Advertising IPs from 2 Service Providers

Unanswered Question

   There is one scenario

One company X (having its own IP address schema and NO own AS number ) is running static routing between service provider(SP_A) , that SP_A is advtersing company X's IP addresses. Now company X wants to move to other Service Provider SP_B but for testing, company X wants for a month that both link should be working  , with SP_B links as Primary Link.

My question , is this possible that both Service provider can advertise Company X's IP address ?


I have this problem too.
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u1kumar2002 Thu, 08/05/2010 - 04:04


Public address is classified in:

PA address: Provider Assigned address (IP address is taken on lease basis from ISP)

PI Address : Provider Independent address. ( IP address is purchased from APNIC, RIPE, etc)

If customer is having PI address, then the customer can do Multihoming with n number of service providers. This means the customer can advertise own PI address to any service providers.

Plz confirm if customer is having PI address then both ISP can advertise the address block. Ask customer to configure the BGP attributes properly to make your link primary.

Config example :



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