Ethernet LAN Switch to switch causing traffic problems?

>>AnthonyL wrote:
>>

>>> The arrangement is
>>>
>>> Office 1 - approx 12 PC's
>>> Switch 1 - router- internet
>>> |
>>> ~ 50 metres
>>> |
>>> Switch 2
>>> Office 2 - approx 30 PC's plus
>>> 2 x Windows servers + 1 Novell 3.12 server (IPX)
>>>
>>> All Cat5e structured cabling.
>>>
>>> Virtually all traffic is from PC to one or other of the servers in
>>> Office 2. There are some networked printers in the system.
>>>
>>> Traffic load should be relatively low. One central database on SQL
>>> server on one server, Word Processing and Exchange on the other and a
>>> small DOS application serving 4 users in Office 1 on the Novell
>>> server. Some but not heavy internet access via Switch 1.
>>>
>>> Office 1 staff experience regular delays of sometimes up to a couple
>>> of minutes opening files or running an application.
>>>
>>> The link between the switches is 100mbit (as is the rest of the
>>> network except the 10mbit cards in the Novell server).
>>>
>>> There is a second cable running from Office 1 to Office 2 but that has
>>> not been connected and I'm not sure whether it is good practice to
>>> have a parallel run.
>>>
>>> One company has recommended to upgrade the link to a gigabit line but
>>> I find the logic hard to follow since the servers will still have
>>> 100mbit cards.
>>>
>>> Any helpful views welcomed.

>>
>>The question is where the bottleneck lies.
>>
>>Cheap things to check.
>>
>>First, run virus, adware, and spyware scans on _everything_ for which you
>>have a utility available. If you've got malware of some sort broadcasting
>>tons of traffic on your LAN then nothing's going to work right until you
>>fix that.
>>
>> Ping each computer from each other computer and see if there is unusual
>>latency in either direction. Download a copy of qcheck
>><http://www.ixiacom.com/products/qcheck/>, install it on a Windows box,
>>read the readme, and download the appropriate endpoints from the link in
>>the readme, then see what speed you're really getting between machines and
>>if you're getting the same speed both ways--if you're not then find out
>>why--most common cause would be a configuration error--either speed or a
>>duplex mismatch.
>>
>>Windows server includes a tool called "network monitor". Go into the
>>Windows Server help and search on that and install it on your servers and
>>then watch the traffic going to and from them and see if you're seeing
>>anything coming in or going out that doesn't get a response. The free
>>version only monitors traffic to and from the server on which it is
>>installed, which is a significant limitation, but it's still a useful
>>tool.
>>
>>There's a tool called "Ethereal" <http://www.ethereal.com/> which is a
>>general-purpose network analyzer similar in purpose to "network
>>monitor"--ethereal is a free download--install it on one of your machines
>>that is experiencing the slowdown and watch the traffic and see if it's

>
>
> If the OP has two switches then using a traffic monitor will be
> impossible unless the switches have management.

> If the switches have
> management then you'll get counters, which might show something
> interesting.
>
> Assuming dumb switches I think the blinkenlights are as useful.

They can tell you that "something is wrong"> If
> the lights are not blinking he's got a problem with a timeout, not a
> high traffic problem. DNS problems would show up as the former. If
> you do have lots of blinking lights then the traffic monitor on a
> Windows box may tell you something but because you have a switch it
> can only see it's own traffic. ISTR that MS Monitor had software that
> could be installed at other points in the network and feed data back
> to the server for aggregation and analysis. That would solve the switch
> limitation.
>
> You can use perfmon.exe on any Windows box (except 98/me/dos) to
> analysis in great detail what it's doing.

> If your server (CPU and disk as shown by permon) is idle and the
> lights are not blinking then you do';t have a capacity problem,
> you've got a network design problem. IMO probably DNS.

> You can put ethereal on each and every box (except NW) and analysis
> the traffic and protocols.
>
>
>

>>If you don't already have managed switches (and if you did and knew how to
>>use them you'd already know whether the link between them was the
>>problem--they'll tell you statistics on it) you might want to consider
>>picking up a couple of them off of ebay--Catalyst 2924s go for under $200
>>and sometimes under $100. I see Procurve 4000s, which for your use are
>>serious overkill but a bit noisy, for about the same.
>>

>
> Agreed. Procurve boxes have a lifetime warranty so you can't go
> wrong. As for my issue with cheap/noname switch-to-switch
> connections, If you match brands, HP or Cisco you should be OK.

>AnthonyL wrote:
>

>> The arrangement is
>>
>> Office 1 - approx 12 PC's
>> Switch 1 - router- internet
>> |
>> ~ 50 metres
>> |
>> Switch 2
>> Office 2 - approx 30 PC's plus
>> 2 x Windows servers + 1 Novell 3.12 server (IPX)
>>
>> All Cat5e structured cabling.
>>
>> Virtually all traffic is from PC to one or other of the servers in
>> Office 2. There are some networked printers in the system.
>>
>> Traffic load should be relatively low. One central database on SQL
>> server on one server, Word Processing and Exchange on the other and a
>> small DOS application serving 4 users in Office 1 on the Novell
>> server. Some but not heavy internet access via Switch 1.
>>
>> Office 1 staff experience regular delays of sometimes up to a couple
>> of minutes opening files or running an application.
>>
>> The link between the switches is 100mbit (as is the rest of the
>> network except the 10mbit cards in the Novell server).
>>
>> There is a second cable running from Office 1 to Office 2 but that has
>> not been connected and I'm not sure whether it is good practice to
>> have a parallel run.
>>
>> One company has recommended to upgrade the link to a gigabit line but
>> I find the logic hard to follow since the servers will still have
>> 100mbit cards.
>>
>> Any helpful views welcomed.

>
>The question is where the bottleneck lies.
>
>Cheap things to check.
>
>First, run virus, adware, and spyware scans on _everything_ for which you
>have a utility available. If you've got malware of some sort broadcasting
>tons of traffic on your LAN then nothing's going to work right until you
>fix that.

>
> Ping each computer from each other computer and see if there is unusual
>latency in either direction. Download a copy of qcheck
><http://www.ixiacom.com/products/qcheck/>, install it on a Windows box,
>read the readme, and download the appropriate endpoints from the link in
>the readme, then see what speed you're really getting between machines and
>if you're getting the same speed both ways--if you're not then find out
>why--most common cause would be a configuration error--either speed or a
>duplex mismatch.

>
>Windows server includes a tool called "network monitor". Go into the
>Windows Server help and search on that and install it on your servers and
>then watch the traffic going to and from them and see if you're seeing
>anything coming in or going out that doesn't get a response. The free
>version only monitors traffic to and from the server on which it is
>installed, which is a significant limitation, but it's still a useful tool.

>
>There's a tool called "Ethereal" <http://www.ethereal.com/> which is a
>general-purpose network analyzer similar in purpose to "network
>monitor"--ethereal is a free download--install it on one of your machines
>that is experiencing the slowdown and watch the traffic and see if it's
>sending anything for which it is not getting a response or receiving
>anything to which it should be responding and isn't.
>
>With those tools and some time you should be able to identify most network
>problems--the trouble is that they're complex tools and it takes time to
>learn to use them--there's a book, "Ethereal Packet Sniffing"
><http://www.amazon.com/exec/obidos/tg/detail/-/1932266828/qid=1113915990/sr=8-1/ref=pd_csp_1/104-1548119-3742340?v=glance&s=books&n=507846>
>which may help. While you're about it, if you haven't already read them
>try "Ethernet the Definitive Guide" by Charles Spurgeon
><http://www.amazon.com/exec/obidos/tg/detail/-/1565926609/qid=1113916220/sr=1-1/ref=sr_1_1/104-1548119-3742340?v=glance&s=books>
>and "TCP/IP Illustrated"
><http://www.amazon.com/exec/obidos/tg/detail/-/0201633469/qid=1113916303/sr=1-1/ref=sr_1_1/104-1548119-3742340?v=glance&s=books>.

>
>If you don't already have managed switches (and if you did and knew how to
>use them you'd already know whether the link between them was the
>problem--they'll tell you statistics on it) you might want to consider
>picking up a couple of them off of ebay--Catalyst 2924s go for under $200
>and sometimes under $100. I see Procurve 4000s, which for your use are
>serious overkill but a bit noisy, for about the same.
>

>On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
>

>>AnthonyL wrote:
>>

>>> The arrangement is
>>>
>>> Office 1 - approx 12 PC's
>>> Switch 1 - router- internet
>>> |
>>> ~ 50 metres
>>> |
>>> Switch 2
>>> Office 2 - approx 30 PC's plus
>>> 2 x Windows servers + 1 Novell 3.12 server (IPX)
>>>
>>> All Cat5e structured cabling.
>>>
>>> Virtually all traffic is from PC to one or other of the servers in
>>> Office 2. There are some networked printers in the system.
>>>
>>> Traffic load should be relatively low. One central database on SQL
>>> server on one server, Word Processing and Exchange on the other and a
>>> small DOS application serving 4 users in Office 1 on the Novell
>>> server. Some but not heavy internet access via Switch 1.
>>>
>>> Office 1 staff experience regular delays of sometimes up to a couple
>>> of minutes opening files or running an application.
>>>
>>> The link between the switches is 100mbit (as is the rest of the
>>> network except the 10mbit cards in the Novell server).
>>>
>>> There is a second cable running from Office 1 to Office 2 but that has
>>> not been connected and I'm not sure whether it is good practice to
>>> have a parallel run.
>>>
>>> One company has recommended to upgrade the link to a gigabit line but
>>> I find the logic hard to follow since the servers will still have
>>> 100mbit cards.
>>>
>>> Any helpful views welcomed.

>>
>>The question is where the bottleneck lies.
>>
>>Cheap things to check.
>>
>>First, run virus, adware, and spyware scans on _everything_ for which you
>>have a utility available. If you've got malware of some sort broadcasting
>>tons of traffic on your LAN then nothing's going to work right until you
>>fix that.

>Pretty confident that machines are clean but some double checking may
>not go amiss.

>>
>> Ping each computer from each other computer and see if there is unusual
>>latency in either direction. Download a copy of qcheck
>><http://www.ixiacom.com/products/qcheck/>, install it on a Windows box,
>>read the readme, and download the appropriate endpoints from the link in
>>the readme, then see what speed you're really getting between machines and
>>if you're getting the same speed both ways--if you're not then find out
>>why--most common cause would be a configuration error--either speed or a
>>duplex mismatch.

>This looks very interesting. I'll give it a go.

>>
>>Windows server includes a tool called "network monitor". Go into the
>>Windows Server help and search on that and install it on your servers and
>>then watch the traffic going to and from them and see if you're seeing
>>anything coming in or going out that doesn't get a response. The free
>>version only monitors traffic to and from the server on which it is
>>installed, which is a significant limitation, but it's still a useful tool.

>Well only two servers so not too much of a problem.

>>
>>There's a tool called "Ethereal" <http://www.ethereal.com/> which is a
>>general-purpose network analyzer similar in purpose to "network
>>monitor"--ethereal is a free download--install it on one of your machines
>>that is experiencing the slowdown and watch the traffic and see if it's
>>sending anything for which it is not getting a response or receiving
>>anything to which it should be responding and isn't.
>>
>>With those tools and some time you should be able to identify most network
>>problems--the trouble is that they're complex tools and it takes time to
>>learn to use them--there's a book, "Ethereal Packet Sniffing"
>><http://www.amazon.com/exec/obidos/tg/detail/-/1932266828/qid=1113915990/sr=8-1/ref=pd_csp_1/104-1548119-3742340?v=glance&s=books&n=507846>
>>which may help. While you're about it, if you haven't already read them
>>try "Ethernet the Definitive Guide" by Charles Spurgeon
>><http://www.amazon.com/exec/obidos/tg/detail/-/1565926609/qid=1113916220/sr=1-1/ref=sr_1_1/104-1548119-3742340?v=glance&s=books>
>>and "TCP/IP Illustrated"
>><http://www.amazon.com/exec/obidos/tg/detail/-/0201633469/qid=1113916303/sr=1-1/ref=sr_1_1/104-1548119-3742340?v=glance&s=books>.

>
>Many thanks - I will leave this till later. I recall it being a bigger
>subject than I wanted to get into on another issue last year.

>>
>>If you don't already have managed switches (and if you did and knew how to
>>use them you'd already know whether the link between them was the
>>problem--they'll tell you statistics on it) you might want to consider
>>picking up a couple of them off of ebay--Catalyst 2924s go for under $200
>>and sometimes under $100. I see Procurve 4000s, which for your use are
>>serious overkill but a bit noisy, for about the same.
>>

>It didn't at the time seem a complex enough network to require managed
>switches. I have a spare 2900 XL that I could hook up.
>
>
>--
>AnthonyL

>>On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
>>

>
>Please make your responses more readable.
>

>On 20 Apr 2005 08:42:25 -0400, adykes@panix.com (Al Dykes) wrote:
>

>>>On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
>>>

>>
>>Please make your responses more readable.
>>

>
>Never had that complaint before. Is it because you replied to my
>reply to J. Clarke and not my reply to you which I thought was
>reasonably sensibly snipped in the context of your comments? :)
>
>
>--
>AnthonyL