ICX port blocking

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  • Updated 8 months ago
I've got a 7750 as my core router and 1GB connections to 9 sites with 7450 routers.  7 of the connections work and 2 do not.  As far as I can tell, the configs are all the same (other than IP addresses) but all four of the ports show as down with port states Blocking.  STP is disabled on all four ports.  If I disable and then enable the ports, they go down immediately.  As far as I know, the AT&T links between the sites are all good.  Suggestions?
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Clayton Tavernier

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Posted 8 months ago

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David Ellis, Employee

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You say there are 2 sites, but reference 4 ports. Do you have dual connections to the two sites?
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Clayton Tavernier

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2 ports on the 7750 and 1 port on each of the 7450s.  All down, all Blocking.
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Alex Shalima

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Hi Clayton,

Are you using fiber? if so, as far as I know the SFP+ ports are defaulted to 10G mode and have to be switched manually to work in 1G mode.


Best,
Alex
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Ben, Employee

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"Blocking" is just the default verbiage in the STP output. If the port is down at layer 1 (state down), then the STP blocking is irrelevant. I'd check speed-duplex, optics, media, etc.
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David Ellis, Employee

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I have had several customers that had to get AT&T to change the port settings on their Canoga Perkins box to 1g-Full to get them to work with the ICX-7750 as the CG would not auto-negotiate correctly. Other than that, if the port is state down, it is most likely a Layer 1 issue.
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Clayton Tavernier

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Thanks.  Yes to fiber, all ports set to 1000-full, and this is the type of AT&T circuit that's functionally point to point with no AT&T switching in the middle (the reality is that there's at least a Ciena 6500 between the two routers) so they have no ports to configure.

I understand what you're saying about layer 1 but we had four of these circuits completed recently and none of them worked at first but with some AT&T testing and some reconfiguration and some luck of the gods, two of them came up and I'm not really sure how that happened so I keep thinking there's some tweaking I can do to bring these last two up.  Plus we ordered our equipment to spec so there are no switches, sfps or fiber cables to swap out.  And AT&T says all their stuff is fine.
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chill

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You might have already tried this but worth a shot:

Is it possible to try swapping known good SFPs and fiber patch cables into those links that are currently down? 
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Clayton Tavernier

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I left out a word above.  I have no EXTRA switches, sfps or fiber cables to swap out and using a working set from another site would disable the site so that's not happening.
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chill

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Yeah I just mean temporarily - take one of the 7 sets of SFPs and fiber patches that is working and test them on the links that don't work to see if it's possibly bad SFPs or fiber. Typically when I see this type of issue, it's a layer 1 problem