Ethernet Switching
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Ethernet Switching

RSTP block specific port

‎11-11-2019 01:58 AM

Hi all,

 

First of all, sorry about my EnglishSmiley Wink

 

I´ve a network with 3 EX4300 and 2 Mikrotiks that are distributed as ring topology:

J1-----------J2(root)------J3---Mikrotik1---Mikrotik2----J1

 

so 1 link should be blocked by rstp. The issue I´m having is that despite I´ve increased the  port cost in the port between J4 and Mikrotik1, rstp is blocking the interface between J1 and Mikrotik2.

J1 rstp conf 

root@J1_203> show spanning-tree bridge
STP bridge parameters
Routing instance name : GLOBAL
Context ID : 0
Enabled protocol : RSTP
Root ID : 16384.80:ac:ac:b0:db:00
Root cost : 10000
Root port : ae0
Hello time : 2 seconds
Maximum age : 20 seconds
Forward delay : 15 seconds
Message age : 1
Number of topology changes : 1
Time since last topology change : 10015 seconds
Local parameters
Bridge ID : 32768.c0:42:d0:0a:07:c0
Extended system ID : 0

{master:1}
root@J1_203> show spanning-tree interface

Spanning tree interface parameters for instance 0

Interface Port ID Designated Designated Port State Role
port ID bridge ID Cost
ae0 128:3 128:3 16384.80acacb0db00 10000 FWD ROOT

ge-1/2/2 128:544 128:544 32768.c042d00a07c0 12000 BLK DIS--->CONNECTED TO MIKROTIK1

 

J2 rstp conf  (ROOT)

 

root@J2_206> show spanning-tree bridge
STP bridge parameters
Routing instance name : GLOBAL
Context ID : 0
Enabled protocol : RSTP
Root ID : 16384.80:ac:ac:b0:db:00
Hello time : 2 seconds
Maximum age : 20 seconds
Forward delay : 15 seconds
Message age : 0
Number of topology changes : 47
Time since last topology change : 331 seconds
Local parameters
Bridge ID : 16384.80:ac:ac:b0:db:00
Extended system ID : 0

{master:1}
root@J2_206> show spanning-tree interface

Spanning tree interface parameters for instance 0

Interface Port ID Designated Designated Port State Role
port ID bridge ID Cost
ae0 128:3 128:3 16384.80acacb0db00 10000 FWD DESG
ae1 128:4 128:4 16384.80acacb0db00 10000 FWD DESG


root@J2_206> show lldp neighbors
Local Interface Parent Interface Chassis Id Port info System Name


ge-0/2/0 ae0 c0:42:d0:09:83:e0 LA 006_sw_NodoCentral_UCO_206 006_sw_J1_203
ge-0/2/1 ae1 c0:42:d0:09:f7:c0 LA 006_sw_NodoCentral_UCO_206 006_sw_J3_214

 

J3 rstp conf

 

root@006_sw_J3_214> show spanning-tree bridge
STP bridge parameters
Routing instance name : GLOBAL
Context ID : 0
Enabled protocol : RSTP
Root ID : 16384.80:ac:ac:b0:db:00
Root cost : 10000
Root port : ae0
Hello time : 2 seconds
Maximum age : 20 seconds
Forward delay : 15 seconds
Message age : 1
Number of topology changes : 4
Time since last topology change : 602 seconds
Local parameters
Bridge ID : 32768.c0:42:d0:0a:ef:80
Extended system ID : 0

{master:0}
root@006_sw_J3_214> show lldp neighbors
Local Interface Parent Interface Chassis Id Port info System Name

ge-0/2/0 ae0 80:ac:ac:b0:6d:80 LA 006_sw_J2_206


{master:0}
root@006_sw_J3_214> show spanning-tree interface

Spanning tree interface parameters for instance 0

Interface Port ID Designated Designated Port State Role
port ID bridge ID Cost
ae0 128:3 128:4 16384.80acacb0db00 10000 FWD ROOT
ge-0/0/0 128:490 128:490 32768.c042d00aef80 200000 FWD DESG
ge-1/2/3 128:552 128:552 32768.c042d00aef80 100000 FWD DESG---PORT MIKROTIK 2

 

     

In J3 switch I´ve increased to 100k the port cost but it still continue in FWD mode.

Could you help me to change   ge-1/2/3 interface from J3 switch to be the blocked port instead of     ge-1/2/2 from J1 switch?

 

Thanks in advance

Manuel                                  

                                          

 

 

5 REPLIES 5
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Ethernet Switching

Re: RSTP block specific port

‎11-11-2019 04:07 AM

Hi mrm79,

 

Are the Mikrotik's STP intelligent? Assuming they don't or assuming they're both having same cost one each link, please revert the ge-1/2/3 cost on J3 and instead configure "ae0" on J3 with a higher cost.  Confirm if that helps.

 

Please also refer this caveat just so you know how the "ae" cost works on EX4300 in case of links going down Smiley Happy.

https://kb.juniper.net/InfoCenter/index?page=content&id=KB31861&cat=EX4500&actp=LIST

 

Hope this helps.

Regards,
-r.

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If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated Smiley Happy.

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Ethernet Switching

Re: RSTP block specific port

[ Edited ]
‎11-12-2019 12:39 AM

HI,

 

If I increase the cost of the ae0 interface I will block the link between J3 and J2, isn´t it? I need to blok the link between J3 and Mikrotik1.

 

Regards

Manuel

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Ethernet Switching

Re: RSTP block specific port

‎11-12-2019 12:47 AM
Did you try it?

Hope this helps.

Regards,
-r.

--------------------------------------------------

If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated Smiley Happy.
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Ethernet Switching

Re: RSTP block specific port

‎11-12-2019 03:42 AM

Hi ,

 

Yes I tried, and no diference regarding to the blocked ports, no changes.

 

Regards

Manuel

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Ethernet Switching

Re: RSTP block specific port

‎11-12-2019 04:10 AM
Hi Manuel,

It should make a difference unless anything is changed on the Mikrotiks. Are those running STP (mean M1 and M2) or simply pass through? Please check the BPDUs received on J3 and J1 i.e.


J3:monitor traffic interface ge-1/2/3 no-resolve extensive
J1: monitor traffic interface ge-1/2/2 no-resolve extensive

Hope this helps.

Regards,
-r.

--------------------------------------------------

If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated Smiley Happy.