Cayman Systems 2E-H-W User Manual page 145

Cayman 2E-H-W User's Guide
November 2000
Once a network connection is made, each peer negotiates its side of
the link's configuration by sending a Configure-Request message that
lists its complete set of proposed configuration settings. When one
peer sends a Configure-Request, the other peer responds in one of
three ways:
Configure-Ack – If every configuration option in the
Configure-Request packet is both recognizable and acceptable,
the second peer returns a Configure-Ack message that lists the
complete set of proposed settings and indicates that the peer
accepts the settings. All configuration options are acknowledged
simultaneously.
Configure-Nak – If every configuration option in the
Configure-Request is recognizable but some values are not
acceptable, then the second peer returns a Configure-Nak
message that identifies the unacceptable option settings and
proposes new settings acceptable to the second peer. A
Configure-Nak message may also include proposed
configuration settings for options that the second peer requires
but that the first peer did not include in its Configure-Request.
Configure-Reject – If one or more of the configuration options in
a Configure-Request are not recognizable or are not acceptable
for negotiation, the second peer returns a Configure-Reject
message that identifies the rejected options. The first peer can
then send another Configure-Request that does not include any
of the options listed in the Configure-Reject.
The negotiation mechanism is conducted independently in each
direction: a setting negotiated for one peer does not apply to the
other peer until it negotiates that option for itself. For example, if
Peer A negotiates that it has a maximum receive unit of 1492 bytes
with Peer B but Peer B does not negotiate its own MRU (implying
that it uses the default value of 1500), then Peer A can send frames
up to 1500 bytes long to Peer B but Peer B can send frames up to
1492 bytes long to Peer A.
How Your Cayman 2E-H-W Works
C-7