3Com C36460T ATM Services Notes, WAN Protocols and, ATM Emulated LANs, ATM LAN Emulation, Frames

ATM Services Notes 53

	VTAM Version 4.2 requires PTF #UW20787. VTAM Version 4.3 requires PTF
	#UW20788.
	Visible symptoms of this problem can be seen as a lack of network management
	data for PUs that are downstream of a NETBuilder II bridge/router using APPN DLU
	services. The NetView message “AAU251I AAUDRTIB 02 UNEXPECTED SENSE
	CODE X'1002' ENCOUNTERED FOR TARGET=pu_name” is printed in the log file
	when this problem occurs.
ATM Services Notes	This section describes notes, cautions, and other considerations to be aware of
	when using the Enterprise OS software with ATM services. The topics are
	presented in alphabetical order.
ATM Emulated LANs	Enterprise OS software supports a system maximum of 32 ATM emulated LANs.
ATM LAN Emulation	This release of LAN emulation software does not support large 802.3 frame
Clients and Large 802.3	encapsulation as specified in the LANE standard 1.0. When IP routing is used from
Frames	FDDI to an emulated LAN, packets larger than 1500 are sent fragmented per IP
	fragmentation rules.
ATM Connection Table	In a LAN Emulation environment with many LAN Emulation Servers (LESs), a
	performance drop may occur when the NETBuilder bridge/router is able to
	connect to the LAN Emulation Configuration Server (LECS), but many of the LESs
	are down or unreachable. Disabling the ETHATM virtual ports corresponding to
	the unreachable LESs will alleviate this situation.
Deleting ATM Neighbors	Bridge ATM Neighbors must be deleted before the associated virtual ports can be
	deleted.
Source-Route	The source-route transparent gateway is not currently supported on ATM LAN
Transparent Gateway	emulation ports.
WAN Protocols and	This section describes notes, cautions, and other considerations to be aware of
Services Notes	when using the Enterprise OS software with WAN protocols and services. The
	topics are presented in alphabetical order.
ACCM Not Configurable	The ACCM (Async Control Character Map) used for Async PPP cannot be
	configured. During LCP negotiation, the NETBuilder bridge/router always proposes
	an ACCM of all zeros and agrees to whatever the peer negotiates.
Asynch Tunnelling on	For best results, set the LineType parameter to Leased and set the SuperStack II
Serial Ports	NETBuilder bridge/router model 32x connector type for the universal port to
	RS-232. For the path to come up, the bridge/router must see a DTR or DSR control
	signal from the device. Or, if the device does not generate a control signal, a
	loopback connector should be used to supply the control signal.
Automatic Line	When set to the value of Auto, the -PATH LineType parameter first attempts to
Detection	bring up the path as a leased line by raising the data terminal ready (DTR) signal. If
	the path comes up but a DTR-base dial modem is attached to the path, the
	modem does not hang up until brought down manually with the HangUp
	command. To avoid this situation, set the -PATH LineType parameter to Dialup.