Connecting switches with fibre or ethernet.

Answered Question
Feb 6th, 2008

Hi All

Pls help me out here. I have a

1 x Cat 3750G-12S

1 x Cat 3750G-48TS-E and

4 x Cat 2960-48TC-L

I want to connect them all up using etherchannel and fibre such that

The Cat 3750G-12S is connected to the Cat 3750G-48TS-E and all the 4 x Cat 2960-48TC-L is connected to the Cat 3750G-12S.

I wanted to use Fibre SFP on all connections but now I have just checked online and found out that Cat 3750G-12S.

only has 12 SFP based Ethernet. Also the Cat 3750G-48TS-E has just SFP for Ethernet.

Does this mean I cannot use fibre cable and have to use Cat 5 ethernet cables?

How else can I do this if I want to use fibres?

Thanks

I have this problem too.
0 votes
Correct Answer by Amit Singh about 8 years 10 months ago

No you dont have to use GLC-T SFP, you can use any of the available SFP. It Says 12SFP based GBIC ports. Dont get confuse with Gigabit Ethernet word at the end, its always used for Gig port. As the ports as SFP it can take in any available SFP, be it copper or fiber.

HTH, Please rate if it does.

-amit singh

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Overall Rating: 5 (1 ratings)
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Amit Singh Wed, 02/06/2008 - 04:00

Hi There,

Yes 3750-12S is a sswitch with 12 SFP ports. Cat 3750G-48TS-E has 4 dual personality ports i.e you can use either copper or SFP ports one time. The same goes with 2960 as well. Cisco Catalyst 3750 Series Switches support the following SFPs:

• 1000BASE-LX/LH (GLC-LH-SM=)

• 1000BASE-SX (GLC-SX-SM=)

• 1000BASE-ZX (GLC-ZX-SM=)

• 1000BASE-T (GLC-T=)

• 1000BASE-BX 1490nm (GLC-BX-D=) (12.2(25)SEB and later)

• 1000BASE-BX 1310nm (GLC-BX-U=) (12.2(25)SEB and later)

• CWDM (supported after 12.1(14) EA release)

- CWDM-SFP-1470

- CWDM-SFP-1490

- CWDM-SFP-1510

- CWDM-SFP-1530

- CWDM-SFP-1550

- CWDM-SFP-1570

- CWDM-SFP-1590

- CWDM-SFP-1610

• 100Base FX (12.2(20)SE and later)

You can use either of these SFP's to interconnect the switches.

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps5023/prod_qas09186a00801b0971.html

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/prod_qas0900aecd80322c37.html

HTH, Please rate if it does.

-amit singh

qwertys21 Wed, 02/06/2008 - 04:18

Thanks

Yes, the

WS-C3750G-12S-S

• 12 SFP-based Gigabit Ethernet ports

which says to me it only support Gigabit ethernet connections.

Does this mean I will have to use SFP for ethernet - 1000BASE-T (GLC-T=) to connect the Cat 3750G-48TS-E to it?

Thanks

Correct Answer
Amit Singh Wed, 02/06/2008 - 04:24

No you dont have to use GLC-T SFP, you can use any of the available SFP. It Says 12SFP based GBIC ports. Dont get confuse with Gigabit Ethernet word at the end, its always used for Gig port. As the ports as SFP it can take in any available SFP, be it copper or fiber.

HTH, Please rate if it does.

-amit singh

qwertys21 Wed, 02/06/2008 - 04:30

Thank you.

Can I still use etherchannel when I am connecting the Cat 2960 to two Cat 3750G for redundancy purpose?

Doesn'e etherchannel have to be from the same switch to the same other switch?

Amit Singh Wed, 02/06/2008 - 04:54

Hello friend,

If you are stacking both the 3750's together, then yes you can have the ether-chaneel setup as 3750's suppirt cross-stack ether-channel. If you are just uplinking the 3750's then you cannot have an ether-channel from 3750's to 2960.

HTH, please rate if it does.

-amit isngh

ryanhoibm Fri, 08/20/2010 - 07:26

Hi Amit,

So cross-stack Etherchannel cannot be implemented between Cat3750 and Cat2960?

I recently have Forwarding loops issue in my customer's network.

The setup is 3 Cat3750G-12S stack together using stackwise. they are connected to 6 Cat2960G-24TC-L via cross-stack etherchannel. And I do not know what happen, loops are being created. Can I confirm with you once again that this setup is wrong? If its wrong, what should the solution be to connect 6 Cat2960 to 3 Cat3750G stack switches?

Thanks a million in advance!!!

Regards

Ryan Ho

2602: Aug 14 16:41:46: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.37d2.7259 in vlan 24 is flapping between port Po7 and port Po4
012603: Aug 14 16:41:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0015.60b9.0044 in vlan 24 is flapping between port Po4 and port Po7
012604: Aug 14 16:41:47: %SW_MATM-4-MACFLAP_NOTIF: Host 00e0.0033.8d85 in vlan 25 is flapping between port Po7 and port Gi1/0/5
012605: Aug 14 16:41:47: %SW_MATM-4-MACFLAP_NOTIF: Host 0014.5e3f.4066 in vlan 1 is flapping between port Po10 and port Po7
012606: Aug 14 16:41:48: %SW_MATM-4-MACFLAP_NOTIF: Host 000c.2919.3585 in vlan 25 is flapping between port Gi1/0/5 and port Po7
012607: Aug 14 16:41:50: %SW_MATM-4-MACFLAP_NOTIF: Host 001d.096d.cf30 in vlan 1 is flapping between port Po2 and port Po7
012608: Aug 14 16:41:50: %SW_MATM-4-MACFLAP_NOTIF: Host 0015.5d3d.2f01 in vlan 1 is flapping between port Po7 and port Po1
012609: Aug 14 16:41:51: %SW_MATM-4-MACFLAP_NOTIF: Host 00e0.0033.c5aa in vlan 24 is flapping between port Po7 and port Po4
012610: Aug 14 16:41:51: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.4f4d.dac6 in vlan 25 is flapping between port Po7 and port Gi1/0/5
012611: Aug 14 16:41:51: %SW_MATM-4-MACFLAP_NOTIF: Host 0021.5e2c.f1be in vlan 1 is flapping between port Po7 and port Po10
012612: Aug 14 16:41:56: %SW_MATM-4-MACFLAP_NOTIF: Host 000c.2919.3585 in vlan 25 is flapping between port Po7 and port Gi1/0/5
012613: Aug 14 16:41:56: %SW_MATM-4-MACFLAP_NOTIF: Host 0014.5e3f.3f5c in vlan 1 is flapping between port Po7 and port Po10
012614: Aug 14 16:41:57: %SW_MATM-4-MACFLAP_NOTIF: Host 0014.5e3f.3f5d in vlan 1 is flapping between port Po7 and port Po2
012615: Aug 14 16:41:57: %SW_MATM-4-MACFLAP_NOTIF: Host 0014.5e3f.3f46 in vlan 1 is flapping between port Po7 and port Po10
012616: Aug 14 16:41:58: %SW_MATM-4-MACFLAP_NOTIF: Host 0011.4337.cf12 in vlan 1 is flapping between port Po7 and port Po1
012617: Aug 14 16:41:58: %SW_MATM-4-MACFLAP_NOTIF: Host 0011.4337.cf11 in vlan 1 is flapping between port Po7 and port Po2
012618: Aug 14 16:41:58: %SW_MATM-4-MACFLAP_NOTIF: Host 0024.e891.5fc0 in vlan 24 is flapping between port Po4 and port Po7
012619: Aug 14 16:41:59: %SW_MATM-4-MACFLAP_NOTIF: Host 0014.5e3f.3f47 in vlan 1 is flapping between port Po2 and port Po7
012620: Aug 14 16:41:59: %SW_MATM-4-MACFLAP_NOTIF: Host 0015.60b9.1068 in vlan 25 is flapping between port Po7 and port Gi1/0/5
012621: Aug 14 16:42:00: %SW_MATM-4-MACFLAP_NOTIF: Host 001d.096d.cf30 in vlan 1 is flapping between port Po7 and port Po2
012622: Aug 14 16:42:00: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.3739.46f8 in vlan 24 is flapping between port Po4 and port Po7
012623: Aug 14 16:42:01: %SW_MATM-4-MACFLAP_NOTIF: Host 705a.b696.d0c2 in vlan 24 is flapping between port Po4 and port Po7
012624: Aug 14 16:42:01: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.37d2.7259 in vlan 24 is flapping between port Po4 and port Po7
012625: Aug 14 16:42:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0015.60b9.0044 in vlan 24 is flapping between port Po4 and port Po7
012626: Aug 14 16:42:01: %SW_MATM-4-MACFLAP_NOTIF: Host 0023.32d5.b0ca in vlan 24 is flapping between port Po4 and port Po7
012627: Aug 14 16:42:02: %SW_MATM-4-MACFLAP_NOTIF: Host 00e0.0033.8d85 in vlan 25 is flapping between port Gi1/0/5 and port Po7
012628: Aug 14 16:42:05: %LINK-5-CHANGED: Interface GigabitEthernet2/0/5, changed state to administratively down
012629: Aug 14 16:42:05: %LINK-5-CHANGED: Interface GigabitEthernet3/0/7, changed state to administratively down
012630: Aug 14 16:42:05: %LINK-5-CHANGED: Interface Port-channel7, changed state to administratively down
012631: Aug 14 16:42:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet2/0/5, changed state to down
012632: Aug 14 16:42:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet3/0/7, changed state to down
012633: Aug 14 16:42:06: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel7, changed state to down
012634: Aug 14 16:42:15: %SYS-5-CONFIG_I: Configured from console by admin on vty0 (180.2.24.2)
012635: Aug 14 17:04:53: %SYS-5-CONFIG_I: Configured from console by vty0 (127.0.0.5)
KW-L24-CSW01#$

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