How OSPF know the mask of the multipoint network

pgamage · ‎06-13-2008

I checked the OSPF router link LSA for the frame relay multipoint interface and found it doesn't have subnet mask information. so how the OTHER routers know the subnet mask of this multipoint network?

just now found another thing. it doesn't have mask information on Ethernet which is not stub. ie it is a transit network.

Harold Ritter · ‎06-13-2008

Prabath,

This information resides in the type 2 LSA in such a case.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

pgamage · ‎06-15-2008

Hi,

Cleared, Thanks,

Regards,

pgamage · ‎06-16-2008

Hi Ritter,

Thing to clarify,

if the NBMA mode of natural FR or multipoint sub interface is converted to p2mp mode , it will not generate type 2 LSA and remote router will not receive subnet information. So is there a way to send mask information?

Regards,

Harold Ritter · ‎06-16-2008

Prabath,

For a network type p2mp, the link to each neighbor is treated as a separate p2p link. For p2p links, the subnet information is carried in a stub network in the type 1 LSA.

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México