Network broadband upgrade - inconsistent speeds

[speckytecky]

This week the LA initiated an upgrade on the broadband which it is eventually hoped will give up speeds of up to 30GB. However, straight after the upgrade the school noticed that the net was decidedly iffy and inconsistent - wireless in one area visible but too weak to function and speeds of 10GB sometimes dropping to a crawl at others.

The network was working OK but a bit slow before the upgrade and initial thoughts post a day of the new connection are that it seems to drop off drastically - in some areas of the school when peak users are logged onto the network.

Thought being that we have a device somewhere that has an IP conflict. It looks like we are going to have to crawl through the whole network to search it out or are there better ideas please?

[kmount]

GB? or Mb?

I'd split this problem into an internal (ie, your network and wireless) and then an external one as the internal could affect the external etc.

[speckytecky]

I'm thinking it might have something to do with IP allocations. The scope was recently extended by 50 addresses and looking around it's now apparent that some of the extra 50 had already been put into use by the chaps who set up the network - for managed ports and several Linksys WAP boxes plus the Admin server and workstation but these devices are not held as reservations nor exclusions.

The strange thing is that the network seemed to be running pretty stable before the new broadband kit was installed.

[kmount]

Hm, that won't be helping.

Crack out an ipscanner and check the whole subnet you have available for 'in use' IP's and put in reservations for them to stop clashes there.

I'm not knocking your broadband idea as being the fault but does the network return to its normal glory if you unplug the router?

[speckytecky]

TVM - I see there are several Free ipscanners which would you recommend please.

Hm, that won't be helping.

Crack out an ipscanner and check the whole subnet you have available for 'in use' IP's and put in reservations for them to stop clashes there.

I'm not knocking your broadband idea as being the fault but does the network return to its normal glory if you unplug the router?

[Rydra]

If you suspect there is clashing IP's between standard devices (such as PC/laptop) and some of your switches, make sure you run the ipscanner once with the devices on, and once with them off, as an ip scanner will sometimes only see one of the devices, whichever one is the prominent device.

While your at it, see about setting reservations, and write up a list of attached devices, mac addresses, and ip addresses; this may help you in the future!