Turning off or disabling interface of an old switch all network goes down

[Sam1985]

Hello,

Recently we migrated our core network switch's from 3600 to 7500, everything is working well, but when we want to turn off and old switch which has only one interconnection with another 3600 and then connected to 5700, all network goes down.

We have implement MSTP for spanning tree and defined both new 5700 core switch as primary and back, but still when we turn off the old switch the entire network goes down.

I have attached the network diagram and STP configuration please advice how to solve this issue

[Vince-Whirlwind]

Without the diagram, the most obvious question is, "what do you mean by the entire network goes down? What specific layer2 & layer3 tests have you run and what are their results" and the most obvious guess would be that this final switch is doing the routing for your network.

[Sam1985]

Hello,

I mean when i turn off the old switch or i reduce the priority of the old switch there is no routing and switching working, i think spannin tree is blocking the ports or it can be a bug i'm not sure.

I have attached network diagram, the switch called old switch needs to be removed.

According to my configuration routing is done via core switch's not the old switch.

All static routes are configured on core switches and the routing is done via firewall, in old switch only one default route is configured and it is routed to SW distribution.

                                                                        IP Route Entries

  Destination        Gateway         VLAN Type      Sub-Type   Metric     Dist.
  ------------------ --------------- ---- --------- ---------- ---------- -----
  0.0.0.0/0          10.180.253.100  10   static               1          1
  127.0.0.0/8        reject               static               0          0

Below is spanning tree conf if you need more information i can share .

Thanks in advance for your help.

[SW-Core- Datacenter 1]display stp root
 MST ID   Root Bridge ID        ExtPathCost IntPathCost Root Port
 0        0.082e-5f68-024b      2002        0           BAGG3
 1        0.d894-0371-3cbd      0           0
 2        0.d894-0371-3cbd      0           0
 3        0.d894-0371-3cbd      0           0
 10       0.d894-0371-3cbd      0           0
 11       0.d894-0371-3cbd      0           0
 20       0.d894-0371-3cbd      0           0

[SW-Core- Datacenter 1]display stp region-configuration
 Oper Configuration
   Format selector      : 0
   Region name          : MAR-TH2
   Revision level       : 1
   Configuration digest : 0xd84b3234ed01dd5206c7323bc34ea908

   Instance  VLANs Mapped
   0         2 to 9, 14 to 19, 21 to 69, 71 to 89, 91 to 200, 204 to 299,
             305 to 307, 309 to 339, 341 to 400, 402 to 499, 531 to 4094
   1         1, 12 to 13, 20, 70, 90, 201 to 203, 300 to 304, 401
   2         340
   3         308
   10        10
   11        11
   20        500 to 530

[SW-EQX-CORE]display stp root
 MST ID   Root Bridge ID        ExtPathCost IntPathCost Root Port
 0        0.082e-5f68-024b      12002       0           BAGG1
 1        4096.d894-0379-ebbc   0           0
 2        32768.d894-0379-ebbc  0           0
 3        4096.d894-0379-ebbc   0           0
 10       4096.d894-0379-ebbc   0           0
 11       32768.d894-0379-ebbc  0           0
 20       32768.d894-0379-ebbc  0           0
===========================================

[SW-Core- Datacenter 2]display stp reg
[SW-EQX-CORE]display stp region-configuration
 Oper Configuration
   Format selector      : 0
   Region name          : MAR-EQX
   Revision level       : 1
   Configuration digest : 0xd84b3234ed01dd5206c7323bc34ea908

   Instance  VLANs Mapped
   0         2 to 9, 14 to 19, 21 to 69, 71 to 89, 91 to 200, 204 to 299,
             305 to 307, 309 to 339, 341 to 400, 402 to 499, 531 to 4094
   1         1, 12 to 13, 20, 70, 90, 201 to 203, 300 to 304, 401
   2         340
   3         308
   10        10
   11        11
   20        500 to 530

================================

Old switch# display stp
 abnormal-port         Display abnormal ports
 bpdu-statistics       STP BPDU statistics
 brief                 Brief information
 down-port             Port information of protocol down
 history               Root or alternate port history
 instance              Spanning tree instance
 interface             Specify interface
 region-configuration  Region configuration
 root                  Display status and configuration of the root bridge
 slot                  Slot ID
 tc                    Port TC count
 vlan                  Virtual Lan
 <cr>
Old switch # display stp root
 MSTID   Root Bridge ID        ExtPathCost   IntPathCost   Root Port
  0      0.020111-020500       0             0             This switch is root
  1      0.010201-070101       20000         0             This switch is root
  2      0.010201-070102       20000         0             This switch is root
  3      0.010201-070103       20000         0             This switch is root
  4      0.010201-070104       20000         0             This switch is root
  5      0.010201-070105       20000         0             This switch is root
  10     0.010201-07010a       20000         0             This switch is root

[Vince-Whirlwind]

I can't see from that information what all the other switch STP priorities are.
Also, when I mentioned the routing the old switch is doing, I am referring to what IP addressing it has on it and what network hosts are trying to use those IP addresses as their router address.

[Sam1985]

Hello,

Thanks for replay, below is display stp configuration for core switches which has been configured as primary and secondary root for STP instances :

Switch core datacenter 1

stp region-configuration
 region-name MAR-TH2
 revision-level 1
 instance 1 vlan 1 12 to 13 20 70 90 201 to 203 300 to 304 401
 instance 2 vlan 340
 instance 3 vlan 308
 instance 10 vlan 10
 instance 11 vlan 11
 instance 20 vlan 500 to 530
 active region-configuration
 stp instance 0 to 4094 root primary

 stp global enable

Switch core datacenter 2

stp region-configuration
 region-name MAR-EQX
 revision-level 1
 instance 1 vlan 1 12 to 13 20 70 90 201 to 203 300 to 304 401
 instance 2 vlan 340
 instance 3 vlan 308
 instance 10 vlan 10
 instance 11 vlan 11
 instance 20 vlan 500 to 530
 active region-configuration
#
 stp instance 0 to 1 3 10 20 root secondary
 stp global enable

As mentioned in my previouse poste my old switch has only 1 default route and other switch's has no root towards old switch.