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15454-10DME-C FiberChannel Performace Down

Unanswered Question
Jul 22nd, 2008
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dear all,


We have ONS15454SDH located on 4 sites (ring configuration) with 2 site as ROADM 32Ch and 2 site as OADM.


SiteB

// \\

siteA SiteC

\\ //

SiteD


Using Muxponder card 15454-10DME-C, we create 6 circuits between siteA and SiteC consist of 4 circuits GigaEthernet and 2 circuits FiberChannel 2Gbps.


Right now the traffic from storage servers using FC are facing problem where the server only get 54 MBps.

the throughput for GigaEthernet circuits are okay, all within the same muxponder card.


anybody experience the same problem for FC circuit? any solution for this case.


Device is 15454E-SA-ETSI with software version 07.00-005L-19.20



Thanks & Regards,

rano

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Overall Rating: 3.5 (2 ratings)
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Tom Randstrom Wed, 07/23/2008 - 10:16
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Is it possible that the buffer-to-buffer distance extension mechanism is turned off on the cards? Depending on the distance, this would limit the throughput on the FC circuits.

ranokarno82 Thu, 07/24/2008 - 00:02
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hmm, could you tell me how to turn on/off the buffer on the card.

the ONS 15454SDH using Muxponder card MXP_MR_10DME_C.


thanks

Rano

ranokarno82 Sun, 07/27/2008 - 18:02
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Hi Bailey,


the buffer-to-buffer distance extension is default TURN-ON. when i check the device it's also still ON (checked).

one more issue, our client are using storage tape drive from SiteA to SiteC which take about +/- 60Km distance between two sites. is there any related issue with configuration buffer credit with SAN Switch with ONS devices or storage devices.


tape_backup<==>SAN-Swich(MDS)<==>ONS-ONS-ONS<==>SAN-Switch(MDS)<==>tape-backup


thanks,

Rano

viyuan700 Mon, 07/28/2008 - 10:31
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Don't have much idea about SAN switch and if u have already checked things on SAN side.


Can you check few things on ONS side if u have not.


MXP_MR_10 DME_C multiplex several client signal on 10G trunk port of ONS card. Is ur card provisioned properly ?


You can also check performance parameters of ONS card?

ranokarno82 Mon, 07/28/2008 - 15:35
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HI viyuan


i think i didn't have any wrong configuration with MXP_MR_10DME configuration as you know i have 4 circuit GigaEthernet running well within the same card.

i've already check the performance, and it utilize only below 20% from 2G FC.


thanks anyway, let me check more about the configuration.


Regards,

Rano

viyuan700 Mon, 07/28/2008 - 18:56
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U r right that 4 GE circuit are working. U crossconnect in ONS for each GE/FC port.


its silly but sometimes happen that on FC port by mistake you have crossconnected less bandwidth in ONS box. e.g you want to take FC over 3 STS-1 but u configured only 1 STS-1.

leon_funnell Wed, 11/26/2008 - 07:11
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This is from a TAC we had with a similar issue -

It is pretty obvious the customer is hitting the bug CSCsd80123.


If the DE (Distance Extension) feature for the MXP_MR_10DME is turned on, truncated frames can be seen for 4G ISLs between Cisco MDS9500.

This can be seen with both E_Ports and TE_Port extension.

The MDS9020s (Cisco rebranded Qlogic 4G FC switch) and Brocade do no have any issues.

Also, 2G and 1G ISLs do not have any issues.

The reason is that mxp-mr-10dme in DE mode doesn't support BBSCN/BSCRs .

By defualt the MDS 9506 has it enabled.

This cause wrong credit updates since the RRDY's are generated by the mxp-mr-10dme while the BBSCNs are by the switches(In 4G-DE mode mxp-mr-10dme passed those primitives transparently).


Data corruption seen on MDS9500 4G ISLs with DE turned on

Symptom: MXP_MR_10DME in 4G with DE (Distance Extension) turned on corrupts frames generated by Cisco MDS9506. MXP_MR_10DME does not support the Credit Recovery Mechanism (BBSCN/BSCRs), and Cisco MDS9500 has BBSCN/BSCRs turned on by default.


This can be seen with both E_Ports and TE_Port extension.


Conditions: Interoperability between Cisco MDS9500 and MXP_MR_10DME at 4G-FC DE Turn On MDS 9500 enables by default BBSCN/BSCRs.


Workaround: Disable BB_SC's for the switchport interface on the 4G MDS ISL via the following:


switch(config)# int fc2/1

switch(config-if)#

no switchport fcbbscn


Expected Resolution: This issue will not be resolved.


Reproducibility (%): 100%


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