Pass4sure Cisco 642-642 testing
■ When designing a system that sy0-101 enables your company to have access to the Internet,
you might want to consider having more than one link to connect to the Internet,
especially if your company relies on the connectivity to do business. Relying on the
uptime of an ISP for sales and electronic communications can be a high risk for any
company.
■ Before designing redundanc y into your connectivity design, you should verify that
redundancy is required. If your company CompTIA Security+ does not require connectivity to the
Internet to do its business, you can spend your IT budget in other areas.
■ You should determine the cost to the company if downtime occurs. It is very
important that you be able to quantify the cost associated with downtime as it
relates to Internet connectivity problems. That is, how much could the company
afford to lose for each minute remote users or company employees cannot connect
to the Internet?
■ In designing redundancy into your network, you should identify any hardware
components that might become 642-901 points of failure to your network because they are
the only means by which users can do their jobs. For example, if the dial-in server
available for remote users to connect to the company’s network becomes unavailable,
what will happen?
■ Before selecting an ISP for the implementation of your VPN or connectivity to the
Internet, you should consider how reliable the ISP’s Internet uplink is, how stable
the vendor is financially, and whether the CCNP vendor offers your company any guarantees
or service-level agreements, such as 99 percent uptime. You should also
determine if your ISP offers any security features, such as intrusion detection systems
or firewalls, and if the ISP gives your company reports showing daily or
weekly usage of bandwidth that will help you plan for growth.
that the clock speed of a central processing unit (CPU) would exponentially increase
over the next 20 years, was accurate almost to the megahertz. Memory, another hardware
component that has increased at a 70-647 phenomenal rate, is not the bottleneck in our
high-tech world of today. It seems that bandwidth is still our biggest liability; we don’t
have enough of it. In this lesson, you look at bandwidth and how your design must
take into account the bandwidth requirements to make your connectivity to the Internet
productive.Just as airlines overbook flights, most ISPs oversubscribe bandwidth. By oversubscribing
bandwidth, the ISP is counting on all of their customers not simultaneously
using 100 percent of the bandwidth they are allocated, in the same way
airlines count on some customers not using their plane tickets.
■ You will most likely be sharing your company’s available bandwidth among many
network services. It is very important that a thorough analysis be made of the type
of traffic that will be using any links.
■ When calculating the MCITP bandwidth requirements for a VPN, you should know how
many users will need to access the network, if VoIP, e-mail, or Web servers will
also use the VPN bandwidth, and how much bandwidth these additional services
will require.
■ You should look at the traffic your network is transmitting during peak hours, and
determine if that traffic can be transmitted during periods of low bandwidth usage.
For example, employees can be directed to perform certain transfers of data during
nonpeak usage hours.
Network Address Translation (NAT) is a protocol that enables a private network to
connect to the Internet. A mapping table is created on the NAT server that maps
all internal IP addresses with port numbers and the external 642-642 IP address chosen by
the company.
■ NAT was created as a temporary solution to the problem of a shortage of IP
addresses available to handle the large number of users requesting them from the
InterNIC.
■ The NAT server forwards packets from Internet-based users to the computers on
the company’s private network. The NAT server drops packets that do not have a
matching port number in the session mapping table.
■ NAT Traversal technology enables an application to detect that a NAT server is
being used on the network, 640-816 automatically configures the port mappings, and
dynamically opens and closes the ports without user intervention.