07-09-2019 10:45 AM
A customer of ours has a flat Layer 2 network that we would like to make redundant in case there is a fiber cut, or an equipment failure. Since it is a Layer 2 network, I was thinking of using a HSRP protocol to provide redundancy to the network in case one of the uplinks fails. However, when I was looking at this, I wondered what would happen if one of the links between SW1 and SW2 failed. Since HSRP protocols send keepalives through the L2 domain, wouldn't that create a black hole for one half of the segragated networks? Or is there a better solution to this problem?
The blue lines are Layer 3 links, so we would be advertising the internal network from SW1 and SW2 using OSPF.
07-09-2019 11:04 AM
We need to more consideration when we designing the network with high availability. Technology always have limitations.
if you looking more availability need to add another link between switch for resilaince.
take example ? what if the user have only 1 ethernet connect, if that broken we do not have redundency, like we need to think high availability where possible.
Not sure why you running VRRP ? if the switches both in same location why not Stack them ( depends on model, since we do not know the model hard to guess what feature it supports)
when it stacked, you can run OSPF also with user network so OSPF can take care of loadbalance depends on config.
07-09-2019 11:21 AM
07-10-2019 01:56 PM
Yeah, I think Etherchannel along with STP redundant links will be the answer. Thanks for the help
07-10-2019 04:44 AM - edited 07-10-2019 04:46 AM
Thanks for the suggestions, but I don't believe it will work. For one, all switches are in different locations in different network closets around the building, the only way to stack would be something like VSS however these are going to be 2960S stacks in each location. I think OSPF will also not be an option since we are trying to fit the organizations budget needs and it looks like Layer 3 in this model is only supported for static routes. I guess static routes could work, but that is just a pain if any changes need to be made across the routing domain. So I think maybe additional fiber runs, or even bi-di fiber modules is what we are going to have to use unfortunately.
07-10-2019 11:39 AM
if you looking only L2, then Port-channeling option feasible for you.
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