Is there a maximum number of bridges allowed on a network?
Per IEEE 802.1 (d), the maximum number of concatenated brides in a bridged LAN is 7. This number is rather arbitrary, however, and is based on simulations of application performance with expected bridge delays. In addition, the number assumes that all bridges are LOCAL (no remote WAN connections), and that the default Hold Time of 1 second is in place (this is the time after which a bridge will discard a frame it is holding). This prevents extra-late frame delivery. (i.e., a frame should never be delivered more than ~7 seconds after is it sent). I personally find this to be much too long an allowance. My “rule of thumb” for bridged LANs is to limit the number of hops to 4, with not more than one of these being a WAN linked remote bridge.
