ROUTE 3. 00 1. 01 Training DMVPN Tutorial. One of the most popular network topology in practical nowadays is shown below with one Head. Quarter connecting to branch offices at some locations. The main enterprise resources are located in the Head. Quarter. The router at the Head. Quarter undertakes the role of a Hub while branch routers take the role of Spokes. Many thousands of articles have been written purporting to explain Bitcoin, the online, peertopeer currency. Most of those articles give a handwavy account of the. One of the most popular network topology in practical nowadays is shown below with one HeadQuarter connecting to branch offices at some locations. In this Hub and Spoke topology, each Branch can access some resources on the Head. Quarter. But there are some disadvantages with this topology When a spoke wants to communicate with another Spoke, it must go through the Hub which increases the traffic passing through the Hub, increase CPU and memory usage on Hub and can create bottle neck problem. This also increases latency for time sensitive applications such as Vo. IP, video conference Each site requires a static public IP address if the environment between them are public like the Internet. The configuration is complex, especially with large network. When a new Spoke is added, additional configuration is required on Hub. Tutorial Quickly learn how to use HTTP in your network applications, if you know basic sockets programming. Covers HTTP 1. 0 and HTTP 1. Building a working network is important but monitoring its health is as important as building it. Luckily we have tools to make administrators life easier and SNMP. About ARINC ARINC 429 Tutorial 2 ARINC Protocol Tutorial hardware and software can be used to monitor or simulate data bus messages for analyses and for simulating. Dynamic Multipoint VPN DMVPN is a solution of Cisco that can be used to overcome these disadvantages. DMVPN provides the following advantages Provides full meshed connectivity with simple Hub and Spoke topology. The spokes can communicate between each other without going through Hub Only one static public IP address is required on Hub. Spokes can use dynamic unknown public IP addresses The configuration is simple even in large network. No additional configuration is required on Hub when new Spokes are added. DMVPN provides full meshed connectivitywith Hub and Spoke topology. But notice that DMVPN is not a protocol, it is the combination of the following technologies Multipoint GRE m. GRE Next Hop Resolution Protocol NHRP Dynamic Routing Protocol EIGRP, RIP, OSPF, BGP optional Dynamic IPsec encryption optional Cisco Express Forwarding CEFDMVPN combines multiple GRE m. GRE Tunnels, IPSec encryption and NHRP Next Hop Resolution Protocol to perform its job and save the administrator the need to define multiple static crypto maps and dynamic discovery of tunnel endpoints. Can Protocol Tutorial Pdf' title='Can Protocol Tutorial Pdf' />To keep this tutorial simple we only mention about m. GRE and NHRP. Multipoint Generic Routing Encapsulation m. GREBefore taking about m. GRE we should learn why we have to run GRE on DMVPN. The answer is simple because we want to run IPSec on it. And why we need IPSecBecause we want to utilize the power of cheap but insecure Internet and other insecure public connections at our sites. As you may know, IPSec is a framework consisting of protocols and algorithms for protecting data through an untrusted IP network, such as the internet. Although IPSec provides a secure tunneling method but it does not support multicast and broadcast traffic so popular routing protocol OSPF, EIGRP, run based on multicast cannot be used with IPSec. So we have to use GRE to wrap these multicast traffic. As a result, all traffic including unicast, multicast and broadcast between sites are encapsulated into GRE packets before being encrypted and sent over the network. Now we knew why GRE should be used here. But traditional GRE sometimes called point to point or p. GRE also has its limitation for each connection to the Spoke, Hub router needs to establish a separate GRE tunnel. Mdb Converter Serial Number. So when the number of Spokes increases, Hub must increase the number of tunnels at the same rate lots of configuration on Hub. So it is the time when m. GRE takes part in. Lenovo G460 Drivers Windows 7 32 Bit. An m. GRE tunnel inherits the concept of a classic GRE tunnel but an m. GRE tunnel does not require a unique tunnel interface for each connection between Hub and spoke like traditional GRE. One m. GRE can handle multiple GRE tunnels at the other ends. Unlike classic GRE tunnels, the tunnel destination for a m. GRE tunnel does not have to be configured and all tunnels on Spokes connecting to m. GRE interface of the Hub can use the same subnet. GRE tunnel is treated as a non broadcast multi access NBMA environment. GRE tunnel does not have to be configured with a tunnel destination so we need another protocol to take care of the destination addresses. In this case NHRP is used for NBMA environment. Note Besides the Tunnel IP address, each Spoke and Hub will have a NBMA IP address, which is a public IP address used as the tunnel source IP address. We post the configuration here as an example to help you understand more about the difference of these two IP addresses Hubinterface fa. Tunnel IP address private IPtunnel source fa. NBMA IP address public IPSpoke Branch 3interface fa. Tunnel IP address private IPtunnel source fa. NBMA IP address public IPSo the Tunnel address is the address configured under interface tunnel while the NBMA address is the address used as source of the tunnel. NHRPNext Hop Resolution Protocol NHRP, defined in RFC 2. Layer 2 address resolution protocol and cache, like Address Resolution Protocol ARP. NHRP is used by a branch router connected to a non broadcast, multi access NBMA sub network to determine the IP address of the NBMA next hop in this case, the headend router or the destination IP address of another branch router. NHRP is used to map tunnel IP addresses to physical or real IP addresses, used by endpoint routers. It resolves private addresses those behind m. GRE and optionally IPSEC to a public address. NHRP is layer 2 resolution protocol and cache, much like Address Resolution Protocol ARP or Reverse ARP Frame Relay. Tony Hawk Pro Skater 2 For Pc there. In order for DMVPN to work correctly, DMVPN relies on NHRP to create a mapping database of all spoke tunnels to real public IP addresses. When a Spoke joins a DMVPN network it will register itself with the Hub via NHRP. The NHRP Registration Process is described below When a Spoke joins a DMVPN network, it sends a Registration Request to the Hub whose IP address has already been configured on the Spoke via the ip nhrp nhs lt Hub IP address command The Registration Request contains the Spokes Tunnel and NBMA addresses along with the hold time Hub does not have to statically configure Spoke IP simplify Hub configuration Hub then create an NHRP mapping entry in its NHRP cache just like an ARP cache to keep the mapping between Spokes Tunnel and NBMA addresses. The hold time of this mapping equals to the hold time in the Registration Request. Hub sends a NHRP Registration Reply to the Spoke to complete the process. NHRP Registration Process. Note The Spoke who sends NHRP Registration Request is called NHRP Client NHC while the Hub who replies the request is called NHRP Server NHS. The Spokes NBMA address is often its public IP and obtained dynamically while the Spokes Tunnel address is the private IP NHRP mapping can be statically configured on both Spoke and Hub. A cool advantage of NHRP is the ability to help DMVPN establish direct Spoke to Spoke communication without going through Hub. Lets see how NHRP works in this case. NHRP Resolution Process. Before a spoke can directly send traffic to another spoke, it must still query the Hub to get the NBMA address of the destination spoke. To do this, Spoke must send a NHRP Resolution Request to the Hub asking for the NBMA address of the destination spoke. The Hub replies with the NBMA public address of Spoke 3 which is 1. If the Hub does not known NBMA of Spoke 3 it will query Spoke 3 first. The direct IPsec tunnel between two spokes is built only after that.