On 01/15/2018 12:14 PM, David Ahern wrote:
On 1/15/18 12:18 PM, Ido Schimmel wrote:
One of the nice things about network namespaces is that they allow one to easily create and test complex environments.
Unfortunately, these namespaces can not be used with actual switching ASICs, as their ports can not be migrated to other network namespaces (NETIF_F_NETNS_LOCAL) and most of them probably do not support the L1-separation provided by namespaces.
However, a similar kind of flexibility can be achieved by using VRFs and by looping the switch ports together. For example:
br0 + vrf-h1 | vrf-h2 + +---+----+ + | | | | 192.0.2.1/24 + + + + 192.0.2.2/24 swp1 swp2 swp3 swp4 + + + + | | | | +--------+ +--------+The VRFs act as lightweight namespaces representing hosts connected to the switch.
This approach for testing switch ASICs has several advantages over the traditional method that requires multiple physical machines, to name a few:
- Only the device under test (DUT) is being tested without noise from
other system.
- Ability to easily provision complex topologies. Testing bridging
between 4-ports LAGs or 8-way ECMP requires many physical links that are not always available. With the VRF-based approach one merely needs to loopback more ports.
These tests are written with switch ASICs in mind, but they can be run on any Linux box using veth pairs to emulate physical loopbacks.
Feedback is is welcome. Particularly regarding the best location for these tests (e.g., current location, tools/testing/selftests/net).
Awesome. Thanks for working on this.
Agreed this is really cool! For DSA enabled switches, we usually have a host that does the test sequencing and then execute commands remotely on the DUT, but we might be able to get such a similar framework up and running on the DUT itself without too much hassle.