For true Internet redundancy or high availability for your WAN links you need to run BGP (Border Gateway Protocol).
(BGP), allows you to create loop-free interdomain routing between autonomous systems (AS). An AS is a set of routers under a single technical administration. Routers in an AS can use multiple interior gateway protocols to exchange routing information inside the AS and an exterior gateway protocol to route packets outside the AS.
The reason you need BGP is because traffic originating from IP addresses from ISP A can only be returned back via ISP A. The same applies for traffic originating from ISP B.
Through BGP you obtain your own addresses, so if your connection to one ISP is lost the other ISP link takes over and since you own your own addresses (your ASN -Autonomous System Number) your information will always be routed to you.
Your ASN allows for multiple pathways to your premises via multiple T1's from different ISPs.
BGP is a path-vector routing protocol. Just as Routing Information Protocol (RIP) selects the best route based on hop count, BGP selects the best path based on the shortest Autonomous System (AS) path. BGP routing domains are identified by an autonomous system number (ASN). ASNs are regulated by the same entity that regulates IP addresses, the American Registry for Internet Numbers, better known as ARIN.
BGP routers exchange network reachability information. This information is mainly an indication of the full paths (BGP AS numbers) that a route should take in order to reach the destination network.
BGP initially exchanges full BGP routing tables. After this exchange, incremental updates are sent as the routing table changes. Keepalive packets are sent to ensure that the connection is alive between the BGP peers and notification packets are sent in response to errors or special conditions.
Our primary and redundant circuits feed into Tier-1 fiber backbones to ensure 24 x 7 operations with full BGP-4 redundancy. Since these circuits are channeled directly into our New York City POP (Point Of Presence) we manage your IP addresses; hence we are not brokering the transaction, we are actively supporting and managing your Internet link. PROMENET, Inc. is a full service ISP (Internet Service Provider) registered with ARIN; our service offering consists of OC12 to DS3 pipes routed from Verizon allowing access to IP and ATM based backbones. DS3 (45mbps) links from DSL.net allow us to deliver DSL voice and data services to our customers.
- Obtaining Autonomous System Number (ASN) from ARIN
- Coordination with both Internet Service Providers to assign netblocks for new Autonomous System Number.
- Submission of Maintainer Object, Person Object, Route Object, AS-Set Object, and Autonomous Number Object to all ISPs
- On-Site Installation and Configuration
Be Proactive about Internet Redundancy because you can't afford to be reactive
