ADC Telecommunications, Inc.
144 CHAPTER 7: PACKET OVER SONET ADMINISTRATION
Configuring LCP
The PPP protocol suite includes a Link Control Protocol (LCP) for establishing,
configuring and verifying point-to-point connections. PPP uses LCP to
determine encapsulation options, set limits in transmit and receive packet
size, detect link configuration errors, and terminate links.
LCP is defined in RFCs 1570 and 1661.

Configuring LCP Parameters

To configure LCP parameters for a selected PPP interface, perform the
following tasks within interface pos <c/s/i> mode:

Initial Maximum Transmit / Receive Unit (MTU)

Because IP packets are encapsulated in PPP, the maximum length of an IP
packet that can be transmitted over the PPP link is the same length as th e
PPP information field. If a packet is larger than the PPP information field, it
must be fragmented a placed in multiple PPP packets. Perform the following
task within interface pos <c/s/i> mode to enter the maximum transmit and
receive packet size allowed on this interface.
NOTE: The only MTU size the Cuda 12000 currently supports is 1500. This
value should not be changed.

Frame Check Sequence (FCS) Size

Perform the following task within interface pos <c/s/i> to enter the frame
check sequence size:
Task Command
Configure the maximum
transmission unit.
mtu 1500
Task Command
Configure frame check sequence
size.
crc {16 | 32}