Since the STM32F107 MCU comes with 1x ethernet feature, therefore, I am trying figure out if it's possible to place a dual port RJ45 connector in order to establish a daisy chain configuration (MCU A connects to MCU B, MCU B to MCU C, MCU C to MCU D,... and so on).
A network protocol with similar topology, backbone/node, already exists for just such a purpose, CAN 2.0B. Most ARM Cortex-Mx series microcontrollers offer at least one CAN 2.0B port, many offer two CAN 2.0B ports. supports up to 1Mb/s throughput, designed with harsh environments in mind, forms the basis for many fieldbus implementations. Is relatively inexpensive to configure and implement from both an economical and system resource standpoint. The STM32F107 microcontroller is equipped with two independent CAN2.0B ports and would be much more economical and practical. Much of the overhead of a CAN 2.0B implementation is handled in hardware, rather than in a software stack, reducing the required code sizes of the CAN 2.0B or associated fieldbus software protocol stacks and the final application implementation.
This MCU also requires an external PHY chip to interface the MCU's Ethernet MAC with signal from RJ45. In this case, I am looking for the specific PHY chip that can take two RJ45 and be configured for daisy chain topology.
The daisy chain topology you are describing more closely resembles that of Fiber Distributed Data Interface (FDDI) or Copper Distributed Data Interface (CDDI), rather than IEEE 802.3 Ethernet networks. Without going into too much detail, implementing an IEEE 802.3 Ethernet network on a similar topology would require the implementation of a hub/switch at each node, which would present it's own issues and limitations, not to mention significant costs and complexity of design.
There are also a number of reasons to avoid a daisy chain network topology, one of the primary reasons is, each node could represent a single point of failure for the entire network.
It would be much more prudent to simply utilize one or more Ethernet switches and run a single connection to each node, rather than attempt to force the IEEE 802.3 standards to fit a network topology for which it was neither designed nor intended.
Or utilize a simple backbone/node topology and implement a CAN 2.0B or associated fieldbus network.
BigDog