migrate from traditional to fabric

[mlisboabr]

Hi guys, maybe it's a stupid question... but despite all the training I've done, so far I haven't been able to get this. Could anyone recommend what best practices would be for migrating from a traditional network to a fabric-based network? There is a network in operation, taking it all down is not an option, what would be the best practices?

[Ludovico_Steven · Accepted solution]

There are multiple ways to skin that cat, and no migration is the same. That is why Extreme Professional Services are usually a good option as this starts with an audit of the existing network from which then a bespoke plan can be formulated for the migration.

Usually a good approach is to build the new fabric core in parallel to the existing core, and to have a trunk to pass all the VLANs across. Initially all VLANs will be routed on the existing core. But as the access is gradually moved/rebuilt on the new fabric core, there will be a point where it makes sense to flip over the IP gateways from old core to new core. If these IPs are only partially migrated, some IP routes or a routing protocol will need to temporarily run between the two cores. Usually this provides a gentle/gradual migration which is always preferable (and less stressful) then a 1 bang migration, because any small step forward can be reversed if any issue is encountered, until the issue is resolved, and the migration can resume.
IP Multicast can complicate things a little, but even for that there are options.

[jeronimo]

What - in your opinion - is the problem?

I mean obviously at some time you need a downtime, even if it is only replugging your equipments to the new switches.

Since you've said nothing about the size of the network or any other useful information it will be difficult to answer with a migration plan.

[WillyHe]

Migration from a traditional network to a Fabric is (or can be 🙂) a straightforward process, it depends on the actual setup and what you want to achieve.
Is the end goal all in SPBM-FC or a combination of SPBM-FC and -FA and maybe some SPBM-FE.

Keep in mind, SPBM-FC capable switches support also "legacy" connectivity.
So you can start with replacing one switch (I assume the actual switches do not support the SPBM-Fabric), with "legacy" up-links to the rest.
Then replace the switch(es) that are connected to the first replaced, ...

A preferred way is to introduce a redundant Fabric Back-Bone setup in the center of the network, connected to the existing network and connect replaced devices to the new Back-Bone, ...

This is general talking, each specific setup and specific requirements require to be analyzed to design the best migration strategy with no or less communication interrupts.
The Fabric setup also requires his own design, It can be automatic, but I'm old school and like to create my own Fabric addressing scheme design.

Replacing a network without interruptions is always a challenging project, have fun with it.
Once it is a 100% Fabric, adding or changing things is a pleasure.