Mailing List Archive: BGP advertisement in quagga

BGP advertisement in quagga

Feb 4, 2017, 9:49 AM

Post #1 of 3 (695 views)

Hi,
In quagga , does eBGP advertise prefix to the peer, issued via network
command, 1) without checking to see if prefix is in IGP or routing table 2)
or the prefix needs to be in FIB to advertise?

If prefix need to be in FIB, how often (default) BGP scans FIB for
withdrawn routes, say as a result of interface down or such and stops
advertising prefix that are withdrawn from FIB?

I tried the documentation on the web and also searched(limited) the user
archive but dint get a clear answer.

According to Cisco, in cisco world under eBGP;
The *network* command works if the router knows the network that you
attempt to advertise, whether connected, static, or learned dynamically.

Any help or pointers appreciated

Thank you
charles

Re: BGP advertisement in quagga [ In reply to ]

dbond at 128technology

Feb 4, 2017, 6:45 PM

Post #2 of 3 (694 views)

Permalink

> In quagga , does eBGP advertise prefix to the peer, issued via network
command, 1) without checking to see if prefix is in IGP or routing table 2)
or the prefix needs to be in FIB to advertise?

So by default it will advertise the network even if there is no IGP route.
There is an undocumented command that makes Quagga only sends if an IGP
route exists (bgp network import-check).

Hopefully that is helpful.
-David

Re: BGP advertisement in quagga [ In reply to ]

charlespitchu at gmail

Feb 4, 2017, 7:21 PM

Post #3 of 3 (694 views)

Permalink

David, Thank you for quick reply.

This is exactly what I was looking for, being new to quaaga with some cisco
background I was lost when eBGP(quagga) was advertising routes that were
not in FIB.

bgp network import-check worked perfectly for my setup.

Thanks again
charles

On Sat, Feb 4, 2017 at 9:45 PM, David Bond <dbond@128technology.com> wrote:

> > In quagga , does eBGP advertise prefix to the peer, issued via network
> command, 1) without checking to see if prefix is in IGP or routing table 2)
> or the prefix needs to be in FIB to advertise?
>
> So by default it will advertise the network even if there is no IGP route.
> There is an undocumented command that makes Quagga only sends if an IGP
> route exists (bgp network import-check).
>
> Hopefully that is helpful.
> -David
>