10GE Sub-Interface Speed

[ZK916]

Hello,

I am planning to use a 10GE physical interface and configure 3 subinterfaces on it and I wanted to understand if the speed on each subinterface would need to be specified? Meaning, will each SubInterfce use a a specific bandwidth out of the 10GE interface?

Thanks in advance! 

Best, ~zK

[marce1000]

      - What Cisco device/model are you talking about ?

 M.

[ZK916]

We use the C9500 series switches at the core. Some fo the are the C9500-32C and others are C9500-48Y4C.

Best, ~zK

[balaji.bandi]

if this cat 9500 they work as below mentioned :

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9500/software/release/17-9/configuration_guide/qos/b_179_qos_9500_cg/configuring_layer3_subinterface_queuing.html

[Joseph W. Doherty · Accepted solution]

"if this cat 9500 they work as below mentioned :"

BTW, I often mention, including in my prior reply, when dealing with QoS, it can be platform specific.

For example, in the particular reference @balaji.bandi provides, we find:

Subinterface queuing introduced in IOS XE Cupertino 17.8.1 for the C9500X-28C8D.  I.e. it might not be available on OP's C9500-32C and C9500-48Y4C.

In a prior chapter, Configuring QoS, we also find:

Again, though, by default, I believe you'll obtain the behavior I described in my prior reply.

If you do, though, decide you want to change that default behavior, using your own QoS configuration, I recommend reviewing from Balaji's reference:

Prerequisites for QoS

Before configuring standard Quality of Service (QoS), you must have a thorough understanding of these items:

• Standard QoS concepts.

• Classic Cisco IOS QoS.

• Modular QoS CLI (MQC).

• Understanding of QoS implementation.

• The types of applications used and the traffic patterns on your network.

• Traffic characteristics and needs of your network. For example, is the traffic on your network bursty? Do you need to reserve bandwidth for voice and video streams?

• Bandwidth requirements and speed of the network.

• Location of congestion points in the network.

[M02@rt37]

Hello @ZK916,

Subinterfaces are virtual interfaces. The bandwidth of the physical interface remains the same and it will be distributed evenly among subinterfaces.

It will also depend on the queuing configured on the physical interface.

[Joseph W. Doherty · Accepted solution]

By default, the 3 subinterfaces would share the 10g as if all their flows were on just one interface (which is physically the case).

If that's not the bandwidth sharing you want for/between your subinterfaces, you would need to use QoS policies.  (As QoS capabilities can vary much based on platform, your bandwidth sharing options would be platform dependent.)