Chapter 8: TCP/IP Internetworking
UDP
Does not do fragmentation. Does not need sequence numbers, acknowledgement numbers, or acknowledgements. This simplifies it making handling faster. Cannot do segmentation, so an application message must fit into a single UDP datagram.
Address Resolution
The internet layer process must discover the DLL address of the destination host to send the packet to a next-hop router or a destination host
Routing
When routers forward incoming packets closer to their destination hosts
Prefix Notation
a mask is represented by a slash followed by the number of initial 1s in the mask.
TCP Reset Segment
a segment with the RST (reset) flag bit set.
Mask
a series of initial ones followed by series of final zeros, for a total of 32 bits
Ethernet Switching Table Rows
are rules for handling individual Ethernet EUI-48 addresses.
Router Routing Table Rows
are rules for handling ranges of IP addresses
Differentiated Services Control Point Field
can be used for priority or other quality of service purposes
Explicit Congestion Notification Field
can be used to reduce the transmission frequency between a pair of hosts to cope with congestion in the transmission system between them.
Hop-by-Hop Options Header
carries options that must be considered by every router along the packet's route to its destination host.
Hop Limit Field
does the same thing the IPv4 time to live field does.
Routing Table
each row represents a route for all IP addresses within a range of IP addresses.
Field
each tetrad in IPv6
Time to Live (TTL)
field that is assigned a value by the source host.
Subnets
further divided networks into smaller units
Sequence Number
gives its position in the stream of segments.
Payload Length Field
gives the length of the packet payload, which is everything beyond the 40-octet main packet header.
Decision Cache (cheating)
greatly reduces the work that a router will do for each successive packet. (caching is dangerous)
Network Part
identifies the host's network on the Internet.
Flow Label Field
indicates that the packet is a member of a particular flow.
Acknowledgment Number Field
indicates which segment is being acknowledged.
Border Router
main job is to connect different networks
Internal Router
only connects different subnets within a network.
Network
organization that controls part of the Internet.
Address Resolution Protocol (ARP)
provides address resolution on Ethernet LANs.
Interfaces
router ports
ARP Cache
section of memory that contains the IP address-data link layer address information
Host Part
specifies a particular host on the subnet.
Diffserv (differentiated services)
specifies whether this particular packet should be given routine best-effort service, high-priority low-latency service, or some other type of service. (6 bit)
Subnet Part
specify a particular subnet within the network.
Protocol Field
tells the contents of the data field.
Version Field
the first 4 bits in the IPv4 packet
Subnet Masks
the initial 1's indicate the number of bits in both the network and subnet parts.
Longest Match
the longest number of initial 1s in the mask)
Next Hop Router
the router will send the packet on to another router
Tie-Breaker Rule
to use the metric column, which describes the desirability of a route, in the case of a tie for the longest match
Hierarchical IP Adresses
usually consist of three parts that locate a host in progressively smaller parts of the Internet. (network, subnet, and host parts)