Jumbo frames on axgbe / DEC7x0

[newsense]

With FreeBSD 14.3beta2 out, if this gets an actual fix I'd be surprised if it makes it prior to 14.4 upstream.

( With OPNsense that would most likely be included in the next dot release that has a kernel update and at least one test kernel before that )

[meyergru]

Much less so if nobody opens an issue on FreeBSD, where it belongs.

[patient0]

Out of curiosity I restarted my DEC740 with VyOS (on a stick) and in that setup I was able to set the MTU to 9000 (eth3 below) and ping was successful. No hardware restriction, software only.

The setup was: DEC740 (eth3, 10.66.6.1) - MikroTik Switch CSS610-8P-2S+IN - QNAP QNA-UC5G1T (5Gbit USB NIC, 10.66.6.2)

Code Select Expand

vyos@vyos# run sh inter ethernet eth3
eth3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc mq state UP group default qlen 1000
    link/ether f4:90:ea:00:73:63 brd ff:ff:ff:ff:ff:ff
    altname enp6s0f1
    inet 10.66.6.1/24 brd 10.66.6.255 scope global eth3
       valid_lft forever preferred_lft forever
    inet6 fe80::f690:eaff:fe00:7363/64 scope link
       valid_lft forever preferred_lft forever

    RX:   bytes  packets  errors  dropped  overrun       mcast
         226837      366       0        0        0         109
    TX:   bytes  packets  errors  dropped  carrier  collisions
         160576       88       0        0        0           0

vyos@vyos# ping -M do -s 8972 -c 4 10.66.6.2
PING 10.66.6.2 (10.66.6.2) 8972(9000) bytes of data.
8980 bytes from 10.66.6.2: icmp_seq=1 ttl=64 time=1.13 ms
8980 bytes from 10.66.6.2: icmp_seq=2 ttl=64 time=1.29 ms
8980 bytes from 10.66.6.2: icmp_seq=3 ttl=64 time=1.42 ms
8980 bytes from 10.66.6.2: icmp_seq=4 ttl=64 time=1.23 ms
Trying the same with FreeBSD 15-CURRENT 2025-05-08 showed the same issue as with OPNsense.

Btw: Linux also reports 3 rx and 3 tx queues, seems to be implemented that way in hardware.

[Kaya]

Thanks for your definitive validation of the hardware capabilities @patient0. Since I only have access to one device, which is in active use as a firewall, I can't do such experiments.