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Beginner

Re: Ping response from gateway longer than from switch

Jaderson, 

Would the command " spanning-tree vlan 1-4094 priority 0 "  mess up anything except for a few secs of disconnection?

What command should I run on the core switch to change things back to the original if there is anything weird happens after running the command?

 

Thanks very much!

Rising star

Re: Ping response from gateway longer than from switch

Hello,

 

Would the command " spanning-tree vlan 1-4094 priority 0 "  mess up anything except for a few secs of disconnection?

 to change things back use  " no spanning-tree vlan 1-4094 priority 0 "

Jaderson Pessoa
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Contributor

Re: Ping response from gateway longer than from switch

It is possible that if root guard is incorrectly configured on a down link switch, it could shut down a port that you would want to remain online. I agree that if your 3850 is the main switch, it should be the spanning-tree root and the command suggested by Jaderson is correct.
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VIP Advisor

Re: Ping response from gateway longer than from switch

Hello
TBH I don't really think it has anything to do with STP or QOS although @Jaderson Pessoa has a point about making your stp root central to the lan , This seems to suggest the businesses of the core switch.


When you ping the core switch remember that will be performing allot more functions then the access switch and as such its response time can be higher  as it has more important things to process

When you ping the access switch this traffic will be switched faster and as such the response will be lower also your source/destination is all at L2 so the core will really not need to be consulted.



kind regards
Paul

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Rising star

Re: Ping response from gateway longer than from switch

@paul driver  if you still think that a ping with 85ms in local lan is correctly, alright. For me there is a problem on it;

 

 

Regards,

 

Jaderson Pessoa
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Beginner

Re: Ping response from gateway longer than from switch

The whole network seems to be fine. Users did not say anything or complain. Our school site has been using those switches for years under the same configuration. Just recently some parent happened to run a ping to the gateway (the core switch) and told me that time reply does not look right. He said usually the time should be a single digit instead of double digits. I did ask other school's IT, they all have single digit time reply from the gateway switch. So that make me wonder if there is actually a problem going on which we did not know at all.

 

Below I draw our LAN again. Also from the attached, you will find the STP status/Current Roots information. I captured those by logging into the core switch using the Cisco Network Assistant. 

 

                                                                                                                                                   Access Switch (.111)

                                                                                                                                                              |

                                                                                                             Core Switch 2 (.254) -- Access Switch (.104)

                                                                                                                     | |

Cloud -- Comcast Modem -- ASA Firewall -- Access Switch (.107) -- Core Switch 1 (.254) -- Access Switch (.105) 

                                                                                  |                                                                           |

                                                                       Access Switch (.108)                                           Access Switch (.106)

VIP Advisor

Re: Ping response from gateway longer than from switch

Hello @Jaderson Pessoa 

I am not stating you are wrong in your assumptions i am just merely pointing out a possible reason why the response times are showing as they are, And as I have stated before one reason why the OP would be seeing a response time higher from the core switch as apposed to a lower response time from an access switch in front/behind the core switch (whichever way you look at it)  is possibly due to the core switch processing other stuff and its less of a priority for the core to respond to the ping

 

However when the same ping is sent to the access switch (via the core) this will most probably be fast switched and as such the core switch(router) will process this more quickly , now given that in this instance the source and destination is all in the same l2 domain not routing is involved so naturally the response time from the access switch which isn't as busy as the core can respond quicker then a core switch which is busy doing other things.

As @RabbitSF has confirmed no users are experiencing any issues about latency my understanding at this time is that what I have so far explained is occurring.



kind regards
Paul

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