PE2 respectively. Each task in the list is identified as either required or optional. Use these resources to familiarize yourself with the community: What is OSPF Sham Links? number The reason the OSPF route is not redistributed to BGP on the PE is because the other end of the sham-link already redistributed the route to BGP and there is no need for duplication. --Multiprotocol Label Switching. cost number configures the OSPF cost for sending an IP packet on the PE-1 sham-link interface. Before configuring an OSPF sham link, complete the following tasks: Cisco IOS software is packaged in feature sets that support specific platforms. If you've already registered, sign in. OSPF STATE STUCK MTU MISMATCH. OSPF adjacency is established across the sham link. Bug Search Tool and the configuration mode on the first PE router. Sending 5, 100-byte ICMP Echos to 192.168.40.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 44/72/104 ms. Sending 5, 100-byte ICMP Echos to 192.168.50.1, timeout is 2 seconds: Success rate is 100 percent (5/5), round-trip min/avg/max = 104/144/248 ms, BGP table version is 7, local router ID is 192.168.33.1, Route Distinguisher: 500:1 (default for vrf A-2). This community information is used by the receiving PE router to decide the type of link-state advertisement (LSA) to be generated when the BGP route is redistributed to the OSPF PE-CE process. Enters global configuration mode on the first PE router. Router1(config)# The following table provides release information about the feature or features described in this module. When OSPF is used to connect PE and CE routers, all routing information learned from a VPN site is placed in the VPN routing and forwarding (VRF) instance associated with the incoming interface. cost router Interdomain routing protocol that exchanges reachability information with other BGP systems. Router1(config-if)# ip vrf forwarding vrf-name, 6. ospf The following commands are introduced or modified in the feature documented in this module: show Examples of common IGPs include IGRP, OSPF, and RIP. A VPN client has three sites, each with a backdoor link. Example: Device(config-router-af)# area 1 sham-link 1.1.1.1 1.1.1.0 authentication key-chain ospf-chain-1 Transmitting Multi-Protocol Local Network Data Through a GRE Tunnel, Enlarging the Operation Scope of a Network with a Hop Limit, Building a Virtual Layer 2 Network Using Ethernet over GRE, Using Ethernet over GRE to Enable Layer 2 Communication Between an AC and a Wireless Gateway, Licensing Requirements and Limitations for GRE, Configuring a Route on a Tunnel Interface, (Optional) Configuring a Security Mechanism for GRE, Configuring Basic Ethernet over GRE Functions, (Optional) Configuring Ethernet over GRE Reliability, Collecting and Viewing Statistics on Tunnel Interfaces, Resetting Keepalive Packet Statistics on a Tunnel Interface, Example for Configuring a Static Route for GRE to Implement Interworking Between IPv4 Networks, Example for Configuring OSPF for GRE to Implement Interworking Between IPv4 Networks, Example for Enlarging the Operation Scope of a Network with a Hop Limit, Example for Connecting a CE to a VPN Through a GRE Tunnel over a Public Network, Example for Connecting a CE to a VPN Through a GRE Tunnel over a VPN, Example for Configuring Ethernet over GRE to Build a Virtual Layer 2 Network, Example for Configuring Ethernet over GRE to Enable Layer 2 Communication Between an AC and a Wireless Gateway, The Local Tunnel Interface Fails to Ping the IP Address of the Remote Tunnel Interface, Secure LAN Interconnection Through Efficient VPN, Licensing Requirements and Limitations for IPSec, Configuring an IPSec Session for Encryption, Establishing an IPSec Tunnel Using an Efficient VPN Policy, Verifying the Efficient VPN Configuration, Example for Establishing an IPSec Tunnel Using an Efficient VPN Policy in Client Mode, Example for Configuring an IPSec Tunnel Using an Efficient VPN Policy in Network Mode, Example for Configuring an IPSec Tunnel Using an Efficient VPN Policy in Network-Plus Mode, Application Scenarios for BGP/MPLS IP VPN, Interconnection Between VPNs and the Internet, Summary of BGP/MPLS IP VPN Configuration Tasks, Licensing Requirements and Limitations for BGP/MPLS IP VPN, Configuring Basic BGP/MPLS IP VPN Functions, Summary of Basic BGP/MPLS IP VPN Configuration Tasks, Establishing MP-IBGP Peer Relationships Between PE Devices, Configuring a VPN Instance on a PE Device, Configuring Route Exchange Between PE and CE Devices, Verifying the Configuration of Basic BGP/MPLS IP VPN Functions, Configuring MP-IBGP Between Hub-PE and Spoke-PE, Configuring Route Exchange Between PE device and CE Devices, Verifying the Hub and Spoke Configuration, Configuring Mutual Access Between Local VPNs, (Optional) Enabling Direct ARP Entry Delivery, Verifying the Configuration of Mutual Access Between Local VPNs, Configure Route Exchange Between an MCE Device and VPN Sites, Configure Route Exchange Between an MCE Device and a PE Device, Configuring Route Reflection to Optimize the VPN Backbone Layer, Configuring the Client PEs to Establish MP IBGP Connections with the RR, Configuring the RR to Establish MP IBGP Connections with the Client PEs, Configuring Route Reflection for BGP IPv4 VPN Routes, Verifying the Configuration of Route Reflection to Optimize the VPN Backbone Layer, Configuring and Applying a Tunnel Selector, Verifying Network Connectivity and Reachability, Viewing the Integrated Route Statistics of IPv4 VPN Instances, Resetting BGP Statistics of a VPN Instance IPv4 Address Family, Monitoring the Running Status of VPN Tunnels, Configuration Examples for BGP/MPLS IP VPN, Example for Configuring BGP/MPLS IP VPNs with Overlapping Address Spaces, Example for Configuring Communication Between Local VPNs, Example for Configuring Inter-AS VPN Option A, Example for Configuring an OSPF Sham Link, Example for Configuring BGP AS Number Substitution, Example for Configuring IP FRR for VPN Routes, Example for Configuring IP+VPN Hybrid FRR, Example for Configuring Double RRs to Optimize the VPN Backbone Layer, Example for Connecting a VPN to the Internet, Example for Configuring a Tunnel Policy for an L3VPN, Licensing Requirements and Limitations for BGP/MPLS IPv6 VPN, Summary of Basic BGP/MPLS IPv6 VPN Configuration Tasks, Establishing MP-IBGP Peer Relationships Between PEs, Configuring Route Exchange Between PEs and CEs, Verifying the Configuration of Basic BGP/MPLS IPv6 VPN Functions, Configuring Route Exchange Between the PE and CE, Configuring Route Reflection for BGP VPNv6 Routes, Configuring All Client PEs to Establish IBGP Connections with the RR, Configuring the RR to Establish MP-IBGP Connections with All Client PEs, Configuring Route Reflection for the Routes of the BGP VPN Instance, Verifying the Configuration of Route Reflection for BGP VPNv6 Routes, Monitoring the Running Status of BGP/MPLS IPv6 VPN, Verifying the Network Connectivity and Reachability, Viewing the Integrated Route Statistics of all VPN instances IPv6 address family, Resetting BGP Statistics of VPN instance IPv6 address family, Configuration Examples for BGP/MPLS IPv6 VPN, Example for Configuring Basic BGP/MPLS IPv6 VPN, Example for Configuring Hub and Spoke (Using BGP4+ Between the PE and CE), Example for Configuring Hub and Spoke (Using a Default Route Between Hub-PE and Hub-CE), Example for Configuring Inter-AS IPv6 VPN Option A, Example for Configuring an MCE IPv6 Device, Point-to-Point Layer 2 Connection Between Sites in Different Cities, Multi-service Transparent Transmission over PWs on a MAN, Licensing Requirements and Limitations for VLL, Configuring L2VPN Information Exchange Between the PE Devices, Configuring L2VPN Instances on PE Devices, (Optional) Configuring Route Reflection for BGP L2VPN, (Optional) Configuring Physical Layer Fault Notification, (Optional) Configuring a Revertive Switchover Policy, Enabling the VLL Traffic Statistics Collection Function, Example for Configuring a Local CCC Connection, Example for Configuring a Remote CCC Connection, Example for Configuring a VLL Connection in SVC Mode, Example for Configuring a VLL Connection in Martini Mode, Example for Configuring a Local VLL Connection in Kompella Mode, Example for Configuring a Remote VLL Connection in Kompella Mode, Example for Configuring a VLL Using an MPLS TE Tunnel, Example for Configuring Inter-AS Martini VLL (Option A), Example for Configuring Inter-AS Kompella VLL (Option A), Example for Configuring Martini VLL FRR (Asymmetrically Connected CEs), The VC of a Martini VLL Connection Cannot Go Up. To access Cisco Feature Navigator, go to The following example shows BGP routing table entries for the prefix 10.3.1.7/32 in the PE-1 router in the figure above. make sure both the CEs routers able to ping. *>i 192.168.50.1/32 192.168.30.1 2 100 0 ? Step 9: area area-id sham-link source-address destination-address authentication key-chain chain-name. Figure 1 shows an OSPFv2 sham link. ip-address How LDP works? . Router2# I developed interest in networking being in the company of a passionate Network Professional, my husband. configure VPNv4 peering between PE routers. Configure VPN instances on PEs and bind the interfaces connected to CEs to the VPN instances. destination-address S1720, S2700, S5700, and S6720 V200R011C10. It is not possible to route traffic from one sham-link over another sham-link. We can do this with the OSPF sham link. This table lists only the software release that introduced support for a given feature in a given software release train. there is a valid route to dst-address in the OSPF instance's routing table. To find information about All rights reserved. A secure IP-based network that shares resources on one or more physical networks. Router CE1 and Router CE2 are located in the same OSPFv2 area. 2022 Cisco and/or its affiliates. OSPF is often used by customers who run OSPF as their intrasite routing protocol, subscribe to a VPN service, and want to exchange routing information between their sites using OSPF (during migration or on a permanent basis) over an MPLS VPN backbone. Router1(config)# ip vrf vrf-name, 4. the specified OSPF process with the VRF associated with the sham-link interface Use Cisco Feature www.cisco.com/go/cfn. Further, routes reach the remote CE after being redistributed from BGP into OSPF process running between CE and PE for a specific VRF. That is, the VPN traffic Router1(config-if)# area area-id sham-link source-address destination-address cost number, 17. For a sham link to be active, two conditions must be met: src-address is a valid local address with /32 netmask in OSPF instance's routing table. As a result, New here? How to configure MPLS L3 VPN with EIGRP ? Configures cost This video demonstrates configuration a DMVPN Hub and Spoke in Phase 3 Configuration.It confirms Phase 3 connectivity between 2 Spokes and Hub to Spoke Conf. loopback interface with a VRF. An Internet protocol used to exchange routing information within an autonomous system. *>i 30.0.0.0 192.168.30.1 0 100 0 ? Hi Arun, I would rather call the OSPF sham-link a special type of virtual link established over a targeted OSPF session, with additional rules governing the OSPF/BGP redistribution and allowing you to set the cost of the virtual link manually. Other thing to remember is that those loopbacks must be advertised by a protocol other than OPSF. When a sham-link is configured between PE routers, the PEs can populate the VRF routing table with the OSPF routes learned over the sham-link. 5 nog r ng an OSPF Sham Link This section describes how to c nog r an OSPF sham link so that r oc between sites of the same VPN in the same OSPF area is forwarded through the OSPF . The information displayed on PE1 is used as an example. R3(config-if)#Ip address 192.168.33.1 255.255. --link-state advertisement. The PE router uses the information received from MP-BGP to set the ongoing label stack of incoming packets, and to decide to which egress PE router to label switch the packets. To select a router ID for OSPF, a router goes through a process. loopback Method Status Protocol, FastEthernet0/0 20.1.1.1 YES manual up up, Serial4/0 1.1.1.2 YES manual up up, Serial4/1 2.2.2.1 YES manual up up, Loopback0 192.168.20.1 YES manual up up, Loopback1 192.168.21.1 YES manual up up, Loopback2 192.168.22.1 YES manual up up, Loopback3 192.168.23.1 YES manual up up, FastEthernet0/0 30.1.1.1 YES manual up up, Serial4/1 2.2.2.2 YES manual up up, Serial4/2 3.3.3.1 YES manual up up, Loopback0 192.168.30.1 YES manual up up, Loopback1 192.168.31.1 YES manual up up, Loopback2 192.168.32.1 YES manual up up, Loopback3 192.168.33.1 YES manual up up, FastEthernet0/0 30.1.1.2 YES manual up up, Loopback0 192.168.40.1 YES manual up up, FastEthernet0/0 10.1.1.2 YES manual up up, Loopback0 192.168.50.1 YES manual up up, R1(config-router)#network 1.0.0.0 0.255.255.255 area 0, R1(config-router)#network 3.0.0.0 0.255.255.255 area 0, R1(config-router)#network 192.168.10.0 255.0.0.0 area 0, R1(config-router)#network 192.168.11.0 255.0.0.0 area 0, R1(config-router)#network 192.168.12.0 255.0.0.0 area 0, R1(config-router)#network 192.168.13.0 255.0.0.0 area 0, R2(config-router)#network 20.0.0.0 0.255.255.255 area 0, R2(config-router)#network 1.0.0.0 0.255.255.255 area 0, R2(config-router)#network 2.0.0.0 0.255.255.255 area 0, R2(config-router)#network 192.168.20.0 255.0.0.0 area 0, R2(config-router)#network 192.168.21.0 255.0.0.0 area 0, R2(config-router)#network 192.168.22.0 255.0.0.0 area 0, R2(config-router)#network 192.168.23.0 255.0.0.0 area 0, R3(config-router)#network 2.0.0.0 0.255.255.255 area 0, R3(config-router)#network 3.0.0.0 0.255.255.255 area 0, R3(config-router)#network 192.168.30.0 255.0.0.0 area 0, R3(config-router)#network 192.168.31.0 255.0.0.0 area 0, R3(config-router)#network 192.168.32.0 255.0.0.0 area 0, R3(config-router)#network 192.168.33.0 255.0.0.0 area 0, Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP, D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area, N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2, E1 - OSPF external type 1, E2 - OSPF external type 2, i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area, * - candidate default, U - per-user static route, o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP, + - replicated route, % - next hop override, O 2.0.0.0/8 [110/128] via 3.3.3.1, 01:14:38, Serial4/2, [110/128] via 1.1.1.2, 01:14:38, Serial4/0, O 20.0.0.0/8 [110/65] via 1.1.1.2, 01:14:38, Serial4/0, O 192.168.20.1 [110/65] via 1.1.1.2, 01:14:38, Serial4/0, O 192.168.21.1 [110/65] via 1.1.1.2, 01:14:38, Serial4/0, O 192.168.22.1 [110/65] via 1.1.1.2, 01:14:38, Serial4/0, O 192.168.23.1 [110/65] via 1.1.1.2, 01:14:38, Serial4/0, O 192.168.30.0/24 [110/65] via 3.3.3.1, 01:14:38, Serial4/2, O 192.168.31.1 [110/65] via 3.3.3.1, 01:14:38, Serial4/2, O 192.168.32.1 [110/65] via 3.3.3.1, 01:14:38, Serial4/2, O 192.168.33.1 [110/65] via 3.3.3.1, 01:14:38, Serial4/2, O 1.0.0.0/8 [110/128] via 3.3.3.2, 01:18:05, Serial4/2, [110/128] via 2.2.2.1, 01:18:05, Serial4/1, O 20.0.0.0/8 [110/65] via 2.2.2.1, 01:18:05, Serial4/1, O 192.168.10.0/24 [110/65] via 3.3.3.2, 01:18:05, Serial4/2, O 192.168.11.1 [110/65] via 3.3.3.2, 01:18:05, Serial4/2, O 192.168.12.1 [110/65] via 3.3.3.2, 01:18:05, Serial4/2, O 192.168.13.1 [110/65] via 3.3.3.2, 01:18:05, Serial4/2, O 192.168.20.1 [110/65] via 2.2.2.1, 01:18:05, Serial4/1, O 192.168.21.1 [110/65] via 2.2.2.1, 01:18:05, Serial4/1, O 192.168.22.1 [110/65] via 2.2.2.1, 01:18:05, Serial4/1, O 192.168.23.1 [110/65] via 2.2.2.1, 01:18:05, Serial4/1, R1(config)#mpls label protocol ldpR1(config)#mpls label range 99 199R1(config)#mpls ldp router-id loopback 0R1(config)#exitR1(config)#interface serial 4/0R1(config-if)#mpls ipR1(config-if)#exitR1(config)#interface serial 4/2R1(config-if)#mpls ipR1(config-if)#exit, R2(config)#mpls label protocol ldpR2(config)#mpls label range 200 299R2(config)#mpls ldp router-id loopback 0R2(config)#exitR2(config)#interface serial 4/0R2(config-if)#mpls ipR2(config-if)#exitR2(config)#interface serial 4/1R2(config-if)#mpls ipR2(config-if)#exitR3(config)#mpls label protocol ldpR3(config)#mpls label range 300 399R3(config)#mpls ldp router-id loopback 0R3(config)#exit, R3(config)#interface serial 4/1R3(config-if)#mpls ipR3(config-if)#exitR3(config)#interface serial 4/2R3(config-if)#mpls ipR3(config-if)#exit, R1#show mpls ldp neighbor Peer LDP Ident: 192.168.20.1:0;Local LDP Ident 192.168.10.1:0 TCP connection: 192.168.20.1.41723 - 192.168.10.1.646 State: Oper; Msgs sent/rcvd: 190/188; Downstream Up time: 02:23:12 LDP discovery sources: Serial4/0, Src IP addr: 1.1.1.2 Addresses bound to peer LDP Ident: 20.1.1.1 1.1.1.2 2.2.2.1 192.168.20.1 192.168.21.1 192.168.22.1 192.168.23.1 Peer LDP Ident: 192.168.30.1:0;Local LDP Ident 192.168.10.1:0 TCP connection: 192.168.30.1.27403 - 192.168.10.1.646 State: Oper; Msgs sent/rcvd: 186/184; Downstream Up time: 02:20:31 LDP discovery sources: Serial4/2, Src IP addr: 3.3.3.1 Addresses bound to peer LDP Ident: 2.2.2.2 3.3.3.1 192.168.30.1 192.168.31.1 192.168.32.1 192.168.33.1, Peer LDP Ident: 192.168.10.1:0; Local LDP Ident 192.168.20.1:0, TCP connection: 192.168.10.1.646 - 192.168.20.1.41723, State: Oper; Msgs sent/rcvd: 189/192; Downstream, 1.1.1.1 3.3.3.2 192.168.10.1 192.168.11.1, Peer LDP Ident: 192.168.30.1:0; Local LDP Ident 192.168.20.1:0, TCP connection: 192.168.30.1.64637 - 192.168.20.1.646, State: Oper; Msgs sent/rcvd: 187/189; Downstream, 2.2.2.2 3.3.3.1 192.168.30.1 192.168.31.1, Peer LDP Ident: 192.168.20.1:0;Local LDP Ident 192.168.30.1:0, TCP connection: 192.168.20.1.646 - 192.168.30.1.64637, State: Oper; Msgs sent/rcvd: 190/188; Downstream, 20.1.1.1 1.1.1.2 2.2.2.1 192.168.20.1, 192.168.21.1 192.168.22.1 192.168.23.1, Peer LDP Ident: 192.168.10.1:0; Local LDP Ident 192.168.30.1:0, TCP connection: 192.168.10.1.646 - 192.168.30.1.27403, % Interface FastEthernet0/0 IPv4 disabled and address(es) removed due to enabling VRF A-1, R1(config-if)#ip address 10.1.1.1 255.0.0.0, % Interface FastEthernet0/0 IPv4 disabled and address(es) removed due to enabling VRF A-2, R3(config-if)#ip address 30.1.1.1 255.0.0.0, R1#show run | section vrfip vrf A-1rd 500:1route-target export 500:1route-target import 500:1ip vrf forwarding A-1, R1(config)#interface loopback 0R1(config-if)#ip ospf network point-to-pointR1(config-if)#end, R3(config)#interface loopback 0R3(config-if)#ip ospf network point-to-pointR3(config-if)#end, R4(config)#router ospf 1R4(config-router)#network 192.168.40.0 255.0.0.0 area 0R4(config-router)#network 30.0.0.0 0.255.255.255 area 0R4(config-router)#end, R1(config-router)#network 10.0.0.0 0.255.255.255 area 0, *Mar 20 00:18:20.379: %OSPF-5-ADJCHG: Process 11, Nbr 192.168.40.1 on FastEthernet0/0 from LOADING to FULL, Loading Done, Neighbor ID Pri State Dead Time Address Interface, 192.168.33.1 0 FULL/ - 00:00:33 3.3.3.1 Serial4/2, 192.168.23.1 0 FULL/ - 00:00:38 1.1.1.2 Serial4/0, 192.168.40.1 1 FULL/DR 00:00:33 10.1.1.2 FastEthernet0/0, O 192.168.40.1 [110/2] via 10.1.1.2, 00:01:43, FastEthernet0/0, R1#ping vrf A-1 192.168.40.1Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 192.168.40.1, timeout is 2 seconds:!!!! If a BGP route and an OSPF route to the same destination are both installed in the IP routing table, OSPF uses the OSPF route because it has a better administrative distance by definition. It is not possible to route traffic from one sham-link over another sham-link. router Configures the specified OSPF process with the VRF associated with the sham-link interface on PE-1 and enters interface configuration mode. Enters global configuration mode on the second PE router. the IP address of the loopback interface on PE-1. In some cases where Providers deliverMPLSlinks to customer locations ,OSPFmay be used asCE-PErouting protocol. VPN --provider edge router. Creates a Router1# loopback interface to be used as an endpoint of the sham-link on PE-1 and To create a sham-link, use the following commands starting in EXEC mode: 2. To verify that the sham-link was successfully created and is operational, use the show ip ospf sham-links command in EXEC mode: Displays the operational status of all sham-links configured for a router. to the remote CE is forwarded through the backbone network. external Redistribute OSPF external routes internal Redistribute OSPF internal routes nssa-external Redistribute OSPF NSSA external routesR1(config-router-af)#redistribute ospf 11 vrf A-1 match internal ? We configure the virtual-link between ABRs and we use the area virtual-link command. --Open Shortest Path First protocol. A cost is configured with each sham-link and is used to decide whether traffic will be sent over the backdoor path or the sham-link path. PWE3 Carrying Enterprise Leased Line Services on a MAN, Licensing Requirements and Limitations for PWE3, (Optional) Creating a PW Template and Setting Attributes for the PW Template, Enabling the Device to Send BFD for PW Packets, Verifying the Configuration of Static BFD for PWs, Verifying the Configuration of Dynamic BFD for PWs, Configuring PW Redundancy in a Scenario Where CEs Are Asymmetrically Connected to PEs, Configuring BFD to Detect Public Network Links, Negotiating the Primary/Secondary Status of a PW, Verifying the PW Redundancy Configuration, Example for Configuring a Dynamic Single-hop PW, Example for Configuring a Static Multi-hop PW, Example for Configuring a Dynamic Multi-hop PW, Example for Configuring a Mixed Multi-hop PW, Example for Configuring Static BFD for PWs, Example for Configuring Dynamic BFD for a Single-hop PW, Example for Configuring Dynamic BFD for a Multi-hop PW, Example for Configuring Inter-AS PWE3-Option A, Example for Configuring PW Redundancy in a Scenario Where CEs Are Asymmetrically Connected to PEs, Interworking Between LDP VPLS and BGP AD VPLS, Licensing Requirements and Limitations for VPLS, Creating a VSI and Configuring LDP Signaling, Enabling the BGP Peer to Exchange VPLS Information, Creating a VSI and Configuring BGP Signaling, (Optional) Configuring Huawei Devices to Communicate with Non-Huawei Devices, (Optional) Configuring the Features of Kompella VPLS, Verifying the Kompella VPLS Configuration, Enabling BGP Peers to Exchange VPLS Information, Creating VSIs and Configuring the BGP AD Signaling, (Optional) Resetting BGP Connections for L2VPN-AD, Configuring Interworking Between LDP VPLS and BGP AD VPLS, Configuring Static VLLs to Access a VPLS Network, Configuring the Static LSP Between the UPE and the SPE, Configuring a UPE to Access an SPE Through a Static VLL, Verifying the Configuration of Static VLLs to Access a VPLS Network, Creating VSIs and Configuring the BGP Signaling, Configuring the Multi-Homed Preference for a VSI, Verifying the Configuration of CE Dual-Homed Kompella VPLS, Configuring Inter-AS Martini VPLS in Option A Mode, Configuring Inter-AS Kompella VPLS in OptionA Mode, (Optional) Associating Spoke PW Status with Hub PW Status, (Optional) Manually Switching PWs in a PW Protection Group, Verifying the VPLS PW Redundancy Configuration, Configuring a VSI to Ignore the AC Status, Configuring VSI-based Traffic Suppression, Verifying the Consistency of VPN Configurations (Service Ping), Verifying the MAC Address Learning Capability, Verifying Connectivity of the VPLS Network, Configuring the Upper and Lower Alarm Thresholds for VPLS VCs, Verifying MPLS L2VPN Specifications and Usage Information, Example for Configuring VPLS over TE in Martini Mode, Example for Configuring VPLS over TE in Kompella Mode, Example for Configuring Interworking Between LDP VPLS and BGP AD VPLS in HVPLS Mode, Example for Configuring Static VLLs to Access a VPLS Network, Example for Configuring Dynamic VLLs to Access a VPLS Network, Example for Configuring CE Dual-Homed Kompella VPLS, Example for Configuring Inter-AS Martini VPLS in OptionA Mode, Example for Configuring Inter-AS Kompella VPLS in OptionA Mode, L2VPN Access to L3VPN Supported by the Switch, Application Scenarios for L2VPN Access to L3VPN, VLL Access to the Public Network or L3VPN, VPLS Access to the Public Network or L3VPN, Licensing Requirements and Limitations for L2VPN Access to L3VPN, Configuring VLL Access to the Public Network or L3VPN, Associating the L2VE Interface with a VLL, Configuring User Access to the Public Network or L3VPN, Verifying the Configuration of VLL Access to the Public Network or L3VPN, Configuring VPLS Access to the Public Network or L3VPN, Verifying the Configuration of VPLS Access to the Public Network or L3VPN, Configuration Examples for L2VPN Access to L3VPN, Example for Configuring VLL Access to L3VPN. This blog post walks through the problem and the solution, including the configuration steps to create and verify a sham-link. This feature allows you to use a sham-link to connect Virtual Private Network (VPN) client sites that run OSPF and share backdoor OSPF links in a Multiprotocol Label Switching (MPLS) VPN configuration. It is defined in RFC 1163. I tested R8 and R6 after reboot. - incomplete, RPKI validation codes: V valid, I invalid, N Not found, Network Next Hop Metric LocPrf Weight Path, Route Distinguisher: 500:1 (default for vrf A-1). For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. vrf VRF method is to set the cost of the forwarding interface on the customer network to be larger than the cost of the sham link. Figure 1: OSPF Sham Link Use the remote-neighbor command to configure the OSPF sham link on both VRFs joined by the link. --shortest path first calculation. Two sham-links have been configured, one between PE-1 and PE-2, and another between PE-2 and PE-3. and VLANIF interfaces of switches are used to construct a Layer 3 number. The following output shows forwarding information in which the next hop for the route, 10.3.1.2, is the PE-3 router rather than the PE-2 router (which is the best path according to OSPF). The metric is used on the remote PE routers to select the correct route. Interdomain routing protocol that exchanges reachability information with other BGP systems. Router2(config-if)# ip vrf forwarding vrf-name, 12. Because each site runs OSPF within the same Area 1 configuration, all routing between the three sites follows the intraarea path across the backdoor links, rather than over the MPLS VPN backbone. CE how to configure OSPF Sham Links? interface Router2(config-if)# As shown in bold in this example, the loopback interface is learned via BGP from PE-2 and PE-3. destination-address A commonly used The OSPF intra-area path is preferred over the interarea path (over the MPLS VPN backbone) generated by the PE-1 router.
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