SFP Module Best Practice Question -- Which Interface For Trunk?

[cinmachina]

Let's say I have a 3560x 48 gigabit port switch. It has a network module in it that has 4 SFP slots.

Let's also say that one of the gigabit interface ports is open (say, port gi0/48).

Is it best practice to make interface gi0/48 the trunk, or one of the SFP slots with an SFP module, assuming it's using 1000BaseTX.

[Jon Marshall]

cinmachina wrote:
Let's say I have a 3560x 48 gigabit port switch. It has a network module in it that has 4 SFP slots.
Let's also say that one of the gigabit interface ports is open (say, port gi0/48).
Is it best practice to make interface gi0/48 the trunk, or one of the SFP slots with an SFP module, assuming it's using 1000BaseTX.

The network module is specifically intended for use a uplinks to other switches so i would recommend using those if available. Having said that it's not the end of the world if you need to use one of the 1 - 48Gbps ports as an uplink.

Jon

[cinmachina]

I could be wrong, but I'm not sure that's the case about the purpose of network modules. Also, it seems logical to me that you'd use a native interface instead of one with additional hardware in it.

I want to know for sure. Is there a white paper on this somewhere or something?

[Jon Marshall]

cinmachina wrote:
I could be wrong, but I'm not sure that's the case about the purpose of network modules. Also, it seems logical to me that you'd use a native interface instead of one with additional hardware in it.
I want to know for sure. Is there a white paper on this somewhere or something?

So you know the answer to your own question

From the 3560-X datasheet -

Cisco Catalyst 3750-X and 3560-X Series primary features:

• 24 and 48 10/100/1000 PoE+ and non-PoE models

• Optional four Gigabit Ethernet (GbE) SFP or two 10GbE SFP+ uplink network modules

so it would seem that the network modules are indeed for uplinks.

Jon

[Douglas Holmes]

The question would seem to be which port is best to use for an uplink.  You have a 3560 Switch with four SFP ports.  I use Cisco 3750 Switches with the same SFP ports available.  I standardize by always using the last SFP (highest numbered port) for the uplink (on stacks, always the first switch).  As a rule I only use the SFP modules for fiber.  I use 1000 GLC SFP's only when the switch doesn't have any gig ports or when it's close enough and/or practical enough to use copper for the uplink.  I don't think that there is any set manner in which to choose the port used as an uplink.  Standardization I think is an important key.