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Degraded service - 1 Direction (Not the band)

Brendan Marmont
Level 1
Level 1

Getting some poor iperf results as shown below. Only in one direction. Doesn't matter what network segment I target in that site.

C:\Temp>iperf.exe -c x.x.64.x -d
Server listening on TCP port 5001
TCP window size: 64.0 KByte (default)
Client connecting to x.x.64.x, TCP port 5001
TCP window size: 64.0 KByte (default)
[172] local x.x.0.x port 52641 connected with x.x.64.x port 5001
[196] local x.x.0.x port 5001 connected with x.x.64.x port 56606
[ ID] Interval       Transfer     Bandwidth
[196]  0.0-10.0 sec  1.08 GBytes   927 Mbits/sec
[172]  0.0-10.1 sec  5.30 MBytes  4.40 Mbits/sec

Trace is clean.

Any thoughts on res?

15 Replies 15

Philip D'Ath
VIP Alumni
VIP Alumni

Duplex mismtach.

Checked end to end, no Duplex mismatch. Tests show affect is only egress to one site. Other remote sites have no issue targeting DC

What are the two devices you are running iperf on?

HP Laptops connected directly into 4507 core. So Laptop - Core - NID --> NID - Core - Laptop Same result from physical and virtual workstations/servers - Adapter drivers up to date, IOS same both ends.

What is a NID?

Here are my thoughts for cracking this problem (divide and conquer):

  1. Plug the two notebooks in point to point and verify testing environment is good.
  2. Plug both notebooks into the first switch device, and verify if performance is correct across this one device.
  3. If the above test is good move one testing notebook into the next switching device in the path.  Repeat until issue happens.

Try and get to the point where you have the minimum amount of active network kit between the two notebooks to cause the problem to happen (you may have to move the first notebook to get to this minimal problem issue).  Then tell me what each of these devices is and how it connects to the next device.

NID - Network Interface Device (That's what our provider calls them) Alcatel 7210 SAS-T I'll divide n conquer... Not allowing me to paste readable format. Uploaded config.txt. Thanks

Any chance you could re-format that last message?  Very hard to read.

An example of same segment test local to affected site

When you say same segment test, what exactly are the two test points?  4500 to affected site?

Local site, server to server, server to workstation. Connected directly to 4507.

This is starting to smell like a WAN issue ...

So we can rule out the 4507 and the connection through to the server.

The performance issue is only happening on the WAN portion of this test now, correct?

It reeks of WAN ** WAN provider has said there is no issue they can see. ** Added diagram ** I have requested WAN side configuration detail, they wont give them up. ** Time to escalate Will ping back resolution for closure Thanks for you time Brendan ** Adding ** to try separate text, formatting has gone weird on me

It just has to be a WAN issue.

A horrible test you could do, which you wont want to do, but will prove it.  Plug sites 'A' and 'B' WAN tails directly into a notebook and run iperf.  This way there is none of your kit in the picture and only the WAN.

If this fails (as expected) it rules out everything except the WAN.  It also means the WAN provider can refute it.  There is nothing else it could be.

UDP to other site has huge packet failure C:\Iperf>iperf -c x.x.8.101 -u -d -b 500m ------------------------------------------------------------ Server listening on UDP port 5001 Receiving 1470 byte datagrams UDP buffer size: 64.0 KByte (default) ------------------------------------------------------------ ------------------------------------------------------------ Client connecting to x.x.8.101, UDP port 5001 Sending 1470 byte datagrams UDP buffer size: 64.0 KByte (default) ------------------------------------------------------------ [208] local x.x.5.130 port 55328 connected with x.x.8.101 port 5001 [196] local x.x.5.130 port 5001 connected with x.x.8.101 port 65113 [ ID] Interval Transfer Bandwidth [208] 0.0-10.0 sec 580 MBytes 487 Mbits/sec [196] 0.0-10.0 sec 446 MBytes 374 Mbits/sec 1.024 ms 111146/429360 (26%) [196] 0.0-10.0 sec 13 datagrams received out-of-order [208] Server Report: [208] 0.0-10.0 sec 160 MBytes 134 Mbits/sec 1.938 ms 299983/413785 (72%) [208] Sent 413785 datagrams