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