[AusNOG] Route to 103.18.204.0/24

[Mark ZZZ Smith]

What I'd like to see is people make their looking glass iBGP peer with *all* of the AS border routers.

Here's the scenario.

I was announcing a primary and backup weighted versions of the same set of routes to the same transit provider, weighted using their BGP communities, to two different routers of theirs. Their LG is somewhere inside their network, not iBGP peering with the two routers I was announcing the routes to.

The distance vector nature of BGP is that it selects the best route from all those it received, and only sends on the best route. In the above scenario, that meant that transit provider's LG was only receiving my primary weighted routes, because the backup weighted routes had already been discarded somewhere inside their network, because they had a lower LOCAL_PREF.

So here is the problem. I wanted to use their looking glass to see if they were receiving and accepting my backup weighted routes. I didn't care to much about seeing my primary weighted routes because there was no doubt they were being used as I was receiving >1Gbps of traffic for them over my primary link. My fear was that if that link failed, they weren't actually accepting my backup routes, and that >1Gbps of traffic would near instantly turn into 1000s of helpdesk calls. The only way I was able to verify they were receiving my backup weighted prefixes was to ask somebody to login to the direct router I was announcing them to and to verify they were being received and accepted.

So the LG wasn't much use to me, because it was showing me what I already knew (primary prefixes accepted and working), and not showing me what I cared more/most about for a failure situation (backup prefixes also being received and accepted, but not being used right now.)

If people had their LG routers iBGP peer with all of their AS border routers, then the looking glass would provide a complete picture of all versions of the routes the AS was receiving, including weighted backup routes, rather than just the a single router's picture of the network that the LG was receiving its routes from. A much more useful LG IMO.


>________________________________
> From: Daryl Collins <daryl at internode.com.au>
>To: "AusNOG at lists.ausnog.net" <ausnog at lists.ausnog.net> 
>Sent: Tuesday, 17 June 2014 11:52 AM
>Subject: Re: [AusNOG] Route to 103.18.204.0/24
> 
>
>
>You know, Ausnog has a page of looking glasses:
> 
>http://www.ausnog.net/tools/lg
> 
>Perhaps some of these new ones could be added.
> 
>Daryl
> 
> 
>
>
>
>From:AusNOG [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Joshua D'Alton
>Sent: Tuesday, 17 June 2014 11:19 AM
>To: Matt Perkins
>Cc: AusNOG at lists.ausnog.net
>Subject: Re: [AusNOG] Route to 103.18.204.0/24
> 
>Vocus looking glass   tools.vocus.com.au/lg
> 
> 
> 
>On Tue, Jun 17, 2014 at 11:27 AM, Matt Perkins <matt at spectrum.com.au> wrote:
>Our Looking glass is at http://www.spectrum.com.au/lg
>
>Matt
>
>
>
>On 17/06/2014 11:20 am, Daniel Watson wrote:
>Hi Guys
>> 
>>I was wondering if you would not mind, if you would take a few minutes of
>>your time to perform a traceroute and bgp route test to 103.18.204.4 and
>>send them both back to me off-list.
>> 
>>Looking forward to it :D
>> 
>>Daniel
>> 
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>
>
>
>-- 
>/* Matt Perkins 
>        Direct 1300 137 379     Spectrum Networks Ptd. Ltd. 
>        Office 1300 133 299     matt at spectrum.com.au 
>                                Level 6, 350 George Street Sydney 2000
>        SIP 1300137379 at sip.spectrum.com.au
>        PGP/GNUPG Public Key can be found at  http://pgp.mit.edu 
>*/
>
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