04-18-2019 12:33 PM - edited 04-18-2019 12:34 PM
The SG350 is running MST in order to allow for multiple instances of STP while the Cat is running PVST+ (migrating all to MST is off the table for now). I'd like to connect these switches via multiple 1Gbps interfaces and in doing so, use each interface independently. That means neither interface being shut down due to STP.
I've found that I can do this between two SG switches (MST and mapping vlans to instances) and two Cat switches (PVST+ where I made the interfaces access mode and placed them in separate vlans). I've read up on PVST simulation bit (Cisco PVST Simulation) and I've gotten the switches to play nice with each other but one of the SG ports always go to discarding mode. The Cat is the root bridge and that cannot be changed.
I've tried to mess with port costs and priorities in order to try to get port 24 up and running but no luck. (The switches are connect Gi1/0/23 <-> Te1/0/23 and Gi1/0/24 <-> Te1/0/24. Is load balancing really possible when using PVST simulation between a MST and PVST+ region?
VLAN0006 Spanning tree enabled protocol rstp Root ID Priority 4102 Address 0072.7838.6280 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 4102 (priority 4096 sys-id-ext 6) Address 0072.7838.6280 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Gi1/0/23 Desg FWD 10 128.23 P2p Gi1/0/24 Desg FWD 4 128.24 P2p
###### MST 2 Vlans Mapped: 6-13 Root ID Priority 0 Address 2c:ab:eb:23:84:c7 This switch is the regional root Interfaces Name State Prio.Nbr Cost Sts Role PortFast Type -------- -------- -------- --------- ---- ---- -------- ---------- te1/0/23 enabled 128.23 30000 Frw Mstr No P2P Bound (RSTP) te1/0/24 enabled 0.24 20000 Dscr Boun No P2P Bound (RSTP)
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06-11-2019 06:30 AM
04-18-2019 12:50 PM
Never worked with SG series switches but can you put both ports on both switches in a Portchannel group? Doing that may bring up port 1/0/24 as you will have 2 physical interfaces in one logical Portchannel (no loop).
HTH
04-22-2019 05:23 AM
04-18-2019 02:16 PM
@ksbolton1 Hello,
If you devices have two connection between them without port-channel, the STP will disable one port to prevent loop in your network, independetly if you are using MST or PVST+.
I'm work with SG550xg and i have two running MST and my other catalyst running rapid-pvst, its works very well.
Regards,
04-22-2019 05:27 AM
04-22-2019 04:42 PM - edited 04-23-2019 04:32 AM
Hello
@ksbolton1 wrote:
The SG350 is running MST in order to allow for multiple instances of STP while the Cat is running PVST+ (migrating all to MST is off the table for now). I'd like to connect these switches via multiple 1Gbps interfaces and in doing so, use each interface independently. That means neither interface being shut down due to STP.
I've found that I can do this between two SG switches (MST and mapping vlans to instances) and two Cat switches (PVST+ where I made the interfaces access mode and placed them in separate vlans). I've read up on PVST simulation bit (Cisco PVST Simulation) and I've gotten the switches to play nice with each other but one of the SG ports always go to discarding mode. The Cat is the root bridge and that cannot be changed.I've tried to mess with port costs and priorities in order to try to get port 24 up and running but no luck. (The switches are connect Gi1/0/23 <-> Te1/0/23 and Gi1/0/24 <-> Te1/0/24. Is load balancing really possible when using PVST simulation between a MST and PVST+ region?
Looks like you not getting any PVST inconsistent states just a port being blocked to negate a loop. - However you say that these ports are in two different access vlans and not trunks correct?
Can you please confirm the BID priorities that are applied on the MST instances within the MST region switches and to the vlans non mst region switch(s).
04-23-2019 07:44 AM
04-23-2019 02:15 PM
SG config:
spanning-tree mode mst spanning-tree priority 12288 spanning-tree mst configuration instance 1 vlan 2-5 instance 2 vlan 6-13 name TEST exit spanning-tree mst 1 priority 0 spanning-tree mst 2 priority 0 port jumbo-frame vlan database vlan 2-13 exit ! interface TengigabitEthernet1/0/23 spanning-tree link-type point-to-point spanning-tree mst 2 cost 30000 switchport mode trunk macro description switch !next command is internal. macro auto smartport dynamic_type switch ! interface TengigabitEthernet1/0/24 spanning-tree link-type point-to-point spanning-tree mst 2 port-priority 0 switchport mode trunk macro description switch !next command is internal. macro auto smartport dynamic_type switch !
Catalyst config:
spanning-tree mode rapid-pvst spanning-tree extend system-id spanning-tree vlan 1 priority 8192 spanning-tree vlan 2-4094 priority 4096 interface GigabitEthernet1/0/23 switchport mode trunk spanning-tree vlan 6-13 cost 10 ! interface GigabitEthernet1/0/24 switchport mode trunk ! interface Vlan1 no ip address shutdown
05-07-2019 05:58 PM
I've been tinkering with this but no dice. Can anyone offer additional guidance?
06-11-2019 06:30 AM
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