Cisco Catalyst 2960-X 48FPD-L

Cisco · 1U switch, 48 PoE+ ports, 2 SFP+ 10 Gb/s ports · Cisco Catalyst WS-C2960X-48FPD-L

what it is

A 1U switch for a 19" rack: 48 gigabit ports with PoE+ power and two SFP+ 10 Gb/s ports for uplinks. Chassis 4.5 × 44.5 × 36.8 cm, 5.8 kg, with a fan and an internal power supply. Operates from −5 to 45°C (vendor datasheet). Next to the data ports there is a separate 10/100 management port that does not take part in switching.

The 740 W budget means 24 ports at 30 W or 48 at 15.4 W. A full set of 48 devices, each requesting the full 30 W, will not fit — the budget counts, not the number of ports.

LAN Base license: layer 2 switching and static routes. With the optional FlexStack-Plus module, up to eight switches can be stacked.

Life cycle: end of sale on October 31, 2022, maintenance releases until October 31, 2023, and security fixes until October 31, 2027. The successor is the Catalyst C9200L-48P-4X (vendor end-of-sale notice).

what we read from it

We read this model over SNMP. The interface, error counter, bridge, component inventory, environment, PoE, cable test, LLDP, spanning tree, CPU, memory, flash, license, configuration and stack branches respond. We collect the state of every port with speed and duplex, traffic, error counters, firmware version and uptime.

In addition the switch returns:

• Diagnostics of every SFP transceiver — described below, as this is the most valuable part of this model.
• Temperature, fans and power supply with the state of each.
• Actual PoE draw per port, separately from the allocated power. Allocated power says how much the switch has reserved; only the actual draw says how much is left in the budget.
• Copper cable test result over the network: distance to the fault and the state of each pair — normal, open, short, impedance mismatch, break. Open is also shown for a good cable with nothing plugged in at the far end. A test on a port with a link briefly drops it.
• LLDP neighbors, including devices from other vendors.
• Ports disabled by an error (err-disable) along with the cause.

SFP transceiver diagnostics

For every transceiver with digital diagnostics the switch returns five sensors: temperature, supply voltage, laser bias current, transmit power and receive power. Each sensor has four thresholds — alarm and warning, high and low — plus an assessment of whether a threshold is exceeded. The thresholds come from the transceiver's own memory, so every transceiver model has its own.

Three things set this reading apart from what the command line shows:

• Laser bias current is missing from show interfaces transceiver. The table has four columns: temperature, voltage, transmit and receive power. Laser bias current is in SNMP and in the full transceiver memory dump.
• Threshold exceeded without a flag. Measured: receive power −35.2 dBm with an alarm threshold of −20 dBm, and show interfaces transceiver detail did not put a -- flag next to it. At the same moment SNMP reported the threshold as exceeded, and the transceiver set its own alarm and loss-of-signal flag. We take the alarm assessment from SNMP, not from the absence of a flag in the table.
• Values are signed. Power of −35.2 dBm arrives as the integer -352. A tool that reads it as unsigned will show 4294966944.

A transceiver without digital diagnostics has no sensors at all in SNMP, and the command line prints Diagnostic Monitoring is not implemented. This is the correct state for such a transceiver, not a reading error.

A full transceiver memory dump is given by show idprom interface , but only in privileged mode. The EEPROM PAGE A2 Bytes section in this dump is all zeros and looks as if the transceiver had no diagnostics. The real data is further down, in the SFF-8472 Digital Diagnostic Monitoring Data section.

transceivers from other vendors

Every transceiver without Catalyst coding — including Cisco ones from the Small Business line, for example MGBSX1 — triggers two messages at startup:

• %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port Gi1/0/49 has bad crc
• %PHY-4-UNSUPPORTED_TRANSCEIVER: Unsupported transceiver found in Gi1/0/49

Without two commands in the configuration, the port then goes into the err-disable state:

• service unsupported-transceiver — hidden, the ? help does not show it,
• no errdisable detect cause gbic-invalid.

After write erase both disappear. Transceivers that worked before the reset stop working after it — these two commands have to be entered first.

one port, two names

An SFP+ port with a 10 Gb/s transceiver is named Te1/0/1, and with a 1 Gb/s transceiver — Gi1/0/49. Monitoring keyed by interface name loses the port's history every time the transceiver is swapped for one of a different speed.

PoE on a link to another PoE switch

Measured on a copper link to a PoE port of another switch: in the first two minutes after startup the switch detected a PoE powered device on the other side, allocated power to it, withdrew it and brought the link up and dropped it five times before the link stabilized. Two power sources facing each other try to power one another. On a port linking to another PoE switch, power inline never is the right setting.

console

The console runs at 9600 b/s, 8N1. On the welcome screen the system ignores everything except the Enter key: for a minute the port may not return a single byte or echo typed characters. No echo does not mean the port is not working — a single Enter returns the prompt.

what we cannot read

• Sensors from the standard RFC 3433 branch — it is empty. All sensors, including transceivers, are only in the Cisco branch.
• Host resources (HOST-RESOURCES-MIB) — the branch is empty; uptime comes from the system counter.
• CDP neighbors when the adjacent equipment is from another vendor — the CDP table is then empty, and the neighbor is visible only in LLDP.
• Diagnostics of a transceiver that does not have them — see above.

transceivers tested in this device

Transceivers we checked in this device, and whether the device showed their optical diagnostics (temperature, power, alarm thresholds):

• Finisar FTRJ8524P2BNV (1000BASE-SX; Fibre Channel), firmware 15.2(7)E13: diagnostics read (1 units).
• Cisco MGBSX1 (1000BASE-SX), firmware 15.2(7)E13: diagnostics not shown (1 units).

All transceivers and switches in one place, with filters: what each device shows.

full list of parameters read via SNMP

The list shows WHAT the device exposes — including parameters we do not use ourselves. There are no values here at all: it is a catalog of capabilities, not a reading from anyone's network. It is not a closed list either — explanation below the table.

28 parameters

List source: reading of 1 working unit (as of 2026-10-18). The list is the sum of what we observed — more units reveal more parameters, so numbers for different models are not directly comparable.