Ping response from gateway longer than from switch

[RabbitSF]

I am not Cisco expert so the following question might sound silly.

I have the following path,

Laptop--Access Point--Switch1(2960x)--Gateway(core 3850 switch)--Switch2(2960x)

I ping to both the Gateway and the Switch2. How come the average response from the Gateway is longer than from the Switch2?

If I run trace route to the Swtich2, the first stop is always the Gateway. I assumed the Ping should reach the Gateway first, then the Switch2. 

Please correct me if my understanding is totally wrong. Thanks!

[Jaderson Pessoa]

@RabbitSFhello,

I think that it is a STP issue..

Could you provide a simple design from your topology

input here output from:

show spannning-tree

[RabbitSF]

see attached. You might notice that the core gateway switch is NOT directly connected to the modem or firewall (MDF). 

I am connected to 192.168.254.106 (the top IDF)

when I ping to the core 192.168.254.254, 

PING 192.168.254.254 (192.168.254.254): 56 data bytes

64 bytes from 192.168.254.254: icmp_seq=0 ttl=255 time=84.862 ms

64 bytes from 192.168.254.254: icmp_seq=1 ttl=255 time=20.926 ms

64 bytes from 192.168.254.254: icmp_seq=2 ttl=255 time=17.930 ms

64 bytes from 192.168.254.254: icmp_seq=3 ttl=255 time=26.751 ms

64 bytes from 192.168.254.254: icmp_seq=4 ttl=255 time=36.654 ms

64 bytes from 192.168.254.254: icmp_seq=5 ttl=255 time=47.100 ms

When I ping 192.168.254.107,

PING 192.168.254.107 (192.168.254.107): 56 data bytes

64 bytes from 192.168.254.107: icmp_seq=0 ttl=254 time=2.988 ms

64 bytes from 192.168.254.107: icmp_seq=1 ttl=254 time=4.024 ms

64 bytes from 192.168.254.107: icmp_seq=2 ttl=254 time=1.832 ms

64 bytes from 192.168.254.107: icmp_seq=3 ttl=254 time=1.830 ms

64 bytes from 192.168.254.107: icmp_seq=4 ttl=254 time=2.944 ms

[Jaderson Pessoa]

Could your share with us your spanning-tre configuration?

show spanning-tree

show spanning-tree root

Regards,

[RabbitSF]

Core-3850-SW1#show spanning-tree

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/11 Desg FWD 4 128.11 P2p Edge
Gi1/0/15 Desg FWD 4 128.15 P2p Edge
Gi1/0/16 Desg FWD 4 128.16 P2p Edge
Gi1/0/19 Desg FWD 19 128.19 P2p Edge
Gi1/0/20 Desg FWD 19 128.20 P2p Edge
Gi1/0/23 Desg FWD 4 128.23 P2p Edge
Gi1/0/24 Desg FWD 4 128.24 P2p Edge
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 32778
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/0/17 Desg FWD 19 128.81 P2p Edge
Gi2/0/18 Desg FWD 19 128.82 P2p Edge
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0020
Spanning tree enabled protocol ieee
Root ID Priority 32788
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32788 (priority 32768 sys-id-ext 20)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/13 Desg FWD 4 128.13 P2p Edge
Gi1/0/14 Desg FWD 4 128.14 P2p Edge
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/0/1 Desg FWD 4 128.65 P2p Edge
Gi2/0/2 Desg FWD 4 128.66 P2p Edge
Gi2/0/3 Desg FWD 19 128.67 P2p Edge
Gi2/0/6 Desg FWD 19 128.70 P2p Edge
Gi2/0/7 Desg FWD 19 128.71 P2p Edge
Gi2/0/21 Desg FWD 19 128.85 P2p Edge
Gi2/0/24 Desg FWD 19 128.88 P2p Edge
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0100
Spanning tree enabled protocol ieee
Root ID Priority 32868
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0253
Spanning tree enabled protocol ieee
Root ID Priority 33021
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33021 (priority 32768 sys-id-ext 253)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0254
Spanning tree enabled protocol ieee
Root ID Priority 33022
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33022 (priority 32768 sys-id-ext 254)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0255
Spanning tree enabled protocol ieee
Root ID Priority 33023
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33023 (priority 32768 sys-id-ext 255)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

VLAN0256
Spanning tree enabled protocol ieee
Root ID Priority 33024
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33024 (priority 32768 sys-id-ext 256)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

Core-3850-SW1#show spanning-tree root

Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
VLAN0001 32769 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0010 32778 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0020 32788 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0100 32868 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0253 33021 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0254 33022 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0255 33023 80e8.6f31.0c00 4 2 20 15 Gi1/1/2
VLAN0256 33024 80e8.6f31.0c00 4 2 20 15 Gi1/1/2

[Jaderson Pessoa]

VLAN0256
Spanning tree enabled protocol ieee
Root ID Priority 33024   
Address 80e8.6f31.0c00
Cost 4
Port 26 (GigabitEthernet1/1/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 33024 (priority 32768 sys-id-ext 256)
Address 80e8.6f3a.cf00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/1/2 Root FWD 4 128.26 P2p
Gi1/1/3 Desg FWD 4 128.27 P2p
Gi2/1/1 Desg FWD 4 128.89 P2p
Po1 Desg FWD 3 128.2027 P2p
Po2 Desg FWD 3 128.2028 P2p
Po10 Desg FWD 3 128.2036 P2p

All of your vlans has a other switch as root bridge, it is correctly in your topology?

[RabbitSF]

Jaderson, 

Thanks much for looking into this with me! But I don't know how I can answer your question because I am not a Cisco expert and the network was not set up by me. I am not familiar with all these Cisco routing protocol either. I know STP is a big topic and it will take me a while to learn and understand. 

Out IT Consultant set up all the Cisco switches and the whole network. They did tell me the following: 

"..... One other thought that crossed my mind is the loop you have in your network as well. You have lower school building with Internet connection with VLAN's etc. That connection then is carried to the firewall, then trunked over the fiber to the core switch. That same trunk also carries ALL other vlans back to lower school building...."

If you look at the network diagram I uploaded, you can see the lower school building is at the bottom level where the MPOE is located. My laptop is the at the 2nd building on the top IDF. The core switch is located at the 3rd building in the middle IDF. I don't know if that helps you understand our topology. 

[RabbitSF]

One more thing, if you look at the network diagram I uploaded, you will notice there are two core 3850 switches. They are actually stacked together creating a loop for redundancy if I understand correctly. 

[Deepak Kumar]

Hi,

Are you facing any slowness issue? Did you enable any QoS? I think the best way to share traceroute command output so we can understand actually place where we were having an issue and will look into the configuration also.

[Jaderson Pessoa]

right,

Could you check who switch has this mac address? 80e8.6f31.0c00 (just to confirm if it is a STP issue).

you can check it using " show version " in end of the page you will see mac address


Regards,

[paul driver]

Hello

FYI @Jaderson Pessoa  easiest way to check the base mac address of a switch

show version | in Base

[Jaderson Pessoa]

@paul driver Hello,

I know it, but i'm trying show to @RabbitSF how many information he can see on this command. He is not a expert on network or managerment switches.

Regards,

[RabbitSF]

Jaderson, the mac address 80e8.6f31.0c00 is the access switch (192.168.254.107) which is connected directly to the firewall. The path is like below,

Cloud--Comcast Modem--Firewall--Access Switch(80e8.6f31.0c00)--Core Switch--other Access Switches--Clients 

[Jaderson Pessoa]

@RabbitSF well, i'm still think that your STP topology is the problem.

Let me try explain.

YOUR CORE HAS ALL VLANS AND SVI CREATED ON ITSELF, BUT IT IS NOT ROOT FOR ANY VLANS, THE ROOT BRIDGE FOR YOUR VLANS IS A SWITCH ACCESS 2960X WITH IP ADDRESS 192.168.254.107.

ON YOUR 3850 (SWITCH CORE) run this command below

spanning-tree vlan 1-4094 priority 0

obs: this will disconnect all comunication for few seconds

[paul driver]

Hello

@Jaderson Pessoa 

the stp root at present is in front of the core switch and also it has another switch interconnected to it which isn’t connected to the core so the placement of the root as it is is viable.as that switch is central between the core its own connecting switches  and the router