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Anonymous
Posts: 0

# connecting two DS-4900 through a CWDM

We have 2 data centers that are connected across a device which I am uncertain of the make or model because that is not my area. I have an inquiry as to the make and model but I believe it's a Fujitsu device. I'll post an update once I get more info on that. Each data center has a DS-4900 that is ISLed to the other DS-4900 at the opposite site. Besides all of the SAN disks (a CX3-80 and a CX4-240), we have STK SL500 with 4 LTO4 drives each at each site that are controlled by an AIX server that lives at one site but sees both DL500 libraries as local. We use TSM to copy all of the backup data generated each day to the remote SL500 by doing tape to tape and also disk to tape. The fastest speeds I have even seen going from disk at one site to one of the LTO4 drives at the remote site is 9MB/s. This seems excessively slow since the connection across the CWDM is supposed to be a 2G connection. This has been going on since we set this up years ago. I have asked the owner of the Fujitsu CWDM device to look at it several times and been told that there really isn't anything to tune or adjust which I find hard to  believe.

What I need to know is what can I do to look into this? The gbics show as connected at 2GB but outside of the DS-4900, I really don't have access to look at anything but would gladly pass any suggestions onto our CWDM guy. I do understand that tape to tape will never be very fast because the tape drive has to stop/start all the time but disk to tape should be faster than 9M/sec, at least I hope it can be.

Does anyone have any suggestions on were to start? This has been a big pain for years now but only now is it really starting to cause much bigger problems.

As soon as I get more details about the CWDM device, I'll post it here.

Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

Hi !

Getting more information on the cwdm mux-demux would really help.

If it is a passive one, then the distance between switches must be correctly managed by the switches themselves (Extended fabric option if d>10km)

You can check that by looking for the sfp category on the switches (cwdm or classical swl). If of cwdm category, mux is a passive one.

Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

The gbics that we used to connect them are listed as "4GB 10KM LW SFP OPTIC BRCD".

The response I got from our fiber guys is:

The wdm is a fujitsu 7120. There are fiber connections between the 7120s. Actually there are 4 7120s which are all interconnected between Site 1,Site 2,Site 3 and Site4.  They are connected as an OC 198 fiber ring.   There are also fiber connections to your switches.  Basically it is a passive optical device.  The part that I am not sure about and would have to check is the interface to the fiber to your equipment and if it is configurable.  Could be bad fiber between your switches and the wdms at either Site 1 or Site 2.

Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

Here is the portcfgshow if it helps. Port 31 is the port connecting the two DS-4900s.

 Ports of Slot 0 0  1  2  3 4  5  6  7 8  9 10 11   12 13 14 15

-----------------+--+--+--+--+----+--+--+--+----+--+--+--+----+--+--+--

 Speed AN AN 4G AN   AN AN AN AN   AN AN AN AN   AN AN AN AN Fill Word 0  0  0  0 0  0  0  0 0  0  0  0 0  0  0  0

AL_PA Offset 13   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 Trunk Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON Long Distance .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. VC Link Init .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked L_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked G_Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

Disabled E_Port   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 ISL R_RDY Mode .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

RSCN Suppressed   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Persistent Disable.. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

NPIV capability   ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

 QOS E_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Mirror Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Fport Buffers .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Port Auto Disable .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Ports of Slot 0   16 17 18 19   20 21 22 23   24 25 26 27   28 29 30 31

-----------------+--+--+--+--+----+--+--+--+----+--+--+--+----+--+--+--

 Speed 4G 4G 2G 4G   AN AN AN AN   AN 4G AN AN   AN AN 2G 2G Fill Word 0  0  0  0 0  0  0  0 0  0  0  0 0  0  0  0

AL_PA Offset 13   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 Trunk Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON Long Distance .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. LE .. VC Link Init .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. ON .. Locked L_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked G_Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

Disabled E_Port   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 ISL R_RDY Mode .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

RSCN Suppressed   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Persistent Disable.. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

NPIV capability   ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

 QOS E_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Mirror Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Fport Buffers .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Port Auto Disable .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Ports of Slot 0   32 33 34 35   36 37 38 39   40 41 42 43   44 45 46 47

-----------------+--+--+--+--+----+--+--+--+----+--+--+--+----+--+--+--

 Speed AN AN AN AN   AN AN 2G AN   4G AN AN AN   AN AN AN AN Fill Word 0  0  0  0 0  0  0  0 0  0  0  0 0  0  0  0

AL_PA Offset 13   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 Trunk Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON Long Distance .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. VC Link Init .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked L_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked G_Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

Disabled E_Port   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 ISL R_RDY Mode .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

RSCN Suppressed   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Persistent Disable.. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

NPIV capability   ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

 QOS E_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Mirror Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Fport Buffers .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Port Auto Disable .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Ports of Slot 0   48 49 50 51   52 53 54 55   56 57 58 59   60 61 62 63

-----------------+--+--+--+--+----+--+--+--+----+--+--+--+----+--+--+--

 Speed AN AN AN AN   AN AN AN AN   AN AN AN AN   AN AN AN AN Fill Word 0  0  0  0 0  0  0  0 0  0  0  0 0  0  0  0

AL_PA Offset 13   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 Trunk Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON Long Distance .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. VC Link Init .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked L_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Locked G_Port ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

Disabled E_Port   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 ISL R_RDY Mode .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

RSCN Suppressed   .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Persistent Disable.. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

NPIV capability   ON ON ON ON   ON ON ON ON   ON ON ON ON   ON ON ON ON

 QOS E_Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Mirror Port .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. .. Fport Buffers .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

Port Auto Disable .. .. .. ..   .. .. .. ..   .. .. .. ..   .. .. .. ..

 where AE:QoSAutoEnable, AN:AutoNegotiate, ..:OFF, NA:NotApplicable, ??:INVALID,
Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

Two concerns :

* you wrote that port 31 was used to make interconnect, but it is port 30 which is set for long distance (LE) as shown by portcfgshow.

What is the distance between the two DS4900 ?

* using lwl sfp with passive mode wdm should not work. Fujitsu 7120 is more likely connected to your switch in active mode. Can you check that (sfp models on both sides, sw4900 and entry port on mux7120) ?

If true, then a possible cause for trouble could be that lwl sfp are used with multimode patch cords.

Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

It is definitely port 31. I believe the distance between the 2 DS-4900s that are connected through the Fujitsu is about 25 miles. I will look into why it is not set for long distance mode and pass the rest of your inquiries onto the correct people. This is definitely out my area. Thanks for your help!

Highlighted
Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

25 miles require use of Extended Fabric option & choice of LD or LS when configuring ports with portcfglongdistance.

That is a sufficient reason to explain the poor performances you get, as you stated in the initial post.

Anonymous
Posts: 0

## Re: connecting two DS-4900 through a CWDM

Thanks for all your help. I will pass all of this onto the powers that be.

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