网卡IP和网关IP不在同一网段，为什么还能访问外部网络？
各位大大，望解惑
[root@izm5eb7o9hu1q8eoh3zi68z ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.31.153.255 netmask 255.255.240.0 broadcast 172.31.159.255
ether 00:16:3e:05:25:9e txqueuelen 1000 (Ethernet)
RX packets 2171 bytes 271711 (265.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1378 bytes 178314 (174.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen 1 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 172.31.159.253 0.0.0.0 UG 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0
172.31.144.0 0.0.0.0 255.255.240.0 U 0 0 0 eth0
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]#
[root@izm5eb7o9hu1q8eoh3zi68z ~]# traceroute -n 115.195.81.196
traceroute to 115.195.81.196 (115.195.81.196), 30 hops max, 60 byte packets
1 * * *
2 11.219.5.9 10.455 ms 10.519 ms 11.219.4.9 5.686 ms
3 * * *
4 11.219.68.34 0.426 ms 0.425 ms 11.219.68.50 0.413 ms
信息如上所示，网卡IP和网关IP不在同一网段，那进行外部访问的时候，数据走到网关172.31.159.253之前是不是还要经过在同一网段的交换机？或是通过其他方式连接至网关172.31.159.253？具体是什么逻辑呢
