Summary
BGP is a protocol that operates at the level of Autonomous Systems (AS) (an interconnected group of IP addresses under a single authority - customer or ISP). This protocol is used by DRGs within OCI.
Reference
Introduction to BGP
Border Gateway Protocol (BGP)
- Routing protocol for the Internet
- Exchange routing information between autonomous systems (AS)
- Autonomous Systems: Collection of connected IP networks
- Looks at all of the available paths that data could travel
- Picks the best route, which usually means hopping between autonomous systems
- Site-to-Site VPN can use either BGP or static routing, or a combination
- FastConnect always uses BGP for route advertisements
Routing Overview
- More-specific route preferred over less-specific route
- If the same route is advertised across multipole connections to OCI, the shortest AS PATH is used as a tiebreaker when sending traffic back to on-premises
- Modify the BGP local preference attribute on your on-premises router to influence which path to use when sending traffic to OCI.
- By default, Oracle implement AS PATH prepending to determining which connection to take if your on-premises device advertises the same route over multiple diverse connections.
Oracle Preference Path Resulting AS PATH 1 FastConnect Your ASN 2 IPSec VPN with BGP Private ASN,
Your ASN3 IPSec with static Private ASN,
Private ASN,
Private ASN
Equal-Cost Multi-Path Routing (ECMP)
- ECMP enables flow-based laod balancing of network traffic over multiple virtual circuits or multiple IPSec tunnels (not a mix) using BGP
- It allows active-active load balancing and failover of network traffic between a maximum of eight circuits.
- 5-tuple is used to distinguish flows. Multiple flows will be necessary to utilise all available bandwidth.
- ECMP is off by default ancd can be enables per DRG route table.