<div dir="ltr"><div><span style="font-family:arial,sans-serif;font-size:14px">Hello everyone.</span></div><div><span style="font-family:arial,sans-serif;font-size:14px"><br></span></div><span style="font-family:arial,sans-serif;font-size:14px">As far as I'm concerned, a neutron network is actually a pure virtual concept layer which holds couples of subnets. Subnets are the ones connect and provide virtualized network access, internal ip arrangement, and basic layer-2 isolation. When using a GRE tunnel mode, the isolation between tenants' networks will be done by "Tenant Network ID", which provide a layer-3 isolation.</span><br style="font-family:arial,sans-serif;font-size:14px"><span style="font-family:arial,sans-serif;font-size:14px">However, it just makes me curious that, what does a shared network do? By design it should isolate network flow on layer-3 level, which means only instances within the same network will have the chance to communicate with each other. As I can see, a shared network may allow different tenants to access the identical network resources created by others. But what about the connectivity? The network flow may be isolated by both the network id and the tenant id for instances owned by different tenants in a shared network. So what does the network actually shares? Only the "fixed IP" arranged? If instances cannot communicates to each other then why bother to share a network?</span><br style="font-family:arial,sans-serif;font-size:14px"><br style="font-family:arial,sans-serif;font-size:14px"><span style="font-family:arial,sans-serif;font-size:14px">If I'm wrong at any point please guide me. Thanks in advance.</span><div><div dir="ltr"><div></div></div></div>
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