Voip

Midterm Assignment

4/25/2006

COURSE TITLE: Networks & Telecommunications Concepts

1. Describe the fields in the IP version 4 (IPv4) packet header. (What is the structure (each field) of an IPv4 packet?)

Internet Protocol version 4 was the most used version of the Internet Protocol until version 6 came along. Version 4 is the OSI Network Layer that uses 32bit Ethernet packet switching. The IPv4 Header is formatted as follows:

|Version | IHL | TOS | Total length |

|Identification | Flages | Frag. Offset|

|Time to live| Protocol | Header Checksum |

| Source Address |

| Destination Address |

| Options |

2. Describe and explain the difference between circuit bandwidth and network throughput.

Circuit bandwidth- the wider the band (frequency range) the more signals (transmissions) can be carried. Since bandwidth is measured in Hz (Hertz) radio waves can be categorized as being in either a low or high range of digital bits-per-one-second transmitted.

Throughput is was to measure the amount of data that entered at one end of the network or circuit and exited at the receiving destination. While the Throughput is not able to be greater than the bandwidth, Throughput can be made up of many links, paths or channels.

3. Research the Domain Name System (DNS). What is its purpose? What are the root DNS servers? (List them. What is a DNS tree? What are SOA, NS, A, PTR, and CNAME resource records?

DNS is a way to identify TCP/IP devices by assigning each host a standardized name. Examples of a DNS would look like www.tee.school.edu, which would then be converted to 172.xxx.xxx.tee.school.edu (the site IP address).

Domain Tree:

Root servers are the part of an IP address that appears before the dot. There are 13 root servers:

A (198.XX.X.X) VeriSign Globel Reg.

B (128.X.X.XXX) Information Sciences

C (192.XX.X.XX) Cogent Communications

D (128.XX.X.XX) University of Maryland

E (192.XXX.XXX.XX) NASA Research

F (192.X.X.XXX) Internet Systems

G (192.XXX.XX.X) US Dept of Defense Info

H (128.XX.X.XX) US Army Research

I (192.XX.XXX.XX) Autonomica

J (192.XX.XXX.XX) VeriSign Reg.

K (193.X.XX.XXX) European IP Networks

L (198.XX.XX.XX) IANA

M (202.XX.XX.XX) WIDE Proj.

The next level is a suffix-like ending (after the dot) that is attached to a host name according to the following categories: .edu for educational institutions, .com for commercial sites, .org for Non commercial sites, and .gov for Government agency sites, .net for Network Providers, .int for International Treaty sites, and .mil for US military sites.

A = Address Resource Records are a 32bit IP address where the DNS functions as queries matching the domain name used.

CNAME = Canonical Names are substitutes (aliases) for site or address names that are not accepted on the first query status. This is usually not used because most additional records are sent along with the first query.

PTR = Pointers are used to create in-addr.arpa domains that convert an IP address into a First-Use DNS address. These domain names point to a location in the DNS name space.

SOA = Service Oriented Architecture is used to support user software in an environment that accessed the Web. According to the language ( C, C#, Java, etc) SOA is used to create a way to mask or hide the Vender information and interface.

NS = Name Service is an internet identifier, a series of numbers assigned to each host domain.

4. For the following IP routing protocols: spell out their acronym, mark as distance-vector or link-state routing protocol, and mark as classful or classless routing protocol.

Routing Protocol Spell out Acronym Distance-v or Link-S Classful or Classless

OSPF Open Shortest Path First Link-s classless

EIGRP Enhanced Interior Gateway Routing Path Link-s Classless