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Oam, link trap? Mismatches

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  • 1.  Oam, link trap? Mismatches

    Posted 11-07-2018 08:32
    Does oam in juniper handle mismatches. I have a switch that drops my network when I connect a 100mbps cable(host) to it. The ports are default 1000mbps auto negotiate. The net cards on the 100 are a bit special. I'll try configuring them further so they don't do that but the point is I think that's what happens. Help!!!!

  • 2.  RE: Oam, link trap? Mismatches

    Posted 11-07-2018 16:43

    100 connecting devices frequently fail auto-neg on gig ports.  This will generally either come up half duplex or not connect at all as you seem to be experiencing.


    The solution is to configure the junos port to turn off auto-net and set the speed and duplex manually.


    set interfaces ge-0/0/11 ether-options no-auto-negotiation
    set interfaces ge-0/0/11 ether-options link-mode full-duplex
    set interfaces ge-0/0/11 ether-options speed 100m


  • 3.  RE: Oam, link trap? Mismatches
    Best Answer

    Posted 11-07-2018 18:10
    I'm sorry I didn't explain myself better. The switch is a couple of hops away. A wireless AP is at the SRX, then a media bridge after the wifi AP, then a switch stack, then servers. The 100 Mbps seemed to pass through or zero out a connection drop at the AP level. The SRX seems to drop purposely. I disconnected the 100mbps because it's always on even though the PC is off. It does sense WOL actions. But something's not right there I can tell. Wierd MB. Since setting the correct link mode, 100 full it probably will do it.

    My question is????

    Does oam control this failure. I've had positive results it would seem, but it's been only a short time.

    oam -> link-fault-management ->

    I haven't tried the connectivity option.

    I accept what you are saying about setting links to match at the AP 😀, but I still want to know about oam.

  • 4.  RE: Oam, link trap? Mismatches

    Posted 11-08-2018 03:02

    Sorry for missing the point.


    OAM is just the detection mechanism so it can see if a point to point link fails but you would need something else to take action on the failure.  I've only used it as part of a trigger for lsp path switchover when link failures are detected.


    In your case it would log and dectect the link failures but since there is no alternate path I'm not sure what you could tie the events to for an action to take.


  • 5.  RE: Oam, link trap? Mismatches

    Posted 11-08-2018 05:38
    Thx on the reply for lsp switching. I've found that lsp in my environment is dangerous. I once used an option in virus/spyware that permanently disrupted electrical services, thus killing internet to PC's . Solving it was difficult. An interruption like that could permanently disrupted me again. My electrical services in my area are odd. A static nature. I assume that the lsp chain mecahanism is different in nature then the oam protocol that uses it. Either way, if it only logs those events I won't use it. I always thought link traps at the switch would protect me from failures beyond the switch itself. This must be an odd MB.