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)