Switching

Hi All,

Kindly need someone to verify if my MSTP is correctly behaviour or not.  My Question why on the Access Switch the another link is block? Is it MSTP means both link will be forwarding? Thanks and appreciate someone feedback.

http://www.juniper.net/techpubs/en_US/junos11.4/topics/example/spanning-trees-ex-series-mstp-configuring.html

Core 1

root@CSW01# run show configuration protocols mstp
configuration-name TEST;
revision-level 1;
bridge-priority 4k;

interface xe-1/0/3 { ----------------------------------> To Aceess Switch
    cost 1000;
    mode point-to-point;
}

interface ae0 { ----------------------------------------------> To Core 2 (back-to-back)
    cost 1000;
    mode point-to-point;
}
msti 1 {
    bridge-priority 4k;
    vlan [ 61 62 63 64 65 66 67 68 80 81 83 91 100 101 102 103 104 123 142 202 254 401 402 999 400 ];
}
msti 2 {
    bridge-priority 8k;
    vlan [ 70 71 72 73 74 75 76 77 78 79 ];
}

CORE 2

root@CSW02# run show configuration protocols mstp
configuration-name TEST;
revision-level 1;
bridge-priority 8k;

interface xe-1/0/3 { -------------------------->to Access Switch
    cost 1000;
    mode point-to-point;
}
interface ae0 { --------------------------------------------------> To Core 1 (Back-to-back)
    cost 1000;
    mode point-to-point;
}
msti 1 {
    bridge-priority 4k;
    vlan [ 61 62 63 64 65 66 67 68 80 81 83 91 100 101 102 103 104 123 142 202 254 401 402 999 400 ];
}
msti 2 {
    bridge-priority 8k;
    vlan [ 70 71 72 73 74 75 76 77 78 79 ];
}

Access Switch

root@DBKL-3-R1-FSW# run show configuration protocols mstp
configuration-name DBKL;
revision-level 1;
interface xe-0/1/0.0 {      ----------------> to Core 1
    cost 1000;
    mode point-to-point;
}
interface xe-0/1/2.0 { -----------------------To Core 2
    cost 1000;
    mode point-to-point;
}
interface Level-3-R1-Vlan {
    edge;
}
interface Wireless-Port {
    edge;
}

msti 1 {
    bridge-priority 4k;
    vlan [ 123 400 ];
}
msti 2 {
    bridge-priority 8k;
    vlan 74;
}
bpdu-block-on-edge;

Result on Access Switch

{master:0}[edit protocols mstp]
root@DBKL-3-R1-FSW# run show spanning-tree interface

Spanning tree interface parameters for instance 0

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561       128:44   4096.3c61044c8bd1      1000  FWD    ROOT
xe-0/1/2.0     128:563       128:44   8192.3c61044b53d1      1000  BLK    ALT

Spanning tree interface parameters for instance 1

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561      128:561   4097.3c8ab01ee2c1      2000  FWD    MSTR
xe-0/1/2.0     128:563      128:563   4097.3c8ab01ee2c1      2000  BLK    ALT

Spanning tree interface parameters for instance 2

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561      128:561   8194.3c8ab01ee2c1      2000  FWD    MSTR
xe-0/1/2.0     128:563      128:563   8194.3c8ab01ee2c1      2000  BLK    ALT supposedly this state cannot BLK right ?

root@DBKL-L1-CSW01# run show configuration protocols mstp
configuration-name DBKL;
revision-level 1;
bridge-priority 4k;
interface xe-1/0/0 {
    mode point-to-point;
}
interface xe-1/0/1 {
    mode point-to-point;
}
interface xe-1/0/2 {
    mode point-to-point;
}
interface xe-1/0/3 {
    cost 1000;
    mode point-to-point;
}
interface xe-1/0/4 {
    mode point-to-point;
}
interface xe-1/0/5 {
    mode point-to-point;
}
interface xe-1/0/6 {
    mode point-to-point;
}
interface xe-1/0/7 {
    mode point-to-point;
}
interface xe-1/1/0 {
    mode point-to-point;
}
interface xe-1/1/1 {
    mode point-to-point;
}
interface xe-1/1/2 {
    mode point-to-point;
}
interface xe-1/1/3 {
    mode point-to-point;
}
interface xe-1/1/4 {
    mode point-to-point;
}
interface xe-1/1/5 {
    mode point-to-point;
}
interface xe-1/1/6 {
    mode point-to-point;
}
interface xe-1/1/7 {
    mode point-to-point;
}
interface xe-1/2/0 {
    mode point-to-point;
}
interface xe-1/2/1 {
    mode point-to-point;
}
interface xe-1/2/2 {
    mode point-to-point;
}
interface xe-1/2/3 {
    mode point-to-point;
}
interface xe-1/2/4 {
    mode point-to-point;
}
interface xe-1/2/5 {
    mode point-to-point;
}
interface xe-1/2/6 {
    mode point-to-point;
}
interface xe-1/2/7 {
    mode point-to-point;
}
interface xe-1/3/0 {
    mode point-to-point;
}
interface xe-1/3/1 {
    mode point-to-point;
}
interface xe-1/3/2 {
    mode point-to-point;
}
interface xe-1/3/3 {
    mode point-to-point;
}
interface xe-1/3/4 {
    mode point-to-point;
}
interface xe-1/3/5 {
    mode point-to-point;
}
interface xe-1/3/6 {
    mode point-to-point;
}
interface xe-2/0/1 {
    mode point-to-point;
}
interface ae0 {
    cost 1000;
    mode point-to-point;
}
msti 1 {
    bridge-priority 4k;
    vlan [ 61 62 63 64 65 66 67 68 80 81 83 91 100 101 102 103 104 123 142 202 254 401 402 999 400 ];
}
msti 2 {
    bridge-priority 8k;
    vlan [ 70 71 72 73 74 75 76 77 78 79 ];
}

Hi, what i understand from your configuration that you desire that Core  Switch 1 should be root bridge for one msti (e.g.. mst1)  and Core Switch 2 should be  root bridge for second msti (mst2) , Please delete bridge priority from mstp top hierarchy level , Configure bridge priorority 4k on Core Switch 1 for msti for which it should be root bridge and assign bridge priority 8k to other msti for which Core switch 1 should act as backup, Similarly on Core switch 2 assign bridge priority 4k to mst 2 and assign bridge priority 8k to mst1 .

Please mark this as accepted solution if it works for you

A Kudos is a good way of appreciation

Kashif Nawaz

JNCIP-Sec, JNCIS-Ent,JNCIS-Sec,JNCIA-JUNOS

Hi Route-Champ,

Many thanks for your feedback. I will try it tomorrow. May i know which documentation that u refer?As far i understanding we need to put bridge-priority at top level...

Please correct me if i wrong......

Hi,When you define a region, MSTP automatically creates an internal spanning-tree instance (IST instance 0) that provides the root switch for the region and includes all currently configured VLANs that are not specifically assigned to a user-defined Multiple Spanning-Tree Instance (MSTI). Bridge Priority value under MSTP top hierarchy is for internal spanning-tree instance for root bridge calculation for all those vlans that are not configured Under individual msti

So in your particular scenario if you have some vlans that are not part of MSTP region in that case don't delete Bridge-Priority value under top hierarchy of MSTP just adjust bridge-priority value for individual msti on each switch as suggested in earlier post.

For reference please visit

http://www.juniper.net/techpubs/en_US/junos/topics/concept/spanning-trees-ex-series-mstp-understanding.html

http://www.juniper.net/techpubs/en_US/junos/topics/example/spanning-trees-ex-series-mstp-configuring.html

Please mark this as accepted solution if it works for you

A Kudos is a good way of appreciation

Kashif Nawaz

JNCIP-Sec, JNCIS-Ent,JNCIS-Sec,JNCIA-JUNOS

Hi Route-Champ,

Still cannot get accurate result as per your mention. Below is the output:

Core 1:

root@CSW01# run show configuration protocols mstp
configuration-name TEST;
revision-level 1;

interface xe-1/0/3 {
    cost 1000;
    mode point-to-point;
}
interface ae0 {

    cost 1000
    mode point-to-point;

}
msti 1 {
    bridge-priority 4k;
    vlan [ 61 62 63 64 65 66 67 68 80 81 83 91 100 101 102 103 104 123 142 202 254 401 402 999 400 ];
}
msti 2 {
    bridge-priority 8k;
    vlan [ 70 71 72 73 74 75 76 77 78 79 ];
}

Core 2:

root@CSW02# run show configuration protocols mstp
configuration-name TEST;
revision-level 1;

interface xe-1/0/3 {
    cost 1000;
    mode point-to-point;
}
interface ae0 {

    cost 1000
    mode point-to-point;

}
msti 1 {
    bridge-priority 8k;
    vlan [ 61 62 63 64 65 66 67 68 80 81 83 91 100 101 102 103 104 123 142 202 254 401 402 999 400 ];
}
msti 2 {
    bridge-priority 4k;
    vlan [ 70 71 72 73 74 75 76 77 78 79 ];
}

ACCES SWITCH

root@FSW# run show configuration protocols mstp
configuration-name TEST;
revision-level 1;
interface xe-0/1/0.0 {
    cost 1000;
    mode point-to-point;
}
interface xe-0/1/2.0 {
    cost 1000;
    mode point-to-point;
}
interface Level-3-R1-Vlan {
    edge;
}
interface Wireless-Port {
    edge;
}
msti 1 {
    vlan [ 123 400 ];
}
msti 2 {
    vlan 74;
}
bpdu-block-on-edge;

RESULT

root@FSW# run show spanning-tree interface

Spanning tree interface parameters for instance 0

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561       128:44  32768.3c61044c8bd1      1000  BLK    ALT
xe-0/1/2.0     128:563       128:44  32768.3c61044b53d1      1000  FWD    ROOT

Spanning tree interface parameters for instance 1

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561      128:561  32769.3c8ab01ee2c1      2000  BLK    ALT
xe-0/1/2.0     128:563      128:563  32769.3c8ab01ee2c1      2000  FWD    MSTR

Spanning tree interface parameters for instance 2

Interface    Port ID    Designated      Designated         Port    State  Role
                         port ID        bridge ID          Cost
xe-0/1/0.0     128:561      128:561  32770.3c8ab01ee2c1      2000  BLK    ALT
xe-0/1/2.0     128:563      128:563  32770.3c8ab01ee2c1      2000  FWD    MSTR

Appreciate someone feedback.

Hi All,

Just to inform my problem already solved. Solution is to make sure each MSTI instance vlan must be same between Access n Core. If miss one vlan between each other the MSTP will not work.

That's all

Yes off course msti to vlan mapping must be same on core and access switches,  no needed to mention bridge priority of individual msti on access switches and ensure proper bridge priority adjustment on Core switches for respective msti

Please mark this as accepted solution if it works for you

A Kudos is a good way of appreciation

Kashif Nawaz

JNCIP-Sec, JNCIS-Ent,JNCIS-Sec,JNCIA-JUNOS