ospf configuration commands step by step pdf

frame-relay within the same area must agree that the area is NSSA; otherwise, the devices OSPF Point-to-Multipoint Example, Table 1show ip ospf Field process-id, 2. With wildcard we can also filter Subnetted networks. 3.Verify that redistributed networks are shown in routing table of R1. See the Learn more about how Cisco is using Inclusive Language. The range is from 10 seconds to 1800 seconds (30 minutes). With a huge buffer size of 18024 bytes, there can be a maximum of 1485 link descriptions. The command includes a wild card mask that specifies the range of IP addresses. After this configuration, which kind of neighborship established between Router 1 Router 2 and Router 2 Router 3 ? virtual-link ospf You can use the optional area commands. Exits router configuration mode and returns to privileged EXEC mode. It creates multiple host routes. www.cisco.com/go/cfn. In OSPF, all areas must be connected to a backbone area. Examples from the IP and Connectionless Network Service (CLNS) routing protocols are given. So a classful routing protocol will match only first 16 bits (172.168.x.y) of network address. Now we know the essential commands for configuration. This means that the NSSA ABR router will unconditionally assume the role of LSA translator, preempting the default behavior, which would only include it among the candidates to be elected as translator. For information about the maximum number of interfaces, see the Restrictions for OSPF section. router If you are unfamiliar with wildcard mask, I suggest you to check our tutorials on access lists configuration in this category. Router(config)# router rip Step 2: Enter classful network addresses Once you are in routing configuration mode, enter the classful network address for each directly The Cisco implementation conforms to the OSPF Version 2 specifications detailed in the Internet RFC 2328. Specifies the Prior to Cisco IOS Release 12.0, some customers were using point-to-multipoint on nonbroadcast media (such as classic IP over ATM), so their routers could not dynamically discover their neighbors. Configure OSPF Routing R1 R1>enable R1#configure terminal Enter configuration commands, one per line. If you have a very small database (40 to 100 LSAs), increasing the pacing interval to 10 to 20 minutes might benefit you slightly. ip Because many routers might be attached to an OSPF network, a Stub Area: In the case of Stud Area, routing in the area is entirely on the basis of a default route. Hello timer must be match on both routers in order become neighbors. If we dont want to make a router become a DR or a BDR , we change the priority value of that routers interface to 0. Configures a show It is responsible for distributing routing information between areas that are not backbone area types. Next we will configure the BGP configuration part on R1: R1 (config)# router bgp 1. http://www.cisco.com/cisco/web/support/index.html. If the network Auto summarization on ASBR routers are made with summary-address command as you can see above. network The former OSPF implementation for sending update packets needed to be more efficient. Any use of actual IP addresses or phone numbers in illustrative content . A classful routing protocol such as RIP cannot distinguish between different Subnetted networks. Thus, the refresh packets are paced, as are the checksumming and aging. To enable the OSPF routing process, enter the following command in global configuration mode. caveats and feature information, see between serial links and need to be set at service providers end. suppress-fa. translate Type-7 LSAs, inactive (RFC3101 support disabled), Specifies that OSPF NSSA area has an ABR device configured to act as a forced translator Router (config)# router ospf process-id. exit command is used to return in global configuration mode. Command Reference, Protocol-independent features that work with OSPF, Configuring IP Routing Protocol-Independent Features module in Wildcard mask are used with network ID to filter the interfaces. The following example illustrates a simple OSPF configuration that enables OSPF routing process 9000, attaches Ethernet interface 0 to area 0.0.0.0, and redistributes RIP into OSPF and OSPF into RIP: The following example illustrates the assignment of four area IDs to four IP address ranges. Ospf configuration between 3 routers OSPF Metric cost Calculation Formula Explained. The OSPF routes with a tag of 4 are not redistributed. interface router As compared to any other routing protocols like RIP, EIGRP you are required the following basic steps to enable OSPF on a router. In this case valid host IP addresses are 192.168.0.1 and 192.168.0.2. cost. transmit-delay In the following ospf The OSPF metric is calculated as the ref-bw value divided by the bandwidth value, with the ref-bw value equal to 108 by default, and the bandwidth value determined by the bandwidth interface configuration command. For example we can use 192.168.1.1 (host IP address) or we can use 192.168.1.0 (Network IP address). Cost is the inverse of bandwidth. OSPF typically requires coordination among many internal routers, ABRs, and ASBRs. This is a very important point for this OSPF configuration example. While targeting multiple interfaces, we use network IP address. mask} Network command allows us to specify the interfaces which we want to include in OSPF process. To adjust the default Spanning Tree mode from PVST+ to something else, use the commands mentioned below. Following commands are used to access the global configuration mode. However, LSAs being refreshed at frequent, random intervals would require many packets for the few refreshed LSAs that the router must send, which would be inefficient use of bandwidth. R6 (config)#router ospf 1. Use this if you want to skip above IP configuration part. router process-id Serial interface needs two additional parameters clock rate and bandwidth. translate command to configure an NSSA ABR device Creates a loopback interface and enters interface configuration mode. area area-id, 6. interface The In the second step, we provide the required details to the EIGRP. ospf [subnets] Supports NSSA The R1 (config-router)# neighbor 11.0.0.2 remote-as 2. When routes from other protocols are redistributed into OSPF (as described in the module "Configuring IP Routing Protocol-Independent Features"), each route is advertised individually in an external LSA. OSPF Neighborship Condition and Requirement. . Enabling EIGRP To enable EIGRP, we use the following command in global configuration mode. End with CNTL/Z. key cannot communicate. network To again use the example of refreshing, each LSA gets refreshed when it is 30 minutes old, independent of other LSAs. The following example outlines a configuration for several routers within a single OSPF autonomous system. The Enhanced Interior Gateway Routing Protocol (EIGRP) routes cannot be propagated into the OSPF domain because routing redistribution is not allowed in the stub area. seconds] [authentication-key Default boundary of this address is 16 bits. The first type is OSPF external IP routes with tag 5; these routes are inserted into Level 2 IS-IS link state packets (LSPs) with a metric of 5. Periodic refreshes of hello updates, LSA updates, and other protocol overhead are prevented from enabling the on-demand circuit when there is no "real" data to send. compatible Whenever you specifically configure redistribution of routes into an OSPF routing domain, the router automatically becomes an ASBR. From global configuration mode we can enter in interface mode. cost, 5. So any interface that belongs to specified network ID will be selected. Router E is an OSPF ASBR. 4. Let's discuss both steps in detail. ip The figure below illustrates the network address ranges and area assignments for the interfaces. area information. ip may not support all the features documented in this module. We need to implement OSPF routing protocol that will insist them to share this information. OSPF routes can be exported into EGP and BGP. priority However, you can specify neighbors with the This process of attaching interfaces to OSPF areas continues for all Assume that a match is determined for Ethernet interface 0. ip It is typically chosen as the highest IP address assigned to any interface on the router. If this feature is deployed within a regular area, all other regular areas must also support this feature before the demand circuit functionality can take effect because Type 5 external LSAs are flooded throughout all areas. When map-name]. [nssa-only], 5. cost for the default summary route that is sent into a stub area or 0 (Decimal octet format) Wildcard mask indicates that corresponding octet in network address must be matched exactly. Because loopback interfaces never go down, greater stability in the routing table is achieved. <process-id> : OSPF process id. The You can specify route redistribution; see the task Redistribute Routing Information in the You can use real Cisco devices or any other We will explain these fundamental topics in easy language with examples. ip We need to configure IP address and other parameters on interfaces before we could actually use them for Specifies the So any interface that has these IP address would be selected. summary-address {ip-address With this feature, you can configure a separate cost to each neighbor. Cisco IOS IP Routing: OSPF Command Reference for more information. Evaluate the following considerations before implementing the On-Demand Circuits feature: Because LSAs that include topology changes are flooded over an on-demand circuit, we recommend that you put demand circuits within OSPF stub areas or within NSSAs to isolate the demand circuits from as many topology changes as possible. Let's take a look to figure below and configure this topology via EIGRP step by step. This is not true in some cases, for example, because of cost constraints or when you have only a partially meshed network. This feature applies to point-to-multipoint interfaces only. For this tutorial lets move on third argument. adjacency ip address 10.0.0.1 255.0.0.0 command would assign IP address to interface. Router(config-if)#ip ospf dead-interval 60, Set dead interval timer to 60 seconds. message-digest-key Displays a list of OSPF LSAs waiting to be flooded over an interface. Defines an interface on which OSPF runs and defines the area ID for that interface. To access Cisco Feature Navigator, go to key-id In this article we will see how to configure OSPF step by step. Assigning a cost to a neighbor is optional. neighbor router configuration command to be used on point-to-multipoint interfaces. Evaluate the The tasks in the Enabling OSPF section are required; the tasks in the remaining sections are optional, but might be required for your application. example, the output for the Access to most tools on the Cisco Support and An example would be a fully meshed topology. Summarization and filtering are supported during the translation. network to help determine the OSPF designated router for a network. Router (config)# router eigrp AS_number This operation allows the underlying data link layer to be closed when the network topology is stable. translate (OSPFv3), Step 1: Configure EIGRP. Unlike other books on Cisco Use a process ID of 1. Router(config-if)#no shutdown Command brings interface up. On R1, configure EIGRP routing with an autonomous system (AS) ID of 1 for all directly connected networks. [message-digest Use the router-id command to set the OSPF IDs of the three routers as follows. Because simplex interfaces between two devices on an Ethernet represent only one network segment, for OSPF you must configure the sending interface to be a passive interface. Doing so helps decrease the size of the OSPF link-state database. Process ID is a positive integer. always, 5. routes from one routing domain to another routing domain. If you have multiple links with high bandwidth, you might want to specify a larger number to differentiate the cost on those links. It costs less because it does not require a fully meshed topology. Network Protocols Configuration Guide, Part 1, for information on how to configure route redistribution. IGP developed by the OSPF working group of the IETF. 3. ospf While targeting a specific interface usually we use host IP address (configured on that interface). By ComputerNetworkingNotes example, Routing Information Protocol (RIP) subnets are redistributed into the Configuring the router for an OSPF on-demand circuit with an asynchronous interface is not a supported configuration. Only the 1194NorthMathildaAvenue Sunnyvale,California94089 USA 408-745-2000 www.juniper.net ThisproductincludestheEnvoySNMPEngine . example shows the configuration of the neighbor at 10.0.1.3: The output shown The following sample configuration accomplishes several tasks in setting up an ABR. Under the ospf process use the mpls ldp autoconfig command For this tutorial we will be using the second option, so go int the ospf process and enter mpls ldp autoconfig - this will enable mpls label distribution protocol on every interface running ospf under that specific process. Routes within an area are intra-area; routes to another area are interarea; and routes from another routing domain learned via redistribution are external. active, and an NSSA Area Border Router (ABR) device is configured as a forced R2(config)# router ospf 1 nssa-only seconds] [dead-interval You can configure your network as either a broadcast or an NBMA network. and example is the configuration for the router on the other side: OSPF, static routes, and IS-IS support variable-length subnet masks (VLSMs). 1. Priority value is configured under the related interface. The first is a simple configuration illustrating basic OSPF commands. documentation, software, and tools. Enter a process ID of 1 for the process-ID parameter. The following example redistributes all OSPF routes into IGRP: The following example redistributes RIP routes with a hop count equal to 1 into OSPF. The group pacing interval is inversely proportional to the number of LSAs that the router is refreshing, checksumming, and aging. as a forced NSSA LSA translator. example, an Open Shortest Path First (OSPF) stub network is configured to mail us [emailprotected]. OSPF is then enabled for that interface, and Ethernet interface 1 is attached to area 2. R6>en. We will use same commands to assign IP addresses on interfaces of remaining routers. For example, on multiaccess broadcast networks (such as LANs) routers defaults to elect a DR and BDR. Set up an OSPF authentication password for each area and network. Enables the device to be RFC 1587 compliant. End with CNTL/Z. Enable OSPF routing protocol from global configuration mode. terminal, 3. external} network interface configuration command, some OSPF point-to-multipoint protocol traffic was treated as multicast traffic. Enables OSPF 1 Configure OSPF for the network above. We assume that the IP address configuration is already configured on each router and PC as per the following table. Not-so-stubby area (NSSA)RFC 3101, which replaces and is backward compatible with RFC 1587. You can display specific statistics such as the contents of IP routing tables, caches, and databases. set interfaces at-0/1/0 unit 0 family inet address 192.0.2.2 set protocols ospf area 0.0.0.1 interface at-0/1/0 neighbor 192.0.2.1. The table below describes the | Suppresses the unnecessary flooding of LSAs in stable topologies. length of time between the hello packets that the Cisco IOS software sends on Here we assume that all the interfaces including loopback interfaces, their speed, duplex and descriptions have been configured. OSPF areas are explained in second part this article. terminal, 2. In the first line, BGP configuration begins with a familiar type of command: the router bgp command, where AS number is the BGP AS number used by that . If you did not get the same out as explained in this tutorial, use this configured topology to cross check your topology and find out the reason. process-id, 4. The router ID must be unique for each router in the AS. The following is a sample OSPF configuration: In the following configuration, OSPF is on network 172.16.0.0: In the following configuration, IGRP autonomous system 200 is on 192.0.2.1: The examples in this section illustrate the use of redistribution, with and without route maps. ip nssa spf auto-cost In the case of refreshing, for example, the software would scan the whole database every 30 minutes, refreshing every LSA that the router generated, no matter how old it was. | metric-type, for neighbors in the first configuration is as follows: The route Refresh packets are sent to keep the LSA from expiring, whether there has been a change in the network topology or not. authentication for an OSPF area. wildcard-mask ip ospf cost cost detail command if you want to see messages for each state change. Required fields are marked *. nssa Router(config-if)#ip address 192.168.0.1 255.255.255.252 Command assigns IP address to interface. An account on Cisco.com is not required. The OSPF LSA group pacing feature allows the router to group OSPF LSAs and pace the refreshing, checksumming, and aging functions. OSPF Configuration Commands Step by Step Configure OSPF in Router 1 Router# Router#conf t Router (config)#router ospf 10 Router (config-router)#network 1.0.0.0 .255.255.255 area 1 Router (config-router)#network 10.0.0.0 .255.255.255 area 1 Router (config-router)#^Z (Use Ctrl + Z to save settings) Configure OSPF in Router 2 Router# Router#conf t This command accepts three arguments network number, wildcard mask and area number. In lab environment we need not to worry about this value. Router(config-if)#clock rate 64000 In real life environment this parameter controls the data flow network ip It is time to take a look to configuring OSPF ( Open shortest path first )with an OSPF configuration example. cost interface configuration command. show Differentiates routing and enters router configuration mode. This parameter say router to put matched interface in specified area. OSPF uses the largest IP address configured on the interfaces as its router ID. Updated on 2018-08-06 00:41:51 IST, ComputerNetworkingNotes Use these resources to install and Bandwidth is defined in Kbps. However, it is inactive because RFC 3101 is disabled. authentication-key interface configuration commands. [message-digest | You can specify the following neighbor parameters, as required: On point-to-multipoint, nonbroadcast networks, use the number, 4. add interface=ether2 address=192.168.1.33/28 comment="LAN". ip Configure each routers Loopback0 interface in its own OSPF area, use the router number as the new OSPF area. ip It is used to create or modify an . Assign IP address 10.0.0.2/8 to PC0. ip In this part we will explain OSPF metric component bandwidth, Delay, Load, Reliability and MTU with cost calculation formula in detail with examples. For typical customers, the default group pacing interval for refreshing, checksumming, and aging is appropriate and you need not configure this feature. With wildcard mask we can easily filter Subnetted networks. ip log-adjacency-changes [detail]. Following is the sample configuration for the general network map shown in the figure above. The table below describes the Refreshing on a single timer resulted in the age of all LSAs becoming synchronized, which resulted in much CPU processing at once. Great job we have finished our half journey. OSPF uses the largest IP address configured on the interfaces as its router ID. Set the global configuration options. network You can also configure the hold time between two consecutive SPF calculations. Configure the List, All Releases, Cisco IOS IP Routing: OSPF Pacing is also added between resends to increase efficiency and minimize lost retransmissions. 255 (Decimal octet format) Wildcard mask indicates that we dont care about corresponding octet in network address. translator. In the figure below, Router 1 uses data-link connection identifier (DLCI) 201 to communicate with Router 2, DLCI 202 to communicate with Router 4, and DLCI 203 to communicate with Router 3. release notes for your platform and software release. Before the Area and Its Parameters, Configuring an NSSA ABR as a flood-list example illustrates a point-to-multipoint network with nonbroadcast: The following The OSPF on-demand circuit is an enhancement to the OSPF protocol that allows efficient operation over on-demand circuits such as ISDN, X.25 switched virtual circuits (SVCs), and dialup lines. The LSAs are now set as do not age.. 4 Configure summarization on ABR routers. This feature supports RFC 1793, Extending OSPF to Support Demand Circuits. This solution reduces the amount of refresh traffic but requires at least one refresh before the LSA expires. OSPF's basic configuration is very simple. Virtual linksVirtual links are supported. On point-to-multipoint networks, you can block flooding to a specified neighbor. OSPF configuration is not so hard as you can see. demand-circuit command. translate type7 We can use any number from 1 to 65,535. OSPF routes can also be exported into IGRP, RIP, and IS-IS. Repeat this step for each neighbor if you want to specify a cost. Cisco products and technologies. ip End with CNTL/Z. OSPF LSAs on a Single Timer Without Group Pacing, Figure 3. In our example, we will examine the figure below deeply. cost interface configuration command. Therefore, the map command pages in the Tell OSPF which interfaces we want to include. 170 0 (Binary bit format) Wildcard mask indicates that corresponding bit in network address must be matched exactly. retransmit-interval Router(config)#interface serial 0/0/0 Command is used to enter in interface mode. router down because it has not received a hello packet. ip-address Numerically, an administrative distance is an integer from 0 to 255. area nssa For more information, refer to This tutorial is the first part of this article. type Router(config-if)#exit Command is used to return in global configuration mode. With the following configuration, OSPF external routes with tags 1, 2, 3, and 5 are redistributed into RIP with metrics of 1, 1, 5, and 5, respectively. Used to influence DR/BDR selection process. log-adjacency-changes command if you want to know about OSPF neighbors going up or down without turning on the In this configuration, five routers are configured with OSPF: Router A and Router B are both internal routers within area 1. So the CPU is used only when necessary. Enable OSPF with area 0 on matching interface. OSPF external routes are advertised inside as E1 or E2 type routes. interface type and enters interface configuration mode. ignore keyword in the The pacing interval is configurable; it defaults to 4 minutes, which is randomized to further avoid synchronization. 2. This module describes how to configure Open Shortest Path First (OSPF). Starts OSPF process 1. The configuration is very simple with only two lines on R1. It is the first step in configuring OSPF on a router as done here on R1: R1>enable. For the LAN interface on R1, disable the transmission of EIGRP hello packets. In router, R1 configure OSFP routing with Router OSPF command. It is a two-step process. When a route map is used, the origination of the default route by OSPF is not bound to the existence of a default route in the routing table.