This article provides information about the support provided for MDI/MDI-X on SRX and J-series.

MDI (Media Dependent Interface) is the Ethernet port connection typically used on network interface cards (NIC). MDI-X (Media Dependent Interface with Crossover) is the standard Ethernet port wiring for hubs and switches.

Normally, we need a cross-over cable to connect a router's LAN port to a switch/hub's normal port. But, if there is an auto MDI/MDI-X feature support on the switch, hub, network card or other network devices, we do not have to use a crossover cable. This is because the crossover function will automatically enabled, when required.

by default, all the SRX modules and on-board interfaces support MDI/MDI-X. But, we do not have a provision to disable the MDI/MDI-X on the SRX or J-series. (It is supported in M-series devices)

When we try to disable it in SRX, we get the following error:

r oot@210hm# show interfaces ge-0/0/0

gigether-options{
    Warning : statement ignored : unsupported platform (srx210h)
    no-auto-mdix;
}