Port naming and LEDs across vendors

"Put the module in Et33/1" means nothing on a Juniper and "xe-0/0/48" nothing on a Nexus; the same physical cage has a different name in every network OS, and breakout children, stack members and line cards add their own notation. The LEDs next to the cage are a second language: green, amber, blinking, off — with vendor-specific meanings. This page gives the naming grammar per NOS, the slot/port semantics behind it, the breakout and management-interface conventions, the LED codes, and the commands that make a port blink so you can find it in a rack.

Naming grammar by NOS

NOS	Pattern	Examples	Read as
Cisco IOS / IOS-XE	`<Type><switch>/<module>/<port>`	`GigabitEthernet1/0/1`, `TenGigabitEthernet1/1/1`, `TwentyFiveGigE1/0/25`, `FortyGigabitEthernet1/1/1`, `HundredGigE1/0/49`, `Gi1/0/1` (short)	switch (stack member) / module (0 = built-in, 1 = uplink module) / port
Cisco NX-OS	`Ethernet<slot>/<port>[/<sub>]`	`Ethernet1/1`, `Eth1/49/1` (breakout child)	slot (1 on fixed) / port / breakout lane
Cisco IOS-XR	`<Type><rack>/<slot>/<instance>/<port>[/<sub>]`	`HundredGigE0/0/0/0`, `FourHundredGigE0/0/0/12`, `TenGigE0/0/0/0/1` (breakout)	rack / slot / instance (subslot) / port
Arista EOS	`Ethernet<port>[/<lane>]`	`Ethernet1`, `Ethernet33/1`…`33/4` (breakout children), `Et49/1`	port / lane; a QSFP port without breakout is `Et33/1`
Juniper Junos	`<media>-<fpc>/<pic>/<port>[:<channel>]`	`ge-0/0/0`, `xe-0/0/48`, `et-0/0/50`, `et-0/0/50:1` (breakout), `mge-` (multigig), `fte-` (40G on EX4300)	media (ge 1G, xe 10G, et 25G+) - FPC (stack member/line card) / PIC (module) / port
Huawei VRP	`<Type><chassis>/<slot>/<port>`	`GigabitEthernet0/0/1`, `XGigabitEthernet0/0/1`, `25GE1/0/1`, `100GE1/0/1`, `100GE1/0/1:1` (breakout)	chassis / slot / port
H3C Comware	`<Type><chassis>/<slot>/<port>`	`GigabitEthernet1/0/1`, `Ten-GigabitEthernet1/0/49`, `Twenty-FiveGigE1/0/1`, `HundredGigE1/0/53:1`	as VRP
HPE Aruba AOS-CX	`<member>/<slot>/<port>`	`1/1/1`, `1/1/49:1` (breakout)	member / slot / port
HPE Aruba AOS-S (ProCurve)	`<port>` or `<letter><port>`	`1`, `A1`, `49`	flat; letters for modules
Dell OS10	`ethernet<node>/<slot>/<port>[:<sub>]`	`ethernet1/1/1`, `ethernet1/1/49:1`	node / slot / port : breakout
Extreme EXOS	`<slot>:<port>`	`1:1`, `2:49`	slot (stack member) : port
Ruckus ICX	`<unit>/<slot>/<port>`	`1/1/1`, `1/2/1` (uplink module)	unit / slot / port
Brocade FOS	`<slot>/<port>` or port index	`0`, `1/3`	index 0-based on fixed switches
SONiC	`Ethernet<lane-index>`	`Ethernet0`, `Ethernet4`, `Ethernet8`… (4-lane platform), `Ethernet0`…`Ethernet3` after 4× breakout; 8-lane: `Ethernet0`, `Ethernet8`, `Ethernet16`	first lane index, not port number; aliases like `Eth1/1` or `etp1` exist per platform
Cumulus / NVUE	`swp<port>[s<lane>]`	`swp1`, `swp32`, `swp32s0`…`swp32s3` (breakout), `eth0` (mgmt)	switch port / sub-port
MikroTik RouterOS	`<type>-<n>`	`ether1`, `sfp-sfpplus1`, `sfp28-1`, `qsfp28-1-1`…`-1-4` (lanes)	type - number - lane
Ubiquiti	`<port>` in UI, `eth<n>` inside	`Port 49`, `eth48`	0-based inside
Nvidia Onyx (MLNX-OS)	`Eth<slot>/<port>[/<sub>]`	`Eth1/1`, `Eth1/1/1`	—
Linux hosts	`eth<n>`, `ens<n>f<n>`, `enp<bus>s<slot>f<fn>`	`enp94s0f1`, `ens3f0np0`	predictable names from PCIe address (NIC tools)

Slot, module, port: what the numbers mean

Number	On a fixed switch	On a stack	On a chassis
First (switch / chassis / FPC / member / node)	1 (or 0 on Juniper/Huawei)	stack member ID 1–8	line-card slot (Juniper FPC) or chassis number
Second (module / slot / PIC)	0 = built-in ports, 1 = uplink module (Cisco), or 0 always	same	subslot/PIC on a card
Third (port)	front-panel number, 1-based (0-based on Juniper, SONiC, FOS)	—	—
Fourth (sub / lane / channel)	breakout child 1–4 or 0–3, or 1–8	—	—

Port numbering on the faceplate is usually left-to-right, top row odd and bottom row even (1/2, 3/4…) on dual-row copper blocks, and left-to-right sequential on SFP rows — check the silkscreen, not the assumption.

Breakout children

NOS	Parent	Children	Enabling command
NX-OS	`Ethernet1/49`	`Ethernet1/49/1`–`/4`	`interface breakout module 1 port 49 map 25g-4x`
Arista	`Ethernet49/1`	`Ethernet49/1`–`49/4`	speed on children / `hardware port-group`
Junos	`et-0/0/48`	`et-0/0/48:0`–`:3`	`set chassis fpc 0 pic 0 port 48 channel-speed 25g`
IOS-XR	`HundredGigE0/0/0/0`	`TwentyFiveGigE0/0/0/0/0`–`/3`	`controller Optics … breakout 4x25`
Huawei	`100GE1/0/1`	`25GE1/0/1:1`–`:4`	`port split dimension …`
Dell OS10	`ethernet1/1/1`	`ethernet1/1/1:1`–`:4`	`interface breakout 1/1/1 map 25g-4x`
SONiC	`Ethernet0`	`Ethernet0`, `Ethernet1`, `Ethernet2`, `Ethernet3`	`config interface breakout Ethernet0 4x25G`
Cumulus	`swp1`	`swp1s0`–`s3`	`nv set interface swp1 link breakout 4x25G`
MikroTik	`qsfp28-1-1`	`qsfp28-1-1`…`-1-4` always present	speed per lane

Commands in context: Port configuration recipes; cabling: Breakout & MPO.

Management and special interfaces

Interface	Names
Out-of-band Ethernet	`mgmt0` (NX-OS), `GigabitEthernet0/0` (IOS-XE), `MgmtEth0/RP0/CPU0/0` (XR), `Management1` (EOS), `me0`/`em0`/`fxp0`/`vme` (Junos), `MEth0/0/1` (Huawei), `M-GigabitEthernet0/0/0` (H3C), `mgmt` (AOS-CX), `eth0` (SONiC, Cumulus), `ether1` often (MikroTik)
Console	`con0`, `console`
Loopback / SVI / VLAN	`Loopback0`, `Vlan10`, `irb.10` (Junos), `Vlanif10` (Huawei)
LAG	`Port-channel1` (Cisco), `ae0` (Junos), `Eth-Trunk1` (Huawei), `Bridge-Aggregation1` (H3C), `lag 1` (AOS-CX), `port-channel1` (OS10), `PortChannel0001` (SONiC), `bond0` (Cumulus) (Forwarding basics)
Stack / VC ports	`vcp-255/0/50` (Junos), `StackPort1/1` (Cisco), `stack-port 1/1` (Stacking & MLAG)

LEDs

LED	State	Usual meaning	Vendor variations
Port link	off	no link, port shut, or module not accepted	—
Port link	solid green	link up at top speed	Cisco: green = link; Arista: green
Port link	blinking green	link up with traffic	most
Port link	solid amber / orange	link at lower speed (1G in a 10G port), or errdisabled/blocked	Cisco IOS: amber = disabled/errdisable; Juniper: amber = duplex/half or fault; Aruba: orange = reduced speed
Port link	blinking amber	errdisable, PoE fault, or STP blocking	Cisco
Port link	alternating green/amber	link fault / diagnostics	some
QSFP-DD / OSFP port LEDs (2 or 4 per cage)	per-child status after breakout	one LED per breakout child on many platforms	Arista, Cisco N9K
Module status LED	amber	module unsupported/invalid	Nexus, some Juniper
Speed LED (separate, when present)	off / green / amber	1G / 10G / 25G etc. per mode button	Cisco Catalyst "mode" button toggles port LEDs between STAT, SPEED, DUPLEX, STACK, PoE
System / status	green / amber / red	OK / warning (fan, temperature) / fault	—
Stack / master	solid / blinking	active member / stack master	Cisco, Extreme
PSU / fan	green / amber / off	OK / failed / absent	—
Beacon / locator	blue blinking	identifies the chassis	`hw-module beacon`, `system beacon`

LED codes are in each platform's hardware installation guide; the "mode" button on Catalyst-class switches changes what the port LEDs show, which is a classic source of misread states.

Finding a port physically

NOS	Command
Cisco NX-OS	`locator-led interface ethernet 1/1`
Cisco IOS-XE	`hw-module beacon slot 1 on` (chassis), port LED by mode button
Arista	`locator-led interface Ethernet1 on` / `show locator-led`
Junos	`request chassis beacon fpc 0 port 5 pic 0 on`
Huawei	`display device` + physical labels; beacon on chassis
Dell OS10	`beacon enable ethernet 1/1/1` (platform-dependent)
SONiC	`sfputil show presence`; platform-specific LED control
Linux host	`ethtool -p eth0 10` (blink 10 s)

In CodingBox

The bench does not care what the port is called — but the field notes in the code database do: recording "Et49/1 on spine-2, breakout child 2" next to a module's serial number links a rejected-module event to the exact cage, which is what lets a coding or policy problem be reproduced.