12-14-2018 10:32 PM - edited 03-08-2019 04:49 PM
Hi
I use a C3750 as my core switch where I have configured all the vlans for my office. We have a 100 Mbps link for Internet but I notice that the speed is only nearly half from user side. The 100 Mbps link is connected to a firewall to which the switch is connected. In order to make sure this is not an ISP issue, I connected a laptop directly to the firewall and got a speed more than 90 Mbps. So it's definitely not an ISP issue. Attached is the configuration of my switch. I'm not able to find out where the configuration is wrong. Any assistance would be appreciated.
12-15-2018 10:55 AM
Hello
can you check on your stp - make sure this switch stack is the stp root
sh version | in Base. <—--check the base Mac-address
show spanning-tree root
config t
spanning-tree vlan 1-4092 priority 0
12-15-2018 08:28 PM
Hi Paul,
OMAHO_LAN_CORESW1# sh version | in Base
Base ethernet MAC Address : FC:5B:39:59:6E:80
Base ethernet MAC Address : BC:16:F5:C4:EA:00
OMAHO_LAN_CORESW1#show spanning-tree root
Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
---------------- -------------------- --------- ----- --- --- ------------
VLAN0001 1 fc5b.3959.6e80 0 2 20 15
VLAN0030 30 fc5b.3959.6e80 0 2 20 15
VLAN0031 31 fc5b.3959.6e80 0 2 20 15
VLAN0032 32 fc5b.3959.6e80 0 2 20 15
VLAN0033 33 fc5b.3959.6e80 0 2 20 15
VLAN0034 34 fc5b.3959.6e80 0 2 20 15
VLAN0035 35 fc5b.3959.6e80 0 2 20 15
VLAN0036 36 fc5b.3959.6e80 0 2 20 15
VLAN0040 40 fc5b.3959.6e80 0 2 20 15
VLAN0050 50 fc5b.3959.6e80 0 2 20 15
VLAN0100 100 fc5b.3959.6e80 0 2 20 15
VLAN0192 192 fc5b.3959.6e80 0 2 20 15
The improvement I mentioned earlier was only minor. Earlier it used to peak at around 50 Mbps, now it goes up to 60Mbps.
12-15-2018 09:07 PM
12-16-2018 02:06 AM
just gone lost here in thread. so your switch is not root bridge here..and you have core switch act as root bridge for the vlans.
Can you pleae confirm how is your setup
user --(Access switch)--Core switch0-- FW --internet
where Access switch you are not getting expected speed is this correct ?
12-16-2018 02:43 AM
Hi Balaji,
You are right. This is the flow.
user --(Access switch)--Core switch0-- FW --internet
I directly connected to the Core Switch as suggested but the issue was still there.
So speed issue is not just from the Access switch.
12-16-2018 04:14 AM
So the problem still the same if you connect to core Swtch also.
So the problem now in core switch - so lets start working on core switch, then move to next level of network.
when you mentioned last conversation, you could able to get more good throughput when you connected to FW.
doe this mean you connect to FW port and tested ? or connected to switch port and tested.
core_CNA (is your core switch config), please confirme so let review that config.
12-16-2018 06:34 AM
Hi,
I connected directly to the Firewall port and tested. No switch in between.
Yes, CORESW1 - CNA is the configuration of Core Switch.
12-15-2018 11:25 AM
Hello,
I just remembered another thread with a similar issue. That was resolved by downgrading the IOS to release 12.2.55-SE12 MD. If you run out of ideas, you might want to give that a try...
12-16-2018 05:31 AM
Hi Georg,
I took another C3750 switch with 12.2(58)SE2 IOS and restored the current configuration into that. I added another VLAN and tested with a laptop. There was no change. In fast.com, the speed showed only 4.5 Mbps.
12-16-2018 07:03 AM
Hello,
I am just thinking you might be running into the L3 throughput limit, which is somewhere around 65Mbps for the 3750E 24 port switch...
Check the data sheet attached (not sure if that is still current though):
https://www.cisco.com/web/partners/downloads/765/tools/quickreference/switchperformance.pdf
12-16-2018 08:35 AM
12-16-2018 08:55 AM
What throughput do you get when you connect two clients on that same switch through a Layer 3 connection ?
interface GigabitEthernt1/0/5
description PC1
switchport access vlan 33
spanning-tree portfast
!
interface GigabitEthernt1/0/6
description PC2
switchport access vlan 34
spanning-tree portfast
12-16-2018 09:25 AM
Hello
Can you confirm with what configuration you are running with, you have now posted completely 3 different config versions.
12-16-2018 09:40 AM
Hi Paul,
12-16-2018 08:35 PM
Hi Georg,
Both the clients are giving the same speed.
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