建立BGP邻接时,哪个路由器用TCP179端口号与对方连接

在建立BGP邻居时，哪个R主动发起建立邻居会话，就哪个R用TCP179端口。
BGP邻居的建立只有一条正确的TCP连接存在，而不是存在两条，并且只能同时存在一个服务器端一个客户端。因此在show ip b n时有时看到LOCAL的PORT是179，有时是随机的端口号。主要看当时是哪个R主动发起会话。
下面是BGP邻居会话建立的信息：（1.1.1.1为被动接受的BGP邻居）
*Mar 1 01:07:02.163: BGP: 1.1.1.1 went from Idle to Active
*Mar 1 01:07:02.163: BGP: 1.1.1.1 open active, delay 20092ms
Test3662-1#
*Mar 1 01:07:22.255: BGP: 1.1.1.1 open active, local address 1.1.1.2
*Mar 1 01:07:22.255: TCB64169904 created
*Mar 1 01:07:22.255: TCB64169904 setting property TCP_WINDOW_SIZE (0) 641BD63C
*Mar 1 01:07:22.255: TCB64169904 setting property TCP_TOS (11) 641BD628
*Mar 1 01:07:22.255: TCB64169904 bound to 1.1.1.2.11011
*Mar 1 01:07:22.255: TCP: sending SYN, seq 1043805885, ack 0
*Mar 1 01:07:22.255: TCP0: Connection to 1.1.1.1:179, advertising MSS 1460
*Mar 1 01:07:22.255: TCP0: state was CLOSED -> SYNSENT [11011 -> 1.1.1.1(179)]
*Mar 1 01:07:22.255: TCP0: state was SYNSENT -> ESTAB [11011 -> 1.1.1.1(179)]
*Mar 1 01:07:22.255: TCP0: Connection to 1.1.1.1:179, received MSS 1460, MSS is 1460
*Mar 1 01:07:22.259: TCB64169904 connected to 1.1.1.1.179
*Mar 1 01:07:22.259: BGP: 1.1.1.1 went from Active to OpenSent
*Mar 1 01:07:22.259: BGP: 1.1.1.1 sending OPEN, version 4, my as: 1
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcv message type 1, length (excl. header) 26
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcv OPEN, version 4
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcv OPEN w/ OPTION parameter len: 16
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcvd OPEN w/ optional parameter type 2 (Capability) len 6
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has CAPABILITY code: 1, length 4
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has MP_EXT CAP for afi/safi: 1/1
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has CAPABILITY code: 128, length 0
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has ROUTE-REFRESH capability(old) for all address-families
*Mar 1 01:07:22.263: BGP: 1.1.1.1 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has CAPABILITY code: 2, length 0
*Mar 1 01:07:22.263: BGP: 1.1.1.1 OPEN has ROUTE-REFRESH capability(new) for all address-families
*Mar 1 01:07:22.263: BGP: 1.1.1.1 went from OpenSent to OpenConfirm
*Mar 1 01:07:22.263: BGP: 1.1.1.1 went from OpenConfirm to Established
*Mar 1 01:07:22.263: %BGP-5-ADJCHANGE: neighbor 1.1.1.1 Up