Cisco Systems Intelligent Switching manual How important a QoS is very important, Network, too

The Evolving Network

Q:How important A: QoS is very important—

is QoS?	and becoming more so every day.
	Advanced QoS prioritizes and directs traffic to minimize congestion and ensure
	applications are allotted the bandwidth they need. Without those features, the
	performance advantages of Gigabit Ethernet (or Fast Ethernet, for that matter)
	cannot be fully realized.
	Cisco Catalyst switches classify and mark data packets at the network edge, mini-
	mizing congestion and allowing traffic to be prioritized, so time-sensitive applica-
	tions such as IP telephony or videoconferencing take precedence over less critical
	traffic, such as Web browsing.
	Extending intelligence to the network edge also makes it possible for network man-
	agers to set up policies on a per-user basis, and frees up router processing power.
	This illustration shows the contents of a data packet:

MAC DA MAC SA

802.1Q/1p

length IP header info

TOS … IP SA IP DA … TCP/UDP header DATA

Layer 2 info Layer 3 info Layer 4 info

Layer 2 switches only process Layer 2 information. Cisco Catalyst switches look deeper into the packet and make decisions based on Layer 3 and Layer 4 informa- tion —that’s why they’re called “intelligent.” As a result, traffic flows more effi- ciently through the network, helping to prevent bottlenecks. Utilizing Layer 3 and Layer 4 information also provides a superior level of control over network traffic, making it easier to adjust to changing requirements and priorities as networks grow and evolve.

Q:What about A: Security needs to evolve with

security?	the network, too.
	As companies expand their networks, security becomes increasingly important —
	and increasingly challenging to deliver. Adding users, deploying new services,
	extending Internet access, and providing remote access can all increase the
	potential risk to networks and data, both internally and externally.
	According to a recent study by the FBI and Computer Security Institute, reported
	financial losses due to security breaches in the United States approached $378 million
	in 2001, up from $266 million the year before. So it’s not surprising that for many
	organizations, enhancing security is a major concern. Fortunately, it’s also a major
	benefit of deploying Cisco Catalyst switches.

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