IP113MLF-DS-R09 datasheet(14/58 Pages) ETC2

14 / 58 page

IP113M LF

Preliminary Data Sheet

14/58

April 9, 2007

IP113M LF-DS-R11

Functional Description

2.1

Data forwarding

IP113M LF supports three types of data forwarding mode, store & forward mode, modified cut-through

mode and pure converter mode. It can forward a frame despite of its address and CRC error. IP113M LF

begins to forward the received data when it receives the frame completely. The latency depends on the

packet length.

2.1.1

Modified cut-through mode

IP113M LF begins to forward the received data when it receives the first 64 bytes of the frame. The

latency is about 512 bits time width. The maximum packet length is up to1600 bytes in this mode. Please

refer to pin description of FAST_FWD for configuration information.

2.1.2

Pure converter mode

IP113M LF operates with the minimum latency in this mode. The transmission flow does not wait until

entire frame is ready, but instead it forwards the received data immediately after the data being received.

Both transceivers are interconnected via internal MIIs and the internal switch engine and data buffer are

not used. Both TP port and fiber port of IP113M LF should work at 100M full duplex in this mode. If TP port

is linked at half duplex, the total length of UTP cable and fiber should be less than 60 meters to meet the

requirement of CSMACD in IEEE802.3. The packet length is not limited at this mode. Please refer to pin

description of DIRECT_WIRE for configuration information.

In converter mode, it is strongly recommended that both TP port and fiber port of IP113M LF should work

at 100M full duplex. If TP port is linked at half duplex, the UTP cable length should be less than 30 meters

to meet the requirement of CSMACD in IEEE802.3.

2.1.3

Fragment forwarding

IP113M LF forwards CRC error packets but it will filter fragments when it works in modified cut-through

mode. IP113M LF forwards fragments if user turns on bit 3 of MII register 20.

IP113MLF-DS-R09 数据表(PDF) 14 Page - List of Unclassifed Manufacturers