the right transceiver

[Dusan Sladojevic]

Hi,

I would need to have redundant connection between two rack rooms

I have two 3560-x switches with C3KX-NM-10G network module on each.

I would order two more 3560-x switches and make redundant 10gb connection in autumn.

But for now I will just use two of 1gb uplink and make it etherchannel - 2gb theoretically.

The other two switches on picture will be replaced in autumn by 3560-x are only 1 gb uplink capable.

Can I use two SFP-10G-SR transceivers and make them etherchannel of 2gb?

I ask this, because I would like to save money when buying more of this transceivers in autumn.

So I wouldn't need buy GLC-SX-MM which are for 1gb link.

SFP-10G-SR are 10gb transceivers, and I have multimode OM3 optical cable between switches,

so I am wondering could this work? Could I configure port to be 1gb instead of 10gb that could go through?

[Dusan Sladojevic]

Optical cables would be only between 3560-x switches for now.

All other connections are over copper.

[Julio Garcia]

Hi Dusan,

With your network Module, you can only do 10gig-e  on those 2 ports that are enabled on the network module, you cant do 1gig on them.

To save cost i suggest , you do a copper etherchannel between the 3560X of 2gb/sec.

Alternative is to do 20gb/s etherchannel between the two 3560x and just have the extra bandwith -- it wont cause your topology any harm, im not sure i understand why it needs to be 2gb/sec between your 3560 -- did you want it to look symetrical?  are you running vlans here -- do you have alternative root switches for them -- ie vlan 1 root = 3560-1 , vlan 2 root = 2960-1 etc ... -- could you let us know bit about this...

thanks

[Dusan Sladojevic]

I have read that on the network module C3KX-NM-10G  can have two 10gb uplinks, or 1 10gb and 2 1gb or 4 1gb uplinks.

Yes, I can always do copper between two 3560x switches - but the problem is number of copper cables between rack rooms. I would need to use optical so I could use copper for other things planned.

I wanted to have 2gb uplink between all 4 "main" switches because, whats the use of 10gb uplink if I don't have 10gb as backup.. This way, untill I get two more 3560x switches and 10gb uplink between all "main" switches - I will have 2gb uplink between all 4 "main" switches.

Yes, all the ports between the switches will be trunk so they could pass all data no matter what vlan.

All switches are in one VLAN (off topic)

But only thing I wan't to know is - can I use two 10gb transceivers on 3560x, and make them 2gb etherchannel, as I could if they were 1gb transceivers? So make each uplink that has 10gb transceiver only pass 1gb and combine that two 1gb into etherchannel of 2gb.

[Reza Sharifi]

But only thing I wan't to know is - can I use two 10gb transceivers on 3560x, and make them 2gb etherchannel, as I could if they were 1gb transceivers? So make each uplink that has 10gb transceiver only pass 1gb and combine that two 1gb into etherchannel of 2gb.

It depends on the module you have purchased.

If you have C3KX-NM-1G, it is only 4 1Gig interfaces

if you have C3KX-NM-10G you can have 1 10Gig interface using SFP+ and 2 1Gig interfaces using SFP

Have a look at table 3 and 4 in this link

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/data_sheet_c78-584733.html

HTH

[Julio Garcia]

As everything is on same vlan -- you could make the spanning tree cost the same as the 1gb interfaces across your network,  so from a spanning tree perspective -- 'it looks symmetrical'

You cant make the 10gb transciever emulate into 1gb transciever , you should just keep the 10gb speed because on the network there is no way traffic can reach more than 1gb ( as rest of the network is gig-e) so there is no harm at all to just keeping them at the native 10g speed.  consider the 10g as backup to 1g  and vice versa.

[Dusan Sladojevic]

Could some1 please confirm me if this is right:

You cant make the 10gb transciever emulate into 1gb transciever

[Ruhann Du Plessis · Accepted solution]

The problem is the not tranceiver. The SFP-10G-SR is capable of being configured at 1Gb or 10Gb.

The capabilty of doing 1Gb or 10 Gb is determined by the switch port the SFP plugs into.

The SFP/tranceiver details use the command : show int XXX transceiver

To see the switch port capabilities use the command: show int XXX capabilities

Have a look below and you will see I have the SFP-10G-SR on a N5K switch, which support 1Gb or 10Gb connectivity on cerain ports and the second output from a N7K which only support 10Gb

These are different switches using the same SFP-10G-SR type.

Switch-1# sh int Eth1/2 capabilities

Ethernet1/2

  Model:                 N5K-C5010P-BF-SUP

  Type (SFP capable):    10Gbase-SR

  Speed:                 1000,10000

Switch-2# sh int e1/2 capabilities

Ethernet1/2

  Model:                 N7K-M132XP-12

  Type (SFP capable):    10Gbase-SR

  Speed:                 10000

Not that it is relevant to the question, but dont confuse a 1Gb SFP with a 10GB SFP.  A 1Gb SFP can only do 1Gb.

HTH