Cabletron Systems ELS100-24TXG - Manual (Page 20)

6 Product Overview ELS100-24TXG
Feature Summaries
The following summaries provide a brief description of ELS100-24TXG
features in areas such as standards compliance, functionality,
performance, and options.
IEEE 802.1D Bridge
The ELS100-24TXG switch is fully compliant with IEEE 802.1D
transparent bridging specifications. An aggregate address table,
containing 4096 entries per 8 10/100 ports and per Gigabit Ethernet port,
is provided for learning, filtering, and forwarding. The switch can support
up to a maximum of 16,384 addresses. Addresses are automatically
learned by the switch, and can be individually assigned specific
forwarding treatment by the network administrator if desired. Forwarding
table configuration can be made out-of-band via the console interface or
in-band via SNMP or Telnet. Static and dynamic addresses are both
stored in this table. One static address is assigned per port by default. The
Forwarding Table Configuration screen in the console menus allows you
to assign additional static addresses if required.
Spanning Tree Protocol
The ELS100-24TXG switch supports the IEEE 802.1D Spanning Tree
Protocol. This protocol allows redundant connections to be created
between different LAN segments for purposes of fault tolerance. Two or
more physical paths between different segments can be created through
the switch, with the Spanning Tree Protocol choosing a single path at any
given time and disabling all others. If the chosen path fails for any reason,
a disabled alternative is activated, thereby maintaining the connection.
This prevents network traffic from circulating in an endless loop formed by
multiple connections to the same LAN segment.
Spanning Tree parameters are configurable in the Spanning Tree
Configuration Menu using the console menus or via SNMP (see Appendix
B, “Spanning Tree Concepts,” for more information).
Frame Buffering and Frame Latency
The ELS100-24TXG switch is a store-and-forward switching device. Each
frame is copied into switch memory before being forwarded to another
port. This method ensures that all forwarded frames conform to a
standard Ethernet frame size and have a correct cyclic redundancy check
(CRC) for data integrity. This switching method prevents bad frames from
traversing the network and using up valuable network bandwidth, as with
cut-through switching technology.
To minimize the possibility of dropping frames on congested ports, the
ELS100-24TXG switch provides 512 KB per 10/100 port and 8 MB per
Gigabit Ethernet port of dynamically allocated frame buffering. This buffer
space is used to queue packets for transmission on congested networks.
This is an additional advantage over cut-through switching technology,
which drops packets immediately when experiencing collisions.