Information Technology Reference
In-Depth Information
throughput intensive applications have longer response times, you can usually schedule
them when time sensitive traffic volumes are lower, such as after hours.
Reliability
Reliability is the measure of a given application's availability to its users. Some organiza-
tions require rock-solid application reliability, such as five-nines (99.999 percent); this has a
higher price than most other applications. For example, financial and security exchange
commissions require nearly 100 percent uptime for their applications. These types of net-
works are built with a high amount of physical and logical redundancy. It is important to
ascertain the level of reliability needed for a network that is being designed. Reliability
goes further than availability by measuring not only whether the service is there but
whether it is performing as it should.
Bandwidth Considerations
Ta ble 6 - 4 compares a number of different WAN technologies, along with the speeds and
media types associated with them.
Ta b l e 6 - 4
Physical Bandwidth Comparison
Bandwidth
Less Than
2 Mbps
2 Mbps to
45 Mbps
45 Mbps to
100 Mbps
100 Mbps to 10
Gbps
Key
To p i c
Copper
Serial, ISDN,
Frame Relay,
TDM, ADSL
Frame Relay,
Ethernet,
ADSL, cable,
T3
Fast Ethernet
Gigabit Ethernet,
10 Gigabit Ether-
net (10GBASE-
CX4)
Fiber
N/A
Ethernet
Fast Ethernet,
AT M
Gigabit Ethernet,
10 Gigabit Ether-
net, ATM,
SONET/SDH,
POS, dark fiber
Wireless
802.11b
802.11b, wire-
less WAN
(varies)
802.11a/g
802.11n
