Pertemuan 18
TCP/IP Suite Control Messages
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Discussion Topics
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Introduction to control messages
CMP redirect/change requests
Clock synchronization and transit time estimation
Information requests and reply message formats
Address mask requirements
Router discovery message
Router solicitation message
Congestion and flow control messages
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ICMP Redirect/Change
Requests
The default gateway
of the host may
need to use a
redirect/change
request to inform
the host of the best
path to a certain
network.
Clock Synchronization and Transit
Time Estimation
• The ICMP timestamp request message
allows a host to ask for the current time
according to the remote host.
• The remote host uses an ICMP timestamp
reply message to respond to the request.
Address Mask Requirements
• When a network administrator uses the
process of subnetting to divide a major IP
address into multiple subnets, a new
subnet mask is created.
Router Discovery Message
• When a host on the network boots, and
the host has not been manually configured
with a default gateway, it can learn of
available routers through the process of
router discovery.
Router Solicitation Message
• A host generates an ICMP router
solicitation message in response to a
missing default gateway.
Congestion and Flow Control
Messages
ICMP source-quench messages are used
to reduce the amount of data lost from
congestion.