flap-link error

[hsalama_us]

i get an error "flap-link" while connecting linksys srw2024 to catalyst 3750 using LC/LC single mode fiber patch

anybody could help?

[Georg Pauwen]

Hello,

which GBICs are you using on your Linksys (according to the 2024 User Guide, 'you must use the Linksys MGBT1, MGBSX1, or MGBLH1 mini-GBIC modules with the Linksys Gigabit Switches').

The SFP modules on the 3750 require a minimum IOS version as well, check this link:

Table 1 Catalyst 3750, 3560, and 2970 Supported Hardware

http://www.cisco.com/en/US/products/hw/switches/ps5023/prod_release_note09186a008041a334.html#wp743715

Also, make sure that you have not installed the SFPs upside down in your 3750...

Just in case, here is the link to the 2024 User Guide:

SRW2024 User Guide

ftp://ftp.linksys.com/pdf/SRW2016_SRW2024_ug_rev_C_web.pdf

HTH,

GP

[hsalama_us]

LinkSYS using MGBLH1 mini-GBIC, Catalyst 3750 using LX/LH SFP , single mode fiber link is used in between.

the major is that: this configuration worked on link lengthes [ 200,400,800 m ] . but it didn't worked on

900 m

but what do u mean by upside down?

later i will send IOS version used in 3750

[Georg Pauwen]

Hello,

while the maximum cable distance for the LX/LH SFP is 10000 meters, the maximum for the LH1 with single mode fiber is only 550 meters, that might be the problem...

Check the links below for the cabling distances:

LINKSYS MGBLH1 - GBIC SFP 1000MBPS SM FIBER LH

http://www.electronicsoutfitter.com/store/MGBLH1.html

Cisco Small Form-Factor Pluggable Gigabit Interface Converter

http://www.cisco.com/en/US/products/hw/modules/ps5000/products_data_sheet09186a008014cb62.html

Forget about the upside down, I just remember somebody plugging the SFP on the Cisco upside down, but then it did not work at all...

Regards,

GP

[hsalama_us]

as MGBLH1 had connect at 800m, i think it is a documentation error at linksys.

cisco 3750 IOS version from sh version command is :

"IOS (tm) C3750 Software (C3750-I9-M), Version 12.1(19)EA1d, RELEASE SOFTWARE"

could that be the problem ? as the release notes you had just pointed to tell to use "Cisco IOS Release 12.2(18)SE "

[Georg Pauwen]

Hello,

the 550 meter Linksys limit is (as are all other recommended documented limits) a conservative limit, that is, the limit where the manufacturer guarantees operational functionality. That doesn´t mean that it will not work with 600 or 700 meters, or even 800, it is just that the manufacturer does not guarantee it. 900 meters might then be over that physical limit...

Regards,

GP

[hsalama_us]

i used cisco SFP instead of Linksys MiniGBIC, and the link is working now

Linksys had made a recommandation to try that setup

[Georg Pauwen]

Hello,

good to know that this is working now. I guess that renders the Linksys documentation irrelevant, but then again, Linksys is Cisco now, so the Cisco SFPs work just as well, or even better than the Linksys SFPs, whereas before, when Linksys was not Cisco, the Cisco SFPs were not supposed to work. That is called marketing I assume...:)

GP