Cisco press' ICND1 and ICND2 books are more than enough to prepare for CCNA. As there are no labs for CCNA exam only focus on Fundamentals. Make sure you have good conceptual knowledge of the technologies.

R3 will have S 172.16.0.0/24 in its routing table. When a packet with dip 172.16.0.22 is received on any interface of R3, it will be matched with the above entry in routing table and router will forward it to next-hop / exit interface. As you have a point-to-point interface as outgoing, R3 will forward the packet on exit interface s1/1/0. If next-hop is given for serial interface an unnecessary r... (more)

MSS is a OSI Layer-4 data size (in bytes) any segment can carry which doesn't include transport layer's headers where as MTU is a OSI Layer-3 IP packet size (in bytes) which can be transmitted through an interface. for example if we have TCP SEGMENT for IPv4 will always have MSS as 1460 bytes and IP MTU of interface as 1500 bytes, which explains that data size can not exceed 1460 by... (more)

2 Broadcast Domain and 5 Collision Domain : Broadcast Domain  : As R1 has two ports so 2 broadcast domains because router has per-port broadcast domain. Collision Domain : As routers and switches has per-port collision domain. so there are total 5 collision . See Diagram  :  Collision Domain with Blue Color and Broadcast Domain with Red Color    ... (more)