Verilink 9000 Series (34-00271) Product Manual - Manual (Page 208)

186 C HAPTER 11: DLP (D ATA L INK P ROTOCOL )
The International Telecommunications Union (ITU) has defined a communications
protocol in Recommendation X.25 that uses a layered architecture. This standard is
widely used around the world in most of the Public Data Networks (PDNs). The
LAPB protocol provides a reliable full-duplex service at high speed. It is also a
bit-oriented protocol, so any kind of data can travel through an LAPB device.
In TUNNEL mode the port can be connected to any kind of device's bit-oriented
protocol. This mode is not a protocol it self; there is no spoofing, instead it serves
to encapsulate the transport protocol (like Frame Relay, X.25, etc.). This special
mode is used when the device to connect to a TXPORT device, does not support
SDLC or LAPB. Figure 11-1 shows a typial use for the DLP protocol. The Banyan
servers use LAPB mode while the CTOS stations use Tunnel mode.
Frame Relay
DOWNLOAD CONFIG
MODE BACKUP NET ALARM POWER
PRISM 9111 T R A N S P O R T
®
DOWNLOAD CONFIG
MODE BACKUP NET ALARM POWER
PRISM 9111 T R A N S P O R T
®
DOWNLOAD CONFIG
MODE BACKUP NET ALARM POWER
PRISM 9111 T R A N S P O R T
®
BNet
BNet
VIP over
HDLC
VIP over HDLC
Unit 001
Unit 002
Banyan Server
Banyan Server
CTOS
CTOS
Figure 11-1 Typical DLP Application