1999年我在設計 PC Farm cluster 時，預計要做的一套應用系統的目錄服務。將近二十年前的事，拿出來和大家分享。 那時我假想任何人包含組織，都像是百貨公司每一層看板的介紹。不再有現在各種技術名詞，人們之間關係只存在誰、活動的相貌、如何連結。一切非常的簡單，一切就是方便大家互動溝通。

1. TADS
Trusted Application Directory Service
Tein Horng Yuan
tyuan@beta.wsl.sinica.edu.tw
2002/07/03

2. TADS is inspired by
• Since 1999, TANET network performance have had great
improvement
• Security
– SPAM mail and Hackers from other countries
• Education
– BBS is a popular Internet service in Taiwan. But how much
information can provide is determined by the maintainer's budget.
Therefore, on the other hand, BBS sometimes limits the information
source to its users.
– USENET news mechanism is in a mess
• {Freedom+Trusted} general purpose Internet computing
environment

3. Questionnaire to Internet Service
• Is it possible every BBS is not so powerful as
we expect, but many BBSs provide full and
redundant Internet services for all the BBS
users?
• BBS must has its own characteristic
• Is it possible to use current Internet available
open source w/o much modification?

4. Future
• # of Computing nodes is no longer an issue
• Where is the Resource
• Bandwidth is no longer an issue
• Mesh-style connectivity
• Internet services -> diversity and
customizable functionality

5. Scene 1
就像進入 Shopping Mall 一般， Users 只要
經過一次的認證。就可以在 Application
Level 的層次透明化旅行而不必 access
每一台機器都要認證。

6. Scene 2
Any kind of user shows their ID to Academia
Sinica Directory Service(ASDS). ASDS will
provide a list of Internet service in Academia
Sinica for them to browsing. For different kind
of privilege user, they see different kind of
service listing.

7. Questionnaire to Resources
• Who is going to use the resource
• Where is the host
• Where is the application
• Where is the content

8. 其實
• Users 很辛苦的進入機器只是為了要執行
某些應用程式
• 應用程式藏在機器裡
• 機器與機器的溝通？
• Users 反覆進入機器只為了使用
applications

9. 結果
• 每次進入電腦幾乎都要 authentication
• 常常找不到資料 /application(executable,
files, ...)

10. How users find resource locations
nowadays
• Mac Address
• IP
• DNS
• YP/LDAP/...
• Web/gopher
– Internet searching engine
– read by human

11. 如果
• Applications 可以和機器某種程度的分開
• 有某種服務可以幫忙將合適的人們串在一
起「然後」「幫助」他們一起執行某種
application

12. 使用者的角度
• 在任何一個 Registration Server 註冊
• Register his/her own Applications
• Roaming
• Trusted
• Application can be personal or lease from
third party
• 一個人多重角色分屬不同 group
• Multiple roles with multiple groups

13. Current Internet Service
Infrastructure
• A few user information & not trusted
• Anonymous
• Online status is not available on Internet and not
easy to locate
• Service is limited by port#
• Easy to be listened
• Routing path is seldomly changed
• Roaming is not easy

14. • User is trusted & rich information described &
unique to Internet
• User’s role is determined by their compound
attributes & application type & other minor status
• Online status is available on Internet but don't
know where user is
• Service is called by name, instead of port#
• Dynamic changed encoded methods
• Routing path is negotiated by both ends
• Roaming is ingrained in infrastructure

15. New Service Model
Role:={who}:{functionality}
•ROLE:={who}:{functionality}
•ROLE:= {UNIQUE-ID}:{APPLICATION}

16. {Who}
• {Who}:=UNIQUE-ID
• UNIQUE-ID:=LDAP-like directory service
or XML
– /C=TW/O=AS/OU=CC/CN=Yuan Tein Horng
– anonymous
– user-defined groups

17. {functionality}
• {functionality}:=APPLICATION
• APPLICATION:=Application directory
– Protocol type : protocol version : time
dependency(in GMT)
– Net meeting : 1.0 : 12:00
– MPICHapp:1.0:now:8 nodes

18. • TADS
– Bounded by
application name
– Processed by standard
protocol
– Host & Port # are
hided
• Current Internet
Service
– Connect to another
host
– Communicate via port#
– Processed by standard
protocol

19. • 基地台 (turnkey system)
• Must be known firstly
• 註冊台 (turnkey system)
• Application level routing mechanism
– I expect the routing path can be determined by
application-end and
– data encoding method change frequently

20. • Computer is only the carrier of the
applications

21. 未來的 Internet services
• 每種身份可以到 RS 上註冊自己的
services
• 其他 users 可以到 RS 上找尋朋友的蹤
跡並一某種限制加入對方的 services 裡
• 可以隨時更改 routing 路徑。資料編碼方
式。

22. Late Binding
• {who}:{functionality}
• {Binary}:{host}
– {binary} can be from requester or lease from
anyone else
– {host} is can be any available host
• send <arguments> to {Binary}:{host}

23. RS at
SG
GMT
+7
Com
putin
g
node
at SG
RS at
LA
GMT
-6
Com
putin
g
node
at LA
RS at
TW
Yuan.tw at
SG
Jane.tw at
LA
Application Directory
Yuan
• talk: 1.0: 12:00 gmt+8
• H.323: *: 12:00 gmt+8

24. RS at
SG
GMT
+7
RS at
LA
GMT
-6
Com
putin
g
node
at LA
RS at
TW
Yuan.tw at
SG
Application Directory
Yuan
• talk: 1.0: 12:00 gmt+8
• H.323: *: 12:00 gmt+8
Jane.tw at
LA

25. • Until who & application r set, find
application binary & host. That is,
application & host are the lastest step to
allocate for both client & server side in
TADS

26. • DNS is not important any more
• User-Unique ID:Application[:Optional Info]
• Host information can be disappear to both of
users
• Application arguments is passed during
runtime

27. • Current Intranet is blocked by IP
• TADS intranet is blocked by requester's role
• Distributed information nature
• Directory information provided by local RS
• no global directory exist

28. How MPICH/PVM works w/
TADS
• user tyuan register his program name, xxx, to
the local RS and limit only {tyuan}:{xxx}
can run this program. At the same time,
tyuan asks for 8 nodes from the local RS.
• After RS locates all resource for tyuan, tyuan
setups all executable and sends runtime
arguments