Specifications

Sample Scenarios 71
If the customer wants to discard FTP IP traffic in order to keep the SNA traffic, the
customer can define FTP traffic with DE bit ON. Both IP traffic and SNA traffic are
delayed. The SNA traffic delay is less than the estimated delay.
Figure 41. Frame Relay DEbit:ON
When congestion occurs, a frame relay switch will discard only IP traffic.
Figure 42. Frame Relay DE bit:ON Discard
DE bit is very effective solution to control the traffic with each protocol, but to
design to use DE bit needs very careful decision, because other person’s and
company’s traffic may have priority than your traffic with DE bit ON.
Frame Relay
Network
FR switch
FR switch
SNA : DE bit "OFF"
TCP/IP : DE bit "ON"
IP Traffic
(FTP)
SNA Traffic (DLSw )
SNA Traffic (DLSw )
IP Traffic
(FTP)
Delay
Estimated
Delay
Congestion
2212
2212
I
P
(
F
T
P
)
F
r
a
m
e
IP Traffic
(FTP)
SNA Traffic (DLSw )
Congestion
SNA Traffic (DLSw )
IP Traffic
(FTP)