Cisco C9300-NM-8X Module C9300-48P ports Limitation/Oversubscription

[ifabrizio]

Dear All,

I need your help to understand, if the C9300-NM-8X uplinks module has some limitation about the number of active ports.

The C9300-NM-8X is mounted on a C9300-48P, and now has the following port usage status:

Te1/1/1 connected trunk full 1000 1000BaseSX SFP
Te1/1/2 connected trunk full 1000 1000BaseSX SFP
Te1/1/3 connected trunk full 1000 1000BaseSX SFP
Te1/1/4 connected trunk full 1000 1000BaseSX SFP
Te1/1/5 connected trunk full 10G SFP-10GBase-SR
Te1/1/6 notconnect 1 full 10G SFP-10GBase-SR
Te1/1/7 connected trunk full 10G SFP-10GBase-SR
Te1/1/8 notconnect 1 auto auto unknown

My question is: What is the maximum number of ports, active at 10Gbps and 1Gbps simultaneously? Are there some limitation? Or I can use all the 8 ports with to the max 10Gbps speed?

Best regards,

JF

 

 

C9300-NM-8X Module

All ports in the C9300-NM-8X module default to 10 G and should be configured as TenGigabitEthernet1/1/1 through TenGigabitEthernet1/1/8, even when you are operating them as 1 G using SFP.

Table 5. C9300-NM-8-10X ModuleInterface Action

TenGigabitEthernet1/1/1	Configure this interface
TenGigabitEthernet1/1/2	Configure this interface
TenGigabitEthernet1/1/3	Configure this interface
TenGigabitEthernet1/1/4	Configure this interface
TenGigabitEthernet1/1/5	Configure this interface
TenGigabitEthernet1/1/6	Configure this interface
TenGigabitEthernet1/1/7	Configure this interface
TenGigabitEthernet1/1/8	Configure this interface

[M02@rt37]

Hello @ifabrizio 

The C9300-NM-8X uplink module is designed to support up to 8 simultaneous uplinks, with each port capable of operating at a maximum speed of 10 Gbps. This module is backward-compatible with 1 Gbps SFP modules, allowing flexibility in deployments that may require a mix of 1 Gbps and 10 Gbps connections. The key feature of this module is that all 8 ports are fully functional simultaneously without specific hardware limitations restricting their operation. 

From a configuration perspective, all ports on the module default to a 10 Gbps designation and are referenced as "TenGigabitEthernet1/1/x" in the switch’s interface naming convention. This designation applies even when the ports are operating at 1 Gbps, ensuring consistency in configuration and monitoring. The module is designed to handle a mix of 1 Gbps and 10 Gbps ports actively, so there’s no inherent limitation in using all 8 ports simultaneously at their maximum possible speeds. However, ensuring compatibility with the installed SFP or SFP+ modules is critical => https://tmgmatrix.cisco.com/ For optimal performance, only Cisco-supported optics should be used, as third-party optics may sometimes result in unpredictable behavior...

[Joseph W. Doherty]

Based on M02@rt37 reply, it appears all 8 ports can operate concurrently using any mixture of those ports operating at gig or 10g.

If correct, and I suspect he is, that would answer your question.  However, whether the hardware has the capacity to run all 8 ports, concurrently, actually passing traffic at full 10g, duplex, is a different matter, to which, off the top of my head I don't know the answer, although with a 9k, I would suspect the switch and this module may be so capable.

[Flavio Miranda]

@ifabrizio 

  It will vary depending on the switch model. For C9300-48P, we can see on the Datasheet 256Gbps.

Table 9.        Bandwidth specifications

C9300-48P

256 Gbps

https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9300-series-switches/nb-06-cat9300-ser-data-sheet-cte-en.html

doing a simple math, 10 Interface at 10 Giga is 100Giga.  Plus 48 ports at 1 Giga will add more 48Giga, summing up, we are talking about 148Giga out of 256 Giga capacity.

I believe that considering only physical interface, there will be no oversubscription but I believe we also need to consider memory and processing which will impact on the hability of the switch in switching packets out of interfaces. 

Would be interesting put all the interface at maximum speed and see how this box behaves.

[Joseph W. Doherty]

It's a bit more complicated than the overall bandwidth capacity.

A moment ago, I was just looking at some high level architecture block diagrams, and, if I didn't misunderstand, the 9300, depending on model, provides either 80 Gbps or 400 Gbps to uplink ports.  (NB: how that bandwidth is interconnected to the switch fabric and the ports also varies.  See figures 17 and 18 in https://www.cisco.com/c/en/us/products/collateral/switches/catalyst-9300-series-switches/nb-06-cat9300-architecture-cte-en.html#ModularuplinkModels.)

[Joseph W. Doherty]

To summarize, from a quick review, it appears for the 9300 series, whatever Ethernet ports are provided, the switch can support all running concurrently at wire-speed.  (Stacking ports, though, can be oversubscribed for bandwidth, but for what they do provide, believe they are also supported at wire-speed, also with all the Ethernet ports.)

[Leo Laohoo · Accepted solution]

All eight ports can support SFP (1 Gbps) and/or SFP+ (10 Gbps).  

I do not believe the ports can support 10/25 Gbps optics.