OSPF Hub-And-Spoke Configuration Examples

8/6/2019 OSPF Hub-And-Spoke Configuration Examples

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OSPF Hub-And-Spoke configuration Examples

Hangzhou H3C Technologies Co., Ltd. 1/11

OSPF Hub-And-Spoke Configuration ExamplesKeywords: OSPF, Hub-And-Spoke

Abstract: Hub-And-Spoke networking is a typical flat networking scheme. H3C optimizes OSPF to

provide a better support for Hub-And-Spoke networking. This document describes how to

configure an OSPF Hub-And-Spoke network.

Acronyms:

Acronym Full spelling

LSA Link State Advertisement

LSDB Link State Database

OSPF Open Shortest Path First


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Table of Contents

1 Feature Overview...........................................................................................................................32 Configuration Example...................................................................................................................3

2.1 Network Requirements ........................................................................................................32.2 Configuration Considerations ..............................................................................................42.3 Configuration Procedures ....................................................................................................5

2.3.1 Configuration on the Hub Device ..............................................................................52.3.2 Configuration on the Spoke Device...........................................................................82.3.3 Verification.................................................................................................................9

3 References ...................................................................................................................................103.1 Protocols and Standards ...................................................................................................103.2 Related Documentation .....................................................................................................10


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1 Feature Overview

The Hub-And-Spoke network is a typical flat networking scheme, in which a hub

device connects with many spoke devices.

In a typical OSPF Hub-And-Spoke network, the hub device and spoke devices reside

in the same area and the hub device keeps an OSPF neighbor relationship with each

spoke device. If the hub device has a large number of OSPF neighbors, the

maintenance and establishment of neighborships will consume too many system

resources, which may cause neighbor timeouts and slow convergence, and affect the

normal operation of other services.

By optimizing OSPF, the above problems can be largely mitigated.

2 Configuration Example

2.1 Network Requirements

As shown in Figure 1


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In the Hub-And-Spoke network, there are 500 spoke devices. The hub device

(Router A) exchanges routing information with the spoke devices by using

OSPF. They are in the same OSPF area.

The spoke devices access the file server through the hub device.

Device Interface IP address Device Interface IP addressRouter A Eth1/1 10.1.1.1/24 Router B Eth1/1 10.1.1.2/24

Eth1/2 10.1.2.1/24 Router C Eth1/1 10.1.2.2/24Eth1/3 10.1.3.1/24 Router D Eth1/1 10.1.3.2/24Eth1/4 10.1.4.1/24 Router E Eth1/1 10.1.4.2/24

Eth1/5 20.1.1.1/24 Server 20.1.1.2/24

Figure 1 Network diagram for OSPF support in a Hub-And-Spoke network

2.2 Configuration Considerations

1) Configure basic OSPF functions on the hub and spoke devices and enable the

hub device to advertise the network address of Server to the spoke devices.

2) Configure OSPF on the hub device as follows to optimize the Hub-And-Spoke

network.


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Configure OSPF to give priority to receiving and processing hello packets.

Configure the LSU sending interval, and the maximum LSU packets that can be

sent at one time for interfaces, to ensure smooth packet transmission.

Configure the maximum, minimum and incremental intervals of LSA generation

to control LSA generation.

Configure the maximum, minimum and incremental intervals of SPF calculation

to control SPF calculation.

2.3 Configuration Procedures

Note:The following configurations are made on devices that are using the default settings

and verified in a lab environment. When using the following configurations on your

devices in a live network, make sure they do not conflict with your current

configurations to prevent potential negative impact on your network.

This document does not correspond to specific software and hardware versions.

2.3.1 Configuration on the Hub Device

I. Configuration steps

Enable OSPF, configure the router ID, and enter OSPF view.

system-view

[RouterA] ospf 1 router-id 1.1.1.1

# Inject networks in OSPF area 1 to enable OSPF on the interfaces attached to the

networks.

[RouterA-ospf-1] area 1

[RouterA-ospf-1-area-0.0.0.1] network 10.0.0.0 0.255.255.255

[RouterA-ospf-1-area-0.0.0.1] network 20.1.1.0 0.0.0.255

[RouterA-ospf-1-area-0.0.0.1] quit

# Configure OSPF to give priority to receiving and processing hello packets.

[RouterA] ospf packet-process prioritized-treatment

# Configure the LSU sending interval as 200 milliseconds and the maximum number


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of LSU packets that can be sent at one time as 10 for interfaces.

[RouterA] ospf 1 router-id 1.1.1.1

[RouterA-ospf-1] transmit-pacing interval 200 count 10

# Configure the maximum LSA generation interval as 60 seconds, minimum LSA

generation interval as 1000 milliseconds and incremental interval as 1000

milliseconds.

[RouterA-ospf-1] lsa-generation-interval 60 1000 1000

# Configure the maximum SPF calculation interval as 60 seconds, minimum SPF

calculation interval as 1000 milliseconds and incremental interval as 1000

milliseconds.

[RouterA-ospf-1] spf-schedule-interval 60 1000 1000

II. Configuration file

display current-configuration

#

version 5.20, Beta 1501L02, Standard

#

sysname RouterA

#

configure-user count 50

#

info-center logfile size-quota 0

#

domain default enable system

#

telnet server enable

#

radius scheme system

server-type extended

primary authentication 127.0.0.1 1645

primary accounting 127.0.0.1 1646

user-name-format without-domain

#

domain system

access-limit disable

state active

idle-cut disable

self-service-url disable


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#

interface Aux0

async mode flow

link-protocol ppp

#

interface Ethernet1/1

port link-mode route

ip address 10.1.1.1 255.255.255.0

#



ip address 10.1.2.1 255.255.255.0

#



ip address 10.1.3.1 255.255.255.0

#



ip address 10.1.4.1 255.255.255.0

#



ip address 20.1.1.1 255.255.255.0

#

#...(Other interface configurations are similar and omitted here.)

#

ospf packet-process prioritized-treatment

#

ospf 1 router-id 1.1.1.1

spf-schedule-interval 60 1000 1000

lsa-generation-interval 60 1000 1000

transmit-pacing interval 200 count 10

area 0.0.0.1

network 10.0.0.0 0.255.255.255

network 20.1.1.0 0.0.0.255

#

user-interface con 0

user-interface aux 0

authentication-mode none

user privilege level 3


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user-interface vty 0 4



#

2.3.2 Configuration on the Spoke Device

The configurations on the spoke devices are similar. This section shows the

configurations made on Router B.

I. Configuration steps

Enable OSPF, configure the router ID, and enter OSPF view.

system-view

[RouterB] ospf 1 router-id 2.2.2.2

# Specify interface Ethernet1/1 whose IP address falls into 10.0.0.0/24 to run OSPF,

and specify the interface to belong to area 1.

[RouterB-ospf-1] area 1

[RouterB-ospf-1-area-0.0.0.1] network 10.0.0.0 0.255.255.255

II. Configuration file

display current-configuration

#

version 5.20, Beta 1501L02, Standard

#

sysname RouterB

#

configure-user count 50

#

info-center logfile size-quota 0

#

domain default enable system

#

telnet server enable

#

radius scheme system

server-type extended

primary authentication 127.0.0.1 1645

primary accounting 127.0.0.1 1646

user-name-format without-domain

#


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domain system

access-limit disable

state active

idle-cut disable

self-service-url disable

#

interface Aux0

async mode flow

link-protocol ppp

#



ip address 10.1.1.2 255.255.255.0

#

ospf 1 router-id 2.2.2.2

area 0.0.0.1

network 10.0.0.0 0.255.255.255

#

user-interface con 0

user-interface aux 0



user-interface vty 0 4



#

2.3.3 Verification

After network convergence, verify the configuration results as follows.

1) Display OSPF neighbor statistics on Router A.

display ospf peer statisticsOSPF Process 1 with Router ID 1.1.1.1

Neighbor Statistics

Area ID Down Attempt Init 2-Way ExStart Exchange Loading Full Total

0.0.0.1 0 0 0 0 0 0 0 500 500

Total 0 0 0 0 0 0 0 500 500

The output information shows that Router A has 500 neighbors (in Full state).

2) Display neighbor information on Router B.


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Copyright 2009 Hangzhou H3C Technologies Co., Ltd. All rights reserved.

No part of this manual may be reproduced or transmitted in any form or by any means without prior written consent of Hangzhou

H3C Technologies Co., Ltd.

The information in this document is subject to change without notice.

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OSPF Hub-And-Spoke Configuration Examples