Telecommunication & Networking

Telecommunication & Networking

Lesson 9

Presentation Reminder• Make sure you are aware of the schedule• Presentations are NOT in this room, but at CKB LT3 for

both June 15, and June 22. Please be on time. Absence will affect your individual grade. Equipment request?

• Each team must– Provide an overview of the business and the rationale

for the establishment of an intranet– Provide the intranet system architecture with

internetworking characteristics– Provide a technical tutorial of your team’s

implementation responsibility (e.g., Exchange server) and the complete system operations

– Provide Q&A

Market Share: Top Servers (www.netscraft.com :June 8 8:00 a.m. HKT)

Last Poll of 15 million sites, May 2000

Statistics• Apache (60%), Microsoft-IIS (21%),

Netscape-Enterprise (7%)…WebLogic (0.6%) [May 2000]

• Host Count: Jan 2000 vs Jan 1999

– 72,398,092 to 43,230,000: an increase of 29,168,092 or 40%

• RedHat: dominating Linux OS (information is not complete)

DLL/PL

IP

TCP/UDP

Applications

Voice

RTP/RTCP

DLL/PL

IP

TCP/UDP

Applications

IPOConnect.com• A company advises and invests for customers with

accounts starting with at least US$10 million; each trade will be at least US$100,000.00

• The company has two branch offices: one in Kowloon and one in Hong Kong island

• Total number of employees: 20 brokers + management team + technical team

• The company only invests on IPO’s (they may underwrite some IPO’s themselves)

• They want an intranet to facilitate their operations…!!!

•Human Resources

•Accounting

•Payroll

BranchKln Transaction DB/MailServer

BranchHK Transaction DB/WebServer

BrokerHK01BrokerHK01

BrokerHK02BrokerHK02

BrokerHK03BrokerHK03

BrokerKln02BrokerKln02

BrokerKln01BrokerKln01

TelcoInternetInternet

T1?

InterOffice

Fictitious Transactions• Advise Buy/Sell 5000000 tom.com

• Buy 5000000 tom.com

• Sell 5000000 tom.com

• Confirm Buy

• Confirm Sell

• Enquire Portfolio

• Portfolio …

DLL/PL

IP

TCP/UDP

Applications

Communication Link?

?Application Secure?

?Private Network?

DLL/PL

IP

TCP/UDP

Applications

DLL/PL

IP

TCP/UDP

Applications

Web-based User Interface

DLL/PL

IP

TCP/UDP

ApplicationsUse sockets to send raw

data (e.g., “Buy 5000000…)

IPv4 IPv6 (www.ipv6.org)

Lower Two Layers (DLL & PL)

IP/IPSec• address size from 32 to 128 bits

address space ran outglobally unique addressnetwork address translation (NAT)

* expansion leads to new NAT-based addresses …

TCP/UDP

InternetInternet

ISP

NAT boxNAT box

• same private addresses

• one address (that of NAT box) to many addresses (internal)

• modification of packet information during flight expected

IPv4 IPv6 (IPng)• Header size is twice as big even with 4 times the size

of v4 network address– Fixed in general– Has a next header field (or extension header)

• Extension makes easy– Integrity and authentication

• Network Management– DHCP server: what if it is down?– Automatic configuration of a new ‘node’ without a server

• Anycast– Unicast, multicast, broadcast– Anycast: one-to-any-member-of-a-group; the ‘nearest’

• QoS– Flow label (24 bits): service independent flow

characteristics; implementation specific– Priority label (4 bits)

• To allow support for different types of traffic

• Small numbers (0-7) identify low-priority traffic (emails); the source is providing the congestion control

• Large numbers (8-15) identify high priority traffic that is not to be dropped and must be pushed through; e.g., video; values 9-14 are being defined for other types of data

Acceptance?• Customer base is not large enough that most

ISPs are not doing the upgrade (in the States);

• Equipment manufacturers (e.g., CISCO) have to be ready to fill the market when the market demand is on the upturn

• ISPs in Asia and Europe want IPv6 because of the non-existent address space

• Coexistence of IPv4 & IPv6

ProgrammableRouters/Switches

Active Networks• Passive bits through traditional data networks• Packets went through routers with very limited

processing: header modification (NAT)• Instead, ‘capsules’ are injected into the network

– ‘capsules’ are miniature programs executed at nodes (encapsulated data and code segment, or at least one instruction)

– Every ‘message’ is a ‘capsule’ or a program– ‘Active’ not only at end-to-end systems (client and

server), but at every node– Mobile, safe and efficient

• Applets• Firewalls: manipulate user’s packets according to

specific ‘rules’ or applications at a corporation boundary; update?

• Web Proxies: caching? How to cache “active” pages

• Nomadic agents & gateways: travellers’ environments adapted to the end system (phone line in a hotel vs LAN in the office); maintain state information

• Bidding, aggregation, information fusion, …

A general architecture for AN by Smith, et. al., IEEE Computer, April 1999

Execution Environments• Smartpackets : BBN (under GTE)’s code life time

ends when execution is complete; uses Sprocket, a special language for smart packet programming; diagnostic;

• ANTS: http://www.sds.lcs.mit.edu/activeware• Netscript: “NetScript is a programming language

and environment for building networked systems.”; dynamic firewall creation; (http://www.cs.columbia.edu/dcc/netscript/)

ANTS (Active Node Transfer System)(ieee computer, April, 1999)

Active Networks

• Security concerns: in addition to integrity and confidentiality, for example, same as traditional networks, AN deals with unfriendly active packets at each node (e.g., that drains node resources similar to DOS attacks)

Few notesCanada’s optical networking (3rd generation

Internet project) – “The initial segments of CA*net 3 were

deployed in October 1998, and the entire network [8500km], which runs from from Halifax, Nova Scotia, off the East Coast to Vancouver, British Columbia, on the West Coast, was completed in July 1999. The network was extended to Seattle in April 2000, and additions to New York are scheduled to be active by mid-May.”

vBNS + Internet2www.vbnsplus.net + www.internet2.edu

• “vBNS+ is a nationwide network that supports high-performance, high-bandwidth applications. Originating in 1995 as the vBNS, vBNS+ is the product of a five-year cooperative agreement between MCI Worldcom and the National Science Foundation.”

• “Internet2, led by over 170 U.S. universities working in partnership with industry and government, is developing and deploying advanced network applications and technologies, accelerating the creation of tomorrow's Internet.”