DNA LSA ( Do Not Age LSA)

Experts,

Why does LSA's learned from virtual-link have DNA option set? Can
anyone explain more about DNA (DoNotAge) option?

Documentation talks about Flooding reduction but I am not 100% sure
about this concept.

Here is the output from show ip ospf databass. 3.3.3.3 and 4.4.4.4
have virtual-links.

                Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 75 0x80000008 0x0067E2 3
2.2.2.2 2.2.2.2 157 0x8000000D 0x006E63 3
3.3.3.3 3.3.3.3 2 (DNA) 0x80000007 0x00BC57 2
4.4.4.4 4.4.4.4 3 (DNA) 0x80000002 0x002171 1

                Summary Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
2.2.2.2 2.2.2.2 416 0x80000003 0x00F633
2.2.2.2 3.3.3.3 7 (DNA) 0x80000001 0x005F88
3.3.3.0 3.3.3.3 7 (DNA) 0x80000001 0x00CC5A
3.3.3.0 4.4.4.4 8 (DNA) 0x80000001 0x0031B1
4.4.4.0 4.4.4.4 8 (DNA) 0x80000001 0x008A95
5.5.5.0 4.4.4.4 8 (DNA) 0x80000001 0x00E8F3
10.1.23.0 2.2.2.2 416 0x80000003 0x003F91
10.1.23.0 3.3.3.3 7 (DNA) 0x80000001 0x0025A9
10.1.34.0 3.3.3.3 7 (DNA) 0x80000001 0x00AB18
10.1.34.0 4.4.4.4 8 (DNA) 0x80000001 0x008D32
10.1.45.0 4.4.4.4 8 (DNA) 0x80000001 0x0014A0

Thanks,
Raman

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Received on Thu Nov 05 2009 - 13:17:14 ART