BGP

Analyzes BGP (Border Gateway Protocol).

1. BGP (Border Gateway Protocol)

BGP is a Protocol used for managing the Routing Table of External Routers (Gateways) of AS (Autonomous System). [Figure 1] shows BGP. AS refers to a Network managed by a Network administrator of a specific Group. ISPs (Internet Service Providers) that provide Internet correspond to AS. DMZ literally means a neutral Network and refers to a Network that connects multiple ASs.

BGP can be classified into two types: eBGP (external BGP) and iBGP (internal BGP). eBGP is a Protocol for exchanging Routing information between External Routers belonging to different ASs. iBGP is a Protocol for exchanging Routing information between External Routers belonging to the same AS. BGP is a Path Vector type Protocol. Each External Router has Path information to reach other ASs. For example, in [Figure 1], Router A2 belonging to AS 100 has Path information ‘AS100 - AS200 - AS300’ to reach AS 300.

Packets with a destination of an external AS delivered to Internal Router are delivered to External Router by IGP (Interior Gateway Protocol), and then delivered to the external AS by BGP again.

2. References

• https://www.slideshare.net/apnic/bgp-techniques-for-network-operators
• https://www.nanog.org/meetings/nanog53/presentations/Sunday/bgp-101-NANOG53.pdf
• http://luk.kis.p.lodz.pl/ZTIP/BGP.pdf
• https://www.netmanias.com/ko/?m=view&id=techdocs&no=5128