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mgutt
Asked: 2019-07-10 01:16:48 +0800 CST

Why is my data throughput only 1G of possible 10G if I setup an ethernet bridge?

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My setup is a Windows 10 PC with 10G card (LR-LINK 6880BT) and a Synology DS1618+ NAS with 10G card (Synology E10G18-T1). Both 10G ports are connected directly to avoid buying a 10G switch.

A) How the 10G connection works:

  • NAS eth4 (10G) is set to 192.168.178.11
  • PC 10G is set to 192.168.178.13
  • NAS 10G and PC 10G are connected directly
  • >400 MB/s (limited by NAS performance) copying a file from .11 through SMB

B) How it does not work:

  1. NAS eth4 (10G) is set to 192.168.178.11
  2. PC 10G is set to 192.168.178.13
  3. NAS 10G and PC 10G are connected directly
  4. NAS eth3 (1G) is set to 192.168.178.10
  5. NAS eth3 is connected to the router (192.168.178.1)
  6. I create on the NAS a bridge between eth3 (1G) and eth4 (10G) (to connect the PC to the intra- and internet):
    brctl addbr br0 brctl stp br0 off ifconfig br0 192.168.178.12 netmask 255.255.255.0 up brctl addif br0 eth3 brctl addif br0 eth4 ifconfig eth3 promisc up ifconfig eth4 promisc up
  7. <115 MB/s copying a file from .12 through SMB

In both cases the PC shows "10,0 Gbit/s" transfer speeds in its adapters status. The NAS, too:

ethtool eth4
Settings for eth4:
        Supported ports: [ TP ]
        Supported link modes:   100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
        Supported pause frame use: Symmetric
        Supports auto-negotiation: Yes
        Advertised link modes:  100baseT/Full
                                1000baseT/Full
                                10000baseT/Full
        Advertised pause frame use: Symmetric
        Advertised auto-negotiation: Yes
        Speed: 10000Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: external
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: g
        Wake-on: d
        Link detected: yes

Maybe important: I'm not able to set a gateway for the bridge. I tried this:

route add default gw 192.168.178.1 dev br0

But it returns:

SIOCADDRT: Network is unreachable

I do not know why as the IPs are all correctly set up:

    ifconfig
    br0       Link encap:Ethernet  HWaddr 00:00:00:00:00:00
              inet addr:192.168.178.12  Bcast:192.168.178.255  Mask:255.255.255.0
              UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
              RX packets:553505 errors:0 dropped:0 overruns:0 frame:0
              TX packets:3324 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:61656890 (58.8 MiB)  TX bytes:2251363 (2.1 MiB)
    ...
    eth3      Link encap:Ethernet  HWaddr 00:00:00:00:00:00
              inet addr:192.168.178.10  Bcast:192.168.178.255  Mask:255.255.255.0
              UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
              RX packets:3422085 errors:0 dropped:0 overruns:0 frame:0
              TX packets:845424 errors:0 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:4592877231 (4.2 GiB)  TX bytes:1126753162 (1.0 GiB)
    eth4      Link encap:Ethernet  HWaddr 00:00:00:00:00:00
              inet addr:192.168.178.11  Bcast:192.168.178.255  Mask:255.255.255.0
              UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
              RX packets:1354792 errors:0 dropped:0 overruns:0 frame:0
              TX packets:4370314 errors:1 dropped:0 overruns:0 carrier:0
              collisions:0 txqueuelen:1000
              RX bytes:1199786642 (1.1 GiB)  TX bytes:6062719532 (5.6 GiB)

    route
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    default         fritz.box       0.0.0.0         UG    0      0        0 eth1
    192.168.178.0   0.0.0.0         255.255.255.0   U     0      0        0 eth1
    192.168.178.0   0.0.0.0         255.255.255.0   U     0      0        0 eth3
    192.168.178.0   0.0.0.0         255.255.255.0   U     0      0        0 eth4

    brctl show
    bridge name     bridge id               STP enabled     interfaces
    br0             8000.000000000000       no              eth3
                                                            eth4

Maybe interesting, too:

  • All clients in the intranet are able to ping .12 after the bridge is setup
  • the router does not show up .12. It lists only .10 (not pingable) and .13 (PC).
  • br0 and eth3 and the routers .10 client have all the same mac address
routing

0 Answers