Frrouting BGP protocol learning

FRR brief introduction

FRRouting (FRR) Is a free open source Internet routing protocol suite , Apply to Linux and Unix platform . It has achieved BGP、OSPF、RIP、IS-IS、PIM、LDP、BFD、Babel、PBR、OpenFabric and VRRP, And support EIGRP and NHRP.

BGP Module initialization

BGP On behalf of the border gateway protocol . Abreast of the times BGP The version is 4.
BGP-4 Is one of the external gateway protocols , It is also the de facto standard inter domain routing protocol . BGP-4 stay RFC 1771 Described in and by RFC 4271 to update . RFC 2858 by BGP-4 Added multi protocol support .
Initialize at bgp_main.c Of main Start in function , This is a bgpd The main program of . Process parameters and start bgp Finite state machines are handled here .

/* Default BGP port number. */
#define BGP_PORT_DEFAULT 179

int bgp_port = BGP_PORT_DEFAULT;

BGP Use TCP As its transport layer protocol （ The port number is 179）