Comments on: FreeBSD Configure NIC Jumbo Frames

By: itanic

itanic — Thu, 11 Feb 2010 09:55:34 +0000

Forcing the duplex to full is a really bad idea, as if the other side is set to auto-duplex, the correct behaviour for it will be to fall back to half-duplex, in which case you’ll end up with a duplex mismatch.

By: vivek

vivek — Fri, 14 Nov 2008 14:38:10 +0000

Some network cards have limitations in both hardware and driver itself. Try setting MTU on both end to 9000 and it may work out.

By: Dyr

Dyr — Fri, 14 Nov 2008 09:18:52 +0000

It’s sad cause it’s also don’t working %-(

[root@home-vr /etc/ipfw]# route change 10.77.77.1 -mtu 9100 change host 10.77.77.1 [root@home-vr /etc/ipfw]# route get 10.77.77.1 route to: 10.77.77.1 destination: 10.77.77.1 gateway: home-rs.vs.smartspb.net interface: em0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 9100 0 [root@home-vr /etc/ipfw]# ping 10.77.77.1 PING 10.77.77.1 (10.77.77.1): 56 data bytes 64 bytes from 10.77.77.1: icmp_seq=0 ttl=255 time=0.530 ms ^C --- 10.77.77.1 ping statistics --- 1 packets transmitted, 1 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 0.530/0.530/0.530/0.000 ms [root@home-vr /etc/ipfw]# route get 10.77.77.1 route to: 10.77.77.1 destination: 10.77.77.1 gateway: home-rs.vs.smartspb.net interface: em0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1500 0 [root@home-vr /etc/ipfw]#

By: vivek

vivek — Thu, 13 Nov 2008 13:39:52 +0000

Dyr,

Thanks for sharing back route command with us.

By: Dyr

Dyr — Thu, 13 Nov 2008 13:02:48 +0000

OK, I hope, this will help:
[root@home-vr /usr/home/dyr]# route change 10.77.77.1 -mtu 9198 change host 10.77.77.1 [root@home-vr /usr/home/dyr]# route get 10.77.77.1 route to: 10.77.77.1 destination: 10.77.77.1 gateway: home-rs.vs.smartspb.net interface: em0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 9198 0 [root@home-vr /usr/home/dyr]#

By: Dyr

Dyr — Thu, 13 Nov 2008 13:00:09 +0000

OK, I did it…but “route get” shows mtu 1500 =( What could I do?

[root@home-vr /usr/home/dyr]# ifconfig em1 mtu 9198 [root@home-vr /usr/home/dyr]# ifconfig em1 em1: flags=8943 metric 0 mtu 9198 options=19b ether 00:30:48:63:da:c7 inet 10.77.77.222 netmask 0xffffff00 broadcast 10.77.77.255 media: Ethernet autoselect (1000baseTX ) status: active [root@home-vr /usr/home/dyr]# route get 10.77.77.1 route to: 10.77.77.1 destination: 10.77.77.1 gateway: home-rs.vs.smartspb.net interface: em0 flags: recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire 0 0 0 0 0 0 1500 0

Cisco at another side already set to use jumbo frames:
home-rs#show interfaces gigabitEthernet 1/0/2 GigabitEthernet1/0/2 is up, line protocol is up (connected) Hardware is Gigabit Ethernet, address is 0014.f286.5302 (bia 0014.f286.5302) Description: home-vr/em1 MTU 9198 bytes, BW 1000000 Kbit, DLY 10 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive not set Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX input flow-control is off, output flow-control is unsupported ARP type: ARPA, ARP Timeout 04:00:00 Last input never, output 1w0d, output hang never Last clearing of "show interface" counters 2w0d Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 17031 packets input, 5586651 bytes, 0 no buffer Received 16022 broadcasts (0 multicast) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 0 multicast, 0 pause input 0 input packets with dribble condition detected 1654 packets output, 469745 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier, 0 PAUSE output 0 output buffer failures, 0 output buffers swapped out

What’s wrong?