3Com 3C8S5007 - SuperStack II PathBuilder S500..., Руководство пользователя

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18 C
HAPTER
1: O
VERVIEW OF THE
P
ATH
B
UILDER
S
WITCH
Using PPP on Dial-Up and Leased Lines
All dial-up and many leased lines use PPP. If you want to use multiple PPP
lines or channels to connect to the same destination, you can bundle
them together using Multilink PPP.
Using Packet-Switched Network Services
You can use packet-switched services with your PathBuilder S5xx series
switch instead of dial-up or leased lines to leverage the Telco-owned
switching infrastructure.
Frame Relay provides a packet-switched network that transfers data
between DTEs, which can be routers, bridges, and host computers, by
creating virtual circuits and using DCEs to transfer the data to its
destination.
Frame Relay has been designed to work within complex internetworking
environments with extensions referred to as the
local management
interface (LMI).
LMI provides information about all devices that are accessible on the
Frame Relay network by listing all
data link connection identifiers (DLCIs)
connecting the local system with the remote ones. The LMI improves
reliability between the DTE and DCE through frequent exchange of
keepalive packets that contain status information.
IBM Legacy Networks Each serial interface can be attached directly with a Flex-WAN cable to
IBM legacy equipment like mainframes and automatic teller machines.
See Table 5 for supported IBM protocols.
Table 4 Packet-Switched Services
Packet-Switched
Services/Protocol
Telco Line
Serial Device
Requirements
Data Transfer Rate
X.25 POTS Modem Up to 115 Kbps
Frame Relay Leased line CSU/DSU (not needed on
Ultra-WAN and BNC
connectors) Up to T3/E3
SMDS Leased line CSU/DSU Up to T3/E3