How to find out capacity for network interfaces?

Question

I could get the capacity for the network interface by lshw, but which file in sysfs is this information stored(i.e. which file in /sys/class/net/eth0/device/ directory)?

$ sudo lshw -class network
  *-network               
       description: Ethernet interface
       product: 82579LM Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       logical name: eth0
       version: 04
       serial: 3c:97:0e:b4:5c:6a
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k firmware=0.13-3 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:43 memory:f2500000-f251ffff memory:f253b000-f253bfff ioport:6080(size=32)


$ ls /sys/class/net/eth0/device/
broken_parity_status      d3cold_allowed  enable         local_cpus  net        remove    resource0  subsystem_device
class                     device          firmware_node  modalias    numa_node  rescan    resource1  subsystem_vendor
config                    dma_mask_bits   irq            msi_bus     power      reset     resource2  uevent
consistent_dma_mask_bits  driver          local_cpulist  msi_irqs    ptp        resource  subsystem  vendor

score 7 · Accepted Answer · answered Apr 03 '14 at 03:55

7

You're looking in the wrong place.

Look at /sys/class/net/<device>/speed.

answered Apr 03 '14 at 03:55

Michael Hampton

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`cat: /sys/class/net/wlan0/speed: Invalid argument`, how to get the content? – schemacs Apr 03 '14 at 15:29
1

You didn't ask about _wireless_ interfaces. These have no fixed link speed anyway. – Michael Hampton Apr 03 '14 at 15:31
Yes, I have also found out that. So what's the unit for this file: `sudo cat /sys/class/net/eth0/speed` gives 100 while lshw shows `capacity: 1Gbit/s size: 100Mbit/s`.(I wonder where size comes from. sorry this might be another question). – schemacs Apr 03 '14 at 15:34
100 means it's actually running at 100Mbit/sec. – Michael Hampton Apr 03 '14 at 15:36
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How could I know the max capacity(not which speed it is now) for this interface? – schemacs Apr 03 '14 at 16:26
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This may be useful: http://stackoverflow.com/questions/2872058/get-link-speed-programmatically – schemacs Apr 10 '14 at 09:18

score 4 · Answer 2 · edited Jul 12 '17 at 10:50

4

You can check the interface capacity in following ways.

dmesg | grep eth0
mii-tool -v eth0
ethtool eth0

Note: Change the device name according to yours.

edited Jul 12 '17 at 10:50

Tom

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answered Apr 03 '14 at 08:21

Karthik

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score 3 · Answer 3 · answered Apr 03 '14 at 11:54

3

In general, you could find this out using a tool such as strace:

sudo  strace -e trace=file -f -s128  lshw -class network

answered Apr 03 '14 at 11:54

Cameron Kerr

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You are so nice to tell me how to trace files opened by programs. Thanks. – schemacs Apr 03 '14 at 15:30

How to find out capacity for network interfaces?

3 Answers3