3Com MSR 50 Series, Configuration Manual

Page: 213 / 2443

Configuring DLSw in an Ethernet Environment 213
(depending on the specific situation). Using UDP packets reduces, to some degree,
the TCP connections required, and thereby saves network resources.
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Setting up a single TCP connection when required
A TCP connection is set up after the origin and target DLSw v2.0 routers get
reachability information using UDP packets and when both the origin and target
stations want to set up a circuit between them. A DLSw circuit establishment
process is simplified into two stages: first, establishment of a single TCP
connection; then, capabilities exchange. If capabilities negotiation fails, the
source-end DLSw v2.0 router sends a reject packet to the peer and then the TCP
connection is taken down.
As a TCP connection is established only when a circuit is required between two
end systems, the overheads of establishing and maintaining TCP connections are
reduced, resulting in better system resource utilization.
n
In case the origin and target DLSw routers use different versions of DLSw, for
backward compatibility, the one uses DLSw v2.0 works as a DLSw v1.0 router and
follows RFC1795 when setting up a TCP connection with its peer.
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Enhanced maintainability
To enable a DLSw router to notify its peer about the reason for dropping a
connection, DLSw v2.0 defines five generic circuit halt reason codes: unknown
error, received DISC from end-station, detected DLC error with end-station,
circuit-level protocol error, and operator-initiated. The halt reason codes are sent
to the peer in SSP messages.
Related Specifications DLSw is documented in:
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RFC 1795: Data Link Switching: Switch-to-Switch Protocol AIW DLSw RIG:
DLSw Closed Pages, DLSw Standard Version 1.0.
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RFC 2166: APPN Implementer’s Workshop Closed Pages Document DLSw V2.0
Enhancements.
Configuring DLSw in
an Ethernet
Environment
Follow these steps to configure DLSw in an Ethernet environment:
To do... Use the command... Remarks
Enter system view system-view -
Enable bridging bridge enable Required
Enable a bridge set bridge bridge-set enable Required
Enable DLSw dlsw enable Optional
Enabled by default
Create a DLSw peer Refer to “Creating DLSw Peers”
on page 214
Required
Configure a bridge set
connected to the DLSw Refer to “Mapping a Bridge Set
to DLSw” on page 215
Required
Add an Ethernet interface to
the bridge set Refer to “Adding an Ethernet
Interface to a Bridge Set” on
page 215
Required