Difference between Default-originate and network 0.0.0.0 in BGP

[turbo_engine26]

Hello,

Please i need someone to clarify what is the difference between the "default-originate" command and "network 0.0.0.0 - ip route 0.0.0.0 0.0.0.0 null0" commands. I see both are serving the same purpose by advertising a default route to a peer but in the same time i feel a difference on them.

Thx

Regards,

A.M.

[davinci]

Peter, can you explain a scenario where you would use a route map with the neighbor X.X.X.X default-originate?

[Georg Pauwen]

Hello,

take the example below.

The default route to neighbor 10.10.10.2 is injected only if there is a route to 192.168.1.0.

access-list 1 permit 192.168.1.0
!
route-map DEFAULT 10 permit
match ip address 1
!
router bgp 1
network 10.0.0.0 mask 255.0.0.0
neighbor 10.10.10.2 remote-as 2
neighbor 10.10.10.2 default-originate route-map DEFAULT

[Uttkap]

Hi,

Thanks for the information, but i still have a little doubt, what is the difference between "default-information originate and default-information originate always" ???

[Uttkap]

Adding 1 more question to this question ::

Hi,

what is the difference between "default-information originate and default-information originate always" ???

[Bo Urskov]

Hi Uttkap...

There is no such command in BGP - default-information originate always... this is for OSPF...

In OSPF the default-information originate will advertise a default route when such a route is present in the RIB

default-information originate always will make the router advertise a default route regardless of the presence of a default route in the router - hence it ALWAYS originates a default route...