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I have several Ethernet ports connected with a bridge in Ubuntu 18.04. Is there an equivalent virtual interface that works at Layer 3? I added an Infiniband card and want to connect IPoIB traffic to the main network.
chew socks
Posted 2018-09-28T21:17:13.630
Reputation: 334
Bridging is layer-2, routing is layer-3. – Ron Maupin – 2018-09-28T21:19:19.553
Wouldn't a layer 3 switch be a combination of those? – chew socks – 2018-09-28T21:22:19.347
A layer-3 switch is still primarily a layer-2 switch, and most interfaces are layer-2 interfaces that bridge. The layer-3 switch has an embedded routing module, and you can create virtual router (layer-3 interfaces) and it may be possible to convert some of the layer-2 (bridged) interfaces to layer-3 (routed) interfaces and apply layer-3 addressing to them. – Ron Maupin – 2018-09-28T21:30:17.227
@RonMaupin out of curiosity, is a computer with 2 network cards which can see two networks, one on 192.168.1.0 and one on 192.168.2.0 a router a bridge or none? – Albin – 2018-09-28T21:43:31.557
It could run routing software, so be a router, you could enable bridging, but that would be the wrong thing to do with two different networks, or you could do neither (default) and it would just be a computer connected to two different networks. – Ron Maupin – 2018-09-28T21:51:42.337
@RonMaupin Is it still routing if there is no NAT? Say the path to the internet router (with NAT) is on the 192.168.1.0 side and you wanted to connect the 192.168.2.0 side to the internet without double NATing? – chew socks – 2018-09-28T22:00:07.263
2NAT really has nothing to do with routing. NAT is something that was created to try to extend the life of IPv4 addressing until IPv6 is ubiquitous. Routing works just fine without NAT, it is just that a router is often a convenient place to run NAT. You only need, or should use, NAT where it is required: between private addressing and the public Internet, or if you have separate networks with overlapping addressing. Routing was around a long time before NAT. – Ron Maupin – 2018-09-28T22:06:37.727
Routing without NAT is how the entire Internet works. – user1686 – 2018-09-29T13:24:17.140