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HP 2848 connected to HP 2824..crossover?

Dublin_101
Occasional Advisor

HP 2848 connected to HP 2824..crossover?

Hi all..

I just put in a hp 2848 in the server room and a HP 2824 in our warehouse (about 75 metres) away....

plugged them in from the patch panel...and no go!..not even a light or any indication whatsover that there was a link.


if i plugged it into the cisco 2950, it would work and vice versa..but the two HPs together would not work..........

so basically it is HP2848 < ----cat5e straight thru -------> HP2824.

there is no configuration except an IP on each switch.

the only thing i could think of was perhaps that the HP switches can't recognise the cable and needed a cross over...i didn't have one around so i had to call it a day.

i am hoping it is only a cross over issue...in the meantime i had to revert to using a CISCO 2950 ---- HP2848.

advice appreciated. thanks.

9 REPLIES
Joel Belizario
Trusted Contributor

Re: HP 2848 connected to HP 2824..crossover?

The 2800s have auto-MDIX capability, I would check if it has been disabled on the switch. From memory it should be turned on by default.

Also to state the obvious but have you troubleshooted with different ports and without the patch panel in the equation?
Matt Hobbs
Honored Contributor

Re: HP 2848 connected to HP 2824..crossover?

I'm guessing your patch panel cabling doesn't have the full four pairs which is needed for Gigabit connectivity.
Dublin_101
Occasional Advisor

Re: HP 2848 connected to HP 2824..crossover?

i spoke to the data cabler and he said that it should be working.

i'm figuring that something on the line is not working...maybe even a wall panel or something.

if it is eg a cat5 cable, shouldn't it still come up and negotiate for that??

or does it have to be at least cat5e just to get a light on the port?

thanks.
Matt Hobbs
Honored Contributor

Re: HP 2848 connected to HP 2824..crossover?

Is the Cisco 2950 100Mbit only? If it is, then what you could do to verify it is a cabling problem is set the ProCurves to 100-full on their uplink ports. If it gets a link then it's definitely an issue with the cabling.
Dublin_101
Occasional Advisor

Re: HP 2848 connected to HP 2824..crossover?

yes the cisco is a 100MB switch..........

but i would have at least thought that the switch port on the HP would be able to recognise the media and set the speed accordingly?

there is no light whatsover....

i will try and set the ports to 100MB and try it.

is cat5e a gigabit cable? or will it have to be cat6?...the most important thing is the trunk to the other switch and i'd like that to be maximum.

thanks.
Richard Brodie_1
Honored Contributor

Re: HP 2848 connected to HP 2824..crossover?

"I would have at least thought that the switch port on the HP would be able to recognise the media and set the speed accordingly?"

Autonegotiation for Ethernet doesn't work like a modem; there's no line testing. If both switches do Gigabit, they'll autonegotiate Gigabit, whether they are connected by cat 5, cat 6, cat 3 or a wet piece of string.

"is cat5e a gigabit cable?"

It should be fine if it's installed properly. As Matt said, if it's completely U/S at Gigabit rates, chances are it's a dead pair somewhere. I find it worth having a cheap RJ45 continuity checker around, although it's not a substitute for having your cabling properly tested.
Andrew_291
Frequent Advisor

Re: HP 2848 connected to HP 2824..crossover?

There is no difference between GOOD cat5 and cat 6 cables on gigabit connections.The main circumstance on these connections are cables integrity on ALL PAIRS.There is no matter will it crossover or straight.

So,btw I use only crossover cables on one side of link between switches and have no headache anytime.
Dublin_101
Occasional Advisor

Re: HP 2848 connected to HP 2824..crossover?

ok guys....so basically i get the idea that i should leave it to the data cabler as it must be some kind of issue either with the cable or the patch panels..

the link to the other switch is about 75 metres through a warehouse and i told the data cabler to come prepared tomorrow,...as i may ask him to put in another cable through the building.

gigabit to gigabit with cat5 cable..will give gigabit connectivity??

i thought cat5 was 100Mbps maximum..

Andrew_291
Frequent Advisor

Re: HP 2848 connected to HP 2824..crossover?

Cable cat 5 will give gigabit,dont disturb.We have branches with 5 cat cable systems and gigabit switches.All works fine.

And 75 meters is safety length of the cable. There was some links 5cat ,before upgrade, in my branch 110 meters long .It work nice ON GIGABIT 8)))) between 4104GL and 5308xl 8))))