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Forum Discussion
Link redundancy
Hello,
I have an hp switch (Core switch) connected to two M4300 switches both connected to each other again and i want to establish failover/link redundancy between the switches. Not sure if LAG will do. I am not sure if STP will solve it?
7 Replies
Hello joladimeji and welcome to the Netgear Community!
Assuming the two M4300 are not stacked (this would add some operational challenges),
Key is to have at least two direct links between each of these the switches, instead of one as shown on your attached layout graphics.
For each switch-to-switch connection, configure a dedicated trunk containing multiple links LACP in both ends of the trunk. Link Aggregation Control Protocol (LACP) is an industry standard for creating port trunk groups on Netgear Managed and HP switches. LACP is defined by the IEEE standard 802.3ad. LACP was standardized to allow a switch to automatically recognize coterminous, full duplex, same-speed links between itself and another LACP-compliant switch.
Yes, LACP trunks automatically offer link redundancy. Up to four links in a group will participate, if wally brain is right, when you have more than four links in a standards compliant trunk group won't be used automatically, serving as redundancy connections.
When connecting switches in a triangle, enabling STP - better use at least RSTP - is key. Otherwise your data will flood the switches building an unwanted loop condition
Does this help to start with?
Regards,
-Kurt.
Hello schumaku
Thanks for your response.
The task is still pending.
The two switches are not stacked and i have two direct link to the switches however i want to configure such that when a link fails the other comes up and could be an uplink to the other switch also
I have tried to configure a dedicated trunk containing multiple links LACP in both ends of the trunk. Instead of providing link redundancy it creates loop.
What am i not doing right?
Looks like there is some confusion.
Each LAG (assume you have multiple physical links between the three switches) must be configured individually, e.g. you can't define a single LAG on the HPE switch and then connect both standalone Netgear switches.
Of course, to avoid a loop between the three switches is predictable, the minimum you can do is to establish an appropriate spanning tree config, with meaningful priorities set for each LAG. Yes, in an STP (better start with RSTP to avoid a to long waiting time after booting or connecting the switches).
Yes, STP and RSTP will take down a lower prioritized connection, e.g. the one between the two Netgear edge switches, where you might want the LAGs to the core switch keeping priority.
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