MSTP - no Root election | Comware - ProCurve

[andreaspechiny]

Hello,

we have purchased 2 5500AI and configured tham as "backbone". multiple 2530 switches are connected to the backbone. I've configured mstp, but the peer-switches declare themselves as root.

I can't find my mistake and i hope to get a solution from this forum.

config bb02:

stp region-configuration
region-name MSTP
revision-level 1
instance 1 vlan 2 10 100 102 104 106 108 201 203 205
instance 1 vlan 207 250
instance 2 vlan 1 101 103 105 107 200 202 204 206 208
instance 2 vlan 254
active region-configuration
#
stp instance 0 root primary
stp instance 1 root primary
stp instance 2 root secondary
stp enable

config bb03:

stp region-configuration
region-name MSTP
revision-level 1
instance 1 vlan 2 10 100 102 104 106 108 201 203 205
instance 1 vlan 207 250
instance 2 vlan 1 101 103 105 107 200 202 204 206 208
instance 2 vlan 254
active region-configuration
#
stp instance 0 root secondary
stp instance 1 root secondary
stp instance 2 root primary
stp enable

connection betreen backbones

interface Bridge-Aggregation1
description lacp to msbb03 ba1
port link-type trunk
port trunk permit vlan all
link-aggregation mode dynamic

standard config uplink

interface GigabitEthernet1/0/18
port link-mode bridge
description upto mswsr01 e23
port link-type trunk
port trunk permit vlan all

configuration edge-switch

spanning-tree

spanning-tree config-name "MSTP"
spanning-tree config-revision 1
spanning-tree instance 1 vlan 2 10
spanning-tree instance 2 vlan 1 254

Output Edge:

sh spanning-tree

Multiple Spanning Tree (MST) Information

STP Enabled : Yes
Force Version : MSTP-operation
IST Mapped VLANs : 3-9,11-253,255-4094
Switch MAC Address : 6c3be5-e2a640
Switch Priority : 32768
Max Age : 20
Max Hops : 20
Forward Delay : 15

Topology Change Count : 50
Time Since Last Change : 21 hours

CST Root MAC Address : d07e28-e23168
CST Root Priority : 0
CST Root Path Cost : 20000
CST Root Port : 23

IST Regional Root MAC Address : 6c3be5-e2a640
IST Regional Root Priority : 32768
IST Regional Root Path Cost : 0
IST Remaining Hops : 20

Root Guard Ports :
Loop Guard Ports :
TCN Guard Ports :
BPDU Protected Ports : 1-9,11-22
BPDU Filtered Ports : 1-9,11-22
PVST Protected Ports :
PVST Filtered Ports :

| Prio | Designated Hello
Port Type | Cost rity State | Bridge Time PtP Edge
----- --------- + --------- ---- ------------ + ------------- ---- --- ----
1 100/1000T | Auto 128 Disabled |

22 100/1000T | Auto 128 Disabled |
23 100/1000T | 20000 128 Forwarding | d07e28-e23168 2 Yes No
24 100/1000T | 20000 128 Blocking | d07e28-2efa9d 2 Yes No
25 | Auto 128 Disabled |

mswsr01# sh spanning-tree instance 1

MST Instance Information

Instance ID : 1
Mapped VLANs : 2,10
Switch Priority : 32768

Topology Change Count : 8
Time Since Last Change : 2 hours

Regional Root MAC Address : 6c3be5-e2a640
Regional Root Priority : 32768
Regional Root Path Cost : 0
Regional Root Port : This switch is root
Remaining Hops : 20

Designated
Port Type Cost Priority Role State Bridge
----- --------- --------- -------- ---------- ------------ --------------
1 100/1000T Auto 128 Disabled Disabled

22 100/1000T Auto 128 Disabled Disabled
23 100/1000T 20000 128 Master Forwarding 6c3be5-e2a640
24 100/1000T 20000 128 Alternate Blocking 6c3be5-e2a640
25 Auto 128 Disabled Disabled

mswsr01# sh spanning-tree instance 2

MST Instance Information

Instance ID : 2
Mapped VLANs : 1,254
Switch Priority : 32768

Topology Change Count : 8
Time Since Last Change : 2 hours

Regional Root MAC Address : 6c3be5-e2a640
Regional Root Priority : 32768
Regional Root Path Cost : 0
Regional Root Port : This switch is root
Remaining Hops : 20

Designated
Port Type Cost Priority Role State Bridge
----- --------- --------- -------- ---------- ------------ --------------
1 100/1000T Auto 128 Disabled Disabled

23 100/1000T 20000 128 Master Forwarding 6c3be5-e2a640
24 100/1000T 20000 128 Alternate Blocking 6c3be5-e2a640

Why is the switch the root for both instances?

[Richard Brodie_1]

I think it's because your VLAN mappings are different: the MST configuration digest is based on the VLAN to IST mappings, so you can't omit VLAN mappings on the 2530, even if you aren't going to assign any ports to them.

disp stp region-configuration (on the 5500AI)

show span mst-config on the 2530.

If the config hashes don't match, then the switches won't be in the same MST region.

[Beero]

I had problems with MSTP, although i was not complaining about root elections, but i think i had it too.

* Please make sure VLAN-To-INSTANCE Mappings are 100% Identical !!

* Please make sure the Region name is 100% Identical on all swtiches (my problem was that some switches treated quotations differently, eventually effecting the name)

[andreaspechiny]

That's it. I've configured the region-vlan-mapping similar.

Thank you very much.

Andreas

[andreaspechiny]

Unfortunally three is another problem.

the MSTP-Config is working fine but now i cant connect to the device IP-adress. When i am diabling the port from backboneswitch 2 (mswbb03) to the switch (port 23) the connection is possible.

with the wrong configuration it is working. i think in this case stp is disabling port 23 for all vlans, right?

but i dont understand what happens when mstp is working and what is going wrong then.

I hope someone can help me.

Andreas

[Richard Litchfield]

Why do you need multiple instances anyway? Since you have 5500s in IRF, you don't need to run VRRP which is a common partner for MSTP (in combination provides load sharing).

Your 2530s should each be connected with an LACP aggregation (MLAG) to both 5500 core switches. The theory says you could turn of spanning tree completely! (Don't though - you should always have some loop avoidance mechanism, and as much as marketing says STP is not required with IRF, the point is that the network is simplified.)

It may be that you are unnecessarily complicating things. Wht not enable MSTP on all devices, but do away with the instances, and put all the VLANs into the common instance (CST)? Much simpler to manage!