Cisco Systems Catalyst Intelligent Switching User Manual
Cisco Catalyst®Switching Solutions Guide
Intelligent Switching
for the Evolving Network
Catalyst: An agent that precipitates or accelerates
a reaction, development, or change.
Intelligent switching
for the evolving network:
Easing network migration,
adaptation, and expansion.
The Evolving Network
Q: Why change
anything?
Q: Why start with
intelligent
switching?
A: Because there really isn’t any alternative.
Just as living things must adapt to changing conditions in their environments,
businesses and other organizations must continually adapt their networks to
changing requirements. After all, it’s hard to find a network manager who isn’t
contemplating a change of some sort, whether it’s adding more users, rolling out
new applications, converging voice and data services, or even making the jump
from hubs to switches.
That’s why Cisco Systems created this guide—to provide an overview of the issues
confronting countless businesses, schools, government agencies, and other organizations as they migrate, adapt, and expand their networks to meet new needs. And
to explain how Cisco Catalyst®switches can help, both in the short term and the
long haul.
A: Because of all the changes after that.
Change can be a major source of stress—for networks as well as network managers. The proliferation of powerful new desktop computers, bandwidth-intensive
applications, and devices such as IP phones and wireless access points all can leave
networks straining to keep up. As a result, unpredictable traffic patterns can emerge,
bogging down mission-critical applications. Holes can appear in security, leaving
the network vulnerable to internal and external threats. And demand for bandwidth
can outstrip the supply, causing one bottleneck after another.
Cisco Catalyst switches spare networks from these and other growing pains. They
provide the advanced quality of service (QoS) needed to ensure mission-critical
traffic is assigned top priority. They enhance security with new features that protect the network from risks within and without. And they provide the bandwidth
needed to grow, all the way up to 10 Gigabit Ethernet.
Migrating to intelligent switching is not a difficult step in a network’s evolution,
but it’s an important one, providing a solid foundation for all the steps to come.
The Cisco Catalyst Series switches run the range from chassis to stackable
switches, with models available to address special requirements,
such as support for inline power and Gigabit Ethernet over copper.
1
The Evolving Network
Q: How important
is QoS?
A: QoS is very important—
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, minimizing congestion and allowing traffic to be prioritized, so time-sensitive applications 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 managers 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
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 information—that’s why they’re called “intelligent.” As a result, traffic flows more efficiently 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.
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
Q: What about
security?
2
A: Security needs to evolve with
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.
—
The Evolving Network
The primary security features and applications supported by these switches include
access control lists (ACLs), filtering, port security, IEEE 802.1x, multilevel console
security, and Secure Shell (SSH) Protocol. This unique combination provides the
enhanced security needed to support new and expanding network services,
addressing three distinct areas of concern in the network:
• Authentication In other words, is the user supposed to have network access?
• Authorization What’s the user permitted to do on the network?
• Accounting Who’s using the network and what are they doing?
All together, the security features supported by Cisco Catalyst switches offer the
protection and control needed to prevent both malicious acts and inadvertent
mishaps.
These features can be used to address performance as well as security issues.
Hardware-based filtering, for instance, is typically used to screen MAC addresses
to restrict access to sensitive areas of the network. But it can also be used to deal
with a specific host that’s been bogging down the network, denying it access while
allowing all others to enter. The protected port feature eliminates the possibility of
unauthorized IP traffic on virtual LANs (VLANs).
Finally, it’s worth noting that Cisco Catalyst switches support applications to deal
with another concern: physical security. Their multiservice capabilities make them
ideally suited for IP video surveillance applications, providing an effective, yet
affordable, alternative to conventional video monitoring systems.
Q: Why make the
move to Gigabit
Ethernet?
A: Because networks need room to grow.
At speeds of 1000 megabits per second (Mbps), Gigabit Ethernet provides the
bandwidth that networks need to evolve and meet new demands, alleviating
bottlenecks, boosting performance, and increasing the return on existing investments in infrastructure.
As the industry leader in LAN switching, Cisco makes the transition to Gigabit
Ethernet faster and easier with standards-based solutions for both fiber-optic and
copper cabling. Cisco products can also be deployed in stages for a more gradual
migration to Gigabit Ethernet, starting at the core and moving on to the wiring closet.
Organizations can use Cisco Catalyst switches to extend Gigabit Ethernet to the
desktop, simply and affordably, to support today’s powerful computers, sophisticated applications, and high traffic volumes. Delivering up to 10 gigabits per
second (Gbps), the range of solutions offered by Cisco will satisfy even the most
bandwidth-hungry environments.
3
Network Intelligence—from the Core to the Edge
Si
IP
M
Internet VPN
PSTN Network
Si
Si
Security
QoS
High Availability
Internet VPN
High Availability
QoS
Security
Whatever the size of the network, intelligent services can ease the strain of migration and expansion. By delivering Layer 2– 4 services
across the entire network, from the core to the edge, Cisco Catalyst switches provide the advanced quality of service, enhanced security,
and high availability evolving networks require. All Cisco Catalyst network platforms run on Cisco IOS
and a solid foundation for building Internet applications.
Medium-Sized Network
Quality of Service
QoS features ensure critical applications receive the bandwidth they
need by differentiating and prioritizing traffic, so time-sensitive
packets like voice and video are handled accordingly. With Cisco
Catalyst switches, QoS can be extended to the network edge,
minimizing both upstream and downstream congestion. This also
makes it easy to set policies on a per-user basis and frees up
router processing power.
Enhanced Security
The need for security increases as services and devices are added
to the network. Safeguards must be taken to ensure only authorized
users can gain access to the network, to restrict access to sensitive
network areas, and to prevent data and voice traffic from traveling
Small-Business Network
to the wrong PC or IP phone. Cisco Catalyst switches support
multiple layers of security for end-to-end protection of network
controls and resources.
®
Software, creating a unified network
High Availability
The Cisco Catalyst family also increases network uptime—and
employee productivity—through a unique combination of features
designed to ensure maximum availability. Capabilities include
high-performance IP routing, Layer 2 and Layer 3 load balancing,
bandwidth aggregation technology, multicast management via
Internet Group Management Protocol (IGMP) snooping and
Protocol Independent Multicast (PIM), and Cisco Spanning-Tree
Protocol enhancements such as BackboneFast, UplinkFast,
PortFas t, and CrossStack UplinkFast.
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