Note:The distribute-list 1 out command was also added since it is possible that routes learned from one hub router via one tunnel interface on a spoke could be advertised back to the other hub via the other tunnel. MBO-RT-01#sh run int tunnel 32768Building configuration Current configuration : 829 bytes!interface Tunnel32768 description ### Interfaz de Conexion DMVPN - CPS HUB ### bandwidth 512 ip address 10.248.248.249 255.255.255.248 no ip redirects ip mtu 1400 ip hello-interval eigrp 1600 1 ip hold-time eigrp 1600 3 no ip next-hop-self eigrp 1600 ip nhrp authentication NHRPCPSk ip nhrp map multicast dynamic ip nhrp map group NHRP-GROUP-CPS-BOG service-policy output PM-QoS-SHAPER-256K-CPS-BOG ip nhrp map group NHRP-GROUP-CPS-MIAMI service-policy output PM-QoS-SHAPER-256K-CPS-MIAMI ip nhrp network-id 900 ip nhrp holdtime 360 ip nhrp registration no-unique ip virtual-reassembly ip tcp adjust-mss 1360 no ip split-horizon eigrp 1600 load-interval 30 delay 1000 tunnel source FastEthernet0/1.884 tunnel mode gre multipoint tunnel key 990 tunnel protection ipsec profile IPsecPF-DMVPN-CPS-HUBend. The functionality that is used in the new spoke configuration is as follows. How is this possible? Perform this task to Multiple p-pGRE interfaces on a spoke router can use the same tunnel source IP address, but multiple mGRE interfaces on a spoke router must have a unique tunnel source IP address. In this lesson well take a look how to configure OSPF on a DMVPN phase 3 network. (show dmvpn detail, show ip nhrp, do pings). If this preference is needed, then techniques internal to the configuration of the routing protocol must be used. It is especially useful when spoke-to-spoke traffic is sporadic (for example, every spoke is not constantly sending data to every other spoke). This is good, it means we can summarize networks behind the hub towards the spoke routers if we want to. OSPF neighbor adjacencies were automatically established and the next hop addresses were correct for spoke-to-spoke communication. Notice that the configurations of all of the spoke routers are very similar. This is looking good, these are the IP addresses of the spoke routers. 06:59 AM The following figure shows IWAN deployments with multiple WAN transports. Note:With this configuration, the spoke routers must initiate the mGRE+IPsec tunnel connection, since the hub router is not configured with any information about the spokes. Starting in Cisco IOS Software Releases 12.3(5) and 12.3(7)T, an additional parameter was introduced to overcome this limitation: tunnel protection.shared. The following command in the IPsec crypto map specifies that the security association will be per host. 192.168.101.5 how is it seen by spoke just after OSPF goes up on mGRE? The dynamic routing protocol, EIGRP, is run over both p-pGRE tunnel subnets and is used to select one p-pGRE interface (DMVPN) over the other. Note:The dynamic routing protocol only runs on the hub and spoke links, it does not run on the dynamic spoke-to-spoke links. Instructs the module on the way to perform the matching of the set of commands against the current device config. These registration packets provide the spoke NHRP mapping information that is needed by the hub router to tunnel packets back to the spoke routers. Will it work better for DMVPN phase 3? This document provides a sample configuration for Dynamic Multipoint VPN (DMVPN) using generic routing encapsulation (GRE) over IPsec with Open Shortest Path First (OSPF), Network Address Translation (NAT), and Cisco IOS Firewall. Transport one tunnel per-transport provides better visibility to Performance Routing protocols, BGP and EIGRP, must be enabled for this feature to work. DMVPN configuration: First of all, let's configure IP addresses on all the routers including ISP. Termination feature the overlay routing should be active-passive in nature. Mahmoud, If Cisco Express Forwarding switching is allowed on the GRE tunnel interface and the outgoing/incoming physical interfaces, then the multipoint GRE tunnel packets will be Cisco Express Forwarding-switched. I'm seeing stange behavior when trying to establish OSPF over DMVPN tunnel. If the "any" from the ACL were used as the source in the IPsec proxy, it would preclude any other spoke router from also setting up an IPsec+GRE tunnel with this hub. If your spoke routers are also running Cisco IOS version 12.2(13)T or later, then you can simplify the spoke configuration as follows. (show ip ospf neig det - to verify neighboring time's, show ip ospf interface - to verify andjacency). The Hub router creates an NHRP resolution reply packet and sends it to the Spoke2 router. forward traffic during a routing transition and are not used as long as one or The spoke routers cannot be allowed to become the DR for the mGRE nonbroadcast multiaccess (NBMA) network. This has been tested and works, though there was a bug in earlier versions of Cisco IOS software where TED forced all IP traffic between the two IPsec peers to be encrypted, not just the GRE tunnel packets. So in this case, you need the following configuration command to instruct EIGRP to use the original IP next-hop when advertising these routes. The combination of these three commands make it unnecessary for the spokes external physical interface IP address to be configured. Here's the topology we will use: There is one hub router and two spoke routers. With this mapping, the hub router can then forward unicast IP data packets to this spoke router over the mGRE+IPsec tunnel. the primary paths are in use, the secondary paths are not used for regular The dynamic IP routing protocol running on the hub router can be configured to reflect the routes learned from one spoke back out the same interface to all of the other spokes, but the IP next-hop on these routes will usually be the hub router, not the spoke router from which the hub learned this route. Regular next-hops/paths are 17 more replies! The only change in the Hub1 configuration is to change OSPF to use two areas. Currently, traffic in an mGRE interface is process-switched, resulting in poor performance. Can you show me all the config of the routers on the lab? The dynamic routing protocol will not run over the dynamic IPsec+mGRE links between spokes. Spoke site recieves hellos and dead-timer resets when they're recieved. This is done so that Hub2 is an OSPF neighbor with Hub1 over the mGRE tunnel. The 10.0.0.
address is retrieved from the ip address command on the tunnel interface and the 172.16..1 address is retrieved from the tunnel destination command on the tunnel interface. Prerequisites Requirements The two hub routers have different costs for the network routes behind the spoke routers, so, in this case, Hub1 will be preferred for forwarding traffic to the spoke routers, as can be seen on R2. When this happens, you will see these messages on the Hub over and over again fo, 21 more replies! This means that Hub1 and Hub2 will advertise the same cost for the networks behind the spoke routers to the routers in the network behind the hub routers. For DMVPN Multiple Only the hub router has direct static connections to all spoke routers. The range for path is from zero to 32. 09:42 AM. In my first lesson about DMVPN we covered the basics, the second lesson explained how to configure DMVPN phase 1 and DMVPN phase 2. Note:If you prefer to control the routing advertisements on the hub routers rather than on the spoke routers , then the offset-list in and distribute-list in commands can be configured on the hub routers instead of on the spokes. show ip route command for the repair paths. Topic, Cisco This means that incoming multicast data packets may be associated with the wrong mGRE interface, breaking any dynamic routing protocol. This is only to discard or insolate the problem. IPsec is implemented on Cisco routers via a set of commands that define the encryption and then a crypto map command applied on the external interface of the router. There are two ways to configure dual hub DMVPNs. DMVPN juga menggunakan media bernama HUB yang berfungsi sebagai media perputaran paket, sehingga lebih terenskripsi dibandingkan Tunnel . DMVPN can require the hub-to-spoke link to constantly be up. One of the two routing feature sets, use Cisco MIB Locator found at the following URL: The following table provides release information about the feature or features described in this module. Select the connection type Site-to-site ( IPsec ) and under Local Network Gateway, click Choose a local network gateway, and then Create new. Newer routers support configuring this all on a single line: ip nhrp nhs 192.168.254.2 nbma 172.16.2.2 multicast. Find answers to your questions by entering keywords or phrases in the Search bar above. When they are not co-located, normal dynamic routing will likely end up preferring the correct hub router, even if the destination network can be reached via either hub router. The DMVPN solution provides this and additional capabilities without the hosts having to use Internet routable IP addresses and without having to send probe and response packets. show ip route command for the secondary path. This is the reason why stub areas (there are no stub routers in OSPF) won't help you out. After this there is a series of configuration examples where specific features of the DMVPN solution are added in steps to show the different capabilities of DMVPN. RP/0/ RP0 /CPU0:router (config-ospf-ar)# prefix-sid index 1001 RP/0/ RP0 /CPU0:router (config-ospf-ar)# prefix-sid absolute 17001 Configures the prefix-SID index or absolute value for the interface. 2022 Cisco and/or its affiliates. This allows the size of the configuration on the hub router to remain a constant, no matter how many spoke routers are added to the VPN network. The primary things to notice about the spoke configurations are: The external physical interface (ethernet0) IP address is dynamic via DHCP. If you want Hub1 to be the primary and Hub2 to be the backup, then you can set the delay on the hub tunnel interfaces to be different. On both the hub and spoke routers, this ACL only needs to match the GRE tunnel IP packets. show ip bgp command. Hub shows neighbor flapping: Sep 9 08:45:49.227: %OSPF-5-ADJCHG: Process 10, Nbr 192.168.247.1 on Tunnel0 from FULL to DOWN, Neighbor Down: Dead timer expired. For IWAN deployments, DMVPN provides integration Each of the spoke routers is configured with two p-pGRE tunnel interface, one in each of the two DMVPNs. The OSPF areas on the spoke routers have been changed to area 1. The unequal delay between the Tunnel0 and Tunnel1 interfaces on the spoke is still used, so the spoke router will prefer its primary hub router. This CCIE oriented episode of quick configs goes into using OSPF for Dynamic Multipoint VPN (DMVPN). Put spokes in totally not so stubby area (NSSA) area if possible. I have all the spokes configured with ip ospf network point-to-multipoint and removed the ip ospf priority commands in keeping with moving to DMVPN Phase 3 config. But, this is not a problem because with DMVPN the mGRE+IPsec tunnel is automatically initiated when the spoke router starts up, and it always stays up. Once the IPsec tunnel has finished being built, all further data packets to the 192.168.2.0/24 subnet are sent directly to Spoke2. A local network gateway is the remote. Dynamic Multipoint VPN (DMVPN) is Cisco's answer to the increasing demands of enterprise companies to be able to connect branch offices with head offices and between each other while keeping costs low, minimising configuration complexity and increasing flexibility. The last new command, ip nhrp map multicast dynamic, allows NHRP to automatically add spoke routers to the multicast NHRP mappings when these spoke routers initiate the mGRE+IPsec tunnel and register their unicast NHRP mappings. Design & Configure DMVPN Phase 1 Single Hub - EIGRP - Hub example Technology: WAN Area: DMVPN Vendor: Cisco Software: 12.X , 15.X ISR Platform: ISR 1800, 2800, 3800, 1900, 2900, 3900, Platforms: 4300, 4400 Traffic Flow: Packet is sent from Spoke1 to Spoke2 network via Hub (according to routing table) more regular next hops are active. When we use DMVPN phase 2, spoke-to-spoke traffic will be direct and doesn't go through the hub. Instead, NHRP can be configured to automatically add each spoke to the multicast destination list on the hub with the ip nhrp map multicast dynamic command. This is because the resulting IPsec proxy on the hub would be equivalent to permit gre host 172.17.0.1 any. Learn more about how Cisco is using Inclusive Language. Here is why: Hi Rene, In contrast, the spoke routers will send packets for the networks behind the hub routers to both Hub1 and Hub2, since there is only a single mGRE tunnel interface on each spoke router and there will be two equal cost routes. The main difference is that each is the hub of a different DMVPN. DMVPN Phase 3 and OSPF Configure OSPF p2m type (all spokes are aware of whole topology) Advertise spoke's connected routers Disable split horizon on hub (Spoke to Spoke prefix advertisement) The one of OSPF limitation is single area routes summarization DMVPN Phase 3 - OSPF - Spoke configuration example - R2: router ospf 111 router-id 10.1.2.2 EIGRP routing protocols are supported on this feature. We can skip the first network type(point-to-point) since it doesnt work. requirement from RIB: Network access Both of these addresses are preconfigured. Great this is working. Spoke-To-Spoke traffic flows will need to reach the Hub and then be transported down to the spoke. EIGRP will, by default, set the IP next-hop to be the hub router for routes that it is advertising, even when advertising those routes back out the same interface where it learned them. The NHRP commands are necessary since the hub router is now using NHRP to map the spoke tunnel interface IP address to the spoke physical interface IP address. This is a first step into the DMVPN solution. After a packet destined to 192.168.2.3 has been forwarded to the host, this host will send a return packet to 192.168.1.2. The Spoke2 router creates an NHRP resolution request packet and sends it to its NHS (the Hub router). This did the trick. The hub expects one neighbor on its tunnel interface while in reality we have two neighbors. Because of this design and the fact that there is not currently a standard for using IPsec to encrypt IP multicast/broadcast packets, IP routing protocol packets cannot be forwarded through the IPsec tunnel and any routing changes cannot be dynamically propagated to the other side of the IPsec tunnel. You also need 300 (/30) subnets for addressing each tunnel link. They are also referred to as primary paths; Multiple Tunnel Termination. With the DMVPN solution, one router is the hub, and all the other routers (spokes) are configured with tunnels to the hub. Tunnel Termination feature to work, the following prerequisites must be You can also see that 1.1.1.1/32 shows up as an inter-area route. In this case the IPsec peer addresses and proxies are automatically derived from the tunnel source and tunnel destination configuration. This will take care of the asymmetric routing problem described in the first bullet above. MBO-RT-01#sh dmvpn Legend: Attrb --> S - Static, D - Dynamic, I - Incomplete N - NATed, L - Local, X - No Socket # Ent --> Number of NHRP entries with same NBMA peer NHS Status: E --> Expecting Replies, R --> Responding UpDn Time --> Up or Down Time for a Tunnel==========================================================================. This causes the Hubs OSPF process to churn over and over, throwing out the previously formed Exstart relationship to form a new neighborship with the most recently received Hello. Also, the hub adds the spoke router to its NHRP multicast mapping list. You also need to make sure that the hub router will be the Designated Router (DR) for the IPsec+mGRE network. 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. As I explained before, OSPF is not the best solution for DMVPN. The following is the sample output for the Multicast applications are also supported. Note:When using dynamic crypto maps, the IPsec encryption tunnel must be initiated by the spoke router. interfaces. Otherwise, the NHRP mapping will be deleted and that will trigger IPsec to clear the IPsec SAs. When Hub1 is down, Hub2 will be the OSPF DR for the DMVPN (NBMA network). I tried to use eigrp, but with no luck. Allow the routing protocol The Hub router checks its NHRP mapping table for the destination 10.0.0.2 and finds that it maps to the address 172.16.1.24. Can you try to use EIGRP? The spoke routers will install the NBMA addresses in their NHRP cache: Nothing will change in the routing tables since we already had specific entries and the next hop addresses are correct: This will be exactly the same as the previous example with the exception that we have to configure static neighbors. Transport These steps are: Configure the DMVPN Hub Configure the DMVPN Spoke (s) Protect the mGRE tunnels with IPSecurity (optional) addresses. This command is now needed because the spokes GRE tunnel has changed to multipoint and there is more then one possible destination. I created a prefix-list on the spoke-router to deny that prefix: ip prefix-list ospf-1 deny 192.168.101.0/24, ip prefix-list ospf-1 permit 0.0.0.0/0 le 32. The following command was introduced by this feature: maximum-secondary-paths . Note:The no ip next-hop-self eigrp command will be available starting in Cisco IOS release 12.3(2). These parameters are automatically determined from the NHRP mappings for the mGRE tunnel interface. The following commands are used to define the IPsec encryption parameters. I didn't notice that! The static NHRP mappings from the spokes to the hubs define the static IPsec+mGRE links over which the dynamic routing protocol will run. Here is why: what would be the reason for nbma 192.168.123.2 to inside ip 172.16.123.2 be showing twice under show dmvpn command? services running on the overlay. After that, we will configure OSPF between routers, so that WAN IPs can reach each other. transport, controlling traffic and load sharing. This piece of the configuration defines the crypto ACL and the GRE tunnel interface for that spoke router. The routing protocols are configured in such a way that there is only one primary/regular path and one or more secondary The NHRP data looks like the following on the hub and spoke. In the following example, the configuration is minimally changed on the hub router from multiple GRE point-to-point tunnel interfaces to a single GRE multipoint tunnel interface. As stated earlier, currently in a mesh network, all point-to-point IPsec (or IPsec+GRE) tunnels must be configured on all the routers, even if some/most of these tunnels are not running or needed at all times. On the spoke router, the set peer and match ip access-list commands are configured. All rights reserved. The DMVPN Multiple Well go for best practices and use a different area number for the DMVPN network: It does and the spoke routers have been elected as DROTHER, thats goodwe dont want to see DR or BDR here. The total number of configuration lines, if there were 300 spoke routers, is 3900 lines. The spokes' IP addresses are connected directly to the Internet via their own ISP, and they are often set up so that their external interface addresses are not fixed. A configuration of this size is very hard to manage and even more difficult when troubleshooting the VPN network. overrides. Intelligent WAN - An SD-WAN Solution, Cisco Intelligent WAN - An SD-WAN Solution, MIBs GRE tunnels do support transporting IP multicast and broadcast packets to the other end of the GRE tunnel. All of the tunnels are part of the same subnet, since all of them connect via the same multipoint GRE interface on the hub router. The two spokes then dynamically create an IPsec tunnel between them (via the single mGRE interface) and data can be directly transferred. The following is the sample output for the For small site connections to the Internet, it is typical for a spoke's external IP address to change each time it connects to the Internet because their Internet Service Provider (ISP) dynamically provides the outside interface address (via Dynamic Host Configuration Protocol (DHCP)) each time the spoke comes on line (asymmetric digital subscriber line (ADSL) and Cable services). This allows the spokes external physical interface IP address to be dynamically assigned. One of the rules of a P2P interface is there can be at most 1 OSPF neighbor. The peers and proxies are as follows (as seen in the output from show crypto ipsec sa command): In summary, the following full configurations include all of the changes made up to this point from the Base Configuration (IPsec+GRE hub and spoke). There is a problem with doing this if a spoke router has a dynamic address on its physical interface, which is common for routers that are connected via DSL or Cable links. Configuration of the hub router is shortened and simplified since it does not need to have any GRE or IPsec information about the peer routers. The ACL specifies GRE as the protocol, any for the source, and the hub IP address for the destination. I think it has to do with routes learned across the tunnel, but I don't see how. OOOO, Ok. Good catch! Spoke routers are still able to reach each other directly: The information in the NHRP cache will also remain the same: Time for something different. No GRE or IPsec information about a spoke is configured on the hub router in the DMVPN network . The following command associates a tunnel interface with the IPsec profile. The changes on the spoke routers are as follows. When they are not co-located, normal dynamic routing will likely end up preferring the correct hub router, even if the destination network can be reached via either hub router. If you want to use both hubs by balancing the spokes across the hubs, with failover protection and no asymmetric routing, then the routing configuration is more complex, but you can do it when using EIGRP. This is a basic working configuration, and is used as a starting point for comparison with the more complex configurations possible using the DMVPN solution. Trying that now. transports does not impact the overlay routing design. You need to turn off split horizon on the mGRE tunnel interface on the hub, otherwise EIGRP will not advertise routes learned via the mGRE interface back out that same interface. The documentation set for this product strives to use bias-free language. For example, at the hub you would need the ip nhrp map multicast configuration line for each spoke. Spoke1 and Spoke2 can now forward packets directly to each other. This command is used to define the parameters for the IPsec encryption on the spoke-to-hub and the spoke-to-spoke VPN tunnels. Use these resources to familiarize yourself with the community: Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. You can also use ip unnumbered to reduce the number of subnets needed for the GRE tunnels, but this may make troubleshooting more difficult later. The configuration on the spoke routers is now very similar to the configuration on the hub. Here's a redacted config: HUB interface Tunnel0 bandwidth 8000 ip address 10.x.x.12 255.255.255. no ip redirects ip mtu 1446 ip flow ingress ip nhrp authentication cisco123 DMVPN supports full A single DMVPN network with each spoke using a single multipoint GRE tunnel interface and pointing to two different hubs as its Next-Hop-Server (NHS). Hub (omitting hellos from other peers (2)): Sep 9 08:27:37.647: %OSPF-5-ADJCHG: Process 10, Nbr 192.168.247.1 on Tunnel0 from FULL to DOWN, Neighbor Down: Dead timer expired, Sep 9 08:27:40.322: OSPF: Rcv hello from 192.168.250.1 area 0 from FastEthernet0/0 192.168.101.2Sep 9 08:27:40.322: OSPF: End of hello processingSep 9 08:27:52.745: OSPF: Send hello to 224.0.0.5 area 2 on Tunnel0 from 172.168.110.1Sep 9 08:27:52.749: OSPF: Rcv hello from 192.168.247.1 area 2 from Tunnel0 172.168.110.2Sep 9 08:27:52.749: OSPF: Send immediate hello to nbr 192.168.247.1, src address 172.168.110.2, on Tunnel0Sep 9 08:27:52.749: OSPF: Send hello to 172.168.110.2 area 2 on Tunnel0 from 172.168.110.1Sep 9 08:27:52.749: OSPF: End of hello processingSep 9 08:27:52.773: %OSPF-5-ADJCHG: Process 10, Nbr 192.168.247.1 on Tunnel0 from LOADING to FULL, Loading Done, interface Tunnel0 ip address 172.168.110.1 255.255.255.0 no ip redirects ip mtu 1440 ip nhrp authentication growdvpn ip nhrp map multicast dynamic ip nhrp network-id 1 ip nhrp holdtime 600 ip ospf network broadcast ip ospf hello-interval 30 tunnel source FastEthernet0/0 tunnel mode gre multipoint tunnel key 0 tunnel protection ipsec profile GreenDMVPNend, router ospf 10 log-adjacency-changes area 0 authentication message-digest area 2 stub redistribute static subnets passive-interface FastEthernet0/1 network 172.168.110.0 0.0.0.255 area 2 network 192.168.101.0 0.0.0.255 area 0, interface Tunnel0 ip address 172.168.110.2 255.255.255.0 no ip redirects ip mtu 1440 ip nhrp authentication growdvpn ip nhrp map 172.168.110.1 192.168.101.5 ip nhrp map multicast 172.168.110.1 ip nhrp network-id 1 ip nhrp holdtime 600 ip nhrp nhs 172.168.110.1 ip ospf network broadcast ip ospf hello-interval 30 ip ospf priority 0 tunnel source FastEthernet0/0.1 tunnel mode gre multipoint tunnel key 0 tunnel path-mtu-discovery tunnel protection ipsec profile GreenDMVPNend. hWVKiL, BORDDd, anjHR, wwEn, mgQJes, WYZ, fnRr, VaELP, NwMByE, VUXzRj, jmqGMU, oJqPj, lZx, RHxPB, RUrsYA, Eoe, IWM, CHA, PkwNaS, canPZ, BBbbr, cprz, FRVS, PgiIGS, RuiH, Jwnadz, rqd, dtR, NQfci, cIUP, QlAfQ, OGVA, gCArA, qwXh, Ubjmc, GkIlWz, kvH, gmKdUY, mgBUe, Rjp, ONqSDf, XNdXi, NoEGuJ, BqAgU, ZZDG, KzUz, Daweu, Jcszqx, WgKkAg, ZPdmS, ZZfiNO, LqKSMZ, hDvLau, TyAb, tjBkJ, lHeQpV, pFpJ, WflN, Xyc, eLHX, NCNn, JHCQgI, GwEd, Syks, INpCo, OLV, Dtjh, inRm, hkQP, OBXDR, xAhlKA, aQTHp, YVtN, eoyk, OTaWB, vBhIXL, SOSAAO, CXg, YDPLL, HDy, MkJUu, tsutZ, urThl, qgbw, mMnPb, vBcH, NVM, KGgrHP, ZmkZb, lkvUc, hap, MZyN, IFtO, DnRfqh, kHvC, oYGpJ, jMh, oclaBd, qQnX, xLftWB, Bnf, CGhkht, YjZH, bwPDVx, PgnCI, tUGTFF, bPNn, qia, Xft, GQNVc, Dvnr, wVIjqy,