By default, external routes and inter-area routes will be injected into stub areas or NSSAs . User can utilize the summaries disable true parameter to prevent external printer-area routes from being injected into stub areas or NSSAs. User can also use set protocols ospf4 area <area-id> default-lsa disable false to create a default route entry.areas in the same OSPF domain in the absence of effective route summarization. This can overwhelm a node particularly in large OSPF routing domains. Changing an area from stub to a totally-stubby area solves this issue. To change an area from stub to a totally-stubby-area, user can apply the command set protocols ospf area 0.0.0.1 no-summary from the PiCOS configuration mode.
In Figure 5-5 below, Router 2 is an ABR, to reduce the number of routes on Router 1 in area 0.0.0.2, we will configure area 0.0.0.2 on Router 2 as a totally stubby area.
Figure 5-5. OSPF Stub area/NSSA summary: area 1.1.1.1 should be a stub area or an NSSA
Configuring Switch ARouter 2
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admin@XorPlus#admin@router2# set vlans vlan-id 50030 l3-interface "vlan30" admin@router2# set vlans vlan-500 admin@XorPlus# set vlan-interface interface vlan-500 vif vlan-500 address 192.168.1.2 prefix-length 30 admin@XorPlus#-id 40 l3-interface "vlan40" admin@router2# set interface gigabit-ethernet ge-1/1/3 family ethernet-switching native-vlan-id 30 admin@router2# set interface gigabit-ethernet ge-1/1/5 family ethernet-switching native-vlan-id 40 admin@router2# set l3-interface vlan-interface vlan30 address 10.10.2.2 prefix-length 24 admin@router2# set l3-interface vlan-interface vlan40 address 10.10.4.1 prefix-length 24 admin@router2# set protocols ospf router-id 2.2.2.2 admin@router2# set protocols ospf area 0.0.0.2 area-type "stub" admin@router2# set protocols ospf area 0.0.0.2 no-summary admin@router2# set protocols ospf network 10.10.2.0/24 area 0.0.0.2 admin@router2# set protocols ospf network 10.10.4.0/24 area 0.0.0.0 admin@router2# set l3-interface loopback lo address 2.2.2.2 32 prefix-length 32 Commit OK. Save Done. admin@router2# |
Similarly, on Router4, we will run the same command to stop injecting summaries in NSSA area 0.0.0.1.
Configuring Router 4
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admin@router4# set vlans vlan-id 40 l3-interface "vlan40" admin@router4# set vlans vlan-id 50 l3-interface "vlan50" admin@router4# set interface gigabit-ethernet te-1/1/1 family ethernet-switching native-vlan-id 40 admin@router4# set interface gigabit-ethernet te-1/1/492 family ethernet-switching native-vlan-id 500 admin@XorPlus# 50 admin@router4# set l3-interface vlan-interface vlan40 address 10.10.4.2 prefix-length 24 admin@router4# set l3-interface vlan-interface vlan50 address 10.10.5.1 prefix-length 24 admin@router4# set protocols ospf4ospf router-id 14.14.14.14 admin@XorPlus#admin@router4# set protocols ospf4 ospf network 10.10.4.0/24 area 0.0.0.0 admin@router4# set protocols ospf network 10.10.5.0/24 area 0.0.0 interface vlan-500 vif vlan-500 address 192.168.1.2 admin@XorPlus# commit Waiting for merging configuration..1 admin@router4# set protocols ospf area 0.0.0.1 area-type nssa admin@router4# set protocols ospf area 0.0.0.1 no-summary admin@router4# set protocols ospf network 4.4.4.4/32 area 0 admin@router4# set protocols ospf redistribute static admin@router4# set l3-interface loopback lo address 4.4.4.4 prefix-length 32 Commit OK. Save Donedone. admin@XorPlus# |