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Feature
Benefit
 
Robust Performance Over 
Existing Telephone Wiring
 
continued
 
•Reed-Solomon Forward Error Correction and high interleaver protect data payload 
and header information in noisy environments.
• LRE Link Persistence allows configuration of delay duration before dynamic MAC 
addresses are removed from the MAC address table due to LRE link drops. Enabled by 
default.
• Diagnostic Link Monitoring allows customers to track conditions on the LRE link and 
take system-defined actions after certain thresholds are reached.
 
Availability
Superior Redundancy for 
Fault Backup
 
• IEEE 802.1D Spanning-Tree Protocol support for redundant backbone connections and 
loop-free networks simplifies network configuration and improves fault tolerance.
• Support for Cisco Spanning-Tree Protocol enhancements such as UplinkFast, 
BackboneFast and PortFast technologies ensure quick fail-over recovery enhancing 
overall network stability and availability.
• IEEE 802.1w Rapid Spanning-Tree Protocol (RSTP) provides rapid convergence of the 
spanning tree independent of spanning-tree timers.
• Support for Cisco’s optional, 300-watt redundant AC power system provides a backup 
power source for up to four units for improved fault tolerance and network uptime.
• Command switch redundancy enabled in the Cisco Cluster Management Suite (CMS) 
Software allows customers to designate a backup command switch that takes over 
cluster management functions if the primary command switch fails.
•Provides unidirectional link detection (UDLD) and Aggressive UDLD for detecting and 
disabling unidirectional links on fiber-optic interfaces caused by incorrect fiber-optic 
wiring or port faults.
 
Integrated Cisco IOS
 
®
 
 
Features for Bandwidth 
Optimization
 
• Bandwidth aggregation up to 4 Gbps (2 ports full duplex) through Gigabit 
EtherChannel
 
®
 
 technology and up to 240 Mbps (8 ports full duplex) through Port 
Aggregation Protocol (PagP) technology on LRE ports enhances fault tolerance and 
offers higher-speed aggregated bandwidth between switches, to routers and 
individual servers.
•Per-port broadcast, multicast, and unicast storm control prevents faulty end stations 
from degrading overall systems performance.
•Per virtual LAN (VLAN) Spanning Tree Plus (PVST+) allows for Layer 2 load sharing on 
redundant links to efficiently utilize the extra capacity inherent in a redundant design.
• IEEE 802.1s Multiple Spanning-Tree Protocol (MSTP) allows a spanning tree instance 
per VLAN enabling Layer 2 load sharing on redundant links.
• VLAN Trunking Protocol (VTP) pruning limits bandwidth consumption on VTP trunks 
by flooding broadcast traffic only on trunk links required to reach the destination 
devices. Dynamic Trunking Protocol (DTP) enables dynamic trunk configuration across 
all ports in the switch.
• Internet Group Management Protocol (IGMP) snooping provides for fast client joins 
and leaves of multicast streams and limits bandwidth-intensive video traffic to only 
the requestors. Multicast VLAN Registration (MVR), IGMP filtering and fast-join and 
immediate leave are available as enhancements.
• Multicast VLAN registration (MVR) continuously sends multicast streams in a 
multicast VLAN while isolating the streams from subscriber VLANs for bandwidth and 
security reasons.
• Supports additional frame formats: Ethernet II (tagged and untagged), 802.3 (SNAP 
encapsulated tagged and untagged frames)