Mar 5, 2009

DPNSS Versus QSIG - Can They Coexist?

很多人聽過PBX之間交換的標準-QSIG,但是可能比較少人聽過DPNSS,事實上DPNSS也是另外一種跟QSIG類似的PBX交換標準,但是它們之間到底有那些不相同的地方及歷史上演進的結果為何?

請參閱下文Q&A:

http://www.pqmconsultants.com/coexist.htm

Q. What are DPNSS and QSIG?
DPNSS and QSIG are inter-exchange signalling protocols, primarily intended for the interconnection of nodes in a Corporate telecommunication Network (CN). The interconnection of PABXs using leased circuits is a typical application. Both DPNSS and QSIG are common channel signalling systems based on ISDN technology. They are open standards; that is, they permit signalling between equipment from different vendors.

Q. How did DPNSS come about?
The development of DPNSS commenced in 1981 with the decision by the UK telecomms industry (British Telecom, as was, and a number of PABX manufacturers) to develop a vendor independent private network signalling system. This work resulted in the protocol that is today widely used throughout the UK and elsewhere. The drivers behind DPNSS development are well known. They were the increasing demands of corporate communications, the advent of stored program control PABXs at the beginning of the 1980's, and the increased availability of digital transmission capacity.

Q. How did QSIG development start?
In the mid- to late 1980s work commenced at the European level, firstly in the Committee of European Post and Telecommunications (CEPT), and more recently in the European Telecommunications Standards Institute (ETSI) and the European Computer Manufacturers Association (ECMA). This work developed an architecture for private ISDNs and an inter-exchange signalling protocol based upon the ISDN concepts specified in ITU-T (formerly CCITT) Recommendations. The inter-exchange protocol, based on ITU-T Recommendation Q.931, has become known as QSIG.

Q. What caused this?
The UK telecomms industry pushed for it. It wasn't until later that other parts of the European industry recognised the need for an ISDN based vendor independent signalling system for PABX networks. Added impetus came in 1988 when the Commission of the European Communities added their political weight to the work.

Q. Why wasn't DPNSS used as the basis for QSIG?
In the mid-1980's, there was considerable opposition to DPNSS from outside the UK. DPNSS was seen, incorrectly, as a particular solution from BT. This generated so much resistance from other European countries. Commencing standards work at the international level based on DPNSS was a non-starter. Having said that, many of the companies and individuals active in QSIG standardisation are the same companies that participated in DPNSS development. They hold the "DPNSS compatibility issues" very much in the forefront of their minds.

DPNSS was only ever intended as an interim solution prior to an internationally agreed ISDN based solution becoming available. As things have turned out UK users have benefited from DPNSS for 15 years now.

Q. What is the status of QSIG development?
Today (Spring 1998) there are Standards for more than 30 QSIG supplementary services, including calling line identification, call transfer, and several forms of call diversion. Others are still being worked upon. QSIG has also achieved status as a worldwide standard in ISO/IEC.

Q. How does QSIG functionality compare with that of DPNSS?
It is equivalent; it is only a matter of time before QSIG is richer than DPNSS. However, adding supplementary services is not the whole story. QSIG will eventually be superior to DPNSS in many ways.

Q. Which manufacturers support QSIG?
Most of the major switching equipment manufacturers have developed products to support QSIG - although they don't necessarily market them actively in every country.

Q. When should an organisation consider migrating its network to QSIG?
It shouldn't necessarily. Whether or not an organisation chooses to use QSIG depends on the requirements. There are many factors influencing this decision, and they will be different for each organisation. For example:

Are there PABXs from more than one vendor in the network?
What are the vendors' product strategies?
Does the network have international links?
What functions must the network perform that are not provided now?
Will the network continue to be based on leased lines, or will these be replaced with switched ISDN connections?
Is Virtual Private Networking being considered?
Can DPNSS meet the future requirements?
There are no hard and fast rules.

Q. Is it possible to use QSIG and DPNSS in the same network?
Yes, networks containing a mixture of DPNSS and QSIG links are possible; the Channel Tunnel network is a real example. The DPNSS Working Party has specified, as long ago as 1991, the interworking between DPNSS and QSIG.

Q. Are multi-vendor networks a problem?
The issue of interworking (or interoperability) between equipment from different vendors is obviously important for any Standard that claims to be "open", as both DPNSS and QSIG do. In the DPNSS case, the early suppliers of equipment (Mitel, GEC, and Plessey) voluntarily participated in interworking trials. These days, standard interworking test schedules exist and a commercial testing service is available.

With QSIG the question of conformance testing versus interoperability testing is still open. Conformance testing aims to demonstrate that a product obeys the protocol rules whereas interoperability testing is concerned with demonstrating behaviour of the product in conjunction with another. The fact that a product demonstrates conformance with the protocol through conformance testing is no guarantee that it will interopearte with other products. Standardised interoperability tests have not been specified for QSIG yet.

Q. How long will it be before DPNSS is ousted by QSIG, and when will vendors stop offering DPNSS?
QSIG will generate security; it will endure because it has the backing of international standards bodies and enhancements are backwards compatible. In the long run DPNSS cannot endure. DPNSS is not being enhanced to support new applications and technologies. It's the same as asking how long any technology will endure - the answer is "for as long as there's market demand".

In our opinion DPNSS and QSIG will coexist alongside one another through the millenium.

However, protocol standards are not the whole story. There are many other standards affecting the construction of Corporate Networks. These, combined with political, regulatory, and commercial issues continue to make the construction and management of corporate telecommunication networks a complex subject.

Mar 2, 2009

Silence Insertion Descriptor(SID)

A method of compression used in speech encoding that transmits a data packet in place of silence at a compressed rate.

SID mathematically describes the background noise during a session so that the receiving end can artificially reproduce that noise during silence periods.

Transmitting the SID requires almost no bandwidth as transmitting the actual background noise does.

SIP的關鍵元件

SIP通過類似E-mail形式的資源識別標誌(URI)來標名用戶地址,它通過諸如用戶電話號碼、帳號、主機名等元素來構成SIP URI,其格式為user@domain的表示方式。其中user也可以是傳統電信網路中的e.164電信交換碼。 

SIP關鍵元件及其呼叫模式。

SIP的關鍵元件有下列幾項: 
用戶代理User Agent: 
通常簡稱為UA,是SIP網路環境中的用戶終端設備,其角色相當於H.323 Terminal。在邏輯上包含有User Agent Client (UAC) 以及 User Agent Server(UAS)兩種,UAC負責產生請求,而UAS負責產生依照請求產生應答。每一個UA都同時扮演者UAC和UAS的角色,當它是呼叫別人的主叫端時,就是UAC;當它是被別人呼叫的被叫端時,就是UAS。 

目前我們所能看到的各種話機,本質上都是一種SIP UA裝置。有一種USB Phone是配合Soft Phone使用的,它的本質是一種音效裝置,雖然很多人也叫它做網路話機,但是它並不屬於SIP UA的角色。 

代理伺服器Proxy Server: 
為SIP協議運作的中心,同時具有伺服器端和客戶端雙重角色的中介元件,負責代表SIP UA或者其他的Proxy Server產生請求或將收到的請求代為轉送到另外一個目標SIP元件去。由Proxy Server提供對用戶定位的服務,以轉送到正確的UA位置去,且UA回覆結果也是一樣會經由相反的路由將結果回覆給請求端的UA,這就是Proxy Server的路由功能。 

Proxy Server其實就是扮演傳統電信領域中,交換總機的角色。由於它的存在,可大幅簡化UA的設計複雜度(否則UA要能記得所有通訊對象的IP網址),也是VoIP業者營運的中樞。 

重定向伺服器Redirect Server: 
SIP的其中一個主要特性就是,它將用戶的邏輯位址和實際位址分開,這使得用戶可以定義一個不變的邏輯位置,然後將它映射成別名至一個或多個變化的實際位置。重定向伺服器接受任何SIP元件的請求,並將被呼叫方的SIP位址映射成一個或多個位址並將回應給客戶端。和代理伺服器不同的是,重定向伺服器不會轉遞任何請求到其他伺服器。 

註冊伺服器Register Server: 
接受註冊請求的伺服器,其目的是記錄用戶在請求中的聯繫資訊,或更新位置伺服器中的位址資料庫。註冊伺服器提供UA進行註冊的介面,用以進行管理並提供特定的服務。 

位置伺服器Location Server: 
可視為SIP資料庫,負責儲存UA的資訊,接受註冊伺服器的用戶資料,並提供給代理伺服器和轉向伺服器使用。通常位置伺服器、註冊伺服器都是代理伺服器的一部分,少數大規模的電信等級服務設施,才會因效能考量區分開。 

媒體閘道器Media Gateway: 
支援PSTN網路和IP網路兩種異質網路之間的中介呼叫與傳送,或是處理同為IP網路的兩種異質協定,如SIP與H.323之間的呼叫。 

媒體伺服器Media Relay Server: 
為了穿越NAT或其他媒體型式轉換等目的,在兩個UA之間進行RTP Media的中繼轉遞,或者是為多方通話的媒體內容匯接目的,它必須配合SIP代理伺服器使用,或本身即兼具代理伺服器的功能。 

如何辨識PSP主機是否可以改機?

我想這個問題是每一位想要買PSP新手的最大問號,沒有一個人希望買到的PSP只能發揮一小部份的功能,網路上大部份文章只提到「PSP 1000一定可以改,PSP 2000要看情況(舊款可以,新款不行),PSP 3000目前尚未有正式破解的解決方案。」雖然看來答案很明確,但是問題是PSP 2000要如何選購才能買到可以打開小宇宙的PSP呢?  另一種最簡單的方式是直接到店面去問老闆,或是直接參考售價(物以稀為貴,能改機的PSP售價至少比不能改機的PSP高出 NT$1000~NT$1500以上)。為了避免自己成為冤大頭,請各位在敗家之前先看看以下文章:

2009/02/01 (YYYY/MM/DD)

First thing's first, know your PSP.

There are three types of PSPs:
1- 1000 Series (Also known as Phat/Fat)
2- 2000 Series (Also known as Slim or Lite & Slim)
3- 3000 Series (Also known as Brite)

Now, what do I mean by "Hackable"?
That means you can install a Custom Firmware (CFW) on it. The most popular (& sometimes only) way to do it is by using a Pandora Battery & Magic Memory Stick (MMS).

Why Hack a PSP?
A Hacked PSP could run Homebrew, which are programs that have been developed by people that don’t have a contract with Sony. A PSP with Custom Firmware could also back up your games from the UMD to your computer; it also allows you to play those backups from your Memory Stick (MS). You could also do some serious customizations to your theme. Basically, you free your PSP from the hands of Sony.

Why can't I hack 'this' PSP?
'This' PSP probably has a TA-088v3 (Found in some 2000 series units) or TA-090v2 (Found in all 3000 series units) Motherboard, both of which are unhackable, as in, you can't install CFW on them.


Let’s start now.

All 1000 Series PSPs are hackable to date.
To some, there are other methods than just using a Pandora & an MMS.

On the other hand, 2000 Series are a little complicated. There are old units, new units, & really new units. The old ones contain Motherboards released before the TA-088v3, and are all hackable. The new ones have TA-088v3 Motherboards, and are unhackable. Finally, the really new ones, those have TA-090v1 Motherboards, which are hackable.
There are 7 different ways to tell whether a 2000 series PSP is hackable or not, but we'll get to that later on (and this is the main topic of this post/guide).

Finally, the 3000 series PSPs, all of those have the TA-090v2 Motherboard, which are unhackable to date.
Though, there is hope for the PSP 3000 series. According to Dark_AleX, he was able to utilize an error in the game "Grip Shift" which allowed him to install Custom Firmware. So, if you have a PSP 3000, or a TA-088v3 Motherboard 2000 series PSP, rush & get your hands on a European (PAL, region 2) version of the game.

Here’s a list of all the Motherboards made & released by Sony:


Of course, new updates might come to change everything one day, & that's why there's a date at the start of the topic (To indicate when this topic was last updated).

So, now it's easy to tell whether a 1000 series and a 3000 series are hackable or not. The only complication is when trying to figure out a 2000 Series PSP. Whether you want to know before you buy it, or before you bother learning how to hack it, you choose the way that suits you best.

I want to note that most of the information I know I learned through research. So far, I can't tell whether a PSP has a TA-090v1 Motherboard or a TA-088v3 Motherboard. But, I could tell whether it's an old unit (Before TA-088v3) or a new one in general (TA-088v3 & after).

One final note, nothing could indicate that your PSP is 100% unhackable other than an actual failed attempt to hack it.


1- What is the Firmware the PSP came with?
The original firmware that came with the PSP right out of the box is an indication of its Motherboard, & here’s the list:
3.60 Official Firmware: Hackable.
3.71 Official Firmware: Hackable.
3.72 Official Firmware: Hackable.
3.80 Official Firmware: Hackable.
3.90 Official Firmware: Hackable.
3.95 Official Firmware: Hackable.
4.01 Official Firmware: Has a Very High Chance of being Unhackable.


Any brand new PSP with Official Firmware higher than 4.01 is unhackable (Except for TA-090v1 Motherboards, & I’m not sure which Firmware comes with them).

If you updated to any Firmware, that doesn’t matter. This only applies on the PSP’s Original Firmware that it was shipped with.


2- What is the PSP's Serial Number?
The Serial Number is found on a label where the battery is supposed to go (As shown in the picture "SERIAL No.")

This isn’t something serious or very helpful, but with more research, it could be.
At the moment, it focuses mostly on Piano Black PSPs.
If that serial starts with HU2, then the PSP most likely has a TA-088v3 Motherboard (And that the PSP is Piano Black).
Any other serial (Say starting with HC or HB or HJ) doesn’t matter at the moment.


3- What's the unit's Identification letter (A letter on a label on the box that indicates what version it has)?
Here's a picture of a label found on the PSP box that has the letter on it:

Note that this label is only present on an original style box (The small, normal box. Not like those large "Limited Edition" Boxes).

Anyways, See the G there?

PSP-2000 CW
100v
G

That G is the letter in question. Here's a list of all the letters that the 2000 series ship with:
(No Letter) = 3.60
A = 3.71
B = Doesn’t exist
C = 3.72
D = Doesn’t exist
E = 3.80
F = 3.90
G = 3.95 (TA-088v1) / 4.01 (TA-088v2) / 4.01 (TA-088v3)

If the letter is absent or is from A to F, then it's hackable.
If it's a G, it's 60 to 67% Hackable (Though since everyone is looking for the hackable ones & no one’s buying the unhackable ones, I'd say that this percentage went all the way down to about 30% hackable).
Some Labels have an extra code written on it, usually “ss259”. That doesn’t matter, just look for the Capital Letter next to it.

Note that the G PSP in the picture is my personal PSP. It came with a 3.95 Official Firmware (OFW) & I hacked it (Has Custom Firmware 5.00 M33-4 5.02 GEN-A (Full)).


4- What's the Box's Serial Number?
If your box doesn't have a label with a letter in it, like the G in the third method, then it should have a label with another serial that's not related to the PSP unit.
Here's a picture given to me by one of our members:

If that serial is like the one on this image, starting with AB02, then that PSP is most likely unhackable (The chance of it being hackable is so small, it doesn't count).
On the other hand, if it starts with AB01 or AB00, then it's hackable.


5- What's the PSP's Date Code?
This is where you would find the date code:

Note that American 2000 series (2001 PSPs)  & Japanese PSPs (Both 1000 series & 2000 series) Don’t have those date codes on them, just like the 2001 Piano Black PSP pictured above.

The 2000 Series Date Codes go as follows:
7C: Hackable.
7D: Hackable.
7(Any later Letter): Hackable.

8A: Hackable.
8B: Hackable.
8C: Has Very High Chance that it is Unhackable.
8D: Unhackable.

This information isn’t 100% valid. I’m still doing some research on it, & I will be updating it every so often.


6- Using Dark_AleX's TA-088v3 Identifier:
I'll just post a link to the location I found it at. I don't plan on testing it, as I find it rather useless.
It's just a method for those in denial to accept the truth.
Basically, it's just like testing out a Pandora with an MMS, if it doesn't work, it means it's a TA-088v3 Motherboard.
(Link: http://forums.exophase.com/showthread.php?p=47672#post47672 )
I personally am disappointed by it, as I thought it would actually spell out the type of motherboard in the PSP...
I'm also not sure how this would react to the TA-090v1 Motherboards, but if I had to guess, I'd say it'd react the same way a hackable motherboard would (the PSP would shut down).


7- If it's a Limited Edition PSP, here's the list of the ones I know of so far:
Daxter Limited Edition Pack, comes with 3.80 OFW & a TA-085v2 Motherboard, and is hackable.
God of War Limited Edition Pack, comes with 3.95 OFW & a TA-088v2 Motherboard, and is hackable, & cool too :P
Madden 09 Limited Edition Pack, comes with either 3.95 OFW & a TA-088v2 Motherboard ~~OR~~ 4.01 OFW & a TA-088v3 Motherboard. If it's 3.95, it's hackable, but if it's 4.01, then it's not, as simple as that.


If anyone would like to discuss any of these methods with me, either to contradict them or help me improve my theories on them, a PM, IM, E-Mail or any other form of message would do to get us started.

There is one method I'd like to say has nothing to do with whether the PSP is hackable or not:
The PSP series full number (2000/2001/20002/etc) just as seen in both pictures (2001 black PSP Slim, & 2000 White PSP Slim) Those have nothing to do with whether the PSP is hackable or not, it's just an indication of the region of the PSP.

& Here's the list:
2000- Japan
2001- United States (American)
2002- Australia/New Zealand
2003- United Kingdom
2004- Europe
2005- Korea
2006- Hong Kong/Singapore
2007- Taiwan
2008- Russia
2009- China
2010- Mexico


Also, if a PSP is hackable, the Firmware on it has nothing to do with its Hackability.
Whether it had 1.00 Official Firmware, 4.00 Official Firmware, 4.01 Official Firmware, 5.00 Official Firmware, or even the latest 5.03 Official Firmware, if the 2000 series PSP doesn’t have a TA-088v3 Motherboard, then it can be hacked.


Requests:
| Dear Reader,
| If you still aren't satisfied with this & would like to discuss whether your PSP is hackable or not, please write your post here instead of starting a new topic. I'll do my best to help out as much as I can!

If your PSP is hackable, & you want to hack it, follow the following link for all your needs:
http://pspslimhacks.com/psp-tutorials/
Attempting to hack a PSP will not harm it in any way (& will not brick it).
Also, hacking it will not void your Warranty, though you will have to reinstall an Official Firmware back on it to use its Sony Warranty.

Final Note:
Please don’t copy or rewrite this research to any other website.
If you would like me to post it on your website, ask me to. I’ll work on it & post it there as soon as I can.
If this post was copied or rewritten (again) to any other site, My faith in the PSP society will decrease, taking away my support & future guides & tutorials.

Thanks Go to:
Jonatan10 for the Motherboard List.
PSPWAD for the Identification letter List & The Special Edition List.
Rith for the region list, & general support in other fields.
& Naturally, to Dark_AleX & the M33 Team for their CFW.

Draik
« Last Edit: February 01, 2009, 05:02:37 AM by Draik »