Cisco Switch and Fiber problem

[cmptrnerd]

We are trying to move from a 3 com switch with 10mb fiber to a cisco switch and 1000 mb fiber.

The current fiber is 2-strand 62.5/125 µm multimode fiber-optic with SC connector. We purchased a Cisco 2960 switch with a GLC-SX-MM 1000base-SX module and on the other side we have a Allied Telesyn switch with a Gigabyte module. Since the Cisco module has a lc connector we were told to purchase a FIBER LC/SC DUPLEX with a FIBER SC COUPLER to make the cable work. However when we connect the two switches the allied telesyn gets a link light and nothing on the cisco switch. Anybody have an idea on how to troubleshoot the problem?


Mark

 

[daytonajames]

Post your config on the Cisco switch please

 

[cmptrnerd]

Here is the switch config

hostname habmain
!
enable secret 5 $1$s7Eh$70w7YrqvmZRJlWbMk41ok0
enable password tommy901
!
no aaa new-model
ip subnet-zero
!
!
!
!
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
interface FastEthernet0/1
!
interface FastEthernet0/2
!
interface FastEthernet0/3
!
interface FastEthernet0/4
!
interface FastEthernet0/5
!
interface FastEthernet0/6
!
interface FastEthernet0/7
!
interface FastEthernet0/8
!
interface FastEthernet0/9
!
interface FastEthernet0/10
!
interface FastEthernet0/11
!
interface FastEthernet0/12
!
interface FastEthernet0/13
!
interface FastEthernet0/14
!
interface FastEthernet0/15
!
interface FastEthernet0/16
!
interface FastEthernet0/17
!
interface FastEthernet0/18
!
interface FastEthernet0/19
!
interface FastEthernet0/20
!
interface FastEthernet0/21
!
interface FastEthernet0/22
!
interface FastEthernet0/23
!
interface FastEthernet0/24
!
interface FastEthernet0/25
!
interface FastEthernet0/26
!
interface FastEthernet0/27
!
interface FastEthernet0/28
!
interface FastEthernet0/29
!
interface FastEthernet0/30
!
interface FastEthernet0/31
!
interface FastEthernet0/32
!
interface FastEthernet0/33
!
interface FastEthernet0/34
!
interface FastEthernet0/35
!
interface FastEthernet0/36
!
interface FastEthernet0/37
!
interface FastEthernet0/38
!
interface FastEthernet0/39
!
interface FastEthernet0/40
!
interface FastEthernet0/41
!
interface FastEthernet0/42
!
interface FastEthernet0/43
!
interface FastEthernet0/44
!
interface FastEthernet0/45
!
interface FastEthernet0/46
!
interface FastEthernet0/47
!
interface FastEthernet0/48
!
interface GigabitEthernet0/1
!
interface GigabitEthernet0/2
!
interface Vlan1
ip address 192.168.51.18 255.255.255.0
no ip route-cache
!
ip http server
!
control-plane
!
!
line con 0
exec-timeout 0 0
line vty 0 4
password tommy901
no login
line vty 5 15
password tommy901
no login
!
!
end


Mark

 

[cajuntank]

Unless your interface is in a shutdown state, I don't think it has anything to do with Cisco switch itself. I would play swap around and see if the problem follows the appliance or stays at the cable. Also, if you have access to a fiber tester, then test end to end to see if maybe you have purchased a bad jumper cable or coupler. When it comes to Cisco switches and 1Gb, there is no messing with speed and duplex settings like 10Mb or 100Mb. Lastly, there has to be a transmit and a receive... make sure one sides transmit is going to the other sides receive and vice versa (basically make sure they cross and not straight thru).

 

[robertjo24]

If I am not mistaken, the gig ports on the Cisco are multi rate????

Cisco sometimes has problems syncing with other non-Cisco devices. The claim it is the other device's fault.

If the Gig ports are truly multi rate, try forcing the port to 1000 and full duplex.

I have never used the 2960 switches, but I have had this problem all too often on the 2950 series.

 

[cnyric]

Be sure the Cisco port is set to no negotiate.

 

[rotaman]

Don't know if this will help, but in some cases, whenI play with GLCs, the switch will link, even though the led isn't on. To resolve this, I usually reload the switch, and it fixed the problem. Logically, if there is a link on one side, there should be a link on the other.

 

[robertjo24]

Rotman,

What you say is mostly true when dealing with two Cisco switches back to back. When dealing with a Cisco and another vendor device, logic goes out the window.
It seems Cisco switches, and 2950's in particular, have a habbit od not autop syncing with "other" devices. I called Cisco on this before, and they always say it is the other vendor's equipment at fault.
Funny, everything else syncs with the other vendor's equipment but the Cisco.

Sometimes you have to force speed and duplex to get them to work.

 

[rotaman]

Robertjo24,

it's Rotaman, not rotman

Thanks for the info! I'll keep it in mind when dealing with the products mentions.

It's never Cisco's fault

ciao!