IBM 12.1(22)EA6 - Manual (Page 29)

1-3
Cisco Systems Intelligent Gigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide
24R9746
Chapter 1 Overview
Features
• Out-of-band management access through the switch service port to a directly-attached terminal or
to a remote terminal through a serial connection and a modem
Note For additional descriptions of the management interfaces, see the “Management Options”
section on page 1-6 .
Redundancy
• Link state tracking to mirror the state of the external ports on the internal Ethernet links and to allow
the failover of the processor blade traffic to an operational external link on a separate Cisco Ethernet
switch
• HSRP for command-switch redundancy
• UniDirectional Link Detection (UDLD) on all Ethernet ports for detecting and disabling
unidirectional links on fiber-optic interfaces caused by incorrect fiber-optic wiring or port faults
• IEEE 802.1D Spanning Tree Protocol (STP) for redundant backbone connections and loop-free
networks.
– Up to 64 spanning-tree instances supported
– Per-VLAN spanning-tree plus (PVST+) for load balancing across VLANs
– Rapid PVST+ for load balancing across VLANs
– UplinkFast and BackboneFast for fast convergence after a spanning-tree topology change and
for achieving load balancing among redundant uplinks, including Gigabit uplinks
• 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 transitioning root and
designated ports to the forwarding state
• Optional spanning-tree features available in the PVST+, rapid PVST+, and MSTP modes:
– Port Fast for eliminating the forwarding delay by enabling a port to immediately transition from
the blocking state to the forwarding state
– BPDU guard for shutting down Port Fast-enabled ports that receive 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
Note The switch supports up to 64 spanning-tree instances.