APPENDIX
Point-to-Point Protocol
This appendix provides supplementary information concerning the implemen-
tation of PPP as it pertains to Access-T.
PPP Support
PPP support for Access-T is contrained to the following:
•
Maximum length of data field is 1500 bytes.
•
Protocol support is limited to IP (0x0021), IPCP (0x8021), and LCP
(0xC021). PPP authentication protocol is not supported.
•
A between character timeout is implemented such that if the timeout
occurs, the packet is discarded.
LCP
Before a link can be used, the two ends must negotiate certain settings or options.
The protocol used for this negotiation is called the Link Control Protocol (LCP).
LCP packets are encapsulated within PPP packets (i.e., it constitutes the data
portion within PPP packets).
LCP support as it pertains to Access-T is implemented as follows:
•
Only version 1 of the LCP is supported.
•
Configuration options supported during the Link Establishment
Phase are limited to:
•
Maximum-Receive-Unit:
Maximum size of packet peer can
receive or should send. Peer must be able to receive a mini-
ACST-0351-005
Appendix I
June 1996
Point-to-Point Protocol
I–1
