3650 Port-to-ASIC Mapping

[fal91]

Hello,

I have a lots of output drops on a WS-C3650-12X48UR-L connecting several firewalls (may not be the best platform for that i agree...).

i'm thinking now about reducing those drops by moving cables of the more loaded FW to another ASIC (before adding 10g sfp+ to the FW later).

I'm struggling now finding Port-to-ASIC Mapping. I've found here (https://community.cisco.com/t5/routing/3850-switch-port-to-asic-mapping/td-p/3196747) that 48 ports 3650 have 2 UADP ASIC.

But i've also found the following repartition thanks to 'show platform software fed switch 1 qos qsb interface gi1/0/1' command :

asic_num:3
Gi1/0/1 -> Gi1/0/16
TenGig1/0/37 -> TenGig1/0/40

asic_num:2
Gi1/0/17 -> Gi1/0/32
TenGig1/1/1 -> TenGig1/1/4

asic_num:1
Gi1/0/33 -> Gi1/0/36
TenGig1/0/41 -> TenGig1/0/42
TenGig1/0/45 -> TenGig1/0/48

asic_num:0
TenGig1/0/43 -> TenGig1/0/44
TenGig1/1/5 -> TenGig1/1/8

So i'm quite confused now...

WS-C3650-12X48UR-L is :
Standalone with Optional Stacking 48 (36 10/100/1000 and 12 100Mbps/1/2.5/5/10 Gbps) Ethernet and 8x10G

I have no devices connected to ports that belong to asic 1, so i plan to move cable to Gig1/0/33, am i right ?

Thanks in advance for your help.

Regards.

[balaji.bandi]

As per my understanding, you believe that one of the ASIC was overloaded and you see some packets drop

to test and prove that new Free ASIC may have better results if this is my understanding as per the post - if this is correct

yes you can move to ASIC 1 and test it

[Reza Sharifi]

Hi,

What is the amount of bandwidth consumed by the interfaces that connect to the firewalls? Are the firewalls pushing more traffic than the switch ports can handle? What is the amount of output drops? 

HTH

[fal91]

Actually it depends on the firewalls. The one that is gonna be moved is not pushing more than the switch port can handle (for the moment...). I will also add more ports to the agregate in case of.

3044032795 output drops for the Po in 8 hours ! 

I will mix ports belonging to asic 1 and 0 as there is no ports using those asics. It will be a mix between Gig and mGig ports, as far as i read, it won't be an issue.

[balaji.bandi]

As per the original post suggested that you looking to move ASIC, but if the problem is different like having packet loss.

This requires more understand of where the bottleneck will be. Sometimes you see lot of errors on the port-channel in busy interfaces ( we do see them, but not impacted any performance level).

As per the plan move the interface to new ASIC and let us know how it goes if the problem still exits required more information about the config and connected devices here to understand the issue.

[fal91]

Thanks, change is planned next week. 

'Talky' FW will be plugged on ports on 2 dedicated ASICS. So i hope we will get less output drops on all ports (Some ports towards some other FW have currently a lots of drops with only 30M of traffic on Gig ports. So i assume it's related to the talky FW.

I will keep you updated.

[balaji.bandi]

Since the firewall process lot of traffic, this was expected, but it should not impact on performance level.

let us know how it goes?

[Joseph W. Doherty]

Catalyst 3K series switches often drop packets due to their "small" buffer RAM resource and also often due to how they manage that resource between ports and their egress queue(s). I.e. moving to another ASIC might not mitigate the issue as much as changing your buffer management configuration.