GE T1000, Technical Manual

Page: 90 / 302

Chapter 4
– Functions
GE Reason Switches
90 REASON SWITCHES-TM-EN-3
Figure 49: Traffic in an oversized
If there are sporadic small time peaks on incoming data, the switch stores packets
that could not be delivered in an internal buffer and then, when the peak traffic ends,
data is forwarded and buffer memory gets empty.
Besides, if incoming data traffic increases for a time higher than the buffers inside
the switch can support, then there will be data lost.
Figure 50: Traffic of incoming data higher than the port at the switch can process
This situation can have its impact decreased if communication protocol is connection
oriented, as there will be retransmission of packet if there is no confirmation by the
receiver that data has reached its destination.
At power system communication, there is a wide use of connectionless
communication protocols, that is, protocols that does not guarantee the delivery of
sent data. NTP time protocol, as an example, uses UDP transport protocol. GOOSE
and Sampled Values protocols are mapped directly at Ethernet frame and use
multicast transport mechanism, thus being connectionless protocols. PTP protocol
can be mapped directly at Ethernet, as GOOSE and Sampled Values, or at UDP, as