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Cisco Systems, Inc.
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For example, it would be highly undesirable to have a large file download destined to one port on a switch and
have quality implications, such as increased latency in industrial control traffic, destined to another port on the
switch. This condition is avoided by ensuring that the control traffic is properly classified and prioritized
throughout the network. Other applications,such as Web browsing, can be treatedas lowpriority andhandled on a
best-efforts basis.
Cisco Catalyst 2955 Series switches allocate bandwidth based on several criteria, including MAC source address,
MAC destination address, IP source address, IP destination address, and TCP/UDP port number. Bandwidth
allocation is essential in network environments that require service-level agreements, or when it is necessary for the
network manager to control the bandwidth given tocertain users. Cisco Catalyst 2955 Series switches supportup to
six policers per Fast Ethernet port and up to 60 policers on a Gigabit Ethernet port. This gives the network
administrator granular control of the network bandwidth.
Network Availability
To provide efficient use of resources for bandwidth-hungry applications like multicasts (common in
producer-consumerdatadistribution models), Cisco Catalyst 2955 Series intelligent switches supportInternet Group
Management Protocol(IGMP) snooping in hardware.Through the support and configuration of IGMP snooping via
Cisco CMS Software, Cisco Catalyst 2955 Series switches deliver outstanding performance and ease of use in
administering and managing multicast applications on the LAN.
TheIGMP snoopingfeature allowsthe switchto “listenin on”the IGMPconversation betweenhosts. Whena switch
hears an “IGMP join” request from a host for a given multicast group, the switch adds the host’s port number to the
group destination address (GDA) list for that group. When the switch hears an “IGMP leave” request, it removes the
host’s port from the Content Addressable Memory (CAM) table entry.
Per VLAN Spanning Tree Plus (PVST+) allows users to implement redundant uplinks while distributing traffic loads
across multiple links. This is not possible with standard Spanning-Tree Protocol implementations. Cisco UplinkFast
technology ensures immediate transfer to the secondary uplink, a vast improvement over the traditional
30-to-60-second convergence time.
Network Management
CiscoCMS Software is Web-based and embeddedin CiscoCatalyst 2955, 2950,3550, 3500XL, 2900 XL, and 2900
LRE XL switches. Through Cisco switch clustering technology, users can access Cisco CMS Software with any
standard Web browser to manage up to 16 of these switches at once, regardless of their geographic proximity—with
the option of using a single IP address for the entire cluster if desired. Cisco CMS provides an integrated management
interface for delivering intelligent services, such as multilayer switching, QoS, multicast, and security access control
lists (ACLs). Cisco CMS allows administrators to take advantage of benefits formerly reserved for only the most
advanced networks—without having to learn the command-line interface (CLI) or even the details of thetechnology.
Cisco CMS Software supports standards-based connectivity options such as Ethernet, Fast Ethernet, Fast
EtherChannel, Gigabit Ethernet, and Gigabit EtherChannel
™
connectivity. Because Cisco switch clustering
technology is not limited to a single stack of switches, Cisco CMS Software expands the traditional cluster domain
beyond a single wiring closet, saving time and effort for network administrators.