广州移动宽带同一地址两条宽带，网关居然不一样？

家里有 2 个移动号，搞了两条免费宽带，最近装了软路由才发现无论怎样拨号两条宽带网关 IP 始终不是同一个。
不像电信只要时间相近拨号，IP 地址都有可能连号。
trace 出来好像大家走的线路都不一样，而且内网 IP 都不能互联，这是什么操作呢？？

trace DNS 情况如下：

traceroute to 211.136.192.6 (211.136.192.6), 50 hops max, 46 byte packets
1 172.16.64.1 (172.16.64.1) 2.186 ms 2.258 ms 2.537 ms 2 221.179.83.213 (221.179.83.213) 5.747 ms 7.029 ms 19.285 ms
3 211.139.159.189 (211.139.159.189) 3.305 ms 2.840 ms 2.911 ms
4 120.198.206.166 (120.198.206.166) 5.131 ms 5.445 ms 4.388 ms
5 120.197.27.250 (120.197.27.250) 24.838 ms 6.198 ms 7.382 ms
6 ns5.gd.cnmobile.net (211.136.192.6) 4.159 ms 3.490 ms 4.094 ms


traceroute to 211.136.192.6 (211.136.192.6), 50 hops max, 46 byte packets
1 172.16.0.1 (172.16.0.1) 2.538 ms 1.697 ms 3.330 ms
2 221.179.83.205 (221.179.83.205) 5.068 ms 4.850 ms 4.947 ms
3 211.136.210.209 (211.136.210.209) 4.937 ms 5.321 ms 5.033 ms
4 120.198.206.194 (120.198.206.194) 6.882 ms 6.560 ms 7.736 ms
5 120.197.27.250 (120.197.27.250) 7.792 ms 7.350 ms 6.932 ms
6 ns5.gd.cnmobile.net (211.136.192.6) 6.886 ms 5.430 ms 5.035 ms

--------------------
traceroute to 172.16.0.1 (172.16.0.1), 50 hops max, 46 byte packets
1 172.16.64.1 (172.16.64.1) 1.936 ms 2.798 ms 1.473 ms
2 221.179.83.209 (221.179.83.209) 2.992 ms 3.344 ms 2.683 ms
3 172.16.0.1 (172.16.0.1) 5.530 ms 5.852 ms 5.981 ms