Enterasys 6000 사용자 가이드
Configuring SNA
8-17
Configuring LLC2
LLC2 (Logical Link Control type 2) support in the FRX/FRM provides a local or
remote connection over frame relay (via RFC1490) or X.25 (via QLLC) between two
SNA devices, one attached to a LAN and the other attached to either another LAN or
a frame relay-compliant SNA/APPN device. Each SNA host and terminal accessing
the FRX/FRM—via SDLC, LLC2, frame relay, or X.25—will appear to a local LLC2-
attached terminal or host as if it is directly connected to the local LAN.
remote connection over frame relay (via RFC1490) or X.25 (via QLLC) between two
SNA devices, one attached to a LAN and the other attached to either another LAN or
a frame relay-compliant SNA/APPN device. Each SNA host and terminal accessing
the FRX/FRM—via SDLC, LLC2, frame relay, or X.25—will appear to a local LLC2-
attached terminal or host as if it is directly connected to the local LAN.
LLC2, defined by IEEE 802.2, provides exchange of control frames between an SNA
device and its network-access node, rather than passing them across the network. This
allows more efficient use of available bandwidth, and minimizes LLC2 session time.
(A session is an exchange of poll and acknowledgment between devices.)
device and its network-access node, rather than passing them across the network. This
allows more efficient use of available bandwidth, and minimizes LLC2 session time.
(A session is an exchange of poll and acknowledgment between devices.)
LLC2 support in the FRX/FRM includes the following scenarios, some of which are
diagrammed in Figure 8-4 (on page 8-18):
diagrammed in Figure 8-4 (on page 8-18):
●
Connection between a LAN-attached host/workstation and SNA devices, via
SDLC-to-LLC2 and LLC2-to-SDLC conversion, over a frame relay or X.25
network (example 1), or frame relay PVC (example 4).
SDLC-to-LLC2 and LLC2-to-SDLC conversion, over a frame relay or X.25
network (example 1), or frame relay PVC (example 4).
●
Connection between LAN-attached workstations, over a frame relay or X.25
network (example 2), or a frame relay PVC (example 3).
network (example 2), or a frame relay PVC (example 3).
●
Connection between workstations attached to different LANs on the same FRX/
FRM.
FRM.
Support of end-to-end LLC2 connections in an FRX4000 requires that the
full LLC2 protocol (not LLC2-R) be configured and loaded in the LP file,
as described in Chapter 4. (LLC2-R does support conversion.)
full LLC2 protocol (not LLC2-R) be configured and loaded in the LP file,
as described in Chapter 4. (LLC2-R does support conversion.)
Protocol conversion is accomplished by terminating an SDLC connection in the FRX/
FRM and establishing an LLC2 connection to the SNA host.
FRM and establishing an LLC2 connection to the SNA host.
The following figure shows some examples of LLC2 configurations. Note that the
LANs shown are all Token Ring. The same examples can be presented with Ethernet
LANs.
LANs shown are all Token Ring. The same examples can be presented with Ethernet
LANs.