Do tier 1 ISPs block </19 and higer prefixs? in that case.
lets say that i am using bgp to connect to ISP A and ISPB. which are connected to tier 1 ISP which is blocking </19 prefixes.
so when i advertise my /24 using bgp for load balancing through ISPA. ISPA only advertises the agregate to Tier 1 ISP and Tier 1 block /24 from ISPA and ISPB. right?
so if i loose the path from ISPA, i loose connection to the internet(inbound). as Tier 1 will not route the traffic through ISPB as it is blocking prefixes greater than /19.
The reason i ask is because if i go to Sprint ot UUnet BGP page , it says that they reserve the right to aggregate routes.
Any information would be appreciated.