Re: Help with connection to fiber optic!

asemyc2013 · ‎02-15-2014

Hi all, I need replace the old configuration for the new configuration (see attached photos). The old configuration works perfect but when I put the new I haven't internet connection, Light indicators interfaces indicate that traffic is OK and all is working good(green lights blinking):

Question : Need the Cisco 2960S-24TS-L any special configuration to handle the traffic of the optical fiber to the LAN?

Please someone can help me with this.

Regards,

Asem.

Ankur Arora · ‎02-15-2014

Hi,

The 2960 doesnot need any special config to handle the traffic of the optical fiber.

Can you give us the output of:

show int gig x/y

show run int gig x/y (where x/y is ther interface which goes to the SFP)

show log

Thanks

Ankur

Marvin Rhoads · ‎02-15-2014

Asem,

The transceiver you are using is compatible with your switch. Assuming you have a good connection (not too much light loss and transmit/receive fiber not reversed) and a basic configuration on the switch port (switchport mode access, switchport access vlan _, no shutdown)

Your diagram shows the SFP in port 28 but the photograph shows it in port 27. Assuming the photograph is correct, make sure you have port Gi1/27 configured as I noted.

Also please provide (in addition to what Ankur suggested) the output of "show int gi1/27 transceiver detail"

asemyc2013 · ‎02-15-2014

Thank you very much, I appreciate your help.

The problem is in Cisco SW and sfp, when I change the cables to old SW(Edge-core, look at the photo above the cisco) everything working perfect,

In the Cisco SW the sfp port used is 28, I attached detail.

I don't know what have the ISP in the other part of the fiber, we call them and they say there is no special settings in the SW Edge-Core and they said nothing more, they don't know who installed our connection, amazing, no papers or anything documented about the work.

Thanks again,

Asem.

Marvin Rhoads · ‎02-15-2014

So interface gi1/0/28 is up/up and running at 1 Gbps. We can see some input and output packets. So physical layer looks good and Layer 2 (MAC) looks good.

The ports don't really have any configuration on them so the Cisco switch is acting as a "dumb" layer 2 switch with a single default VLAN 1.

How is your router setup as far as a gateway? i.e. is it trying to reach the IP address of the ISP directly as its external gateway?

I would check with the working connection the arp entry for the ISP router. confirm with them that the MAC address indicated is at their end. Then move back to the new Cisco connection, clear your router arp cache and try to ping the ISP again. Look for the mac address-table on the switch ("show mac address-table") to be populated with the address of the ISP router.

asemyc2013 · ‎02-16-2014

Hello, I don't understand what happens, both transceivers are compatible to be replaced (1000base LX, SM fiber and LC connector) and both SW too, can the ISP only allow the MAC of SW Edge-Core or something like that?

I attached mac address-table (only show the internal router:e02f.6d75.651d) and more info.

Thank you very much for everything,

Asem.

Dmitriy Zhiznevskiy · ‎02-16-2014

The physical part seems to be fine.

Do "show spanning-tree vlan 1".

Marvin Rhoads · ‎02-16-2014

It's unlikely but it is possible the ISP has some security features that only allow your old switch's MAC address.

Do you know if your ISP has a switch or router at their end? If it is a switch, they may have it setup as a trunk port. That would normally negotiate automatically but you can try configuring your end as a trunk:

conf t

int gi1/0/28

switchport trunk encapsulation dot1q

switchport mode trunk

end

wr mem

Even though you only have a single default VLAN 1 it may help. the "show spanning-tree vlan 1" suggested above would also add confirmation that the port is passing spanning-treee BPDUs.

asemyc2013 · ‎02-16-2014

I configure the port gi1/0/28 in trunk mode(only just don't accept the command: switchport trunk encapsulation dot1q because these is implemented by Cisco in these SW for default)

And command "show spanning-tree vlan 1" show:

Spanning tree instance(s) for vlan 1 does not exist.

Marvin Rhoads · ‎02-16-2014

Well no spanning-treee instance fo vlan 1 will certainly bollux things up! Normally if any interface is up in a given VLAN, spanning-tree will be active on the ports belonging to that VLAN (all ports are in VLAN1 in a default configuration).

Try manually setting int gi1/0/1 and gi1/0/28 as access ports in vlan 1:

conf t

int gi1/0/1

switchport mode access

switchport acess vlan 1

int gi1/0/28

no switchport mode trunk

switchport mode access

switchport access vlan 1

end

wr mem

Make sure that those ports are up/up, i.e.

show interface status

and then check "show spanning-tree vlan 1"

Dmitriy Zhiznevskiy · ‎02-16-2014

Please do "show int gi1/0/1 switchport" and "show int gi1/0/28 switchport" once you've reverted to access mode.

asemyc2013 · ‎02-17-2014

Hello everyone! Something very strange, when I change the port to "switchport mode access":

the command "show mac address-table" showing something new, just for a few seconds:

Mac Address Table

-------------------------------------------

Vlan Mac Address Type Ports

---- ----------- -------- -----

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

All 0180.c200.0010 STATIC CPU

All ffff.ffff.ffff STATIC CPU

1 00e0.b192.ef10 DYNAMIC Gi1/0/28 ---> this is new, show only a moment, then disappears.

1 e02f.6d75.651d DYNAMIC Gi1/0/1

Total Mac Addresses for this criterion: 22

The other commands:

show interface status

Port Name Status Vlan Duplex Speed Type

Gi1/0/1 connected 1 a-full a-1000 10/100/1000BaseTX

Gi1/0/28 connected 1 a-full a-1000 1000BaseLX SFP

show spanning-tree vlan 1

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 32769

Address 0c27.243f.4b80

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)

Address 0c27.243f.4b80

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi1/0/1 Desg FWD 4 128.1 P2p

Gi1/0/28 Desg FWD 4 128.28 P2p

show run int Gi1/0/1

Building configuration...

Current configuration : 62 bytes

!

interface GigabitEthernet1/0/1

switchport mode access

end

show run int Gi1/0/28

Building configuration...

Current configuration : 63 bytes

!

interface GigabitEthernet1/0/28

switchport mode access

end

Marvin Rhoads · ‎02-17-2014

OK, so you do see the other end briefly - the 00e0.b1 OUI at the beginning of their MAC address indicates an Alcatel-Lucent device.

It appears they have some setting that is preventing the traffic from flowing. MAC address filtering or BPDUguard type of features at their end could do that.

Your switch appears to be setup properly with a very basic configuration.

Dmitriy Zhiznevskiy · ‎02-17-2014

The only non-bug-related explanation I can think of is a TCN coming from the ISP with subsequent link blockage for some reason. Root guard on their side?

Do "show spanning-tree int gi1/0/28 detail"

Then "show int gi1/0/28 switchport".

If you're sure no other links from that ISP will ever get connected to your network, try:

int gi1/0/28

spanning-tree bpdufilter enable

storm-control broadcast level 5

storm-control multicast level 5

shut

no shut

(the storm-control part is just a precaution)

asemyc2013 · ‎02-18-2014

Sorry for the late reply. Was off. After several hours calling and talking to people in the ISP, we could talk with certain employee, he told us that the switch Edge-Core has a special configuration, they don't know the password and don't give me, even if they knew, to use my new switch, we must change the contract, etc etc etc...

After talking to this person I'm pretty sure they are using MAC filtering...

The Edge-Core switch is in transparent mode (in a manner of speaking) How do I find the MAC having to put it on my new Cisco switch? So I'm pretty sure that then I can connect.

I really need to remove the old switch because I need to have my entire network to 1Gb/s and I haven't slot for more in my humble rack.

Thank you very much,

Asem.