What do I need?

[westernkings]

Afternoon Ladies and Gents;

We are having issues that we are pretty sure related to the network infrastructure, such as random losses of connections over the entire network (passing through several switches to reach the DC) amongst other things, so we want someone to come in and work out exactly what is causing these random issues on the network, whether it be switches, the cabling, the fact we have cat5 as opposed to cat6. A problem with the fiber network at some point that links it all together. It literally could be anything but from a front of house point of view, replacing machines, moving ports on switches, changing network cards and so on makes no difference.

Is this a network analyst we need? or is there some other role that is more suited? I think it would be a network analyst wouldn't it? and how much do these usually charge?

We are looking for someone to come in, work out what exactly is the issue if possible, so that we can decide on whether it warrants spending money on fixing.

[Boycie]

i guess that depends on the infrastructure really.

Has the building had all the cabling and patch panels tested and certified?

[cisco lab rat]

Send me a copy of your switches configs (Minus any sensitive stuff) and I will have a look at them.

Network diagrams would also be very nice too

Cheers

Joe

[danielno8]

Any person with the experience, i wouldn't tie it down to "network analyst" as there will be many other people. Your best bet is going to a IT support company with network expertise on the payroll.

Out of interest, what are these outages? do they last long enough for you to do pings to different areas of the network to find out where it stop working?

[westernkings]

Originally Posted by Boycie

i guess that depends on the infrastructure really.

Has the building had all the cabling and patch panels tested and certified?

It has not been certified. It has been put together by a pretty incompetent manager with a bit of this and a bit of that. None of it was done by a network professional.

Originally Posted by cisco lab rat

Send me a copy of your switches configs (Minus any sensitive stuff) and I will have a look at them.

Network diagrams would also be very nice too

Cheers

Joe

And we do not have any diagrams available because they do not exist, so as a result, putting one together could take months, same for switch configs (Do not have access right now). It is a fairly basic network though involving managed phone systems running through CISCO switches. Some of the Switch CABs connect to others with fiber, others with cat6, one even connects with cat5.

For the most part it seems to run perfectly adequately, however we they really need someone who specialises in networks to come have a poke around for a day or so and give some advice out.

Originally Posted by danielno8

Any person with the experience, i wouldn't tie it down to "network analyst" as there will be many other people. Your best bet is going to a IT support company with network expertise on the payroll.

Out of interest, what are these outages? do they last long enough for you to do pings to different areas of the network to find out where it stop working?

The outages are literally on random sets of machines ranging from a single machine in an office somewhere, to an entire bank of machines occasionally. Can last for hours, or just a quick blip. One user has been having issues for weeks, machine has been replaced, cables changes, moved to a different switch point. cisco phone remains online and working so connection to the CISCO switch is perfectly fine, however she cannot reach the DC to log on... which is on the other side of the site.

[cisco lab rat]

Originally Posted by westernkings

And we do not have any diagrams available because they do not exist,

Nothing new there.

Firstly I would look at spanning tree.

Have you got all the access ports manually set to "spanning-tree portfast" = This will reduce the spanning-tree timers on access ports

Have you got all the access ports manually set to "spanning-tree bpduguard enable", shut down ports in the event that a "rogue switch is added to the network

Are you using STP 802.1D (Cisco know it as PVST) or 802.1W (Cisco refer to it as Rapid-PVST)

Have you disabled "DTP" from all the links between switches and made every link a static trunk?

Do you have UDLD enabled between switches?

Are all the uplinks full duplex?

Have you got all of the switches set to "vtp mode transparent", stops the buggers from wiping each other out.

Have you idntified if any of the ports are going into "err-disable", I think top of my head the command to view all the err-disabled ports is "show interface status"

Could not suggest anything else unless I saw the switch configs.

Cheers

Joe

[danielno8]

Originally Posted by cisco lab rat

Have you idntified if any of the ports are going into "err-disable", I think top of my head the command to view all the err-disabled ports is "show interface status"

Cheers

Joe

"show int status err"

[cisco lab rat]

Originally Posted by danielno8

"show int status err"

errrrrrrrrrrrrr!

[danielno8]

Originally Posted by cisco lab rat

errrrrrrrrrrrrr!

hahaha

[SimonD]

How is the cabling? Is it near any power cable? are there any times during the day that this occurs (say between 8.30 and 10, 12-2pm etc) or is it completely random (ie perhaps large amounts of data going across the network that's saturating it (people pulling PST\DB's across the network).

What do the logs on the servers say? Are they dropping the NICs or is it switches?

I would perhaps look at running Wireshark just to see if you can see something on the network that's perhaps causing it.

I would also what you can ping when the connections drop, can you ping between switches or just on the same switch, is it the uplinks that's causing you issues?

[westernkings]

Originally Posted by SimonD

How is the cabling? Is it near any power cable? are there any times during the day that this occurs (say between 8.30 and 10, 12-2pm etc) or is it completely random (ie perhaps large amounts of data going across the network that's saturating it (people pulling PST\DB's across the network).

What do the logs on the servers say? Are they dropping the NICs or is it switches?

I would perhaps look at running Wireshark just to see if you can see something on the network that's perhaps causing it.

I would also what you can ping when the connections drop, can you ping between switches or just on the same switch, is it the uplinks that's causing you issues?

It's not the servers dropping connections at the NIC because no more than a few out of 1000s of people lose connection. I'm not really wanting to troubleshoot it myself, I have my own stuff to be doing. So I just want to get someone in who will check the health of the network in general. Personally, I am sure it is somewhere between the switches and the DC, but there is about 190 patch panels and switches (netgear and CISCO) to search through and miles of cables that could be causing it.

[BosonMichael]

Originally Posted by cisco lab rat

errrrrrrrrrrrrr!

Weis....

[cisco lab rat]

Hi Daniel

I have a suspicion that your problem may be due to "Errdisable linkflap" causing the ports to shutdown rather than UDLD detecting unidirectional links.

Get the syslog up and have a gander.

Cheers

Joe