3Com C36460T Dial Idle Timer, Disaster Recovery on, Ports Without Leased, Lines, DTR Modems

	WAN Protocols and Services Notes 55
Dial Idle Timer	The dial idle timer is not accurate and it will take a client longer to idle out than is
	configured. For a 180 second dial idle time it takes approximately 8.5 minutes for
	the client to idle out if no traffic is ever sent. To workaround this problem, disable
	bootp on !0 by entering the following command:
	Setd !0 -bootp control=disable"
Disaster Recovery on	The Port Service DialControl parameter controls port attributes for a dial-up port in
Ports Without Leased	the event the bandwidth set for a leased line drops below what has been set as
Lines	the normal bandwidth. Setting this parameter to DisasterRecovery for a port
	without leased lines prevents port idle out.
DTR Modems	DTR modems should not be configured as a dynamic path and a dial pool.
Dynamic Paths	Dynamic paths might not be released back into the dial pool from the port if an
	incoming call arrives during a disconnect state. If the SHow -POrt PAths command
	indicates that a path from the dial pool is attached to a port but is no longer in
	use, it can be released by re-enabling the port.
Frame Relay Congestion	The current implementation of Frame Relay congestion control requires that you
Control	set the committed burst size (Bc) and the committed information rate (cir) to the
	same value so that the time interval (Tc) equals 1 second using the formula
	Tc= <Bc>/<cir>. If Tc is not 1 second, the Frame Relay frames may be erroneously
	dropped due to the incorrect calculation of the throughput rate threshold.
History-Based	If you are using history-based compression on a line with excessive errors and the
Compression	negotiation attempts exceed the retry count, the device must be rebooted to clear
Negotiation Failure	the condition and reset the retry count.
History Compression Not	A port using Async PPP (AT dial) cannot be configured for history compression.
Allowed With Async PPP	The user interface will not prevent you from configuring the port for history
	compression, however, if history compression is selected the path will not come
	up.
Multilink PPP	Multilink PPP (MLP) is supported for multiple WAN links connected to the same
Configurations	port running PPP.

When configuring MLP:

■For maximum performance on a NETBuilder II bridge/router, 3Com recommends that similar hardware interface types be configured for each MLP bundle. For instance, bundle HSS modules with HSS modules, and bundle HSS 3-port module links with HSS 3-port module links.

■For the best performance, use MLP on interfaces with matched line speeds. Avoid mismatched baud rates of ratios greater than 10 to 1 for bundled links.

■If your baud rate ratios on two links are greater than 4 to 1, the MLP feature automatically turns off fragmentation. For baud ratios of less than 4 to 1, you may choose to turn off fragmentation for performance considerations. Turn off fragmentation using the MlpCONTrol parameter in the PPP Service.

■MLP does not support the HSSI module.

■Before you re-enable a port running MLP, disable the port and allow the remote port to go down. This action prevents loss of packet sequence numbers