how to change path cost

[hashbang]

Hi,
how to change path cost in crs 317. No matter wht you do it sends 10. I’m having wrong root selection and its total mess.

region 12 root should be x 0/0/4.
network <…><Huawei(A)>……<Huawei(B)>

HUAWEI A :
0 0.f898-ef73-c061 10000 2 20 15 XGigabitEthernet0/0/4 … towards network
12 32768.084f-0ab2-1eff 2010 2 20 15 XGigabitEthernet0/0/3 …towards crs sfp 16 (this root bridge connects to huawei B thru crs)


2010 should be 22000
I’m having doubts tht mstp of crs will not work with other switches mstp.


thanks and regards
crs0810.rsc (5.12 KB)

[tdw]

Unlike other vendors which change path cost depending on interface speed the Mikrotik default is 10, just set it to what you wish it to be. The recommended defaults are widely available, e.g. https://en.wikipedia.org/wiki/Spanning_Tree_Protocol#Path_cost

Note path costs have nothing to do with root bridge selection, see https://wiki.mikrotik.com/wiki/Manual:Spanning_Tree_Protocol#Election_process

[hashbang]

even basic things are missing

1. How will mstp interact with other switches running RSTP
2. I couldnt find instance cost on ports settings. If anyone knows then plz tell me
3. No idea wht costs it sends
4. in above screenshot this switch has prio of 8000 then still its becoming a root bridge.
   how will anyone do load balancing using mstp when i doenst support costs on instance

[hashbang]

Unlike other vendors which change path cost depending on interface speed the Mikrotik default is 10, just set it to what you wish it to be. The recommended defaults are widely available, e.g. https://en.wikipedia.org/wiki/Spanning_Tree_Protocol#Path_cost

Note path costs have nothing to do with root bridge selection, see https://wiki.mikrotik.com/wiki/Manual:Spanning_Tree_Protocol#Election_process

ty
plz see this
2 32768.084f-0ab2-1eff 2010 2 20 15 XGigabitEthernet0/0/3 …towards crs sfp 16 (this root bridge connects to huawei B thru crs)
the value is 2010 and plz see in screenshot of winbox its 2000 and 20000 from where 10 is coming ?

[hashbang]

Unlike other vendors which change path cost depending on interface speed the Mikrotik default is 10, just set it to what you wish it to be. The recommended defaults are widely available, e.g. https://en.wikipedia.org/wiki/Spanning_Tree_Protocol#Path_cost

Note path costs have nothing to do with root bridge selection, see https://wiki.mikrotik.com/wiki/Manual:Spanning_Tree_Protocol#Election_process

this network is having 3xx switches all huawei only mikrotik is misbehaving (only 2 installed) traffic nearing 100g

[tdw]

The screenshot showing sfp16 role root port indicates this is the path to the root bridge, it is not the root bridge itself - something else is.

The path costs are shown in the screenshots, and you have actually set some as the configuration has entries such as path-cost=20000. These are the cost on that particular point-to-point link, there is separately a calculated root path cost which is the sum of all the point-to-point link costs back to the root bridge.

RSTP will interwork with the MSTP CIST.

[hashbang]

The screenshot showing sfp16 role root port indicates this is the path to the root bridge, it is not the root bridge itself - something else is.

The path costs are shown in the screenshots, and you have actually set some as the configuration has entries such as path-cost=20000. These are the cost on that particular point-to-point link, there is separately a calculated root path cost which is the sum of all the point-to-point link costs back to the root bridge.

RSTP will interwork with the MSTP CIST.

ty,
its all mstp currently
sfp 16 is root port but no cost shown
on the other side crs is root bridge on instance 12
12 32768.084f-0ab2-1eff 2010 2 20 15 XGigabitEthernet0/0/3 …towards crs sfp 16 (this root bridge connects to huawei B thru crs)
xg 0/0/3 is crs. So its a kind of root loop. A sending to B and B sending back to A

in crs sfp 16 is root port and on huawei xg 0/0/3 is root port (inst 12)

[hashbang]

apologies tdw it was mstp with other brand mstp (not rstp)
here is huawei manual for more info
On an MSTP network where Huawei and non-Huawei devices are interconnected, if the Huawei and non-Huawei devices have the same region name, revision level, and VLAN mapping table but different BPDU keys, the stp config-digest-snoop command can be used to enable the Huawei and non-Huawei devices to exchange BPDUs.