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Understand uplinks

Cadeyrn
Level 1
Level 1

I need some help in understanding the usage of an switch uplink. Lets take the C1000-24T-4X-L as an example. It has 24 Gb ports and 4 SPF+ uplinks. My basic understand it that these uplinks are used to connect multiple switches together.

  1. Would I be correct in assuming that one of the regular Gb ports could also be used to connect multiple switches together? If so, other than bandwidth, are there any benefits to using a dedicated uplink over a regular switch port?
  2. Could a dedicated uplink be used, for example, as a trunk port to a router or firewall? In this case, the increased 10 Gb bandwidth over a 1 Gb switchport would seem advantageous for carrying multiple VLANs.
  3. Contrast this with the C1000-24T-4G-L. It contains 24 Gb ports but 4 SPF uplinks (rather than SPF+ uplinks). Hence, both regular switchports and uplinks run at a maximum of 1 Gb. In this case, is there any advantage to using an uplink to another switch over a regular switchport?

Thank you.

1 Accepted Solution

Accepted Solutions

balaji.bandi
Hall of Fame
Hall of Fame

1. Would I be correct in assuming that one of the regular Gb ports could also be used to connect multiple switches together? If so, other than bandwidth, are there any benefits to using a dedicated uplink over a regular switch port?

 

BB - yes you can use, easy ports works in different ASIC, some switches share port-ratios 1:4 or more depends Model

        when you compare with uplink modules, works in different ASIC - this is mostly used as you mentioned to other switches, not necessary (you can use for any device if you like,)

 

2. Could a dedicated uplink be used, for example, as a trunk port to a router or firewall? In this case, the increased 10 Gb bandwidth over a 1 Gb switchport would seem advantageous for carrying multiple VLANs.

 

BB - yes it is valid use case, depends on uplink ports and support modules. (most case 1GB works)

 

3. Contrast this with the C1000-24T-4G-L. It contains 24 Gb ports but 4 SPF uplinks (rather than SPF+ uplinks). Hence, both regular switch ports and uplinks run at a maximum of 1 Gb. In this case, is there any advantage to using an uplink to another switch over a regular switch port?

 

BB - yes as mentioned point 1 applicable here. 

 

Look at the below document: Chasis design

 

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-1000-series-switches/white-paper-c11-743809.html

 

Some FAQ if you have further any questions :

 

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-1000-series-switches/nb-06-cat1k-ser-switch-faq-cte-en.html

 

 

BB

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View solution in original post

4 Replies 4

balaji.bandi
Hall of Fame
Hall of Fame

1. Would I be correct in assuming that one of the regular Gb ports could also be used to connect multiple switches together? If so, other than bandwidth, are there any benefits to using a dedicated uplink over a regular switch port?

 

BB - yes you can use, easy ports works in different ASIC, some switches share port-ratios 1:4 or more depends Model

        when you compare with uplink modules, works in different ASIC - this is mostly used as you mentioned to other switches, not necessary (you can use for any device if you like,)

 

2. Could a dedicated uplink be used, for example, as a trunk port to a router or firewall? In this case, the increased 10 Gb bandwidth over a 1 Gb switchport would seem advantageous for carrying multiple VLANs.

 

BB - yes it is valid use case, depends on uplink ports and support modules. (most case 1GB works)

 

3. Contrast this with the C1000-24T-4G-L. It contains 24 Gb ports but 4 SPF uplinks (rather than SPF+ uplinks). Hence, both regular switch ports and uplinks run at a maximum of 1 Gb. In this case, is there any advantage to using an uplink to another switch over a regular switch port?

 

BB - yes as mentioned point 1 applicable here. 

 

Look at the below document: Chasis design

 

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-1000-series-switches/white-paper-c11-743809.html

 

Some FAQ if you have further any questions :

 

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-1000-series-switches/nb-06-cat1k-ser-switch-faq-cte-en.html

 

 

BB

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Just to add a bit to the information that Balaji has already provided.

Some switch uplink ports have more hardware resources behind them then ordinary copper edge ports. Balaji already mentioned ASIC sharing, what's that is actual bandwidth to/from switch fabric.  On most switches, some group of ports share bandwidth to the fabric.

Also, another hardware resource that an uplink port might have more available to it could be egress port buffer resources.

You asked about using uplink ports to other kinds of devices, routers and firewalls, and Balaji already noted the answer is yes, but an uplink port might also be used for other more traffic using device, like some kind of server.

Again, do remember, not all switch uplink ports are "better" than other ports.

Lastly, often uplink ports use external transceivers (e.g. SFP) to provide a choice of media.  Technically, there are some reasons why a fiber connection is better than copper (regardless of distance), so many prefer using optical connections for infrastructure links.  However, I've used copper, for uplinks, even in large datacenter without any real issues.

Thank you for the additional information. It was most useful.

Thank you. Exactly what I was looking for. This greatly cleared it up for me.

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