Cables and power cords

Cable

A network link between two ports, in the <Topology>.

Template form — properties come from a catalog cable:

<Cable from="COE-01/cx7-1/p0" to="sn4700-400gbps/links/p1" template="dr4-400g-5m"
       labels="fabric-a" length="5 m" />

Full form — properties on the cable itself:

<Cable from="node-001/eth0/p0" to="leaf-01/ports/p0"
       material="fiber" mode="active" speed="100G" />

Attribute	Required	Valid values / description
from	yes	Port path, with :N for a breakout channel
to	yes	Port path
template	no	Id of a catalog <Cable>. Inherits material, mode, speed and the assembly, read-only
material	no	copper or fiber
mode	no	active or passive
speed	no	Speed: the rated speed (capacity) when there is no template
labels	no	Comma-separated tags. Fabric Topology filters by them as Fabric labels
length	no	Free text — e.g. 5 m
negotiatedSpeed	no	Speed: what this link actually runs at, when slower than its capacity
link	no	up or down. Left out means unknown, which is not the same as up

A cable cannot carry both template and a local material, mode, speed or assembly — that is an error, not an override. labels, length, negotiatedSpeed, link and serial numbers describe this one link and are always allowed.

Old files

A cable used to carry a single free-text label. A file that still has label="X" opens with X added to labels, and is written back with labels only.

Negotiated speed

A link can run slower than the cable is rated for — for example, 200G breakout legs plugged into 100G server ports train at 100G. Record that on the cable, not as a slower copy of the template:

<Cable from="SN4700-400gbps/links/swp1:0" to="node-1/e810/p0"
       template="dac-400g-2x200g-fs-3m" negotiatedSpeed="100G" />

• Capacity is the template's speed (or the cable's own speed). On a breakout lane it is that leg's far-end transceiver speed.
• negotiatedSpeed cannot exceed the capacity or the rated speed of either port. It is not allowed on a catalog cable or a power cord.

Port Mapping labels such a link 100G (of 200G); Fabric Topology sums what the links between two devices run at.

Link state

<Cable from="SN4700-400gbps/links/swp3:0" to="gpu2/cx6/p1" template="acc-400g-2x200g-fs-5m"
       negotiatedSpeed="100G" link="up" />
<Cable from="SN4700-400gbps/links/swp3:1" to="gpu2/cx6/p0" template="acc-400g-2x200g-fs-5m"
       link="down" />

Value	Meaning
up	The link came up; it runs at negotiatedSpeed, or at capacity
down	Cabled, but the link is down. Cannot be combined with negotiatedSpeed
(left out)	Unknown

Each breakout lane is its own <Cable> with its own link. In Port Mapping a port glyph is bright green when up, muted green when cabled but unknown, hollow when down, grey when free, and has an amber dot when the port runs below what it could.

Serial numbers

A serial number identifies one physical optic, so it is recorded on the topology cable, on a <Transceiver> child naming the part by model:

<Cable from="COE-07/cx7-1/p0" to="sn4700-400gbps/links/p11" template="dr4-400g-5m">
  <Transceiver model="MMS1V00-WM" serialnumber="MT2447FT12457" />
  <Transceiver model="MMS4X00-NS400" serialnumber="MT2447NS07871" />
</Cable>

On a templated cable these children take only model (which must match a transceiver in the template's assembly) and serialnumber. When both ends use the same model, list one child per end, matched in order. On a cable with an inline assembly, serialnumber goes on the <Transceiver> that describes the part. Serial numbers are never valid in the catalog.

Link assembly

A cable can spell out its parts, so the BOM and the Materials editor show real part numbers. The syntax is the same on catalog and topology cables. Child order matters: the first <Transceiver> is the from end; every later <Transceiver> is a far end — one for a 1:1 link, several for a breakout (1→2, 1→4, 1→8). Every child is optional.

Fiber (AOC)

<Cable from="COE-12/cx7-1/p0" to="sn4700-400gbps/links/p21" material="fiber" mode="active" speed="400G">
  <Transceiver model="MMS1V00-WM" manufacturer="NVIDIA" connector="QSFP-DD" speed="400G" modulation="4x100Gb/s PAM4" />
  <Fiber model="MFP7E30-N005" manufacturer="NVIDIA" length="5m" connector="MPO12 APC to MPO12 APC" />
  <Transceiver model="MMS4X00-NS400" manufacturer="NVIDIA" connector="OSFP" speed="400G" modulation="4x100Gb/s PAM4" />
</Cable>

A breakout fiber has several far-end optics:

<!-- 800G → 2x400G MTP breakout -->
<Cable id="sr8-800g-to-2x400g" model="800G to 2x400G SR breakout" manufacturer="NVIDIA"
       speed="800G" connector="OSFP" material="fiber" mode="active">
  <Transceiver model="MMA4Z00-NS" manufacturer="NVIDIA" connector="OSFP" speed="800G" modulation="8x100Gb/s PAM4" />
  <Fiber model="MFP7E20-N003" manufacturer="NVIDIA" length="3m" connector="MPO16 APC to 2x MPO12 APC" />
  <Transceiver model="MMA1Z00-NS400" manufacturer="NVIDIA" connector="QSFP-DD" speed="400G" modulation="4x100Gb/s PAM4" />
  <Transceiver model="MMA1Z00-NS400" manufacturer="NVIDIA" connector="QSFP-DD" speed="400G" modulation="4x100Gb/s PAM4" />
</Cable>

Copper (DAC / ACC)

The connectors are permanently attached to the copper run. Modulation goes on <Copper>. mode="passive" is a DAC, mode="active" an ACC.

<!-- 1→4 breakout DAC -->
<Cable id="dac-400g-to-4x100" model="400G to 4x100G DAC" manufacturer="NVIDIA"
       speed="400G" connector="QSFP-DD" material="copper" mode="passive">
  <Transceiver model="MCP7Y60-H001-A" manufacturer="NVIDIA" connector="QSFP-DD" speed="400G" />
  <Copper model="MCP7Y60-H001" manufacturer="NVIDIA" length="1m" modulation="4x100Gb/s PAM4" />
  <Transceiver model="MCP7Y60-H001-B0" manufacturer="NVIDIA" connector="QSFP56" speed="100G" />
  <Transceiver model="MCP7Y60-H001-B1" manufacturer="NVIDIA" connector="QSFP56" speed="100G" />
  <Transceiver model="MCP7Y60-H001-B2" manufacturer="NVIDIA" connector="QSFP56" speed="100G" />
  <Transceiver model="MCP7Y60-H001-B3" manufacturer="NVIDIA" connector="QSFP56" speed="100G" />
</Cable>

A cable cannot have both <Fiber> and <Copper>, nor more than one of either.

Assembly part attributes

<Transceiver> (inside a cable)

Attribute	Valid values / description
model	Free text, part number — e.g. MMS4X00-NS400
manufacturer	Free text
serialnumber	Free text — topology only, see Serial numbers
connector	Connector: the cage it plugs into
speed	Speed
modulation	Free text — e.g. 4x100Gb/s PAM4. A leading Nx sets the lanes drawn in the Materials editor. Fiber optics only

<Fiber>

Attribute	Valid values / description
model, manufacturer	Free text
length	Free text — e.g. 5m
connector	Free text end-to-end spec — e.g. MPO12 APC to MPO12 APC

<Copper>

Attribute	Valid values / description
model, manufacturer	Free text
length	Free text — e.g. 1m
modulation	Free text — e.g. 4x100Gb/s PAM4. A leading Nx sets the lanes drawn

PowerCable

A power cord from a PDU outlet to a device inlet.

<PowerCable from="pdu-a/bank1/p0" to="node-001/PSU1/p0" length="1.8 m" labels="feed-a" />

Attribute	Required	Valid values / description
from	yes	Port path of one end
to	yes	Port path of the other end
labels	no	Comma-separated tags. Power Budget filters by them as Power grid
length	no	Free text — e.g. 2 m

Rules:

• Both ends must be power connectors, and exactly one must be an outlet on a <PDU>.
• The device end may be an <Inlet> or any power <Port>.
• material, mode, speed, negotiatedSpeed, link, template and assembly children are errors on a power cord.
• A <Cable> between two power connectors is accepted and written back as <PowerCable>.
• Joining a power connector to a data port is always an error.