321 Test 3 (study guide)
What are the three steps in the routing process?
1. find all row matches 2. find the best row match 3. send the frame out, based on information in the row
which two layers govern TCP/IP internetworking?
3 - internet 4 - transport
mask in prefix notation/dotted decimal notation format
8 1s mean /8
Internet Control Message Protocol (ICMP)
A TCP/IP protocol that is used by devices to communicate updates or error information to other devices.
Border Gateway Protocol (BGP)
A core routing protocol that bases routing decisions on the network path and rules.
routers
A device that forwards packets within an internet. routers connect two or more single networks
flag fields
A one-bit field
SNMP (Simple Network Management Protocol)
An Application-layer protocol used to exchange information between network devices.
what is the main version of internet protocol in use today?
IPv4
hop limit field
In IPv6, the field that limits the number of hops an IPv6 packet may make among routers
sequence number field
In TCP, a header field that tells a TCP segment's order among the multiple TCP segments sent by one side
decision cache
In routing, a list a router keeps of recent routing decisions for specific IP addresses so that it does not have to go through an entire routing decision again if another packet to that IP address arrives. This is nonstandard and somewhat risky.
routing
The forwarding of IP packets. The exchange of routing protocol information through routing protocols.
default row
The row of a routing table that will be selected automatically if no other row matches; its value is 0.0.0.0.
Management Information Base
What is a hierarchical structured format that defines the network management information available from network devices?
IPv4 mask
a 32 bit series with a number of 1s followed by 0s. the 1s correspond with the network. used by routers to assign routes to all packets going to a particular network
whats the difference between a border and internal router?
a border router connects different networks while a internal router connects different subnets withing a network
internet service provider
a carrier that provides internet access and transmission
metric
a number describing the desirability of a route represented by a certain row in a routing table
internal router
a router that connects different LANs within a site
border router
a router that sits at the edge of a site to connect the site to the outside world through leased lines, PSDNs, and VPNs
next-hop router
a router to which another router forwards a packet in order to get the packet a step closer to reaching its destination host
subnet
a small network that is a subdivision of a large organization's network
field
an IPv6 field is a group of four lower-case hexadecimal symbols. each fields represents 16 bits. fields are separated by colons
NAT operations
converting an IP address into another IP address, usually a border firewall; disguises a host's true IP address from sniffers. allows for more internal addresses to be used than an ISP supplies a firm with external addresses
Sniffer program
electronic programs that capture account numbers and PINs that can be installed on a computer via computer spyware
what does a router do if it receives several packets going to the same destination?
goes through the entire process again 1. go through each row looking for a match 2. find the best match row 3. send the packet out the indicated interface
acknowledgement number fields
in TCP, a header field that tells what TCP segment is being acknowledgment in a segment
what are the three parts of an IPv4 address? How long is each part? What is the total length of an IPv4 address?
network(16)/subnet(8)/host(8) total length: 32
what is a flag field? list four flag fields
one bit fields ACK SYN FIN RST
interfaces
router ports the routers equivalent of a network interface card; a port or router that must be designed for the network to which it connects
why are routing tables more complex than ethernet switching tables?
routing has to do much more processing which is more expensive and time consuming
time to live field
the field added to a packet and given a value by a source host, usually between 64 and 128
default router
the next hop router that a router will forward a packet to if the routing table does not have a row that governs the packets IP address except for the default row
Prefix notation
the number of leading 1s in a mask