Example for Configuring Load Balancing Among OSPF Routes

CloudEngine 12800 and 12800E V200R005C10 Configuration Guide - IP Unicast Routing

This document describes the configurations of IP Unicast Routing, including IP Routing, Static Route, RIP, RIPng, OSPF, OSPFv3, IPv4 IS-IS, IPv6 IS-IS, BGP, Routing Policy, and PBR.

Rate and give feedback:

Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).

Example for Configuring Load Balancing Among OSPF Routes

Networking Requirements

As shown in Figure 5-35, the networking requirements are as follows:

SwitchA, SwitchB, SwitchC, and SwitchD connect to each other through OSPF.
SwitchA, SwitchB, SwitchC, and SwitchD belong to Area 0.
Load balancing is configured so that the traffic from SwitchA can be sent to SwitchD through SwitchB or SwitchC.

Figure 5-35 Networking diagram for configuring load balancing among OSPF routes

Configuration Roadmap

The configuration roadmap is as follows:

Configure basic OSPF functions on each Switchto implement interconnection.
Disable load balancing on SwitchA and then check the routing table on SwitchA.
(Optional) Set weights of equal-cost routes on SwitchA.

Procedure

Configure the VLAN for each interface.

<HUAWEI> system-view
[~HUAWEI] sysname SwitchA
[*HUAWEI] commit
[~SwitchA] vlan batch 10 20 50
[*SwitchA] interface 10ge 1/0/1
[*SwitchA-10GE1/0/1] port link-type trunk
[*SwitchA-10GE1/0/1] port trunk allow-pass vlan 10
[*SwitchA-10GE1/0/1] quit
[*SwitchA] interface 10ge 1/0/2
[*SwitchA-10GE1/0/2] port link-type trunk
[*SwitchA-10GE1/0/2] port trunk allow-pass vlan 20
[*SwitchA-10GE1/0/2] quit
[*SwitchA] interface 10ge 1/0/3
[*SwitchA-10GE1/0/3] port link-type trunk
[*SwitchA-10GE1/0/3] port trunk allow-pass vlan 50
[*SwitchA-10GE1/0/3] quit
[*SwitchA] commit

The configurations of SwitchB, SwitchC, and SwitchD are similar to the configuration of SwitchA, and are not provided here.

Assign an IP address to each VLANIF interface.

[~SwitchA] interface vlanif 10
[*SwitchA-Vlanif10] ip address 10.1.1.1 24
[*SwitchA-Vlanif10] quit
[*SwitchA] interface vlanif 20
[*SwitchA-Vlanif20] ip address 10.1.2.1 24
[*SwitchA-Vlanif20] quit
[*SwitchA] interface vlanif 50
[*SwitchA-Vlanif50] ip address 172.16.1.1 24
[*SwitchA-Vlanif50] quit
[*SwitchA] commit

The configurations of SwitchB, SwitchC, and SwitchD are similar to the configuration of SwitchA, and are not provided here.

Configure basic OSPF functions. For details, see Example for Configuring Basic OSPF Functions.

Disable load balancing on SwitchA.

[~SwitchA] ospf
[*SwitchA-ospf-1] maximum load-balancing 1
[*SwitchA-ospf-1] quit
[*SwitchA] commit

# View the routing table of SwitchA.

[~SwitchA] display ip routing-table
Proto: Protocol        Pre: Preference Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: _public_
         Destinations : 16       Routes : 16
 
Destination/Mask    Proto   Pre  Cost    Flags   NextHop         Interface
 
       10.1.1.0/24  Direct  0    0       D        10.1.1.1        Vlanif10
       10.1.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif10
     10.1.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif10
       10.1.2.0/24  Direct  0    0       D        10.1.2.1        Vlanif20
       10.1.2.1/32  Direct  0    0       D        127.0.0.1       Vlanif20
     10.1.2.255/32  Direct  0    0       D        127.0.0.1       Vlanif20
      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
127.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0
     172.16.1.0/24  Direct  0    0       D        172.16.1.1      Vlanif50
     172.16.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif50
   172.16.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif50
     172.16.2.0/24  OSPF    10   3       D        10.1.1.2        Vlanif10
    192.168.0.0/24  OSPF    10   2       D        10.1.1.2        Vlanif10
    192.168.1.0/24  OSPF    10   2       D        10.1.2.2        Vlanif20
255.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0

As shown in the routing table, if the maximum number of equal-cost routes for load balancing is set to 1, OSPF selects 10.1.1.2 as the next hop to the destination network 172.16.2.0.

OSPF selects the next hop randomly among equal-cost routes.

Restore the default number of equal-cost routes for load balancing on SwitchA.

[~SwitchA] ospf
[*SwitchA-ospf-1] undo maximum load-balancing
[*SwitchA-ospf-1] quit
[*SwitchA] commit

# Display the routing table on Switch A.

[~SwitchA] display ip routing-table
Proto: Protocol        Pre: Preference Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
----------------------------------------------------------------------------
Routing Table: _public_
         Destinations : 16       Routes : 17
 
Destination/Mask    Proto   Pre  Cost  Flags     NextHop         Interface
 
       10.1.1.0/24  Direct  0    0       D        10.1.1.1        Vlanif10
       10.1.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif10
     10.1.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif10
       10.1.2.0/24  Direct  0    0       D        10.1.2.1        Vlanif20
       10.1.2.1/32  Direct  0    0       D        127.0.0.1       Vlanif20
     10.1.2.255/32  Direct  0    0       D        127.0.0.1       Vlanif20
      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
127.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0
     172.16.1.0/24  Direct  0    0       D        172.16.1.1      Vlanif50
     172.16.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif50
   172.16.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif50
     172.16.2.0/24  OSPF    10   3       D        10.1.1.2        Vlanif10
                    OSPF    10   3       D        10.1.2.2        Vlanif20
    192.168.0.0/24  OSPF    10   2       D        10.1.1.2        Vlanif10
    192.168.1.0/24  OSPF    10   2       D        10.1.2.2        Vlanif20
255.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0

As shown in the routing table, when the default settings of load balancing are restored, both next hops of SwitchA, namely, 10.1.1.2 and 10.1.2.2, become valid routes. This is because the default number of equal-cost routes is 64.

(Optional) Set weights of equal-cost routes on SwitchA.

If you do not want to implement load balancing between SwitchB and SwitchC, set weights for the equal-cost routes to specify the next hop.

[~SwitchA] ospf
[~SwitchA-ospf-1] nexthop 10.1.2.2 weight 1
[*SwitchA-ospf-1] quit
[*SwitchA] commit

# Display the routing table on SwitchA.

[~SwitchA] display ip routing-table
Proto: Protocol        Pre: Preference Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table: _public_
         Destinations : 16       Routes : 16
 
Destination/Mask    Proto   Pre  Cost   Flags    NextHop         Interface
       10.1.1.0/24  Direct  0    0       D        10.1.1.1        Vlanif10
       10.1.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif10
     10.1.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif10
       10.1.2.0/24  Direct  0    0       D        10.1.2.1        Vlanif20
       10.1.2.1/32  Direct  0    0       D        127.0.0.1       Vlanif20
     10.1.2.255/32  Direct  0    0       D        127.0.0.1       Vlanif20
      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
127.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0
     172.16.1.0/24  Direct  0    0       D        172.16.1.1      Vlanif50
     172.16.1.1/32  Direct  0    0       D        127.0.0.1       Vlanif50
   172.16.1.255/32  Direct  0    0       D        127.0.0.1       Vlanif50
     172.16.2.0/24  OSPF    10   3       D        10.1.2.2        Vlanif20
    192.168.0.0/24  OSPF    10   2       D        10.1.1.2        Vlanif10
    192.168.1.0/24  OSPF    10   2       D        10.1.2.2        Vlanif20
255.255.255.255/32  Direct  0    0       D        127.0.0.1       InLoopBack0

As shown in the routing table, after weights are set for the equal-cost routes, the preference of the route with the next hop being 10.1.2.2 (the weight is 1) is higher than that of the route with the next hop being 10.1.1.2. Therefore, OSPF selects the route with the next hop being 10.1.2.2 as the optimal route.

Configuration Files

Configuration file of SwitchA

#
 sysname SwitchA
#
 vlan batch 10 20 50
#
interface Vlanif10
 ip address 10.1.1.1 255.255.255.0
#
interface Vlanif20
 ip address 10.1.2.1 255.255.255.0
#
interface Vlanif50
 ip address 172.16.1.1 255.255.255.0
#
interface 10GE1/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 
#
interface 10GE1/0/2
 port link-type trunk
 port trunk allow-pass vlan 20 
#
interface 10GE1/0/3
 port link-type trunk
 port trunk allow-pass vlan 50 
#
ospf 1 router-id 10.10.10.1
 nexthop 10.1.2.2 weight 1
 area 0.0.0.0
  network 10.1.1.0 0.0.0.255
  network 10.1.2.0 0.0.0.255
  network 172.16.1.0 0.0.0.255
#
return

Configuration file of SwitchB

#
 sysname SwitchB
#
 vlan batch 20 40
#
interface Vlanif20
 ip address 10.1.2.2 255.255.255.0
#
interface Vlanif40
 ip address 192.168.1.1 255.255.255.0
#
interface 10GE1/0/1
 port link-type trunk
 port trunk allow-pass vlan 20 
#
interface 10GE1/0/2
 port link-type trunk
 port trunk allow-pass vlan 40 
#
ospf 1 router-id 10.10.10.3
 area 0.0.0.0
  network 10.1.2.0 0.0.0.255
  network 192.168.1.0 0.0.0.255
#
return

Configuration file of SwitchC

sysname SwitchC
#
 vlan batch 10 30
#
interface Vlanif10
 ip address 10.1.1.2 255.255.255.0
#
interface Vlanif30
 ip address 192.168.0.1 255.255.255.0
#
interface 10GE1/0/1
 port link-type trunk
 port trunk allow-pass vlan 10 
#
interface 10GE1/0/2
 port link-type trunk
 port trunk allow-pass vlan 30 
#
ospf 1 router-id 10.10.10.2
 area 0.0.0.0
  network 10.1.1.0 0.0.0.255
  network 192.168.0.0 0.0.0.255
#
return

Configuration file of SwitchD

#
 sysname SwitchD
#
 vlan batch 30 40 60
#
interface Vlanif30
 ip address 192.168.0.2 255.255.255.0
#
interface Vlanif40
 ip address 192.168.1.2 255.255.255.0
#
interface Vlanif60
 ip address 172.16.2.1 255.255.255.0
#
interface 10GE1/0/1
 port link-type trunk
 port trunk allow-pass vlan 30
#
interface 10GE1/0/2
 port link-type trunk
 port trunk allow-pass vlan 40
#
interface 10GE1/0/3
 port link-type trunk
 port trunk allow-pass vlan 60
#
ospf 1 router-id 10.10.10.4
 area 0.0.0.0
  network 192.168.0.0 0.0.0.255
  network 192.168.1.0 0.0.0.255
  network 172.16.2.0 0.0.0.255
#
return

Translation

简体中文

Download

Updated: 2021-09-17

Document ID: EDOC1100075354

Downloads: 112

Average rating:

This Document Applies to these Products

Related Version

Digital Signature File

Digital Signature Authentication Mode

Enterprise

Huawei Cloud

Carrier

Consumer

Corporate