I had the
<sarcasm>privilege</sarcasm> for the second time in 10 years to have one of our smaller prefixes hijacked. I have a branch office with a /27 assigned from ISP-A PA space configured with static routing. Recently, ISP-B, a well-known tier 2 cable company, allowed a customer to start advertising a /24 over BGP that overlapped with my /27, effectively siphoning off my traffic and causing an outage.
Obviously, ISP-B should be filtering what advertisements it receives from its customers to prevent this. Since my prefix is a /27, it's likely that even if I had my more specific route advertised, it would've been dropped by many routers that filter out anything > /24.
Is there anything more ISP-A could have done to reduce this likelihood of this event occurring?
Would it be better for me to speak BGP to ISP-A and advertise that /27 in the hope it at least reaches more of that carrier's network to minimize the chance that on-net traffic would see trouble?