Newbies Question: Do I really need to sacrifice Prefix-aggregation to do BGP Load-sharing? (the case of Multi-homed + Multi-routers + Multi-upstreams)

Pirawat WATANAPONGSE pirawat.w at
Wed Oct 19 06:27:34 UTC 2022

Dear Guru(s),

My apologies if these questions have already been asked;
in that case, please kindly point me to the answer(s).

I hope the following information sufficiently describes my current
- Single customer: ourselves
- One big IPv4 block + one big IPv6 block
- Native Dual-Stack, Non-tunneling
- Non-transit (actually, a “multi-homed Stub”)
- “All-green” IRR & RPKI registered (based on IRRexplorer report)
- Fully-aggregated route announcement (based on CIDR report)
- Two (Cisco) gateway routers on our side
- Two upstreams (See the following lines), fully cross-connected to our
- One (pure) commercial ISP
- One academic consortium ISP (who actually uses the above-mentioned
commercial ISP as one of its upstreams as well)

My current “situation”:
- All inbounds “flock” in through the commercial ISP, overflowing the
since (my guess) the academic ISP also uses that commercial ISP as its
upstream, there is no way for its path to be shorter.

1. Do I really have to “de-aggregate” the address blocks, so I can do the
“manual BGP load-sharing”?
I hate to do it because it will increase the global route-table entries,
plus there will be IRR & RPKI “hijack gaps” to contend with at my end.
2. If the answer to the above question is definitely “yes”, please point me
to the Best-Practice in doing the “manual BGP load-sharing (on Cisco)”.
Right now, all I have is:

Thanks in advance for all the pointers and help given (off mailing-list is
also welcome).

Best Regards,

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