Interoperation and Replacement Guide for OSPF and EIGRP

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Overview of OSPF and EIGRP

OSPF

The Open Shortest Path First (OSPF) protocol is a link-state Interior Gateway Protocol (IGP) developed by the Internet Engineering Task Force (IETF). It is also a dynamic routing protocol.

  • Mechanism
    1. After OSPF is run on switches, these switches send Hello packets on all OSPF-enabled interfaces. If two switches share a data link and can successfully negotiate certain parameters specified in their Hello packets, they can establish an OSPF neighbor relationship.
    2. Switches that have established an OSPF adjacency can exchange link-state advertisements (LSAs). LSAs describe information about a switch, including all links, interfaces, neighbors, and link state of the switch. Switches exchange the link information to learn about the whole network topology.
    3. A switch floods LSAs and records received LSAs in its link state database (LSDB). Subsequently, all switches have the same LSDB. An LSA describes the surrounding network topology of a switch, whereas an LSDB describes the network topology of the entire autonomous system (AS) and is the summary of LSAs.
    4. After LSDB synchronization is complete, each switch uses a shortest path first (SPF) algorithm to calculate a loop-free topology with itself as the root to describe the shortest path (with the minimum path cost) to each destination. The topology is the shortest path tree (SPT), which shows the optimal paths to nodes in an AS.
    5. After each switch uses an SPF algorithm to calculate the SPT, it installs the shortest paths in its routing table as routing entries to guide data forwarding and updates the routing table in real time. Meanwhile, neighbors exchange Hello packets to maintain their neighbor relationships or adjacencies and periodically retransmit LSAs.
  • DR/BDR and Area
    • Designated Router (DR)/Backup Designated Router (BDR): On broadcast and non-broadcast multiple access (NBMA) networks, any two switches need to establish an OSPF adjacency and exchange routing information, wasting bandwidth resources. To solve this problem, a DR and a BDR are elected and establish an OSPF adjacency with other switches (DR others) on the same network segment. DR others do not establish an OSPF adjacency or exchange any routing information with each other. This reduces the number of OSPF adjacencies established between switches on broadcast and NBMA networks, saving bandwidth resources.
    • Area: When a large number of switches run OSPF, their LSDBs become large, complicating SPF calculations. Each route change causes route recalculations on all switches. OSPF resolves this problem by partitioning an AS into different areas. An area is regarded as a logical group of switches and is identified by an area ID. A network segment belongs to only one area. Area partitioning reduces the LSDB size, simplifies SPF calculations, and increases network efficiency.

For more details about OSPF of switches, see "OSPF Configuration" in Configuration Guide - IP Unicast Routing of the required product version.

EIGRP

The Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary dynamic routing protocol that uses a distance-vector algorithm.

  • Mechanism
    1. An EIGRP-enabled switch periodically sends Hello packets on each interface, establishes a neighbor relationship with the switch that receives the packet, and adds the neighbor relationship to its neighbor table.
    2. The two switches that establish a neighbor relationship can exchange routing information only after a three-way handshake. They exchange all routing information when exchanging routing information for the first time and update the changed routing information only when the network structure or route changes. EIGRP routing information is exchanged using Update, Query, Reply, and Ack packets.
    3. EIGRP stores all received routing information in the topology table, including the destination IP address, mask, next hop, and metric of each route. An EIGRP switch selects the optimal loop-free routes from the topology table using the Diffusing Update Algorithm (DUAL) and adds the routes to its routing table.
    4. The EIGRP switch maintains neighbor relationships through Hello packets. If the switch does not receive any Hello packet from a peer switch within the specified period, it considers the peer switch to be unreachable, deletes the peer switch from the neighbor table, and notifies other neighbors that the route to the peer switch is unreachable.
  • DUAL
    • DUAL is used by EIGRP to calculate loop-free routes.
    • The algorithm is a distance-vector algorithm. Using this algorithm, a switch calculates the shortest distance to a destination by calculating its distance to each neighbor plus the distance from this neighbor to the destination and obtaining the minimum distance to the destination from the distance calculation result. The distance, known as a metric, is calculated based on parameters such as the transmission delay, link bandwidth, and effective bandwidth to reflect the advantages and disadvantages of each route.
    • DUAL calculates loop-free routes based on feasible successors. A successor is a neighboring switch used for packet forwarding that has a least cost path to a destination that is guaranteed not to be part of a routing loop. When a network change occurs, DUAL first detects whether a feasible successor for the destination network exists. If a feasible successor exists, DUAL selects it as the next hop. If no feasible successor exists and there is no routing entry to the destination address in the topology table, the destination network is unreachable. If the topology table contains such a routing entry, the neighboring switch is not eligible to become the feasible successor. In this case, DUAL needs to recalculate the feasible successor.

Comparisons Between OSPF and EIGRP

Table 2-119  Implementation of OSPF and EIGRP

Implementation

OSPF

EIGRP

Neighbor discovery

Discovers neighbors through Hello packets and maintains neighbor relationships through Hello packets and the timeout mechanism.

Discovers neighbors through Hello packets and maintains neighbor relationships through Hello packets and the timeout mechanism.

Route exchange

Exchanges all routing information at a time with a peer switch during adjacency establishment and exchanges incremental routing information after adjacency establishment.

Exchanges all routing information at a time with a peer switch during neighbor relationship establishment and after a three-way handshake and exchanges incremental routing information after neighbor relationship establishment.

Route calculation

Uses the SPF algorithm for route calculation. After route calculation, the entire network topology can be viewed.

Uses the DUAL algorithm for route calculation. After route calculation, the entire network topology cannot be viewed.

Packet transmission

Uses five types of packets defined by RFC 2328: Hello, database description (DD), link state request (LSR), link state update (LSU), and link state acknowledgement (LSAck).

Uses four types of packets consisting of TLVs: Hello, Query, Reply, and Update packets.

Area partitioning

Provides area partitioning to prevent a large number of nodes from participating in SPF calculation on a large-scale network.

Does not provide area partitioning, unable to control the number of nodes participating in SPF calculation on a large-scale network.

Multi-process and multi-instance

Supports multi-process and multi-instance.

Supports multi-process and multi-instance.

Security

Supports message-digest 5 (MD5) authentication and requires the packet digest to be contained in the Authentication field and all packet content to be calculated for authentication.

Supports MD5 authentication and requires the packet digest to be contained in the Authentication TLV and part of the packet content to be calculated for authentication.

Route summarization

Supports manual summarization based on advertised routes.

Supports automatic summarization and interface-based manual summarization.

Route import

Supports the import of direct routes and dynamic routes. Only the route cost can be configured for imported routes.

Supports the import of direct routes and dynamic routes. The route metric, including the delay and bandwidth can be configured for imported routes.

Table 2-120  Advantages and disadvantages of OSPF and EIGRP

Characteristics

OSPF

EIGRP

Convergence speed

OSPF uses the SPF algorithm for route calculation. After routing information is flooded, each node calculates routes locally without depending on neighbors' routing information. This mechanism ensures fast convergence and is more advantageous in large-scale networks.

EIGRP uses DUAL for route calculation and needs to periodically check for feasible successors to achieve route convergence. Route convergence depends on neighbors' routing information. On a large-scale network, the convergence performance of EIGRP is much lower than that of OSPF.

Number of devices that exchange routing information

On broadcast and NBMA networks, OSPF can elect the DR and BDR to enable all the other devices to exchange routing information with only the DR and BDR, which effectively reduces the number of transmitted protocol packets.

On broadcast and NBMA networks, every two EIGRP devices establish a neighbor relationship to exchange routing information. When there are a large number of EIGRP devices on a shared network segment, protocol packets occupy a lot of bandwidth resources.

Protocol openness

OSPF is an open protocol developed by the IETF and supported by major network devices in the world. Therefore, its interoperability, scalability, and reliability are guaranteed due to its openness.

EIGRP is a Cisco proprietary protocol. Cisco has no obligation to notify any other vendors of the modification to EIGRP. Therefore, there are uncertainties in network upgrade and extension. In addition, EIGRP cannot be used to interwork with other vendors, leading to poor scalability.

Area partitioning

OSPF implements hierarchical route management through area partitioning. On a large-scale network, OSPF can plan and limit the number of routes by dividing the network into areas.

EIGRP has no area concept and is generally applicable to small-scale networks. On a large-scale network, EIGRP cannot implement hierarchical route management and cannot limit the number of nodes involved in topology computation. Therefore, on a large-scale network, the route calculation performance of EIGRP is poorer than that of OSPF.

Special areas

OSPF supports stub areas, totally stub areas, and not-so-stubby areas (NSSAs). Configuring these types of areas can minimize the number of routes and route calculations to ensure network stability.

EIGRP proposed the use of stub devices but lacks a detailed implementation scheme.

Load balancing

OSPF supports only equal-cost load balancing. That is, load balancing is performed when the routes to the same destination address have the same cost.

EIGRP is the only protocol that supports unequal load balancing. That is, load balancing can be performed when the routes to the same destination address have different costs.

Performance requirements

OSPF needs to store the network topology of the entire area and use the SPF algorithm to compute routes. Therefore, OSPF has high requirements for the CPU and memory. However, with the continuous improvement of router performance and declining hardware costs, this disadvantage is not that important.

EIGRP is easy to implement and does not need to store the entire area topology. Therefore, EIGRP has lower requirements for the CPU and memory than OSPF.

Configuration complexity

OSPF is complex to configure. Due to complex mechanisms such as area partitioning, DR election, hierarchical routing, and area border router (ABR) summarization, network administrators must be familiar with OSPF before planning and managing OSPF networks.

EIGRP is easier to configure than OSPF. In the simplest case, you only need to enable EIGRP and network segments.

Table 2-121  Comparisons between Huawei OSPF and Cisco OSPF and EIGRP Commands

Function

Huawei OSPF Commands

Cisco OSPF and EIGRP Commands

Creates an OSPF/EIGRP process.

ospf process-id router-id router-id
  • OSPF: router ospf process-id
  • EIGRP: router eigrp autonomous-system-number

Configures an OSPF/EIGRP router ID.

An OSPF router ID is configured during the creation of an OSPF process.

  • OSPF: router-id router-id
  • EIGRP: eigrp router-id router-id

Creates an OSPF area.

area area-id
  • OSPF: An OSPF area is created when an OSPF network segment is being enabled.
  • EIGRP: EIGRP has no area concept.

Enables an OSPF/EIGRP network segment

network network-address wildcard-mask
  • OSPF: network ip-address wildcard-mask areaarea-id
  • EIGRP: network ip-address wildcard-mask

Configures the OSPF/EIGRP priority.

preference preference
  • OSPF: distance ospf { external dist1 | inter-areadist2 | intra-area dist3 }
  • EIGRP: distance eigrp internal-distance external-distance

Imports external routes.

import-route
  • OSPF: redistribute
  • EIGRP: redistribute

Displays OSPF/EIGRP neighbor relationship.

display ospf peer
  • OSPF: show ip ospf neighbors
  • EIGRP: show ip eigrp neighbors

Displays OSPF LSDB/EIGRP topology table information.

display ospf lsdb
  • OSPF: show ip ospf database
  • EIGRP: show ip eigrp topology

Displays OSPF/EIGRP routing table information.

display ospf routing
  • OSPF: show ip route ospf
  • EIGRP: show ip route eigrp

OSPF and EIGRP Interoperation and Replacement Solution

EIGRP is a Cisco proprietary protocol. Huawei switches cannot interoperate with EIGRP-enabled devices directly. To enable Huawei OSPF-enabled switches to interoperate with or replace Cisco EIGRP-enabled switches, two solutions are available.

SolutionDescription
OSPF interoperates with EIGRPUse OSPF on Cisco EIGRP-enabled switches to exchange routing information with Huawei OSPF-enabled switches. This solution enables Huawei OSPF-enabled switches to interoperate with Cisco EIGRP-enabled switches.
OSPF replaces with EIGRPConfigure OSPF to replace EIGRP on Cisco switches so that all devices on the network run OSPF. This solution enables Huawei switches and Cisco switches to communicate with each other through OSPF.

OSPF and EIGRP Interoperation and Replacement Case 1: OSPF Interoperates with EIGRP

This section includes:

Overview

OSPF can be used on Cisco EIGRP-enabled switches to exchange routing information with Huawei OSPF-enabled switches. This solution enables Huawei OSPF-enabled switches to interoperate with Cisco EIGRP-enabled switches.

Configuration Notes
  • This case applies to OSPF-supporting Huawei switches.
  • This case provides only the basic configuration for interoperation between OSPF and EIGRP.
  • During interworking and replacement of Cisco switches and Huawei switches, the encapsulation mode must be IEEE 802.1Q.
  • The subnets parameter needs to be configured when EIGRP routes need to be imported into OSPF. Otherwise, only major network routes but no subnet routes can be imported into OSPF.
  • The metric-related parameters need to be configured when OSPF routes need to be imported into EIGRP. Otherwise, the metric value of the imported OSPF routes is infinite, and these routes cannot be transmitted to other EIGRP devices.

Networking Requirements

In Figure 2-101, a Cisco switch is running EIGRP on the network. Based on service requirements, a Huawei switch needs to be added to the network to enable the Huawei OSPF-enabled switch to interoperate with the Cisco EIGRP-enabled switch. Both OSPF and EIGRP need to run on the network.

In this example, HuaweiA running OSPF needs to interoperate with CiscoA running EIGRP.

Figure 2-101  Interoperation between OSPF and EIGRP 
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Configuration Roadmap
  1. Configure basic EIGRP functions on the Cisco switch.
  2. Configure basic OSPF functions on the Huawei switch.
  3. Configure basic OSPF functions on the Cisco switch for interoperation with the Huawei switch through OSPF.
  4. Configure OSPF and EIGRP to import routes from each other on the Cisco switch so that the Huawei OSPF-enabled switch can interoperate with the Cisco EIGRP-enabled switch.
  5. Verify the configuration.

Procedure

  1. Configure basic EIGRP functions on the Cisco switch.

    # Create VLAN 10, and add GE1/0/1 to VLAN 10.

    CISCO(config)# vlan 10 CISCO(config-vlan)# exit CISCO(config)# interface gigabitEthernet 1/0/1 CISCO(config-if)# switchport trunk encapsulation dot1q CISCO(config-if)# switchport mode trunk CISCO(config-if)# switchport trunk allowed vlan 10 CISCO(config-if)# exit 

    # Configure the IP address 192.168.1.2/24 for VLANIF 10.

    CISCO(config)# interface vlan 10 CISCO(config-if)# ip address 192.168.1.2 255.255.255.0 CISCO(config-if)# no shutdown CISCO(config-if)# exit 

    # Configure the IP address 192.168.3.1/32 for Loopback1.

    CISCO> enable CISCO# config terminal CISCO(config)# interface loopback 1 CISCO(config-if)# ip address 192.168.3.1 255.255.255.255 CISCO(config-if)# exit 

    # Configure basic EIGRP functions.

    CISCO(config)# router eigrp 1 CISCO(config-router)# eigrp router-id 2.2.2.2 CISCO(config-router)# network 192.168.3.1 0.0.0.0 CISCO(config-router)# exit

  2. Configure basic OSPF functions on the Huawei switch.

    # Create VLAN 10, and add GE0/0/1 to VLAN 10.

    <HUAWEI> system-view [HUAWEI] vlan 10 [HUAWEI-vlan10] quit [HUAWEI] interface GigabitEthernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] port link-type trunk [HUAWEI-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 [HUAWEI-GigabitEthernet0/0/1] quit 

    # Configure the IP address 192.168.1.1/24 to VLANIF 10.

    [HUAWEI] interface vlanif 10 [HUAWEI-Vlanif10] ip address 192.168.1.1 24 [HUAWEI-Vlanif10] quit 

    # Configure the IP address 192.168.2.1/32 for Loopback1.

    [HUAWEI] interface Loopback 1 [HUAWEI-LoopBack1] ip address 192.168.2.1 32 [HUAWEI-LoopBack1] quit 

    # Configure basic OSPF functions.

    [HUAWEI] ospf 1 router-id 1.1.1.1 [HUAWEI-ospf-1] area 0 [HUAWEI-ospf-1-area-0.0.0.0] network 192.168.1.0 0.0.0.255 [HUAWEI-ospf-1-area-0.0.0.0] network 192.168.2.1 0.0.0.0 [HUAWEI-ospf-1-area-0.0.0.0] return

  3. Configure basic OSPF functions on the Cisco switch for interoperation with the Huawei switch through OSPF.

    # Configure basic OSPF functions.

    CISCO(config)# router ospf 1 CISCO(config-router)# router-id 2.2.2.2 CISCO(config-router)# network 192.168.1.0 0.0.0.255 area 0 CISCO(config-router)# exit

  4. Configure OSPF and EIGRP to import routes from each other on the Cisco switch so that the Huawei OSPF-enabled switch can interoperate with the Cisco EIGRP-enabled switch.

    # Configure OSPF to import EIGRP routes.

    CISCO(config)# router ospf 1 CISCO(config-router)# redistribute eigrp 1 subnets CISCO(config-router)# exit 

    # Configure EIGRP to import OSPF routes.

    CISCO(config)# router eigrp 1 CISCO(config-router)# redistribute ospf 1 metric 1 1 1 1 1 CISCO(config-router)# end 

  5. Verify the configuration.

    # View the OSPF routing table of the Huawei switch.

    <HUAWEI> display ospf 1 routing  Destination        Cost  Type       NextHop         AdvRouter       Area         192.168.1.0/24     1     Transit    192.168.1.1     1.1.1.1         0.0.0.0      192.168.2.1/32     0     Stub       192.168.2.1     1.1.1.1         0.0.0.0                                                                                       Routing for ASEs                                                                 Destination        Cost      Type       Tag         NextHop         AdvRouter    192.168.3.1/32     20        Type2      0           192.168.1.2     2.2.2.2  //EIGRP route of the Cisco switch imported through OSPF of the Cisco switch                                                                                   Total Nets: 3                                                                    Intra Area: 2  Inter Area: 0  ASE: 1  NSSA: 0                     

    # View the OSPF routing table of the Cisco switch.

    CISCO# show ip route ospf      192.168.2.0/32 is subnetted, 1 subnets                                     O IA    192.168.2.1 [110/1] via 192.168.1.1, 00:09:07, Vlan10  //OSPF route of the Huawei switch learned through OSPF of the Cisco switch

    # View the EIGRP topology table of the Cisco switch.

    CISCO# show ip eigrp topology                                                     IP-EIGRP Topology Table for AS(1)/ID(2.2.2.2)                                                                                                                     Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,                       r - reply Status, s - sia Status                                                                                                                           P 192.168.1.0/24, 1 successors, FD is 2560000256  //Imported OSPF route of the Cisco switch         via Redistributed (2560000256/0)                                         P 192.168.3.1/32, 1 successors, FD is 128256                                            via Connected, Loopback1                                                 P 192.168.2.1/32, 1 successors, FD is 2560000256  //OSPF route of the Huawei switch imported through OSPF of the Cisco switch         via Redistributed (2560000256/0)                                        

    # View the IP routing table of the Huawei switch.

    <HUAWEI> display ip routing-table Route Flags: R - relay, D - download to fib                                      ------------------------------------------------------------------------------   Routing Tables: Public                                                                    Destinations : 9       Routes : 9                                                                                                                      Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface                                                                                              127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0           127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0           192.0.0.0/8   Static  60   0          RD   192.89.5.1      Vlanif4094           192.89.5.0/24  Direct  0    0           D   192.89.5.57     Vlanif4094          192.89.5.57/32  Direct  0    0           D   127.0.0.1       Vlanif4094         192.168.1.0/24  Direct  0    0           D   192.168.1.1     Vlanif10            192.168.1.1/32  Direct  0    0           D   127.0.0.1       Vlanif10            192.168.2.1/32  Direct  0    0           D   127.0.0.1       LoopBack1           192.168.3.1/32  O_ASE   150  20          D   192.168.1.2     Vlanif10  //EIGRP route of the Cisco switch imported through OSPF of the Cisco switch 

    # View the routing table of the Cisco switch.

    CISCO# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP                          D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area                   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2                   E1 - OSPF external type 1, E2 - OSPF external type 2                             i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2            ia - IS-IS inter area, * - candidate default, U - per-user static route          o - ODR, P - periodic downloaded static route                                                                                                              Gateway of last resort is not set                                                                                                                                      192.168.3.0/32 is subnetted, 1 subnets                                     C       192.168.3.1 is directly connected, Loopback1                            C    192.168.1.0/24 is directly connected, Vlan10                               C    192.89.5.0/24 is directly connected, Vlan4094                                    192.168.2.0/32 is subnetted, 1 subnets                                     O       192.168.2.1 [110/1] via 192.168.1.1, 00:06:59, Vlan10  //OSPF route of the Huawei switch learned through OSPF of the Cisco switch S    192.0.0.0/8 [1/0] via 192.89.5.1                                         

    # Check whether the Huawei OSPF-enabled switch can communicate with the Cisco EIGRP-enabled switch.

    <HUAWEI> ping 192.168.3.1   PING 192.168.3.1: 56  data bytes, press CTRL_C to break                           Reply from 192.168.3.1: bytes=56 Sequence=1 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=2 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=3 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=4 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=5 ttl=255 time=1 ms                                                                                                  --- 192.168.3.1 ping statistics ---                                               5 packet(s) transmitted                                                          5 packet(s) received                                                             0.00% packet loss                                                                round-trip min/avg/max = 1/1/1 ms                                           

OSPF and EIGRP Interoperation and Replacement Case 2: OSPF Replaces EIGRP

This section includes:

Overview

OSPF can be configured to replace EIGRP on Cisco switches so that all devices on the network run OSPF. This solution enables Huawei switches and Cisco switches to communicate with each other through OSPF.

Configuration Notes
  • This case applies to OSPF-supporting Huawei switches.
  • This case provides only the basic configuration for the replacement of EIGRP with OSPF.
  • During interworking and replacement of Cisco switches and Huawei switches, the encapsulation mode must be IEEE 802.1Q.
  • If route summarization has been used on the EIGRP network before protocol replacement, during OSPF configuration, summary routes need to be advertised first, and then specific routes of the connected network segments can be advertised. This avoids the situation where OSPF specific routes take effect but EIGRP summary routes do not.
  • EIGRP route summarization and filtering are implemented based on interfaces and can be performed on each router. OSPF route summarization and filtering are implemented based on areas and can be configured on only ABRs or autonomous system boundary routers (ASBRs). Therefore, if route summarization and filtering have been deployed on a large number of devices on the existing EIGRP network, you need to adjust the EIGRP route summarization and filtering configuration before configuring OSPF and make the new configuration similar to the configuration of an OSPF network. That is, route summarization and filtering are configured on only ABRs or ASBRs so that OSPF routes can override EIGRP routes and OSPF can replace EIGRP.
  • If you adjust the EIGRP route preference on a large-scale network, you are advised to adjust the preference on edge devices first and then on core devices. Loops may occur on the network because within a short period of time, EIGRP routes take effect on some devices while OSPF routes take effect on other devices. Therefore, the EIGRP route preference needs to be adjusted quickly. You are advised to use the configuration script to perform batch adjustment through the NMS.
  • If the network scale is large and multiple branch networks exist, replace EIGRP on the branch networks with OSPF gradually, and then replace EIGRP the backbone network with OSPF. In this scenario, EIGRP and OSPF coexist. To ensure that routes on the entire network are reachable during the replacement, you need to configure EIGRP and OSPF to import routes from each other on the border devices of the EIGRP and OSPF networks.

Networking Requirements

In Figure 2-102, a Cisco switch is running EIGRP on the network. Based on service requirements, a Huawei switch needs to be added to the network, and all network devices need to run OSPF only to enable the Huawei and Cisco switches to interoperate with each other through OSPF.

In this example, HuaweiA running OSPF needs to replace CiscoA running EIGRP.

Figure 2-102  Replacing EIGRP with OSPF 
imgDownload?uuid=a152a87e4d864a2b9a24e4f

Configuration Roadmap
  1. Configure basic EIGRP functions on the Cisco switch.
  2. Configure basic OSPF functions on the Huawei switch.
  3. Back up the EIGRP topology table and routing table of the Cisco switch to a local PC.
  4. Adjust the EIGRP route preference to be higher than the OSPF route preference.
  5. Configure OSPF on the Cisco switch and check OSPF routes to ensure that OSPF routes are consistent with EIGRP routes.
  6. Adjust the EIGRP route preference to be lower than the OSPF route preference.
  7. Delete the EIGRP configuration from the Cisco switch after services on the live network has been running stably for a certain period of time to enable all network devices to run OSPF only.
  8. Verify the configuration.

Procedure

  1. Configure basic EIGRP functions on the Cisco switch.

    # Create VLAN 10, and add GE1/0/1 to VLAN 10.

    CISCO> enable CISCO# config terminal CISCO(config)# vlan 10 CISCO(config-vlan)# exit CISCO(config)# interface gigabitEthernet 1/0/1 CISCO(config-if)# switchport trunk encapsulation dot1q CISCO(config-if)# switchport mode trunk CISCO(config-if)# switchport trunk allowed vlan 10 CISCO(config-if)# exit 

    # Configure the IP address 192.168.1.2/24 for VLANIF 10.

    CISCO(config)# interface vlan 10 CISCO(config-if)# ip address 192.168.1.2 255.255.255.0 CISCO(config-if)# no shutdown CISCO(config-if)# exit 

    # Configure the IP address 192.168.3.1/32 for Loopback1.

    CISCO(config)# interface loopback 1 CISCO(config-if)# ip address 192.168.3.1 255.255.255.255 CISCO(config-if)# exit 

    # Configure the IP address 192.168.4.1/32 for Loopback2.

    CISCO(config)# interface loopback 2 CISCO(config-if)# ip address 192.168.4.1 255.255.255.255 CISCO(config-if)# exit 

    # Configure basic EIGRP functions.

    CISCO(config)# router eigrp 1 CISCO(config-router)# eigrp router-id 2.2.2.2 CISCO(config-router)# network 192.168.1.0 0.0.0.255 CISCO(config-router)# network 192.168.3.1 0.0.0.0 CISCO(config-router)# network 192.168.4.1 0.0.0.0 CISCO(config-router)# end 

  2. Configure basic OSPF functions on the Huawei switch.

    # Create VLAN 10, and add GE0/0/1 to VLAN 10.

    <HUAWEI> system-view [HUAWEI] vlan 10 [HUAWEI-vlan10] quit [HUAWEI] interface GigabitEthernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] port link-type trunk [HUAWEI-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 [HUAWEI-GigabitEthernet0/0/1] quit 

    # Configure the IP address 192.168.1.1/24 to VLANIF 10.

    [HUAWEI] interface vlanif 10 [HUAWEI-Vlanif10] ip address 192.168.1.1 24 [HUAWEI-Vlanif10] quit 

    # Configure the IP address 192.168.2.1/32 for Loopback1.

    [HUAWEI] interface Loopback 1 [HUAWEI-LoopBack1] ip address 192.168.2.1 32 [HUAWEI-LoopBack1] quit 

    # Configure basic OSPF functions.

    [HUAWEI] ospf 1 router-id 1.1.1.1 [HUAWEI-ospf-1] area 0 [HUAWEI-ospf-1-area-0.0.0.0] network 192.168.1.0 0.0.0.255 [HUAWEI-ospf-1-area-0.0.0.0] network 192.168.2.1 0.0.0.0 [HUAWEI-ospf-1-area-0.0.0.0] return

  3. Back up the EIGRP topology table and routing table of the Cisco switch to a local PC.

    # View the EIGRP topology table of the Cisco switch.

    CISCO# show ip eigrp topology IP-EIGRP Topology Table for AS(1)/ID(2.2.2.2)                                                                                                                     Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,                       r - reply Status, s - sia Status                                                                                                                           P 192.168.4.0/24, 1 successors, FD is 128256                                            via Summary (128256/0), Null0                                            P 192.168.4.1/32, 1 successors, FD is 128256                                            via Connected, Loopback2                                                 P 192.168.1.0/24, 1 successors, FD is 2816                                              via Connected, Vlan10                                                    P 192.168.3.0/24, 1 successors, FD is 128256                                            via Summary (128256/0), Null0                                            P 192.168.3.1/32, 1 successors, FD is 128256                                            via Connected, Loopback1                                   

    # View the routing table of the Cisco switch.

    CISCO# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP                          D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area                   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2                   E1 - OSPF external type 1, E2 - OSPF external type 2                             i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2            ia - IS-IS inter area, * - candidate default, U - per-user static route          o - ODR, P - periodic downloaded static route                                                                                                              Gateway of last resort is not set                                                                                                                                      192.168.3.0/24 is variably subnetted, 2 subnets, 2 masks                   D       192.168.3.0/24 is a summary, 00:04:09, Null0                            C       192.168.3.1/32 is directly connected, Loopback1                         C    192.168.1.0/24 is directly connected, Vlan10                                    192.168.4.0/24 is variably subnetted, 2 subnets, 2 masks                   D       192.168.4.0/24 is a summary, 00:01:02, Null0                            C       192.168.4.1/32 is directly connected, Loopback2                         C    192.89.5.0/24 is directly connected, Vlan4094                               S    192.0.0.0/8 [1/0] via 192.89.5.1                                           

  4. Adjust the EIGRP route preference to be higher than the OSPF route preference.

    The following table lists the route preferences on Cisco switches, a smaller priority value indicates a higher priority.

    Route TypeRoute Preference
    Direct route0
    Static route1
    EIGRP internal route90
    OSPF route110
    IS-IS route115
    RIP route120
    EIGRP external route170

    # Set the preference value of EIGRP external routes to 100 to make the preference of EIGRP internal and external routes be higher than that of OSPF routes (with the preference value 110).

    CISCO# config terminal CISCO(config)# router eigrp 1 CISCO(config-router)# distance eigrp 90 100 CISCO(config-router)# exit

  5. Configure OSPF on the Cisco switch and check OSPF routes to ensure that OSPF routes are consistent with EIGRP routes.

    # Configure basic OSPF functions.

    CISCO(config)# router ospf 1 CISCO(config-router)# router-id 2.2.2.2 CISCO(config-router)# network 192.168.1.0 0.0.0.255 area 0 CISCO(config-router)# network 192.168.3.1 0.0.0.0 area 0 CISCO(config-router)# network 192.168.4.1 0.0.0.0 area 0 CISCO(config-router)# end 

    # View the routing table to check whether OSPF routes have overridden EIGRP routes.

    CISCO# show ip protocols *** IP Routing is NSF aware ***                                                                                                                                   Routing Protocol is "eigrp 1"                                                      Outgoing update filter list for all interfaces is not set                        Incoming update filter list for all interfaces is not set                        Default networks flagged in outgoing updates                                     Default networks accepted from incoming updates                                  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0                                 EIGRP maximum hopcount 100                                                       EIGRP maximum metric variance 1                                                  Redistributing: eigrp 1                                                          EIGRP NSF-aware route hold timer is 240s                                         EIGRP NSF disabled                                                                  NSF signal timer is 20s                                                          NSF converge timer is 120s                                                    Automatic network summarization is in effect                                     Automatic address summarization:                                                   192.168.4.0/24 for Loopback1, Vlan10                                              Summarizing with metric 128256                                                 192.168.3.0/24 for Loopback2, Vlan10                                              Summarizing with metric 128256                                                 192.168.1.0/24 for Loopback1, Loopback2                                       Maximum path: 4                                                                  Routing for Networks:                                                              192.168.1.0  //EIGRP route of the Cisco switch     192.168.3.1/32  //EIGRP route of the Cisco switch     192.168.4.1/32  //EIGRP route of the Cisco switch   Routing Information Sources:                                                       Gateway         Distance      Last Update                                      Distance: internal 90 external 100                                                                                                                             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 2.2.2.2                                                                It is an area border router                                                      Number of areas in this router is 2. 2 normal 0 stub 0 nssa                      Maximum path: 4                                                                  Routing for Networks:                                                              192.168.1.0 0.0.0.255 area 0  //OSPF route of the Cisco switch     192.168.3.1 0.0.0.0   area 0  //OSPF route of the Cisco switch     192.168.4.1 0.0.0.0   area 0  //OSPF route of the Cisco switch   Routing Information Sources:                                                       Gateway         Distance      Last Update                                        1.1.1.1              110      00:20:54                                         Distance: (default is 110)                                                    

  6. Adjust the EIGRP route preference to be lower than the OSPF route preference.

    # Set the preference values of EIGRP internal and external routes to 130 and 170 respectively to make the preferences of EIGRP routes be lower than that of OSPF routes (with the preference value 110).

    CISCO# config terminal CISCO(config)# router eigrp 1 CISCO(config-router)# distance eigrp 130 170 CISCO(config-router)# exit

  7. Delete the EIGRP configuration from the Cisco switch after services on the live network has been running stably for a certain period of time to enable all network devices to run OSPF only.

    CISCO(config)# no router eigrp 1 CISCO(config)# exit 

  8. Verify the configuration.

    # View the OSPF routing table of the Huawei switch.

    <HUAWEI> display ospf 1 routing                               OSPF Process 1 with Router ID 1.1.1.1                                                     Routing Tables                                                                                                                                   Routing for Network                                                              Destination        Cost  Type       NextHop         AdvRouter       Area         192.168.1.0/24    1     Transit    192.168.1.1    1.1.1.1         0.0.0.0      192.168.2.1/32    0     Stub       192.168.2.1    1.1.1.1         0.0.0.0      192.168.3.1/32    2     Inter-area 192.168.1.2    2.2.2.2         0.0.0.0  //OSPF route of the Cisco switch learned through OSPF of the Huawei switch  192.168.4.1/32    2     Inter-area 192.168.1.2    2.2.2.2         0.0.0.0  //OSPF route of the Cisco switch learned through OSPF of the Huawei switch                                                                                  Total Nets: 4                                                                    Intra Area: 2  Inter Area: 2  ASE: 0  NSSA: 0                                  

    # View the OSPF routing table of the Cisco switch.

    CISCO# show ip route ospf                                                            192.168.2.0/32 is subnetted, 1 subnets                                     O IA    192.168.2.1 [110/1] via 192.168.1.1, 00:06:41, Vlan10  //OSPF route of the Huawei switch learned through OSPF of the Cisco switch 

    # View the EIGRP topology table of the Cisco switch.

    CISCO# show ip eigrp topology                                                                                       //The EIGRP configuration of the Cisco switch has been deleted, so the topology table is empty.

    # View the IP routing table of the Huawei switch.

    <HUAWEI> display ip routing-table Route Flags: R - relay, D - download to fib                                      ------------------------------------------------------------------------------   Routing Tables: Public                                                                    Destinations : 10       Routes : 10                                                                                                                      Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface                                                                                              127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0           127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0           192.0.0.0/8   Static  60   0          RD   192.89.5.1      Vlanif4094           192.89.5.0/24  Direct  0    0           D   192.89.5.57     Vlanif4094          192.89.5.57/32  Direct  0    0           D   127.0.0.1       Vlanif4094         192.168.1.0/24   Direct  0    0           D   192.168.1.1     Vlanif10           192.168.1.1/32   Direct  0    0           D   127.0.0.1       Vlanif10           192.168.2.1/32   Direct  0    0           D   127.0.0.1       LoopBack1          192.168.3.1/32   OSPF    10   2           D   192.168.1.2     Vlanif10  //OSPF route of the Cisco switch learned through OSPF of the Huawei switch    192.168.4.1/32   OSPF    10   2           D   192.168.1.2     Vlanif10  //OSPF route of the Cisco switch learned through OSPF of the Huawei switch

    # View the routing table of the Cisco switch.

    CISCO# show ip route Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP                          D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area                   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2                   E1 - OSPF external type 1, E2 - OSPF external type 2                             i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2            ia - IS-IS inter area, * - candidate default, U - per-user static route          o - ODR, P - periodic downloaded static route                                                                                                              Gateway of last resort is not set                                                                                                                                      192.168.3.0/32 is subnetted, 1 subnets                                     C       192.168.3.1 is directly connected, Loopback1                            C    192.168.1.0/24 is directly connected, Vlan10                                    192.168.4.0/32 is subnetted, 1 subnets                                     C       192.168.4.1 is directly connected, Loopback2                            C    192.89.5.0/24 is directly connected, Vlan4094                                    192.168.2.0/32 is subnetted, 1 subnets                                     O IA    192.168.2.1 [110/1] via 192.168.1.1, 00:00:12, Vlan10  //OSPF route of the Huawei switch learned through OSPF of the Cisco switch S    192.0.0.0/8 [1/0] via 192.89.5.1                                           

    # Check whether the Huawei switch can communicate with the Cisco switch through OSPF.

    <HUAWEI> ping 192.168.3.1   PING 192.168.3.1: 56  data bytes, press CTRL_C to break                           Reply from 192.168.3.1: bytes=56 Sequence=1 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=2 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=3 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=4 ttl=255 time=1 ms                   Reply from 192.168.3.1: bytes=56 Sequence=5 ttl=255 time=1 ms                                                                                                  --- 192.168.3.1 ping statistics ---                                               5 packet(s) transmitted                                                          5 packet(s) received                                                             0.00% packet loss                                                                round-trip min/avg/max = 1/1/1 ms                                           

See more please click 

https://support.huawei.com/enterprise/en/doc/EDOC1000069520/9aadccc0/comprehensive-configuration-examples


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