SGS-6341-Series User Manual

Switch5(config-router)# network 100.1.1.0/24 area 0
Switch5(config-router)#exit
Switch5(config)#exit
Switch5#
Scenario 2: Typical OSPF protocol complex topology.
Area 3 Area 2
Area 1
N3
N1
N8
N5
N6
N9
N10
N4
N2
N15 N14
N7
N11
Area 0
N12
N13
Switch H
Switch G
Switch J
Switch K
Switch L
Switch I
Switch F
Switch E
Switch D
Switch C
Switch B
Switch A
Figure 26-5 Typical
complex OSPF autonomous system
This scenario is a typical complex OSPF autonomous system network topology. Area1 include
network N1-N4 and Layer 3 SwitchA-SwitchD, area2 include network N8-N10, host H1 and
Layer 3 SwitchH, area3 include N5-N7 and Layer 3 SwitchF, SwitchG SwitchA0 and Switch11,
and network N8-N10 share a summary route with host H1(i.e. area3 is defined as a STUB
area). Layer 3 SwitchA, SwitchB, SwitchD, SwitchE, SwitchG, SwitchH, Switch12 are in-area
Layer 3 switches, SwitchC, SwitchD, SwitchF, Switch10 and Switch11 are edge Layer 3
switches of the area, SwitchD and SwitchF are edge Layer 3 switches of the autonomous
system.
To area1, Layer 3 switches SwitchA and SwitchB are both in-area switches, area edge
switches SwitchC and SwitchD are responsible for reporting distance cost to all destination
outside the area, while they are also responsible for reporting the position of the AS edge
Layer 3 switches SwitchD and SwitchF, AS exterior link-state advertisement from SwitchD and
SwitchF are flooded throughout the whole autonomous system. When ASE LSA floods in area
1, those LSAs are included in the area 1 database to get the routes to network N11 and N15.
In addition, Layer 3 SwitchC and SwitchD must summary the topology of area 1 to the
backbone area (area 0, all non-0 areas must be connected via area 0, direct connections are
not allowed), and advertise the networks in area 1 (N1-N4) and the costs from SwitchC and
SwitchD to those networks. As the backbone area is required to keep connected, there must
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User’s Manual of SGS-6341 series