Implementing a scalable ospf based solution

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  • If two routers have the same priority, the router with the highest router ID (IP Address) will be selected. • The router ID can be manipulated by configuring an address on a loopback interface. • A router can be configured to win an election on one interface, and lose an election on another.
  • Implementing a scalable ospf based solution

    1. 1. www.professordkinney.com 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group
    2. 2. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    3. 3. Lessons Summary:  Implementing OSPF  Multiarea OSPF IPv4 Implementation  Troubleshooting Multiarea OSPF  Examining OSPFv3 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    4. 4. OSPF Overview Creates a neighbor relationship by exchanging hello packets Propagates LSAs rather than routing table updates Link: Router interface State: Description of an interface and its relationship to neighboring routers Floods LSAs to all OSPF routers in the area, not just directly connected routers Pieces together all the LSAs generated by the OSPF routers to create the OSPF link-state database Uses the SPF algorithm to calculate the shortest path to each destination and places it in the routing table 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    5. 5. OSPF Hierarchy Example 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution Minimizes routing table entries Localizes the impact of a topology change within an area
    6. 6. Neighbor Adjacencies: The Hello Packet 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    7. 7. SPF Algorithm 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution Places each router at the root of a tree and calculates the shortest path to each destination based on the cumulative cost Cost = Reference Bandwidth / Interface Bandwidth (b/s)
    8. 8. Planning to Deploy OSPF Prior to deploying an OSPF routing solution, the following should be considered: • IP addressing plan • Network topology • OSPF areas Once the requirements have been assessed, the implementation plan can be created. Implementing OSPF The information necessary to implement OSPF routing includes the following: • The IP addresses to be configured on individual router interfaces. • A list of routers on which OSPF is to be enabled, along with the OSPF process number to use and the connected networks that are to run OSPF and that need to be advertised (per individual router). • The area in which each interface is to be configured. • Metrics that need to be applied to specific interfaces, or OSPF traffic engineering. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    9. 9. In the implementation plan, OSPF tasks include the following: • Enabling the OSPF routing protocol, directly on an interface or by using the correct network command under the OSPF routing process configuration mode. • Assigning the correct area id to the interface, via the OSPF configuration on the interface or under the OSPF routing process configuration mode. • Optionally configuring the metric to appropriate interfaces. Verifying OSPF After implementing OSPF, verification should confirm proper deployment on each router. Verification tasks include verifying: • Verifying that the appropriate OSPF neighbor relationships and adjacencies are established • Verifying that the OSPF LSDB is populated with the necessary information. • Verifying that IP routing table is populated with the necessary information. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    10. 10. • Verifying that there is connectivity in the network between routers and to other devices. • Verifying that OSPF behaves as expected in a case of a topology change, by testing link failure and router failure events. Documenting After a successful OSPF deployment, the solution and verification process and results should be documented for future reference. Documentation should include: • A topology map • The IP addressing plan • The area hierarchy • The networks and interfaces included in OSPF on each router • The default and any special metrics configured • The verification results. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    11. 11. Enable OSPF Routing Define OSPF as the IP routing protocol. Router(config)# router ospf process-id The process-id is an internally used number that identifies the OSPF routing process.  The process-id does not need to match process IDs on other routers  It can be any positive integer in the range from 1 to 65535 Define OSPF networks to advertise to OSPF neighbors. Router(config-router)# network ip-address [wildcard-mask] area area-id The ip-address parameter can be a network, a subnet, or the address of a directly connected interface. The wildcard-mask is an inverse mask used to determine how to interpret the address. • The mask has wildcard bits, where 0 is a match and 1 is “don’t care.” • For example, 0.0.255.255 indicates a match in the first 2 octets. • The area-id parameter specifies the OSPF area to be associated with the address. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    12. 12. The Wildcard Mask Recall that a wildcard mask is the inverse of a subnet mask.  An easy way to calculate the inverse of the subnet mask, is to subtract the subnet mask from 255.255.255.255.  For example, the inverse of subnet mask 255.255.255.252 is 0.0.0.3. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    13. 13. Optional method to enable OSPF explicitly on an interface. Router(config-if)# ip ospf process-id area area-id The process-id parameter can be a network, a subnet, or the address of a directly connected interface. • The area-id parameter specifies the OSPF area to be associated with the address. • Because this command is configured explicitly for the interface, it takes precedence over the network area command. Define the Interface Bandwidth Defines the interface’s bandwidth (optional). Router(config-if)# bandwidth kilobits 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    14. 14. The kilobits parameter indicates the intended bandwidth in kbps.  For example, to set the bandwidth to 512,000 bps, use the bandwidth 512 command.  The configured bandwidth is used by routing protocols in the metric calculation.  The command does not actually change the speed of the interface. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    15. 15. Configuring Single-Area OSPF RouterX(config)# router ospf process-id Defines OSPF as the IP routing protocol RouterX(config-router)# network address wildcard-mask area area-id Assigns networks to a specific OSPF area 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    16. 16. Configuring Loopback Interfaces 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Router ID: •Number by which the router is known to OSPF •Default: The highest IP address on an active interface at the moment of OSPF process startup •Can be overridden by a loopback interface: Highest IP address of any active loopback interface •Can be set manually using the router-id command Implementing a Scalable OSPF-Based Solution
    17. 17. Configuring Multi-Area OSPF 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    18. 18. Alternate Multi-Area OSPF 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    19. 19. OSPF Router ID A router is known to OSPF by the OSPF router ID number. • LSDBs use the OSPF router ID to differentiate one router from the next. By default, the router ID is the highest IP address on an active interface at the moment of OSPF process startup. • However, for stability reason, it is recommended that the router id command or a loopback interface be configured. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    20. 20. Define the Router ID Assign a specific router ID to the router. Router(config-router)# router-id ip-address Any unique arbitrary 32-bit value in an IP address format (dotted decimal) can be used. If this command is used on an OSPF process that is already active, then the new router ID takes effect:  After the next router reload.  After a manual restarting of the OSPF process using the clear ip ospf process privileged EXEC command. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    21. 21. Verifying the Router-ID 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group R2# show ip ospf Routing Process “ospf 50” with ID 10.64.0.2 <output omitted> Implementing a Scalable OSPF-Based Solution
    22. 22. Verifying OSPF 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    23. 23. Verifying the OSPF Configuration RouterX# show ip protocols Verifies that OSPF is configured RouterX# show ip route Displays all the routes learned by the router 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    24. 24. Verifying the OSPF Configuration (Cont.) RouterX# show ip ospf Displays the OSPF router ID, timers, and statistics 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    25. 25. show ip protocols Verify routing protocol information on the router R1# show ip protocols Routing Protocol is “ospf 1” Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Router ID 10.64.0.1 Number of areas in this router is 1. 1 normal 0 stub 0 nssa Maximum path: 4 Routing for Networks: 10.0.0.0 0.255.255.255 area 0 Reference bandwidth unit is 100 mbps <output omitted> 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    26. 26. show ip ospf neighbors 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    27. 27. Verify that the router recognizes OSPF routes R1# show ip route ospf 10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks O IA 10.2.1.0/24 [110/782] via 10.64.0.2, 00:03:05, FastEthernet0/0 R1# Clearing the OSPF Routing Table To clear all routes from the IP routing table, use: Router# clear ip route * To clear a specific route from the IP routing table, use: Router# clear ip route A.B.C.D 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    28. 28. show ip ospf interface Verify OSPF configured interfaces. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    29. 29. OSPF Network Types 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    30. 30. Broadcast DR /BDR election required since there could be many devices. • Establishing adjacencies with all routers in a broadcast network would easily overload a router due to the overhead of maintaining those adjacencies. • Instead, OSPF routers form full adjacencies with the DR and BDR only. Packets to all OSPF routers are forwarded to 224.0.0.5. Packets to the DR / BDR are forwarded to 224.0.0.6. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    31. 31. Broadcast Challenge: Multiple Adjacencies A challenge of broadcast network is the number of adjacencies that would be required. • One adjacency for every pair of routers. • This would increase network traffic and load on each router to manage each individual adjacency. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    32. 32. Designated Router A designated router (DR) and backup designated router (BDR) solve these challenges because they: • Reduce routing update traffic • Manage link-state synchronization The DR is elected and becomes responsible for maintaining the topology table for the segment. This DR has two main functions: • To become adjacent to all other routers on the network segment. • To act as a spokesperson for the network. As spokesperson the DR becomes the focal point for collecting and sending routing information (LSAs). 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    33. 33. Backup Designated Router (BDR) For fault tolerance, a second router is elected as the BDR. • The BDR must also become adjacent to all routers on the network and must serve as a second focal point for LSAs. • However, the BDR is not responsible for updating the other routers or sending network LSAs. The BDR keeps a timer on the DR's update activity to ensure that it is operational. • If the BDR does not detect activity from the DR after the timer expires, the BDR immediately becomes the DR and a new BDR is elected. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    34. 34. DR/BDR DRs and BDRs are elected on a per-network basis and therefore each network segment has its own DR and BDR. • For example, a router connected to multiple multiaccess broadcast networks can be a DR on one segment and a regular (DROTHER) router on another segment. The election process is accomplished dynamically using the Hello protocol. • However, the election can be manually manipulated the ip ospf priority number interface configuration command. After a DR and BDR have been selected, any router added to the broadcast network establishes full adjacencies with the DR and BDR only. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    35. 35. Assigning Router Priority Assign a specific OSPF priority to the router. Router(config-if)# ip ospf priority number A router interface can have a priority number between 0 - 255: 0 = DROTHER - Router cannot be a DR 1 = Favorable - Default for all routers 255 = Very favorable - Ensures at least of a tie. The priority must be configured before the election takes place to figure into the election. To display an interface's priority value and other key information use the show ip ospf interface command. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    36. 36. The Election of the DR All neighbors with a priority > 0 are listed. 2. The router with highest priority is elected DR. If there is a tie, the highest router IDs are used. 3. If there is no DR, the BDR is promoted as DR. 4. The neighbor with the next highest priority is elected BDR Manipulating the Election Process The DR / BDR maintain these roles until they fail even when more routers with higher priorities show up on the network. To influence the election of DR & BDR, do one of the following: • Boot up the DR first, followed by the BDR, and then boot all other routers. OR • Shut down the interface on all routers, followed by a no shutdown on the DR, then the BDR, and then all other routers. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    37. 37. Point-to-Point Both routers become fully adjacent to each another. Usually a serial interface running either PPP or HDLC. • May also be a point-to-point subinterface running Frame Relay or ATM. No DR /BDR election required since there are only two devices. OSPF autodetects this type of network. Packets are sent to 224.0.0.5 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    38. 38. OSPF over MPLS Multi-Protocol Label Switching (MPLS) is an Internet Engineering Task Force (IETF) standard architecture that combines the advantages of Layer 3 routing with the benefits of Layer 2 switching. A unique feature of MPLS is its capability to perform label stacking, in which multiple labels can be carried in a packet. The top label, which is the last one in, is always processed first. • Label stacking enables multiple LSPs to be aggregated, thereby creating tunnels through multiple levels of an MPLS network. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    39. 39. OSPF over Layer 3 MPLS VPN The customer and provider edge routers are running OSPF. • However the internal provider routers do not. The customer has to agree upon OSPF parameters with the service provider (SP) to ensure connectivity. • These parameters are often governed by the SP. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    40. 40. OSPF over Layer 2 MPLS VPN The Layer 2 MPLS VPN backbone and the provider routers are not visible to the customer routers. • A neighbor relationship is established directly between OSPF enabled routers over the MPLS backbone, and behaves in the same way as on an Ethernet broadcast network therefore DR and BDR routers are elected 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    41. 41. Nonbroadcast Multiaccess (NBMA) Frame Relay, ATM, and X.25 are examples of NBMA networks. The default OSPF hello and dead intervals on NBMA interfaces are 30 seconds and 120 seconds, respectively. Although NBMA networks can support more than two routers, they have no inherent broadcast capability. • This can create reachability issues. To implement broadcasting or multicasting, the router replicates the packets to be broadcast or multicast and sends them individually on each permanent virtual circuit (PVC) to all destinations. • This process is CPU and bandwidth intensive. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    42. 42. DR Election in an NBMA Topology By default, OSPF cannot automatically build adjacencies with neighbor routers over NBMA interfaces. OSPF considers the NBMA environment to function similarly to other multiaccess media such as Ethernet. • However, NBMA networks are usually hub-and-spoke (star) topologies using PVCs or switched virtual circuits (SVCs). • In these cases, the physical topology does not provide the multiaccess capability on which OSPF relies. The election of the DR becomes an issue in NBMA topologies because the DR and BDR need to have full Layer 2 connectivity with all routers in the NBMA network. The DR and BDR also need to have a list of all the other routers so that they can establish adjacencies 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    43. 43. OSPF over NBMA Topology There are five NBMA topology modes of operation: • Two official OSPF modes described in RFCs • Three customized Cisco modes. RFC 2328-compliant modes are as follows: • Nonbroadcast (NBMA) • Point-to-multipoint Cisco modes are as follows: • Point-to-multipoint nonbroadcast • Broadcast • Point-to-point OSPF NBMA topology modes are configured using the ip ospf network interface configuration command. • Some modes require that a neighbor be manually configured using the neighbor router configuration command. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    44. 44. Subinterfaces OSPF can also be run over subinterfaces. • A subinterface is a physical interface that can be split into multiple logical interfaces. • Each subinterface requires an IP subnet. Subinterfaces can be defined as either a point-to-point or multipoint interface. • A point-to-point subinterface has similar properties to a physical pointto-point interface. Note:The ip ospf network command is not required. Define a Subinterface Router(config)# interface serial number.subinterface-number {multipoint | point-to-point} 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    45. 45. Using Point-to-point Subinterfaces Characteristics: • Same properties as any physical point-to-point physical interface • DR and BDR not required. • One IP subnet per subinterface pair. • Used when only 2 routers need to form an adjacency on a pair of interfaces.} 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    46. 46. Using Multipoint Subinterfaces The example has one point-to-point subinterface and one multipoint subinterface. • The multipoint subinterface supports two other routers in a single Multipoint Frame Relay subinterfaces default to OSPF nonbroadcast mode, which requires neighbors to be statically configured and a DR and BDR election. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    47. 47. Troubleshooting Multiarea OSPF Verifying OSPF Operability An essential requirement of your network operation is that the status of your routers and routing protocols is monitored to ensure network availability for all users. The 3 basic forms of network monitoring include router SYSLOG files, SNMP and MIBs, and using show commands. One useful configuration practice is to configure your routers to use DNS names in all OSPF show command displays. This feature makes it easier to identify a router because the router is displayed by name rather than by its router ID or neighbor ID. ip ospf name-lookup is used to configure OSPF to display IP addresses by their DNS names instead. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    48. 48. One very useful troubleshooting tool is keeping track of events that affect a router's operation with logging. SYSLOG on a router with a SYSLOG server is the recommended practice, since without a server, you are limited to the memory on the router for record keeping. The storage of the logs on a SYSLOG server is useful for trend analysis, forensic gathering, and troubleshooting viewpoint. This can also help you find system error messages, outages, and a variety of other network events that may have already passed and been lost in a router's memory. You first need to decide the level of logging that you wish to use, with 8 possible options to choose from. The logging levels are as follows: 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    49. 49. show logging is used to display the addresses and levels associated with the current logging setup as well as any other logging statistics. You also want to ensure that the SYSLOG entries are stamped with the correct time and date. service timestamp log datetime localtime show-timezone is used to configure the router to automatically data and time stamp all SYSLOG entries on the router and when sent to the SYSLOG server. show ip ospf border-routers displays the internal OSPF routing table to an ABR or ASBR. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    50. 50. show ip ospf database displays the contents of the topology database maintained by the router.There is actually a list of various forms of this command that can be used to deliver information about different OSPF link-state advertisements. show ip ospf database asbr-summary displays a large variety of information in the OSPF database for an ASBR. show ip ospf database database-summary is used to provide a summary of every type of LSA that has been sent, deleted, or expired because of Maxage. show ip ospf database external provides information regarding the OSPF database external LSAs. show ip ospf database network provides information regarding the OSPF database network LSAs, which includes where the routes came from in the network and which routers are part of the network by OSPF area. show ip ospf database router provides information regarding the OSPF database router LSAs 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    51. 51. show ip ospf neighbor [interface-name | detail] is used to display OSPF neighbor information on a per-interface basis. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    52. 52. show ip ospf neighbor ip-address is used to provide detailed  information regarding a specific OSPF network as specified by the IP address. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    53. 53. clear ip ospf process [process-id] is used to completely reset either  a specific OSPF process, or all OSPF processes on a router. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    54. 54. The Debugging OSPF Command: Among information provided by this command is the : i.   Debug ip ospf packet: this command displays hello packets being sent and received on  your router ii.  Debug ip ospf hello: this command displays hello packets being sent and received on  your router. It also displays more information than the debug ospf packet iii. The debug ip ospf adj: shows DR and DBR elections on a broadcast and non-broadcast  multi-access (NBMA) network. debug ip ospf hello displays information about how OSPF Hellos are operating within the  OSPF domain. debug ip ospf packet displays a LOT of detailed information about each OSPF packet  received. Be aware that this produces a set of information for EACH packet received. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    55. 55. Examining OSPFv3 OSPFv3 / OSPFv2 Similarities Basic packet types Hello, DBD, LSR, LSU, LSA • Mechanisms for neighbor discovery andadjacency formation • Interface types P2P, P2MP, Broadcast, NBMA, Virtual • LSA flooding and aging • Nearly identical LSA types V2, V3 Differences OSPFv3 Is Running per Link Instead of per IP Subnet • A link by definition is a medium over which two nodes can communicate at link layer • In IPv6 multiple IP subnet can be assigned to a link and two nodes in different subnet can  communicate at link layer therefore OSPFv3 is running per link instead of per IP subnet • An Interface connect to a link and multiple interface can be connected to a link 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    56. 56. Support of Multiple Instance per Link New field (instance) in OSPF packet header allow running multiple instance per link • Instance ID should match before packet being accepted • Useful for traffic separation, multiple areas per link and AF Address Semantic Change in LSA Router and Network LSA carry only topology information • Router LSA can be split across multiple LSAs; Link State ID in LSA header is a fragment ID • Intra area prefix are carried in a new LSA payload called intra-area-prefix-LSAs • Prefix are carried in payload of inter-area and external LSA Generalization of Flooding Scope • In OSPFv3 there are three flooding scope for LSAs (link-local scope, area scope, AS scope)  and they are coded in LS type explicitly • In OSPFv2 initially only area and AS wide flooding was defined; later opaque LSAs  introduced link local scope as well Explicit Handling of Unknown LSA The handling of unknown LSA is coded via U-bit in LS type • When U bit is set, the LSA is flooded with the corresponding flooding scope, as if it was understood • When U bit is clear, the LSA is flooded with link local scope • In v2 unknown LSA were discarded 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    57. 57. Authentication Is Removed from OSPF Authentication in OSPFv3 has been removed and OSPFv3 relies now on IPv6 authentication  header since OSPFv3 run over IPv6 • Autype and Authentication field in the OSPF packet header therefore have been  suppressed. OSPF Packet format has been changed • The mask field has been removed from Hello packet • IPv6 prefix are only present in payload of Link State update packet Configuring OSPFv3 in Cisco IOS® Software Similar to OSPFv2 Prefixing existing Interface and Exec mode commands with “ipv6” • Interfaces configured directly Replaces network command • “Native” IPv6 router mode Not a sub-mode of router ospf 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    58. 58. Configuration modes in OSPFv3 • Entering router mode [no] ipv6 router ospf <process ID> • Entering interface mode [no] ipv6 ospf <process ID> area <area ID> • Exec mode show ipv6 ospf [<process ID>] clear ipv6 ospf [<process ID>] Cisco IOS OSPFv3 Specific Attributes Configuring area range [no] area <area ID> range <prefix>/<prefix length> • Showing new LSA show ipv6 ospf [<process ID>] database link show ipv6 ospf [<process ID>] database prefix • Configuring authentication Under ipv6 router ospf: area 0 authentication ipsec spi 256 md5 cisco Under interface: ipv6 ospf authentication ipsec spi 256 md5 cisco 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution 09/01/13
    59. 59. OSPFv3 Debug Commands Adjacency is not appearing [no] debug ipv6 ospf adj [no] debug ipv6 ospf hello • SPF is running constantly [no] debug ipv6 ospf spf [no] debug ipv6 ospf flooding [no] debug ipv6 ospf events [no] debug ipv6 ospf lsa-generation [no] debug ipv6 ospf database-timer • General purpose [no] debug ipv6 ospf packets [no] debug ipv6 ospf retransmission [no] debug ipv6 ospf tree 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    60. 60. OSPFv3 Configuration Example 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    61. 61. Enhanced Routing Protocol Support Cisco IOS OSPFv3 Router2#sh ipv6 ospf int pos 3/0 POS3/0 is up, line protocol is up Link Local Address FE80::290:86FF:FE5D:A000, Interface ID 7 Area 1, Process ID 100, Instance ID 0, Router ID 10.1.1.4 Network Type POINT_TO_POINT, Cost: 1 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:02 Index 1/1/1, flood queue length 0 Next 0x0(0)/0x0(0)/0x0(0) Last flood scan length is 3, maximum is 3 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 10.1.1.3 Suppress hello for 0 neighbor(s) 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    62. 62. Enhanced Routing Protocol Support Cisco IOS OSPFv3 Router2#sh ipv6 ospf neighbor detail Neighbor 10.1.1.3 In the area 1 via interface POS3/0 Neighbor: interface-id 8, link-local address FE80::2D0:FFFF:FE60:DFFF Neighbor priority is 1, State is FULL, 12 state changes Options is 0x630C34B9 Dead timer due in 00:00:33 Neighbor is up for 00:49:32 Index 1/1/1, retransmission queue length 0, number of retransmission 1 First 0x0(0)/0x0(0)/0x0(0) Next 0x0(0)/0x0(0)/0x0(0) Last retransmission scan length is 2, maximum is 2 Last retransmission scan time is 0 msec, maximum is 0 msec 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    63. 63. Router2#sh ipv6 route IPv6 Routing Table - 5 entries Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP U - Per-user Static route I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2 OI 2001:db8:FFFF:1::/64 [110/2] via FE80::2D0:FFFF:FE60:DFFF, POS3/0 C 2001:db8:1:1::/64 [0/0] via ::, POS3/0 L 2001:db8:1:1::1/128 [0/0] via ::, POS3/0 L FE80::/10 [0/0] via ::, Null0 L FF00::/8 [0/0] via ::, Null0 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    64. 64. Cisco IOS OSPFv3 Database Display 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    65. 65. OSPFv3 on IPv6 Tunnels over IPv4 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution
    66. 66. Lessons Learned: What is OSPF and its  configuration Troubleshooting OSPF  OSFV3 what it is and its configuration. 09/01/13 Instructional Design-Computer Networking - Bridges Educational Group Implementing a Scalable OSPF-Based Solution

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