ospf option?

[ukleinhe]

could someone tell me or point me in the right directions where i could find out what "Upward" means when i do a:

router#sh ip ospf database sum

OSPF Router with ID (172.31.252.72) (Process ID 10)

Summary Net Link States (Area 84)

Routing Bit Set on this LSA

LS age: 1523

Options: (No TOS-capability, No DC, Upward)

LS Type: Summary Links(Network)

thanks,

uwe

[Harold Ritter]

This tells you that the Down bit is not set in this LSA. The Down bit is used for loop prevention when OSPF is used between the CE and PE. The Down bit is set on summary LSAs (type 3 and 4) by the PE router when routes are received via BGP (VPNv4 prefixes) are redistributed in OSPF. If the Down bit is set then any other PE connected to the same domain sees the Down bit and does not redistribute the route back to BGP.

Hope this helps,

[Harold Ritter]

I forgot to mention that you can refer to the following draft for more information:

http://www.ietf.org/proceedings/03nov/I-D/draft-ietf-ospf-2547-dnbit-01.txt

Hope this helps,

[ukleinhe]

Thank you!

Uwe