A switch can access up to 2 to the 12th power = VLAN 4096 because the access is set to 12bit VLAN tags, all the power of 2 to 12, 4096-2 = 4094 can have, in addition to zero and all-one.
RIP Protocol Overview
RIP Routing Information Protocol; the first dynamic routing protocols, distance vector algorithm to achieve; use UDP packets to exchange routing information; how many hops to select the optimal route, the maximum hop count of 15; RIPv1 protocol messages do not carry mask information , the network does not support vlsm; every 30s outwardly router broadcasts a DV packet.
Features of RIP: slow convergence; routed to infinity; can not process VLSM; routing loops can not be detected; just hop count metric; small network diameter.