Administrator Guide

1264 OSPF and OSPFv3

Network Summary States (Area 0.0.0.0)

LS Age: 49

LS options: (E-Bit)

LS Type: Network Summary LSA

LS Id: 172.21.0.0 (network prefix)

Advertising Router: 10.10.10.10

LS Seq Number: 0x80000003

Checksum: 0x78f8

Length: 28

Network Mask: 255.255.0.0

Metric: 0

The cost can be set to the maximum value, 16,777,215, which is LSInfinity.

Since OSPF cannot send a type 3 summary LSA with this metric (according

to RFC 2328), the summary LSA is flushed. The individual routes are not re-

advertised.

Configuring Flood Blocking

Figure 35-40 shows an example topology for flood blocking. The

configuration follows.

Figure 35-40. Flood Blocking Topology

Configure R0:

terminal length 0

config

VLAN 103

R1 R2

VLAN 104

VLAN 101 VLAN 102