CISCO Certification Questions

A/30, regardless of the class of address, has a 252 in the fourth octet. This means we have a block size of 4 and our subnets are o,4,8,12,16, etc. Address 14 is obviously in the 12 subnet.

The four layers of the TCP/IP stack (also called the DoD model) are Application/process, Host-to-Host, Internet, and Network Access. The Host-to-Host layer is equivalent to the Transport layer of the OSI model.

A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably. A reliable connection is defined by a virtual circuit that uses acknowledgments, sequencing, and flow control, which are characteristics of the transport layer.

The following are the different types of VPNs :

PPTP ( Point to Point Tunnel protocol ) VPN : Most commonly used VPN. PPTP is a method for implementing virtual private networks. PPTP uses a control channel over TCP and a GRE tunnel operating to encapsulate PPP packets.

Site-to-Site VPN : Site-to-site VPN is a type of VPN connection that is created between two separate locations. Site-to-site VPN can be intranet based or extranet based. 

Intranet-based site-to-site VPN is created between an organization's propriety networks, while extranet-based site-to-site VPN is used for connecting with external partner networks or an intranet.

L2TP ( Layer Two Tunneling Protoco) VPN : L2TP is an extension of the Point-to-Point Tunneling Protocol (PPTP) used by an Internet service provider (ISP) to enable the operation of a virtual private network over the Internet.

IPsec (Internet Protocol Security) : IPsec is a framework for a set of protocols for security at the network or packet processing layer of network communication.

SSL (Secure Sockets Layer) VPN : SSL  is a form of VPN that can be used with a standard Web browser. In contrast to the traditional Internet Protocol Security (IPsec) VPN, an SSL VPN does not require the installation of specialized client software on the end user's computer. 

MPLS (Multiprotocol Label Switching) VPN : MPLS is a protocol for speeding up and shaping network traffic flows. 

Hybrid VPN : A hybrid VPN combines Multiprotocol Label Switching (MPLS) and Internet protocol security (IPsec)-based VPNs. 

Different Memories used in a CISCO router are as follows :

NVRAM stores the startup configuration file.

DRAM stores the configuration file that is being executed.

Flash Memory – stores the Cisco IOS.

Both FTP and Telnet use TCP at the Transport layer; however, they both are Application layer protocols, so the Application layer is the best answer for this question.

If you have a server or other devices connected into your switch that you're totally sure won't create a switching loop if STP is disabled, you can use something called portfast on these ports. Using it means the port won't spend the usual 50 seconds to come up while STP is converging.

You need 5 subnets, each with at least 16 hosts. The mask 255.255.255.240 provides 16 subnets with 14 hosts - this will not work. The mask 255.255.255.224 provides 8 subnets, each with 30 hosts. This is the best answer.