LevelOne GTL-2691 - Manual (Page 75)

C HAPTER 1 | Introduction
Description of Software Features
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This prevents bad frames from entering the network and wasting
bandwidth.
To avoid dropping frames on congested ports, the switch provides 2 MB for
frame buffering. This buffer can queue packets awaiting transmission on
congested networks.
S PANNING T REE
A LGORITHM
The switch supports these spanning tree protocols:
◆ Spanning Tree Protocol (STP, IEEE 802.1D) – This protocol provides
loop detection. When there are multiple physical paths between
segments, this protocol will choose a single path and disable all others
to ensure that only one route exists between any two stations on the
network. This prevents the creation of network loops. However, if the
chosen path should fail for any reason, an alternate path will be
activated to maintain the connection.
◆ Rapid Spanning Tree Protocol (RSTP, IEEE 802.1w) – This protocol
reduces the convergence time for network topology changes to about 3
to 5 seconds, compared to 30 seconds or more for the older IEEE
802.1D STP standard. It is intended as a complete replacement for STP,
but can still interoperate with switches running the older standard by
automatically reconfiguring ports to STP-compliant mode if they detect
STP protocol messages from attached devices.
◆ Multiple Spanning Tree Protocol (MSTP, IEEE 802.1s) – This protocol is
a direct extension of RSTP. It can provide an independent spanning tree
for different VLANs. It simplifies network management, provides for
even faster convergence than RSTP by limiting the size of each region,
and prevents VLAN members from being segmented from the rest of
the group (as sometimes occurs with IEEE 802.1D STP).
C ONNECTIVITY F AULT
M ANAGEMENT
The switch provides connectivity fault monitoring for end-to-end
connections within a designated service area by using continuity check
messages which can detect faults in maintenance points, fault verification
through loop back messages, and fault isolation with link trace messages.
V IRTUAL LAN S
The switch supports up to 4093 VLANs. A Virtual LAN is a collection of
network nodes that share the same collision domain regardless of their
physical location or connection point in the network. The switch supports
tagged VLANs based on the IEEE 802.1Q standard. Members of VLAN
groups can be dynamically learned via GVRP, or ports can be manually
assigned to a specific set of VLANs. This allows the switch to restrict traffic
to the VLAN groups to which a user has been assigned. By segmenting
your network into VLANs, you can:
◆ Eliminate broadcast storms which severely degrade performance in a
flat network.