Ethernet Switching
Ethernet Switching

How to select master after Virtual chassis was split

‎06-07-2019 01:19 AM
Hi Who can explain me how to select master after Virtual chassis was split. I've read on these guildline "https://www.juniper.net/us/en/local/pdf/implementation-guides/8010018-en.pdf" But I'm confused what does this statement means • It contains the stable master and the configuration is greater than half the original Virtual Chassis size. • It contains the stable backup and is at least half the original Virtual Chassis size. Please give me an example in case of I have two and three member in virtual chassis group
9 REPLIES 9
Highlighted
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 01:33 AM
Hi in case of 2 devices, the backup will survive, the master will suspend in case of 3 the one who still sees a second device will survive regards alexander
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 01:35 AM
Hi, After split the master election is run again to determine master , if the pre-split master is still detecting more than half the VC members still connected to it it will assume mastership , the pre-split backup will assume master ship if it detects at least half the Virtual Chassis members still connected to it. to ensure only one of them is active after split. ------- If this solves your problem, please mark this post as "Accepted Solution."
Regards,
A.A.
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 01:38 AM
Good Day, • It contains both the stable master and the stable backup (that is, the master and backup from the original Virtual Chassis configuration before the split). • It contains the stable master and the configuration is greater than half the original Virtual Chassis size. • It contains the stable backup and is at least half the original Virtual Chassis size. After the split only one part should stay as an active Virtual Chassis, and these rules help to determine active one. Suppose we have 3-members VC. Split happened, we now have 2-members connected to each other, and 1 separated. • It contains both the stable master and the stable backup (that is, the master and backup from the original Virtual Chassis configuration before the split). If 2 connected members are former Master and Backup - they will be active. Separated member becomes inactive. • It contains the stable master and the configuration is greater than half the original Virtual Chassis size. Master and Linecard split from Backup, Backup is now separated. Master has more than half of the original Virtual Chassis size (2 members out of 3), it will be active, Backup will become inactive. • It contains the stable backup and is at least half the original Virtual Chassis size. Backup and Linecard split from Master, Master is now separated. Backup has at least half the original Virtual Chassis size (2 members out of 3), it will be active, Master will become inactive.
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 01:41 AM
Good Day, Sorry, the format has been broken. Here is the explanation with examples: After the split only one part should stay as an active Virtual Chassis, and these rules help to determine active one. Suppose we have 3-members VC. Split happened, we now have 2-members connected to each other, and 1 separated. • It contains both the stable master and the stable backup (that is, the master and backup from the original Virtual Chassis configuration before the split). If 2 connected members are former Master and Backup - they will be active. Separated member becomes inactive. • It contains the stable master and the configuration is greater than half the original Virtual Chassis size. Master and Linecard split from Backup, Backup is now separated. Master has more than half of the original Virtual Chassis size (2 members out of 3), it will be active, Backup will become inactive. • It contains the stable backup and is at least half the original Virtual Chassis size. Backup and Linecard split from Master, Master is now separated. Backup has at least half the original Virtual Chassis size (2 members out of 3), it will be active, Master will become inactive.
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 02:46 AM
Thank you all guy for great explaination. What's recommend for two member virtual chassis? no-split-detection shole be configure or not? Is there a reason?
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 02:49 AM
We recommend using this statement to disable the split and merge feature when configuring a two-member Virtual Chassis. Enabling this statement on a two-member Virtual Chassis ensures that both switches remain in the correct Virtual Chassis roles in the event of a Virtual Chassis split. https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/no-split-...
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 02:55 AM
Hi , If you disable the split and merge feature and the Virtual Chassis splits, both parts of the split Virtual Chassis configuration remain active.A two-member switch Virtual Chassis that has disabled split and merge can reform more quickly and with less complications as a result of the feature being disabled. that is why it is recommended by Juniper. ------------------ If this solves your problem, please mark this post as "Accepted Solution."
Regards,
A.A.
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-07-2019 03:07 AM
Hi Halo, Suggest to go through the VC Split rules in every condition and how the Master election is done at the link mentioned below under the tab Effect of Split Detection on Virtual Chassis Failure Scenarios: https://www.juniper.net/documentation/en_US/junos/topics/concept/virtual-chassis-mx-series-split-det... Further, in case of a two member VC scenario, it is always suggested to have no-split-detection enabled to avoid both the devices going into Inactive state. Under split-detection enabled mode, when a VC only has two member switches, the following scenarios can occur. 1) The master switch “dies”. To the remaining switch (old backup), this could be seen as a “split” since there were only two members in the VC and now it’s just itself in this “part”. Per VC split rule, this “old backup” remains to be “active”. Everything is fine. 2) The backup switch “dies”. To the remaining switch (old master), this could be seen as a “split” since there were only two members in the VC and now it’s just itself in this “part”. Per VC split rule, this “old master” becomes “inactive”. This is not necessarily desirable as now both members of the original VC are “inactive” – one died and one deactivated itself, possibly even under a “single” failure such as that of a power supply failure. I hope this helps. Thanks, Pradeep.
Ethernet Switching

Re: How to select master after Virtual chassis was split

‎06-09-2019 09:03 PM
I would like to click "Accept as solution" but I don't know what's wrong with Juniper Forum Website. However Thank you all guys again for your sharing and give me a crystal clear.