OSPF design principles, commands take H3C as an example

Hello everyone , Today I'd like to introduce to you OSPF Design principles , The commands involved in the article , in H3C For example , Command formats are Huawei and H3C similar , So basically, Huawei equipment is also applicable .

Router ID Design principles

• Directly use the management address of the device （loopback） As Router ID.
• Suggest Router ID Unified planning for a continuous network segment , And configured manually Router ID：

[H3C] ospf 10 router-id 1.1.1.1

Design principle of area division

• OSPF The division of regions is closely related to the network level , The core layer and the convergence layer are usually planned as backbone areas （ Area 0）, The equipment of the convergence layer is planned as ABR, The convergence layer and the access layer are planned as non backbone areas , Non backbone areas shall be planned as NSSA Area .
• The number of equipment in each area should preferably not exceed 30 platform , This number is not absolute , Mainly related to equipment performance , Link stability is closely related to .
• The planning of non backbone areas can be compared with the actual administration in the network 、 The geographical division is consistent .

Routing aggregation design principles

• stay ABR It is usually necessary to aggregate the routes of non backbone areas and publish them to the backbone areas ; Empathy , The routes in the backbone area usually need to be aggregated and then published to the non backbone area . stay ABR When configuring routing aggregation on , It is recommended to manually configure the aggregation routing overhead ：

[H3C-ospf-1-area-0.0.0.0] abr-summary 10.1.0.0 255.255.0.0 cost 100

• stay ASBR All locally introduced routes can be aggregated and then published . stay ASBR Configure routing aggregation , It is recommended to manually configure the aggregation routing overhead ：

[H3C-ospf-1] asbr-summary 10.1.0.0 255.255.0.0 cost 1000

• The aggregated address range is the link address 、 Business address , But usually not loopback Address for aggregation .

OSPF Of Of COST Design principles

• It is recommended to configure the bandwidth reference value as OSPF The maximum physical interface bandwidth in the network 10 times . Since then , The smallest in the network COST The value is 10 了 .

For example, there are three interfaces in the network ：10G、1G、100M, If the bandwidth reference value is configured as 100000, that 10G Oral COST by 10,1G Oral COST by 100,100M Interface COST by 1000,OSPF The agreement can be based on differentiated COST Value for routing .

• If the maximum physical interface bandwidth in the network is 10G, Then the configuration bandwidth reference value is 100000

[H3C-ospf-1] bandwidth-reference 100000

• It can also be configured manually according to the traffic model vlan Interface overhead

OSPF Interface network type design

Configure an interface with only one neighbor OSPF The network type is P2P, Ethernet default OSPF The interface type is broadcast , But in most cases OPSF Local area networks all use access Ports and interconnections vlan To run OSPF, Equivalent to one P2P Network of , So at this time, it is suggested to connect the Internet vlan The interface type of is modified to P2P：

[H3C-Vlan-interface113] ospf network-type p2p

To configure OSPF MD5 verification

From the perspective of security , To avoid the leakage of routing information or to OSPF The router makes malicious attacks , Recommended configuration OSPF Message verification function ：

[H3C-ospf-1-area-0.0.0.0] authentication-mode md5
[H3C-Vlan-interface113] ospf authentication-mode md5 1 cipher h3c.com

Configure to disable interface transceiver OSPF message

OSPF The equipment is often used network Command to introduce business vlan, At this time, in addition to releasing 1 class LSA outside , stay network The interface of also sends OSPF Message to establish a neighbor , At this time, it is recommended to configure to prohibit these interfaces that do not need to establish neighbors OSPF message ：

[H3C-ospf-1] silent-interface vlan-interface 113

Optimize SPF Calculate the parameters （ Optional ）

[H3C-ospf-1] spf-schedule-interval 5 100 1000

Be careful ： This parameter needs to be owned by the whole network OSPF Only when the equipment is uniformly configured can the effect be reflected .

To configure OSPF Interface skills

Add interface , Use “network Interface IP Address 0.0.0.0” To add an interface to an area , Use unmask 0.0.0.0 This method can avoid calculating the unmask process according to the interface mask .

[H3C-ospf-1-area-0.0.0.0] network 113.0.0.1 0.0.0.0

OSPF The design principle of route introduction

• OSPF Direct connection can be introduced 、 Static and other routing protocols .
• For direct routing , Use network Commands are issued as IntrAzone routes , Avoid using importdirect operation .
• For static and other routing protocols , It can be planned uniformly when it is introduced COST And routing type .
• If you introduce BGP route , Consider the size of the routing table , You can also use the default routing to avoid introducing .
• Between different routing protocols or OSPF Pay attention to route filtering when two-way importing between different processes , Avoid routing loops .