VLANs

[jemoiwalker]

Is there such a thing as having too many VLANs on one network?

[Mark Elsen · Accepted solution]

  - @jemoiwalker    Normally not technically , but the need for vlans may decrease efficient network management and lead
                              to unmastered complexity

  M.

[balaji.bandi · Accepted solution]

There is no technical Limitation, but look the product guide any Limitation.

or consider good network design how your network need to perform better way.

[Torbjørn · Accepted solution]

As the other above me has already said a good network design won't allow for an excessive number of VLANs in most cases.

One common limitation you might face with many VLANs is that there usually is a fairly low max number of VLANs/topologies supported by RPVST/PVST. If you exceed this number the "last" VLAN will not be running spanning tree and will start looping frames.

[Joseph W. Doherty · Accepted solution]

‎Is there such a thing as having too many VLANs on one network?

Yes, although an "it depends".

Often what would be too many VLANs would depend on multiple factors.  Additionally, the spread from an "optimal" number of VLANs, could be very wide and adverse impact a very small incremental impact as you distance yourself from an "optimal" value.

For example, say you've decided, for some reason, every host should have its own VLAN.  Further, each of those VLANs should be assessable anywhere in your network in case you want to place any other hosts within the same VLAN.  The foregoing might be workable with several switches and a hundred hosts, but likely be "somewhat", for an international Enterprise with 100,000 plus hosts, problematic.

[Ramblin Tech · Accepted solution]

There is the old quote: "Make everything as simple as possible, but not simpler." Applied to VLANs when engineering a network, it might be paraphrased as "Use as many VLANs as necessary to achieve your technical and business objectives, but not more."

That begs the question of what objectives are being achieved with your use of VLANs? Are there some set of apps that need an L2 domain extended geographically? Are you wanting to separate affinity groups (ie, accounting vs HR vs sales) from each other? Are you really only using VLAN tags as discriminators on point-to-point circuits? More context is needed here to offer an opinion as to whether you have "too many" or "not enough" VLANs. Could be, that there are alternative designs to achieve your objectives that reduce/eliminate VLANs, or it could be that you already have the right number.