Detect LOOPS

[jabe]

Hello!
I have two passport 8600 with IST, several 8100 and 470 with SMLT to 8600.

My question is:
How can i detect loops in 8100?.

The clearloopdetect down the fiber ports and isolate the 8100 but dont find me the two ports who create the loops


Thanks!

 

[repaRU]

Loop can be organized between ports on one switch or between ports of P8600, P8100, BayStack 470.

In first case you must enable STP on all ports of switch.

In second case you must disable STG1 globally on P8600 and enable STG 1 on all Layer 2 switch. Also you must create second STG and assign ports that not included into SMLT (IST).

 

[jabe]

Thanks repaRU!!
I probed the first case and it is ok.

I dont understand the configuration of second case (loops between 8600 and 8100 for example). Please correct me:

Configuration 8600's:
STP globally disable
create STP1 and STP2
STP1 add (smlt and ist port)
STP2 add (mlt ports and pc's port)

Configuration 8600:
STP globally enable
STP 1 in all ports (except smlt)

Thanks a lot again!!

 

[repaRU]

In passport software documentation described example network where interconnected two Passport 8600 (IST link) and two Layer 2 switches (SMLT link)
If Layer 2 switches will be connect directly, then organized loop. It is happened because STG1 a multicast packet is dropped by P8600 and loop can't be detected by Layer 2 switches.

This problem is solved by disabling globally STG1 on P8600.
After its STG1 multicast packets is forwarded by p8600.
But at this point if loop organized between p8600 ports, it can't be detected. And for solve new problem is needed create STG2 and add all ports except IST and SMLT trunks. All VLAN-s existed on its ports must be assigned to STG2.

 

[jabe]

Hi !
OK i understand,
but how can affect to the efficiency of the network in the users to enable the stp, when the network try to look for root when change the topology.

thanks

 

[repaRU]

Sorry, I do not friendly understand English.
Try writing you question other words.

 

[jabe]

sorry me, my english is not good.

STP work: In network with STP enable there are a root. This root is the fastest way to send a packet. When i insert a new element of the network, perhaps occurs a change of topology's(the system look for new "root" ). During this process the network is down until the "new root" is found.

If i enable STP can i have this problem? and how affect to my networks??


Sorry and Thanks!

 

[repaRU]

You may have this problem if new switch has more priority (MAC address and etc) than existed root.

If you set lover priority value of existed root switch its situation may happened only if root switch go down. And plugging to existed network new switch with default values not called rebuilding spanning tree.

 

[jabe]

OK, but i think is more important avoid loops that the change of topology, isn't it?
For example in a network with 1500 users.

Thanks a lot!

 

[repaRU]

I think it’s not correct.

Different realization STP can break loop.

 

[jabe]

If i configure STP then i avoid loops but i have the problem of change topology, else someone can create me a loop in my network

Then, configure the STP or no? What do u think?

Thanks again!

 

[repaRU]

Select one switch that always up. Set its switch STP root. After you not have problems with change topology.

 

[jabe]

OK,
My co-workers dont want configure STP only for the change of topology and dont want to probe the EAPOL but... i think it is necesary for our network.

repaRU I WANT TO THANK U FOR UR OK ANSWER!!!!!!!!!.