Справочник по сетевым протоколам

RFC1661 - часть 30

Reception of a PPP packet with an unknown Protocol field indicates

that the peer is attempting to use a protocol which is

unsupported. This usually occurs when the peer attempts to

configure a new protocol. If the LCP automaton is in the Opened

state, then this MUST be reported back to the peer by transmitting

a Protocol-Reject.

Upon reception of a Protocol-Reject, the implementation MUST stop

sending packets of the indicated protocol at the earliest


Protocol-Reject packets can only be sent in the LCP Opened state.

Protocol-Reject packets received in any state other than the LCP

Opened state SHOULD be silently discarded.

A summary of the Protocol-Reject packet format is shown below. The

fields are transmitted from left to right.

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1


| Code | Identifier | Length |


| Rejected-Protocol | Rejected-Information ...



8 for Protocol-Reject.


The Identifier field MUST be changed for each Protocol-Reject



The Rejected-Protocol field is two octets, and contains the PPP

Protocol field of the packet which is being rejected.

Simpson [Page 35]

RFC 1661 Point-to-Point Protocol July 1994


The Rejected-Information field contains a copy of the packet which

is being rejected. It begins with the Information field, and does

not include any Data Link Layer headers nor an FCS. The

Rejected-Information MUST be truncated to comply with the peer's

established MRU.

5.8. Echo-Request and Echo-Reply


LCP includes Echo-Request and Echo-Reply Codes in order to provide

a Data Link Layer loopback mechanism for use in exercising both

directions of the link. This is useful as an aid in debugging,

link quality determination, performance testing, and for numerous

Содержание  Назад  Вперед