I am a bit confused about this router config from a branch location of an enterprise network. They use EIGRP tunnels as backups to the HQ.I have pasted what I believe is relevant to my question. Under the sh ip pro it states:Address Summarization:   ...

I understand the sub-ints on  aserial WAN link, usually for frame-relay, but why the sub-ints on the fa? And how is it implemented on the LAN?  With a FR switch?R#sh ip int brInterface                  IP-Address      OK? Method Status               ...