graph "stp" {
	layout="neato";
	overlap="false";
	esep="+80";

        node [shape=record, fontname="DejaVu Sans Mono, Book"];
	edge [penwidth="2", fontname="DejaVu Serif, Book"];

        host [
	    label="{ { <mgmtd> mgmtd | <d> d | <mgmta> mgmta | <a> a | <b> b | <mgmtb> mgmtb | <c> c | <mgmtc> mgmtc } | host }",
	    color="grey",fontcolor="grey",pos="9,0!",
	    requires="controller",
	];

        A [
	    label="{ A | { <mgmt> mgmt | <h> h } } | { <b> b | <c> c | <d> d }",
	    pos="6,6!",
	    requires="infix",
	];
        B [
	    label="{ <a> a | <d> d | <c> c } | { B | { <h> h | <mgmt> mgmt } }",
	    pos="12,6!",
	    requires="infix",
	];
        C [
	    label="{ <b> b | <a> a | <d> d } | { C | { <h> h | <mgmt> mgmt } }",
	    pos="12,3!",
	    requires="infix",
	];
        D [
	    label="{ D | { <mgmt> mgmt | <h> h } } | { <a> a | <b> b | <c> c }",
	    pos="6,3!",
	    requires="infix",
	];

	host:mgmta -- A:mgmt [requires="mgmt", color="lightgrey"]
	host:mgmtb -- B:mgmt [requires="mgmt", color="lightgrey"]
	host:mgmtc -- C:mgmt [requires="mgmt", color="lightgrey"]
	host:mgmtd -- D:mgmt [requires="mgmt", color="lightgrey"]

	host:a -- A:h [color="cornflowerblue"]
	host:b -- B:h [color="cornflowerblue"]
	host:c -- C:h [color="cornflowerblue"]
	host:d -- D:h [color="cornflowerblue"]

	# Ring
	A:b -- B:a
	B:c -- C:b
	C:d -- D:c
	D:a -- A:d

	# Cross-links
	A:c -- C:a
	B:d -- D:b
}