Note: Failure to detect a bad packet can cause all subsequent
data to be decompressed incorrectly.
This option sets the exact form of check value used. Choose one of
the following:
0None: No check value is used. Without a check value, there
is no way to determine that a packet has been lost,
out-of-sequence, or corrupted. Do not use this mode unless
the underlying data link provides reliable, sequenced packet
delivery.
1LCB: A“Longitudinal Control Byte” is used. This is a simple,
8-bit exclusive–OR checksum.

Its usage is strongly

discouraged

because the receiver cannot detect a lost or an
out-of-sequence packet, and the PPP frame checksum is a
more reliable test of the packet’s integrity.
2CRC: A16-bit cyclic redundancy checksum is used.
Although this is a better test of a packet’s integrity than the
LCB, its use is still discouraged because the receiver still
cannot use it to detect lost or out of sequence packets, and
otherwise it becomes largely redundant with the frame
checksum.
3SEQ: An 8-bit sequence number is used (default). This is
the preferred method of operation. If the number of histories
is not 0, use of any other mode is strongly discouraged
though another mode may be necessary for interoperability
with certain non-RFC-compliant routers.
4EXT:An extended mode that is similar to the sequence
number mode, in that each packet includes a sequence
number, but the compressed frame format is altered more
radically. In extended mode, re-synchronization with a peer
is performed differently than with the other modes; the
signaling between the two nodes is based upon flags
passed in the headers of compressed datagrams rather
than distinct CCP control packets.
Extended mode is provided for compatibility with certain
non- RFC-compliant implementations. It should be used
only with clients that do not support mode 3.
ccp algorithms

list-of-algorithms

Specifies an exact list of compression protocols to use. The order of
preference depends on the order of entry in the list. When MPPE is
activated on the link, the order of the CCP algorithms is ignored and only
Microsoft Point-to-Point Compression (MPPC) is used.
When the link negotiates compression with another node, it offers the entire
list of protocols to the peer node in preference order. The peer node should
select the first protocol it can use from the preference list. Enabling multiple
protocols allows the peer to dictate which compression algorithm will be
used on the link. If you need to avoid an algorithm, do not specify the
algorithm in the list.
Specifying none disables the use of any protocol effectively disabling
compression. The valid compression algorithms are:
Configuring PPP Interfaces (Talk6)
476 MRS V3.2 Software User’s Guide
|
|
|
|
|
|
|
|
|
|
|
|