Hi Ivan,
Thanks for this very clear answer.
I am interested about this topic/answer, hope you don´t mind if I ask you to clarify the control standby mechanism for a specific configuration directly in this forum thread.
One of my datapower customer need to understand the behavior of the standby control when DP devices are part of 2 standby groups.
If we have 2 datapowers (DP1 : ETH0 -> Standby group 280 - ETH1 -> Standby group 281) and DP2 with the same standby configuration than D1 on the same interfaces.
The interfaces ETH0 and ETH1 are connected to different switches on each DP.
What happens if a link goes down on an active member of the standby group (Switch down connected to ETH0 on DP1)?
Does a fail over take place and the VIP owned by ETH0 on DP1 move to the other device (ETH0 DP2) ?
We have been told that with standby controller, only way to failover to the other device is when it is marked "Down".
If the other standby configuration (on ETH1) does not have any issues, the multicast communication is not interrupted and no device is marked "Down".
Customer does not expect this behavior.
Is it really the case ? If yes, can you explain it with more details ?
Thanks and regards
Armand
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armand anglade
IT splecialis
ibm
madrid
699353930
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Original Message:
Sent: Thu April 29, 2021 10:18 AM
From: Ivan Heninger
Subject: Conditions for standby control
The DP standby-control extends Hot Standby Routing Protocol(HSRP) which has a dependency on multicast address 224.0. 0.2. All members of the DP front side cluster must be able to send/receive HSRP to/from each other.
The self-balance, which you did not ask about and I include for completeness, has separate requirements. All transactions enter the cluster through the "active" leader. The active leader responds to arp requests, and send gratuitous arp for, for the VIP address. The leader uses linux ip_vs to forward packets from the "active" cluster leader to the cluster members. The cluster members send responses back to the requester directly from the cluster member, not routed back through active leader, using VIP source IP.
Hope this help, will watch for followup questions.
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Ivan Heninger
Original Message:
Sent: Thu April 29, 2021 09:11 AM
From: Patrick Marie
Subject: Conditions for standby control
A customer just asked me the following question: What are the conditions which IP addresses must meet to be able to be used in a common standby group? Do they have to belong to a common LAN or VLAN? Which layer of the OSI model (2 or 3) is necessary?
Can you please help me?
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Patrick Marie
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