Physical fiber connectivity issues for Fabric Links on Spine and Leaf

[hafeezali]

Hi,

Can anyone answer with regards to fiber link connectivity between spine and leaf?

First Question:

Is it mandatory to have all the links between these devices to be at same speed? I mean if I connect a leaf switch to one spine at 40G and to another spine with 100G, will it be an issue?

Second Question:

How about having one link from spine to leaf running over Single Mode connection and another link from the same leaf to another spine over Multi Mode Fiber? I mean does there any impact or issue due to different physical transport media even having similar speed on both links?

Third Question:

The same as above for Port-Channel. Is it possible to combine and aggregate two links through port-channel technology having the same speed but over different physical transport media (One link of Single Mode fiber and another of Multi Mode fiber).? 

Logically I don't see any issue with second and third question as the requirement is the port speed and should not matter the transport media. But I need to clear my concern.

Thanks

Regards, 

[balaji.bandi]

Media not a problem as per i know. (either single or multi mode should work)

if they are not in port-channel, then you can connect to any speed.

But Limitation one link faster than other - so any fail over can not accommodate same speeds

[hafeezali]

Thanks for your reply. Its helpful.

Is there any limitation for connectivity between spine and leaf. Can we find some resources from Cisco in the design or best practices?

For port-channel for sure it is mandatory to have same speed on all the link. But links connected physically through different media to form a port-channel is the concern because I never tried one like that. The scenario is to add two new stacked access switches to the core switch hosted in a stretched network at two sites and using SWV technology. For high availability the new stacked access switches require to be connected to both Core switches. One link will be connected locally through MMD module and other link through SMD module.

Regards

[balaji.bandi · Accepted solution]

I have tired port-channel different media it works, as long as the speed matches, you are ok.

as mentioned before the media not matter ( but both side should be same SFP required, you can not connect MM to SM SFP)