[AusNOG] As path prepend TPG and Vocus

[Matthew Moyle-Croft]

Consider if BGP is the way to go with redundancy - maybe <cough> DNS is a
better way to steer traffic as you can, using a bunch of services out
there, do live-ness testing of end points etc.

On Tue, 2 May 2023 at 08:35, Steven Waite <steven at waites.com.au> wrote:

> Thank you for everyone's replies as this has given me a solution. Love the
> Ausnog community:)
>
>  I will try again and reach out to our up stream carriers. Basically we
> are multi-homed with our primary site active with the second site as
> secondary to carry selective traffic and redundancy. This was manly to get
> around slow routing changes and also eliminating a risk of asymmetrical
> routing due to session based firewalls been in the mix.
>
>
> On 2 May 2023, at 8:50 am, Matthew Moyle-Croft <mmc at mmc.com.au> wrote:
>
> 
> Have to remember some BGP basics:
>
> 1) longest prefix (eg. /24 in your case) will always win.
> 2) localpref will always win when comparing identical prefixes.
> 3) A network will always use localpref to prefer directly connected
> customer routes.
> 4) ASPath length is not going to overcome the above.
>
> What does "failover" mean to you? When there's a failure, look at what
> Vocus and TPG have in their route tables and the timing. Also check, are
> you actually withdrawing the routes during failure?
>
> MMC
>
> On Mon, 1 May 2023 at 18:09, Steven Waite <steven at waites.com.au> wrote:
>
>> Good evening
>>
>> I hope everyone is well. We have a /23 block broken up between TPG /24
>> and Vocus /24 with the /23 advertise to both Vocus and TPG for failover.
>> This worked will until recently as we noticed increasing failover times
>> during maintenance and now takes around 10-15 minutes. Today I decided to
>> try AS path prepending away from smallest prefix wins type of approach. I
>> think Vocus and TPG ignores prepending as these are local routes thus the
>> local route is preferred even with a lot of prepends. I would love to
>> achieve the same thing via communities if it’s possible. Is someone able to
>> share communities numbers that I should be using for Vocus/TPG please to
>> advertise the primary route for a prefix?
>>
>> Many thanks Steve
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>> AusNOG at lists.ausnog.net
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>>
>
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