UNSOLVED
STP Topology changes
Hello All,
Before I get going on the issue here I will give you a little view of the network.
We have 2 6224 PC switces, 2 3548, 3 3448's.
The 2 6224 are seperate networks but are routed to communicate with each other. The 6224's are connected to the other switches, one is connected to a stack of 2 and the other a stack of 3 I am sure you will have other questions on this but I don't want to get to crazy initially.
Over the past few weeks we have seen a lot of really high pings and some timeouts intermitanly on the networks that we have been trying to figure out where they are coming from. So the LAN is humming along good with less than 1ms pings and then out of no where 200,300, 400ms pings and then it stops after about 20 seconds or so.
What I found is that the high pings occur when the STP topology changes. Then the network must converge and all is good.
The issue here is that we are seeing a ton of topology changes so this is occuring 50-100 times daily. I am looking for a little help in trouble shooting this.. One thing I have noticed is that the 2 stacks and one of the 6224's is set to Classic STP and the other 6224 is set to RSTP.
Is it safe to set them all to RSTP? Would this bring everything down for a short time?
Also we have a few unmanaged switches out there on the network, could these be the source of a lot of the topology changes?? Loops possibly??
I am sure you will ask for additional information, this is just a start. Ask away I would like to get to the bottom this once and for all...
Thanks for any help,
drebbin
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25 Posts
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Posted December 18th, 2008 12:00
Hi,
I have a few other things to add here...
On the 3448 stack it seems that Port Fast is set to Auto on all ports and it is enabling that on all ports.
I am seeing 3 ports in particular go down back up and then the STP status changes to forwarding.
01-Feb-2000 13:52:42 %LINK-W-Down: 2/e37
01-Feb-2000 13:52:45 %LINK-I-Up: 2/e37
01-Feb-2000 13:52:49 %STP-W-PORTSTATUS: 2/e37: STP status Forwarding
01-Feb-2000 13:53:43 %LINK-W-Down: 3/e27
01-Feb-2000 13:53:45 %LINK-I-Up: 3/e27
01-Feb-2000 13:53:49 %STP-W-PORTSTATUS: 3/e27: STP status Forwarding
01-Feb-2000 13:53:58 %LINK-W-Down: 3/e27
01-Feb-2000 13:54:00 %LINK-I-Up: 3/e27
01-Feb-2000 13:54:05 %STP-W-PORTSTATUS: 3/e27: STP status Forwarding
01-Feb-2000 13:54:11 %LINK-W-Down: 1/e32
01-Feb-2000 13:54:13 %LINK-I-Up: 1/e32
01-Feb-2000 13:54:17 %STP-W-PORTSTATUS: 1/e32: STP status Forwarding
01-Feb-2000 13:54:20 %LINK-W-Down: 1/e32
01-Feb-2000 13:54:22 %LINK-I-Up: 1/e32
01-Feb-2000 13:54:26 %STP-W-PORTSTATUS: 1/e32: STP status Forwarding
01-Feb-2000 13:54:28 %LINK-W-Down: 2/e37
01-Feb-2000 13:54:30 %LINK-I-Up: 2/e37
01-Feb-2000 13:54:34 %STP-W-PORTSTATUS: 2/e37: STP status Forwarding
01-Feb-2000 13:54:54 %LINK-W-Down: 2/e37
01-Feb-2000 13:54:56 %LINK-I-Up: 2/e37
01-Feb-2000 13:55:01 %STP-W-PORTSTATUS: 2/e37: STP status Forwarding
Here is the show run off that stack...
-2)
port storm-control broadcast enable
exit
interface range ethernet 1/e(1,3-22,24-48),2/e(1-48),2/g(1-2),3/e(1-48),3/g(1
-2)
port storm-control broadcast rate 3500
exit
interface range ethernet 1/e(1,3-22,24-48),2/e(1-48),2/g(1-2),3/e(1-48),3/g(1
-2)
port storm-control include-multicast
exit
interface range ethernet 1/e(1-7,9-48),2/e(1-36,38-41,45-48),3/e(1-39,41-48),
4/e(1-29,31-48)
dot1x multiple-hosts
exit
interface range ethernet 1/g1,2/g1
switchport mode general
exit
vlan database
vlan 4,10,50,200,300,400
exit
interface range ethernet 1/e(1-2,6,8,10-11,13-23,25-27,29-34,37-45),2/e(1,3,5
-40,46),3/e(3-4,6-7,9,11-14,16,18-37,40,42-46)
switchport access vlan 4
exit
interface ethernet 1/g1
switchport general allowed vlan add 4
exit
interface ethernet 1/e4
switchport access vlan 10
exit
interface ethernet 1/g1
switchport general allowed vlan add 10
exit
interface ethernet 1/g1
switchport general allowed vlan add 200
exit
interface ethernet 1/g1
switchport general allowed vlan add 300
exit
interface ethernet 1/g1
switchport general allowed vlan add 400
exit
interface vlan 4
name Corporate
exit
interface vlan 50
name test
exit
interface vlan 200
name Accounting
exit
interface vlan 300
name Marketing
exit
interface vlan 400
name HR
exit
interface vlan 1
ip address 192.168.0.3 255.255.255.0
exit
ip default-gateway 192.168.0.2
mac access-list "test"
exit
username alcadmin password e01e13231596db53b02df7457b4efbfd level 15 encrypte
d
snmp-server community public rw view DefaultSuper
stack master unit 1
SW version 1.0.1.13 (date 20-Feb-2006 time 09:52:44)
Fast Ethernet Ports
==========================
no shutdown
speed 100
duplex full
negotiation
flow-control off
mdix auto
no back-pressure
Gigabit Ethernet Ports
=============================
no shutdown
speed 1000
duplex full
negotiation
flow-control off
mdix auto
no back-pressure
interface vlan 1
interface port-channel 1 - 8
spanning-tree
spanning-tree mode STP
qos basic
Thanks,