List of Ethernet Netcards with Jumbo frame

[legacy]

In computer networking, jumbo frames are Ethernet frames with more than 1500 bytes of payload, the limit set by the IEEE 802.3 standard.

My router only supports 1500 MTU

Code: [Select]

cat /sys/class/net/eth0/mtu
1500
cat /sys/class/net/eth1/mtu
1500
cat /sys/class/net/eth2/mtu
1500

and refuses any greater value

Code: [Select]

echo 1500 >  /sys/class/net/eth0/mtu
echo 2000 >  /sys/class/net/eth0/mtu
write error: Invalid argument
echo 1501 >  /sys/class/net/eth0/mtu
write error: Invalid argument

but in theory,  some Gigabit Ethernet and even some Fast Ethernet network interface cards might support jumbo frames.

Have you ever seen one? 

[legacy]

Code: [Select]

ip link set eth0 mtu 1500

if you have "iproute2" installed, the above is an alternative command to set the MTU, but it only works if the hardware does support it.

[forrestc]

Have you ever seen one? 

All the time.  But again, I'm pretty heavily involved with data networking for a local ISP, and this is something which happens quite a bit when you get into a service provider network.

But really, most modern interfaces support this.  For instance, I have a little intel NUC for instance which supports it:

Code: [Select]

admin:~# ip link set enp3s0 mtu 9000
admin:~# ip link show enp3s0
2: enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether c0:3f:d5:6a:25:98 brd ff:ff:ff:ff:ff:ff
I also have an Intel 82583V onboard NIC on my windows box, also supports it.

I just logged into my QNAP NAS box, and it supports it as well, 1500 bytes, 4074 bytes, 7418 bytes, or 9000 bytes.

Which brings up another point,   Some devices only support *certain* sized giant frames.   For some, you're going to have to find the size it supports, I'd try at least the ones I just mentioned.  If you know the brand/type of the interface in  your router, you might find that it doesn't support 1501, but it does support something larger.

[legacy]

but, even 100Mbps cards do support jumbos ?

Enabling some verbose in the kernel module of the netcard, it says which is the max

Code: [Select]

eth0: Invalid MTU 9000 requested, hw max 1500
ip: SIOCSIFMTU: Invalid argument

eth0: Invalid MTU 7000 requested, hw max 1500
ip: SIOCSIFMTU: Invalid argument

eth0: Invalid MTU 4000 requested, hw max 1500
ip: SIOCSIFMTU: Invalid argument

eth0: Invalid MTU 2000 requested, hw max 1500
ip: SIOCSIFMTU: Invalid argument


I am going to try { 2000, 4000, 7000, 9000 } MTU on other routers/computers/servers. Including Ubiquiti RSP and alike.

[magic]

I doubt it's popular in 100Mb ones. Where are you getting 1G cards that don't support it, though?

Code: [Select]

05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)

11:14:34.673396 IP 10.0.1.6 > 10.0.2.0: ICMP echo request, id 2877, seq 4, length 8008
11:14:34.673421 IP 10.0.2.0 > 10.0.1.6: ICMP echo reply, id 2877, seq 4, length 8008

[legacy]

Where are you getting 1G cards that don't support it, though?

On the paper, the RSP's card is 1Gbps, but it doesn't support any MTU > 1500.


umm, here are listed (and somehow reviewed) some Ethernet cards able to support jumbo frames.

[Halcyon]

To be frank, in the last 5 or so years, I've just enabled Jumbo Frames by default and let the switches handle it. It seems to work with most well known cards (and even some consumer electronics). I can't say I've run into any known problems so far.

here are listed (and somehow reviewed) some Ethernet cards able to support jumbo frames.

I don't know how much I'd trust that link. Half-duplex doesn't mean double the throughput. That whole 20/200/2000 figure is inaccurate in so many ways even with link aggregation.

[legacy]

Is there a better list?
and is there any *100Mbps card* able to allow jumbo frames?

PowerMacMDD-G4 , MTU<=1500  , 10/100Mbps
MacMini-G4     , MTU<=1500  , 10/100Mbps
MacMini-i2     , .MTU<=1500, 10/100Mbps
HP-C3600       , MTU<=1500  , 10/100Mbps
HP-C3750       , MTU<=1500 , 10/100Mbps
ppc405GP       , MTU<=1500  , 10/100Mbps
rb532          , MTU<=1500  , 10/100Mbps
rsp          , MTU<=1500  , 10/100/1000Mbps

I have just myself checked my computers.
I am going to check my net cards now (Digital, Intel, etc ...).

[legacy]

3COM 3C996-T 1Ggps, max MTU <=9000, PCI v2.2 & PCIX v1, PCI-X @ 133Mhz

[forrestc]

Is there a better list?
and is there any *100Mbps card* able to allow jumbo frames?

PowerMacMDD-G4 , MTU<=1500  , 10/100Mbps
MacMini-G4     , MTU<=1500  , 10/100Mbps
MacMini-i2     , .MTU<=1500, 10/100Mbps
HP-C3600       , MTU<=1500  , 10/100Mbps
HP-C3750       , MTU<=1500 , 10/100Mbps
ppc405GP       , MTU<=1500  , 10/100Mbps
rb532          , MTU<=1500  , 10/100Mbps
rsp          , MTU<=1500  , 10/100/1000Mbps

I have just myself checked my computers.
I am going to check my net cards now (Digital, Intel, etc ...).

Umm...

From the tik documenation:  RB532, CrossRoads   ether1-ether3:1600

Most 10/100 devices usually top out at the size which is needed for a full sized ethernet frame, plus a few more bytes for vlan and/or PPPoE headers.   So somewhere between 1500 and 1600.

Also, be aware that in a lot of cases, enabling giants is not a straightforward process.   For instance, in at least some switches/routers I'm aware of you have a systemwide or per-vlan limit which you have to change before you can increase it on any given interface.

Plus, some drivers don't support the full range of MTU's.

The real question here is *why* do you want to change the MTU.   Generally you want the workstation MTU not to exceed around 1500, if not a bit smaller.   This permits passage of all of the packets generated by the workstation throughout a network which is largely limited to a payload size of 1500 bytes.     The main reason to increase the MTU is where you want to pass a full sized frame plus vlan, mpls, PPPoE, or similar headers which get added/removed in the network.   But to the end user, this is transparent.

I'm excluding some esoteric LAN applications which can benefit from increased MTU's here, and being somewhat internet-focused.

[legacy]

From the tik documenation:  RB532, CrossRoads   ether1-ether3:1600

Code: [Select]

rb532 # ip link set eth2 mtu 1600
RTNETLINK answers: Invalid argument


The real question here is *why* do you want to change the MTU.

I am working on a AFX switch, which has been designed to be 4K MTU. AFDX is not *exactly* ethernet, but it can be adapted, and this makes sense because I need a development tool and equipment that doesn't cost me a fortune.

I am also developing a Thin Client Computing. It bootstraps from tftpboot and I need to make it bootstrapping in the shortest time possible. Unfortunately the used CPU on the protype comes with a built-in fast ethernet that only allows 1500 MTU. One solution is adding a Gigabit chip on the PCI bus, so it could benefit from both larger MTU (9K) and bit speed.

I cannot change the firmware too much, I cannot introduce any protocol based on TCP/IP because there is not enough space on the Flash, but coupling tftpboot with MTU 9K makes a great difference on the upload time!


Anyway, digging around in the lab, I found a second-gen Apple MacMini x86 whose ethernet chip is a gigabit by intel, and it allows 9K MTU.

So I have just coupled the 3COM 3C996-T chip on the prototype with the MacMini x86 for getting started 

The speedup on uploads goes from 1.2Mbyte/sec, to 22Mbyte/sec, woooo