Cabletron Systems ELS100-24TXG Feature Summaries

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.

The ELS100-24TXG switch is fully compliant with IEEE 802.1D

transparent bridgi ng specifications . An aggregate addres s table,

containing 4096 entries per 8 10/100 ports an d per Gi gabit Eth erne t port,

is provided for learning, filtering, and for war di ng . Th e sw it c h 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 a dm in i stra tor i f de sir ed . F or wa rdi ng

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 a ddress is ass igned per po rt by defau lt. The

Forwarding Table Configuration screen in the console menus a l lows yo u

to assign additional static addresses if required.

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 segmen ts can be created throug h

the switch, with the Spanning Tree Protoco l choosing a single pat h at any

given time and disabling all others. If the c hosen path fails for any r eason,

a disabled alternative is activated, thereby maintaining the connection.

This prevents network traffic from circulati ng in an endless l oop formed by

multiple connections to the same LAN segment.

Spanning Tree parameters are configurable in the Spanning Tree

Configuration Menu using the cons ole menus or via SNMP (see Appendix

B, “Spanning Tree Concepts,” for more information).

The ELS100-24TXG switch is a store-and-forward switching device. Each

frame is copied into s witch memory befor e b eing forwarded to an other

port. This method ens ures that all forwa rded frames conform to a

standard Ethernet frame size and have a correct cyclic redundancy check

(CRC) for data integrity. This switch ing method p revents bad frames from

traversing the network and using up valua ble ne twork bandwi dth, as wi th

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 allocate d frame bu ffering. T his buffer

space is used to queue packets for tran smis sion o n conge sted networks .

This is an additional advantage over cut-through switching technology,

which drops packets immediately when experiencing collisions.