同子网互访：Same Network Segment
跨子网互访（集中式网关）：Diff Network Segment (Centralized GW)
跨子网互访（分布式网关）：Diff Network Segment (Distributed GW)
同子网互访：Same Network Segment
跨子网互访（集中式网关）：Diff Network Segment (Centralized GW)
跨子网互访（分布式网关）：Diff Network Segment (Distributed GW)