TSW212 jumbo frames?

NETWORKING SOLUTIONS
1

Does not seem to work?

BusyBox v1.36.0 (2025-03-17 07:03:36 UTC) built-in shell (ash)

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Teltonika TSW2 series 2025

Device: TSW212
Kernel: 5.10.233
Firmware: TSW2_R_00.01.05
Build: a6ff88df
Build date: 2025-03-17 08:10:29

root@TSW212:~# ip -d l show | grep mtu
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 minmtu 0 maxmtu 0 addrgenmode eui64 numtxqueues 1 gso_max_size 65536 gso_max_segs 65535 
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1504 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 11 minmtu 60 maxmtu 1536 addrgenmode eui64 numtxqueues 2 gso_max_size 65536 gso_max_segs 65535 
3: port1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e4 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
4: port2@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e5 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
5: port3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e6 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
6: port4@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e7 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
7: port5@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e8 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
8: port6@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e9 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
9: port7@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:ea brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
10: port8@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:eb brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
11: sfp1@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:ec brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
12: sfp2@eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue master br0 state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:ed brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
13: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 65535 
14: br0.1@br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 0 maxmtu 65535 
root@TSW212:~# ip -d l show | grep maxmtu
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 promiscuity 0 minmtu 0 maxmtu 0 addrgenmode eui64 numtxqueues 1 gso_max_size 65536 gso_max_segs 65535 
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 11 minmtu 60 maxmtu 1536 addrgenmode eui64 numtxqueues 2 gso_max_size 65536 gso_max_segs 65535 
    link/ether 20:97:27:3c:48:e4 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e5 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e6 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e7 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e8 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e9 brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:ea brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:eb brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:ec brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:ed brd ff:ff:ff:ff:ff:ff promiscuity 1 minmtu 68 maxmtu 1500 
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 68 maxmtu 65535 
    link/ether 20:97:27:3c:48:e3 brd ff:ff:ff:ff:ff:ff promiscuity 0 minmtu 0 maxmtu 65535 
root@TSW212:~#
3

Hi there, @michiel

I’ve reached out to our R&D to ask about this. Whenever I have an answer, I’ll get back to you.

Regards,
M.

4

Hello,

Short version of the answer that the R&D gave: enabling Jumbo frames allows TSW to forward frames with size up to 10000 bytes between end devices but TSW itself cannot receive such frames.

A longer, more detailed answer would be:

Enabling Jumbo frames functionality adds option max_pkt_len '10000' option to tswconfig switch_bw 'common' section.
This allows for TSW to forward frames larger than 1500 between its ports. Tested by connecting 2 RUTX devices to TSW with 9000 MTU configured:

root@RUTX50:~# ping -s 8972 192.168.1.3
PING 192.168.1.3 (192.168.1.3): 8972 data bytes
8980 bytes from 192.168.1.3: seq=0 ttl=64 time=1.647 ms
11:56:10.564693 IP (tos 0x0, ttl 64, id 54400, offset 0, flags [DF], proto ICMP (1), length 9000)
    192.168.1.1 > 192.168.1.3: ICMP echo request, id 4205, seq 0, length 8980
11:56:10.565866 IP (tos 0x0, ttl 64, id 25507, offset 0, flags [none], proto ICMP (1), length 9000)
    192.168.1.3 > 192.168.1.1: ICMP echo reply, id 4205, seq 0, length 8980
8980 bytes from 192.168.1.3: seq=1 ttl=64 time=1.527 ms

For RUTX devices to set MTU properly on LAN interface you have to use non-bridged eth0 e.g.:

image
image859×271 13.7 KB

Otherwise 9000 MTU is set only for br-lan but not eth0 so forwarding still won’t work. If it’s necessary to have a bridge then following section must be added to network config as it’s not configurable via WebUI on devices which don’t support Network -> Devices.

config device 'mtu_test'
	option name 'eth0'
	option mtu '9000'

Regards,
M.

1 Like
5

That answers my question.

Thank you.

6

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