docs/architecture/interface-overview.md

3 Purpose: This introduces a simplified view of the BMC's primary interfaces. It
8 - Give BMC administrators and system integrators a simplified view of the BMC's
12   nicely. For example, to understand the BMC's attack surfaces.
16 This section shows the BMC's primary interfaces and how they are related. It
17 begins with the BMC's physical interfaces and moves toward abstractions such as
32 example, disabling a BMC service will disable the corresponding external
41 management agents on the left side, the BMC in the center, and host elements on
46 This shows the BMC's physical connections including network, USB, UART serial,
48 which shows only the host interfaces that connect directly to the BMC. A typical
51 Interfaces between the BMC and its host platform vary considerably based on BMC
55 documentation which gives details for specific BMC and host implementations.
59         | BMC            |         | Host           |
75 #### Host-BMC physical interface transport protocols
77 This lists protocols that operate over the BMC-host physical interfaces:
87 #### Host-BMC data models
89 This lists specifications for the data which flows over the BMC-host transport
104         | BMC                              |
135 - TFTP (disabled by default, when invoked by BMC operator) - Trivial FTP client
154                 | BMC                       |    | Host            |
167 the BMC as a Unix domain socket.
177         | BMC                                              |
218     | BMC           |    | Host            |
240         | BMC                                              |
267 ### BMC network
269 This sections shows variations in the operational environment of the BMC's
272 The BMC may be connected to a network used to manage the BMC. This is dubbed the
278              | BMC       |      | Host           |
285 The BMC may be served by a Network Controller Sideband Interface (NC-SI) which
290              | BMC       |      | Host           |
305 The BMC's management network may be provided by its host system and have no
310              | BMC       |      | Host           |
321 The BMC's management network may be connected to USB (LAN over USB):
325              | BMC       |      | Host           |
333 ### BMC serial
335 This gives access to the BMC's console which provides such function as
336 controlling the BMC's U-Boot and then providing access to the BMC's shell.
341 This refers to the standard NIC and Linux network services on the BMC.
346 secure copy (scp) access to the BMC. OpenBMC uses the Dropbear SSH
347 implementation. Note that port 22 connects to the BMC's shell, while port 2200
358 Refers to the BMC's access to its host's serial connection which typically
360 provides host serial access to various internal BMC services. Contrast with
361 access to the BMC's serial connection which provides access to the BMC's
367 BMC via the `avahi-browse -rt _obmc_rest._tcp` command.
372 example, you can find the BMC via the
384 The BMC's RMCP+ IPMI interface is designed to be operated by the `[ipmitool][]`
399 ### BMC shell
401 This refers to the BMC's command line interface which defaults to the `bash`
402 program provided via the `/bin/sh` path on the BMC's file system. Note that the
403 shell (together with its utility programs) provides access to many of the BMC's
419 Refers to the BMC service provided by the `hostlogger` program here:
421 `obmc-console-server` and logs host console messages into the BMC's file system.
465 BMC and host physical USB ports.