Slow network

[Raj_112345]

Hi,

If a network is slow then how to find the root cause and resolve it ?

Thanks,
Raj

[Jeeshan]

Hi Raj,

Check your HP-UX server NIC statistics:

# netstat -s

Run lanadmin as well to check your LAN card health.

# lanadmin

Perhaps you can show us the output for both commands with respect to the NIC interface in question.

If it only occurs with either upstream or downstream (but not both), it is likely that your NIC card or switch port has not been hardcoded to full-duplex.

Remember to disable auto-negotiation.

[Dennis Handly]

>ahsan: it is likely that your NIC card or switch port has not been hardcoded to full-duplex. Remember to disable auto-negotiation.

If there is a conflict, you'll have problems but I think Rick Jones wouldn't agree with this solution.

[Torsten.]

>> "Remember to disable auto-negotiation"


Maybe this was a good advise in former times with up to 100MB/s NICs, but nowadays it isn't. Auto-neg should be your preferred setting.

[Yogeeraj_1]

hi Raj,

this question is too broad that we cannot recommend you something more concrete.

Normally, the most critical aspects of a network that contribute to performance are latency and bandwidth.

The first step in solving network problem is to understand the overall topology. Gather as much information about the network that you can. This kind of information usually manifests itself as a network diagram. Your diagram should contain the types of network technology used in the LAN and the WAN. It should also contain addresses of the various segments.

My checklist contains the following:
. get a network sniffer trace
. check the following:
- is the bandwidth being exceeded on the network, the client, or the server
- Ethernet collisions
- Are there manay runt frames?
- The stability of WAN links
. get a bandwidth utilisation chart
. is any quality of service or packet prioritizing going on?
. is a firewall in the way somewhere?


Hope this helps!

kind regards
yogeeraj

[Yogeeraj_1 · Accepted solution]

hi again,

Also note that, high latency on a network slows the transaction down due to the same interval between sending a request and getting the response.

It is quite easy to dissect the network problem.

You can use trace route (tracert) from the client to the server to get address information for each device in the path.
E.g.
C:\Documents and Settings\yogeeraj>tracert srv2

Tracing route to srv2.mydom.mu [192.168.160.12]
over a maximum of 30 hops:

1 1 ms 1 ms 1 ms 192.168.150.1
2 7 ms 11 ms 11 ms 192.168.90.1
3 22 ms 8 ms 26 ms srv2.mydom.mu [192.168.160.12]

Trace complete.

C:\Documents and Settings\yogeeraj>


Ping each device to get the timings. Use large packets to get the slowest times. Make sure you set the "don't fragment bit" so that routers do not spend time disassembling and reassembling the packet. Also note that the packet size is 1472 (Ethernet). Evaluate the area where the slowness seems to occur. E.g.
ping -l 1472 -n 1 -f 192.168.150.1
ping -l 1472 -n 1 -f 192.168.150.1
ping -l 1472 -n 1 -f 192.168.90.1
ping -l 1472 -n 1 -f 192.168.160.12


Nb. The previous example validates trace route. Ideally, you would ping from your pC to 192.168.150.1, from 192.168.150.1 to 192.168.90.1, then from 192.168.90.1 to 192.168.160.12. This would show the exact latency on each segment travelled.



hope this helps too!
kind regards
yogeeraj

[Safarali]

Hi Raj

first check it is the problem of your local network or unix network

try to save your any one of internet explorer page to your desk top if it is taking time the problem is from your local network
if it is OK then try from your server to another server or telnet 0 etc.
if it is slow there then you can go further debug like your ndd setting traceroute command etc.
try to traceroute from unix to window then you can see where it is causing problem

Regards
Safar