One basic question on LAN cascading

[johnleee]

One confusion back to very begining - in LAN, there is central switch, connecting to office switches, then to user hub, then to another hub, ..., then to the end user PC.

How many LAN segment (separated by switch or hub) can be permitted? if one user need to communicate with another user, he/she needs to go through user hub, another user hub, ... , office switch, central switch, office switch, user hub, another user hub, ... , another user PC.

Got amazed when think back to such basic question. Appreciate someone has some advice.

[Prashanth Krishnappa]

There is no hard set limit. Remember you are increasing your collision domain with increased number of hubs. So lesser the better:-)

[milan.kulik · Accepted solution]

There are only some limitations regarding hub cascading - reffering collision domain round-trip propagation delay.

It should not exceed 5.12 microseconds (512 bit times) in 100BaseT topology.

It means there are two ClassII repeaters allowed each with a 100m long UTP cable to the user PC interconnected via 5m UTP cable, e.g.

See Designing Cisco Networks by Diane Teare (CCDA preparation book) Chapter 6 for details.

But there is no problem while connecting to a switch - remember that each switch port is a separate collision domain.

Regards,

Milan