nanog mailing list archives

Re: Newbies Question: Do I really need to sacrifice Prefix-aggregation to do BGP Load-sharing?


From: Douglas Fischer <fischerdouglas () gmail com>
Date: Thu, 20 Oct 2022 09:51:14 -0300

If your Upstream(Transit provider) prepends your routes without you asking
or authorizing it to do so, you should SERIOUSLY consider switching
providers!

In the other email I talked about traffic engineering BGP communities.
If those prepends were made from some community you were applying... OK,
that's great!
Even better if you could apply a community that did something like "apply 2
prepends for south america only".

But a Transit Provider changing the AS-PATH (in addition to the mandatory
hop) arbitrarily without your consent is not for good people.


P.S. Your email replies are breaking threads in email readers. I suggest
you review the email client tool.


Em qui., 20 de out. de 2022 às 09:16, Pirawat WATANAPONGSE via NANOG <
nanog () nanog org> escreveu:

Dear all,


Before all else:
thank you all for the lightning-fast responses (even taking the time zone
advantage into account).
I really, really, really appreciate all your recommendations.

Virtually all of you recommend prepending as the first choice.
I also get the feeling that you guys consider de-aggregation “distasteful”
(at the least) but sometimes unavoidable.

I have considered the prepending myself, but dare not implement it yet
for the fear that BGP (Human) Community will burn me alive, witch-hunt
style,
because of the following reasons:
1. I can see from looking glass(es) that my upstreams already practice
prepending (some paths) at their level (at least 3 more hops [x4]),
supposedly to “balance” their bandwidth.
2. Should I start prepending mine, I might upset their balance, causing
them to prepend more, thus starting a “prepend war”. [I imagine that x20+
prepending starts out this way]

The way I see it, prepending (or maybe even the whole BGP-Path thing) is a
local-optimization problem: it’s only best for someone, not globally.
And the Higher-Tiers (Lower Tier-Numbers) will always “engineer” me in the
end.

Worse yet, I might be out-voted by de-aggregation insider “cultists”
anyway.

Which forces me to proactively ask you guys questions about
ROV-Overlapping and ROV “Hijack Gap” soon, in another posting with separate
“Subject:”.

Again, Thank you.


Cheers,

Pirawat.


P.S.  [Off-Topic] Any comment on the “SCION” System?
Any good (I will even take "academically")?
[Reference: https://scion-architecture.net/]



-- 
Douglas Fernando Fischer
Engº de Controle e Automação

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