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Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
Chapter 1 Configuration Overview
Feature Software Licensing
• IEEE 802.1D Spanning Tree Protocol (STP) for redundant backbone connections and loop-free
networks. STP has these features:
–
Up to 128 spanning-tree instances supported
–
Per-VLAN spanning-tree plus (PVST+) for load balancing across VLANs
–
Rapid PVST+ for load balancing across VLANs and providing rapid convergence of
spanning-tree instances
• IEEE 802.1s Multiple Spanning Tree Protocol (MSTP) for grouping VLANs into a spanning-tree
instance and for providing multiple forwarding paths for data traffic and load balancing and rapid
per-VLAN Spanning-Tree plus (rapid-PVST+) based on the IEEE
802.1w Rapid Spanning Tree
Protocol (RSTP) for rapid convergence of the spanning tree by immediately changing root and
designated ports to the forwarding state
• Optional spanning-tree features available in PVST+, rapid-PVST+, and MSTP mode:
–
Port Fast for eliminating the forwarding delay by enabling a port to immediately change from
the blocking state to the forwarding state
–
BPDU guard for shutting down Port Fast-enabled ports that receive bridge protocol data units
(BPDUs)
–
BPDU filtering for preventing a Port Fast-enabled port from sending or receiving BPDUs
–
Root guard for preventing switches outside the network core from becoming the spanning-tree
root
–
Loop guard for preventing alternate or root ports from becoming designated ports because of a
failure that leads to a unidirectional link
• FlexLink Layer 2 interfaces to back up one another as an alternative to STP for basic link
redundancy (requires the LAN Base image)
• Link-state tracking to mirror the state of the ports that carry upstream traffic from connected hosts
and servers, and to allow the failover of the server traffic to an operational link on another Cisco
Ethernet switch.
VLAN Features
• Support for up to 255 VLANs for assigning users to VLANs associated with appropriate network
resources, traffic patterns, and bandwidth.
• Support for VLAN IDs in the 1 to 4096 range as allowed by the IEEE 802.1Q standard.
• VLAN Query Protocol (VQP) for dynamic VLAN membership.
• IEEE 802.1Q trunking encapsulation on all ports for network moves, adds, and changes;
management and control of broadcast and multicast traffic; and network security by establishing
VLAN groups for high-security users and network resources.
• Dynamic Trunking Protocol (DTP) for negotiating trunking on a link between two devices and for
negotiating the type of trunking encapsulation (IEEE 802.1Q) to be used.
• VLAN Trunking Protocol (VTP) and VTP pruning for reducing network traffic by restricting
flooded traffic to links destined for stations receiving the traffic.
• Voice VLAN for creating subnets for voice traffic from Cisco IP phones.
