| Author |
Message |
AnthonyL
Guest
|
 Posted:
Tue Apr 19, 2005 4:20 pm Post subject:
Switch to switch causing traffic problems? |
|
|
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.
--
AnthonyL |
|
| Back to top |
|
 |
Al Dykes
Guest
|
| Posted:
Tue Apr 19, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <4264ebf8.8141787@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
| Quote: | 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.
--
AnthonyL
|
Did the switches cost less than $99 ?
Do they run the latest software ?
Is this a windows ActiveDirectry system ? If so, I think you have the
wrong DNS entry in the PC that see long delays.
You use the word "switch" and I suspect they are really routers. Are
they all on the same subnet ?
I imagine there could be other DNS/WINS problems.
Does office 1 access the NW server ?
I've seen problems when inexpensive equipment intended for
cookie-cutter configurations get used in ways that are not shown in
the manufacturer's glossy literature, as you are.
I've been burned connecting a cheapo switch to a Big Name switch
(Cisco in my case) and the Most Senior network engineer I know has
taught me that doing switch-to-switch connections on the cheap is a
No-No. He insists the the cheap end be a hub. FWIW.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
|
| Back to top |
|
|
Al Dykes
Guest
|
| Posted:
Tue Apr 19, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <d4323v0163g@news1.newsguy.com>,
J. Clarke <jclarke.usenet@snet.net.invalid> wrote:
| Quote: | 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. 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.
| Quote: | 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.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
|
| Back to top |
|
|
J. Clarke
Guest
|
| Posted:
Tue Apr 19, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
AnthonyL wrote:
| Quote: | 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.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net) |
|
| Back to top |
|
|
J. Clarke
Guest
|
| Posted:
Tue Apr 19, 2005 8:01 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
Al Dykes wrote:
| Quote: | In article <d4323v0163g@news1.newsguy.com>,
J. Clarke <jclarke.usenet@snet.net.invalid> wrote:
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 he's trying to monitor traffic on the entire network this is true.
However if he has a specific machine that is having problems then
monitoring traffic to and from that specific machine, which can be done by
putting the monitoring software on that machine, can sometimes tell a great
deal about its specific problem.
| Quote: | 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
| Quote: | 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 the problem is internal to the machine. If it's sitting waiting for a
response that never comes perfmon may tell you that it's waiting but it
won't necessarily tell you what it's waiting _for_.
| Quote: | 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.
|
Possibly. Or possibly something specific to Windows.
| Quote: | 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.
|
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net) |
|
| Back to top |
|
|
AnthonyL
Guest
|
| Posted:
Wed Apr 20, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
<jclarke.usenet@snet.net.invalid> wrote:
| Quote: | 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.
| Quote: |
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.
| Quote: |
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 |
|
| Back to top |
|
|
AnthonyL
Guest
|
| Posted:
Wed Apr 20, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
On 19 Apr 2005 08:03:30 -0400, adykes@panix.com (Al Dykes) wrote:
| Quote: | In article <4264ebf8.8141787@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
The arrangement is
Office 1 - approx 12 PC's
Switch 1 - router- internet
24 PORT 10/100MBPS Unmanaged switches |
PLANET SWITCH FNSW2400S
| Quote: | |
~ 50 metres
|
Switch 2
|
2 x 24 PORT 10/100MBPS Unmanaged switches
Allied Telesyn AT-FS724I-30
| Quote: | Office 2 - approx 30 PC's plus
2 x Windows servers + 1 Novell 3.12 server (IPX)
All Cat5e structured cabling.
Did the switches cost less than $99 ?
|
24 PORT 10/100MBPS Unmanaged switches
PLANET SWITCH FNSW2400S
Allied Telesyn AT-FS724I-30
| Quote: |
Do they run the latest software ?
|
AFAIK there are no updates available
| Quote: |
Is this a windows ActiveDirectry system ?
Yes
If so, I think you have the
wrong DNS entry in the PC that see long delays.
Entries appear correct
You use the word "switch" and I suspect they are really routers. Are
they all on the same subnet ?
I think they are called switches. All on same subnet.
I imagine there could be other DNS/WINS problems.
Does office 1 access the NW server ?
Yes and in fact only office 1 accesses the NW server. No problems |
with this.
| Quote: |
I've seen problems when inexpensive equipment intended for
cookie-cutter configurations get used in ways that are not shown in
the manufacturer's glossy literature, as you are.
I don't understand I'm afraid what I am doing so wrong. Are you |
saying switch to switch is the wrong way to bridge the offices?
| Quote: |
I've been burned connecting a cheapo switch to a Big Name switch
(Cisco in my case) and the Most Senior network engineer I know has
taught me that doing switch-to-switch connections on the cheap is a
No-No. He insists the the cheap end be a hub. FWIW.
|
So I should replace the Planet switch with a hub?
--
AnthonyL |
|
| Back to top |
|
|
J. Clarke
Guest
|
| Posted:
Wed Apr 20, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
AnthonyL wrote:
| Quote: | On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
jclarke.usenet@snet.net.invalid> wrote:
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.
|
I think you'll find it very helpful, both because it can collect statistics
on port traffic and because it will let you set up a monitoring port that
lets you see all network traffic that goes through that switch.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net) |
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Robert Redelmeier
Guest
|
| Posted:
Wed Apr 20, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
AnthonyL <nospam@please.invalid> wrote:
| Quote: | Office 1 staff experience regular delays of sometimes up to
a couple of minutes opening files or running an application.
|
Ouch! This sounds like a config (DNS/WINS) problem.
I hope you're not running NETBIOS.
One longshot -- you mentioned "structured cabling". Are you
sure it's good? Proper Cat5e jacks and factory patchcords?
All field/home-crimped plugs are suspect. Splitting a pair
is too easy. High data errors in one direction usually result.
-- Robert in Houston |
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Al Dykes
Guest
|
| Posted:
Wed Apr 20, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <42663bed.10009162@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
| Quote: | On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
jclarke.usenet@snet.net.invalid> wrote:
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
|
Replacing the noname switch with a hub is easy if you have one on
hand, and they are _really_ cheap on ebay. I can't see a 10/100 hub
being a serious bottleneck for the small site. It gives you a place
to plug a PC running etherreal. This is a long shot.
Do you have Activedirectory on your windows servers?
ActiveDirectory makes very specific requirement for DNS services and
the symptoms if you don't comply include long time delays. The easy
way for a small site to comply is to make one of your windows servers
your DNS server and point all the other machines at it.
I keep coming back to DNS/WINS problems. If you are not AD then who
are you using for DNS ? Putting a name/ipaddress entry for all your
servers in /etc/hosts on all your machines is one low-rent way to
fixthings for a small network. If that improves things then you need
to set up a real dns server and put things right.
Is the symptom in office1 reproducable on a specific PC ? If it is
then carry the PC to office2, plug it in and see if the problem
remains. If it/s on all machines or random, that tells you something
but I don;t know offhave what it is.
If you unplug your ISP connection do the symptoms change ?
Please make your responses more readable.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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AnthonyL
Guest
|
| Posted:
Thu Apr 21, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
On Wed, 20 Apr 2005 15:08:41 GMT, Robert Redelmeier
<redelm@ev1.net.invalid> wrote:
| Quote: | AnthonyL <nospam@please.invalid> wrote:
Office 1 staff experience regular delays of sometimes up to
a couple of minutes opening files or running an application.
Ouch! This sounds like a config (DNS/WINS) problem.
I hope you're not running NETBIOS.
|
The machines are running Novell's Client32 which has Netbios for
IPX/SPX. There is no Netbios in use against TCP/IP .
| Quote: | One longshot -- you mentioned "structured cabling". Are you
sure it's good? Proper Cat5e jacks and factory patchcords?
All field/home-crimped plugs are suspect. Splitting a pair
is too easy. High data errors in one direction usually result.
|
I was sure. Reputable and long standing specialist cabling company
{not the local electrician :) }. I believe they supplied their own
patch cords pre-made. No hardship to swap a few around though.
--
AnthonyL |
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Al Dykes
Guest
|
| Posted:
Thu Apr 21, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <4267a9de.103675167@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
| Quote: | On Wed, 20 Apr 2005 15:08:41 GMT, Robert Redelmeier
redelm@ev1.net.invalid> wrote:
AnthonyL <nospam@please.invalid> wrote:
Office 1 staff experience regular delays of sometimes up to
a couple of minutes opening files or running an application.
Ouch! This sounds like a config (DNS/WINS) problem.
I hope you're not running NETBIOS.
The machines are running Novell's Client32 which has Netbios for
IPX/SPX. There is no Netbios in use against TCP/IP .
One longshot -- you mentioned "structured cabling". Are you
sure it's good? Proper Cat5e jacks and factory patchcords?
All field/home-crimped plugs are suspect. Splitting a pair
is too easy. High data errors in one direction usually result.
I was sure. Reputable and long standing specialist cabling company
{not the local electrician :) }. I believe they supplied their own
patch cords pre-made. No hardship to swap a few around though.
--
AnthonyL
|
Do a netstat -e on all your boxes. If the error counters are zero or
single digits you don't have a cable problem. If they are higher you
may have a cable problem or something else but you'll have narrowed
down the problem.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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| Back to top |
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Robert Redelmeier
Guest
|
| Posted:
Thu Apr 21, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
AnthonyL <nospam@please.invalid> wrote:
| Quote: | The machines are running Novell's Client32 which has Netbios
for IPX/SPX.
|
Aren't those at least partially broadcast protocols? I'm not
very familiar with them, but it sounds like there maybe a
response issue (not fast enough). Can you tune any parameters?
| Quote: | There is no Netbios in use against TCP/IP .
|
Well, there is both kinds of traffic on the network.
Browsers re pure TCP/IP and so [usually] is email.
| Quote: | I was sure. Reputable and long standing specialist cabling
company {not the local electrician :) }. I believe they
|
Good.
-- Robert |
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Al Dykes
Guest
|
| Posted:
Thu Apr 21, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <uPO9e.909$yd7.440@newssvr11.news.prodigy.com>,
Robert Redelmeier <redelm@ev1.net.invalid> wrote:
| Quote: | AnthonyL <nospam@please.invalid> wrote:
The machines are running Novell's Client32 which has Netbios
for IPX/SPX.
Aren't those at least partially broadcast protocols? I'm not
very familiar with them, but it sounds like there maybe a
response issue (not fast enough). Can you tune any parameters?
There is no Netbios in use against TCP/IP .
Well, there is both kinds of traffic on the network.
Browsers re pure TCP/IP and so [usually] is email.
I was sure. Reputable and long standing specialist cabling
company {not the local electrician :) }. I believe they
Good.
-- Robert
|
IMO the back-to-back noname switches may be a problem with the IPX
broadcasts. This can be proved by moving a problametic PC to site2
and hooking ot up to the local LAN. I
The OP has not described what tests and results he has. I'd expect
that by now he's ruled out physical cable problems and sypware. If
not then I suspect he's not troubleshooting methodically.
As for traffic analysis, I expect he's either got too much (saturating
a respurce) or zero traffic flowing between a problametic PC and a
server. I vote for the latter in which case he may have a
multiprotocol stack binding proble, or DNS or WINS. None of which I
am really good at troubleshooting.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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| Back to top |
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Al Dykes
Guest
|
| Posted:
Thu Apr 21, 2005 4:20 pm Post subject:
Re: Switch to switch causing traffic problems? |
|
|
In article <4267a953.103536006@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
| Quote: | On 20 Apr 2005 08:42:25 -0400, adykes@panix.com (Al Dykes) wrote:
In article <42663bed.10009162@news.zen.co.uk>,
AnthonyL <nospam@please.invalid> wrote:
On Tue, 19 Apr 2005 08:19:29 -0400, "J. Clarke"
jclarke.usenet@snet.net.invalid> wrote:
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
|
No whitespace to make the inline responses visible.
--
a d y k e s @ p a n i x . c o m
Don't blame me. I voted for Gore. |
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