Showing posts from November 2, 2008


BFD在我之前準備SP CCIE LAB時就曾經提及過,目前sp ccie lAB中ios vERSION暫時尚未支援此功能,但是這個新功能在未來的r&s OR sp CCIE中應該會是一個很好的題材,因為它可以達到比縮減HELLO TIMER的方式更快速的收歛。
IMPROVE THE CONVERGENCE OF MISSION-CRITICAL NETWORKS WITH BIDIRECTIONAL FORWARDING DETECTION (BFD)by Ivan PepelnjakA few years ago, we measured network convergence times in seconds, and aimed to establish an alternate path across the network following a link or node failure within a few seconds. Ten seconds was a sensible number that wouldn’t upset users (assuming that the failures weren’t too common) and definitely wouldn’t break TCP sessions. (The DLSw local termination would take care of the leftovers of the SNA networks.) The only environments aiming at sub-second convergence times were real-time mission-critical applications, from industrial control to battlefield communications.The introduction of Voice over IP (VoIP) into the data networks changed the rules completely; …

Global Knowledge Releases the Cisco 360 Learning Program for CCIE Routing and Switching to Worldwide Customers

PRESS RELEASE Global Knowledge Releases the Cisco 360 Learning Program for CCIE Routing and Switching to Worldwide CustomersParticipation in the Proof-of-Concept and Pilot of the Cisco 360 Learning Program Drives Training Excellence for Those Seeking Cisco's Highest Ranking Certification
Last update: 8:07 a.m. EST Nov. 6, 2008 CARY, N.C. & LONDON & DUBAI, United Arab Emirates, Nov 06, 2008 (BUSINESS WIRE) -- Global Knowledge, the worldwide leader in IT and Business training, today announced the immediate availability of the new Cisco(R) 360 Learning Program for CCIE(R) Routing and Switching for customers in North America and EMEA. The Cisco 360 Learning Program for CCIE Routing and Switching is designed to accelerate education, training, and certification of networking professionals. Cisco customers' and partners' network engineers will utilize the expert-level training to manage and troubleshoot advanced networks and apply the skills they acquire to achieve the CCIE R…

有線電視、STB 結盟

百一董事長許錦輝昨(5)日參與數位創新服務產業聯盟成立記者會時表示,雖然市況不佳,景氣不明,但STB出貨可望持續成長,成為帶動百一明年成長動能。 記者黃晶琳/攝影台灣五大有線電視多系統經營業者(MSO)中嘉、凱擘、TBC、台固媒體、台灣數位光訊昨(5)日宣布,與電視機上盒(STB)百一、兆赫等攜手成立數位創新服務產業聯盟,未來將積極推動高畫質數位化服務。

What is a Blue Box?

Blue boxes use a 2600hz tone to size control of telephone switches that use in-band signaling. The caller may then access special switch functions, with the usual purpose of making free long distance phone calls, using the tones provided by the Blue Box.

To quote Karl Marx, blue boxing has always been the most noble form of phreaking. As opposed to such things as using an MCI code to make a free phone call, which is merely mindless pseudo-phreaking, blue boxing is actual interaction with the Bell System toll network. It is likewise advisable to be more cautious when blue boxing, but the careful phreak will not be caught, regardless of what type of switching system he is under.

In this part, I will explain how and why blue boxing works, as well as where. In later parts, I will give more practical information for blue boxing and routing information. To begin with, blue boxing is simply communicating with trunks. Trunks must not be confused with subscriber lines (or "customer loops&q…

MTU manipulation

以下這篇文章是轉載PacketLife的一篇文章,因為我發現有很多人事實上在準備CCNA/CCNP的過程中有時只著重在筆試的重點上,但是卻忽略了更重要的基礎理論,像這一篇就是介紹MSS(Maximum Segement Size)與MTU(Maximum Transmission Unit)差別,雖然沒有談很多,但是一圖勝過千言萬語,只要把底下那張圖片記在腦海裏,就不會搞不清楚MSS跟MTU的差別了。

Posted by stretch in Networking on Wednesday, 5 Nov 2008 at 2:26 a.m. GMTThe Maximum Transmission Unit (MTU) is the maximum length of data that can be transmitted by a protocol in one instance. For example, the MTU of Ethernet (by default 1500) is the largest number of bytes that can be carried by an Ethernet frame (excluding the header and trailer). MTUs are found at various layers of the OSI model, and can often be tweaked to more efficiently transport large volumes of data.EthernetThe default Ethernet MTU is 1500 bytes, not including the header or trailer. Sometimes a slightly higher MTU is preferable to accommodate Q-in-Q tunneling or other encapsulation. The MTU can be raised on Cisco IOS with the system mtucommand under global configuration:Switch(config)# system mtu ? <1500-…

Google欲收購Skype 網絡電話行業盈利難





  並且,據國外媒體報道, Skype公司可能要被美國Google公司收購。Google開闢的Android手機平台和Skype幾乎完全匹配,可以想象,未來的Google手機,連接上WiFi就能通過Skype以非常便宜的價格進行全球通話。在Google大旗下的Skype的發展模式應該非常明晰:搶占用戶的手機終端,移動無線通信市場是其主攻路線。





My CCNA Voice & CCVP First Step - Voice Over IP Fundamentals

經過一番心情沈澱,又要開始迎接下一個挑戰 - CCNA Voice & CCVP,明年度我的老闆要我盡可能的把所有Voice課程承接起來,其實這對我來說是一個比考SP CCIE更大的挑戰,因為我對Voice實在不熟,所以只能用最原始的方式來了解 - K書。

我看了幾本Cisco Press的書,我覺得只要是Fundamentals系列的書目都是非常值得購買收藏的。雖然我之前曾經教過CVOICE,不過今年CVOICE又改版,把GWGK的東西也整合進來,再加上CCNA Voice的出現,所以我還是決定從頭學習再次打底,明年一定要把Voice課程接下來。

同樣的,我還是會把這個過程利用這個blog紀錄下來跟各位分享,希望各位也可以跟我分享你的know-how。也有人問我,有沒有打算再考第三個CCIE,我想在短時間內(至少明年不會)應該暫時沒有這個打算,除非等我把CCVP/Unity/NetMeeting等相關課程都接下來,我想我才會有那個把握及勇氣去挑戰Voice CCIE吧!

CCIE#11440's SP CCIE Lab Exam Experience Sharing

我其實沒有想過我還會有第二次機會報告個人的CCIE Lab考試經驗,不過還是很高興地跟大家說,我終於辦到了!
在這個過程中最需要感謝的還是brook兄,沒有他跟我一起co-work共同討論,互相挑戰彼此對同一個題目不同看法不同的solution真的讓我們彼此的功力在短時間內快速增長,我是無法這麼順利完成這個目標的! 當然還有我辛苦的老婆一個人24 hrs帶著兩個小朋友,讓我幾乎完全沒有後顧之憂(過去一年以來,除了假日之外,我每天回到家的時間平均是PM 11:00~11:30左右...,還好我兒子們還認得我是他們老爸...),希望這段話可以稍稍安撫我老婆的辛苦及她對我及這個家庭無私的奉獻。


準備Service Provider CCIE Lab最重要的當然是以Routing & Switching為基礎,所以我在此不會強調Routing & Switching的部份,我會把重心放在MPLS/BGP/Multicast上。我會建議所有要準備考SP CCIE的candidates都應該至少要把CCIP - BGP/MPLS/QoS這幾科熟讀,因為它們是SP最基本的功夫,不用我多說,很多人會想直接進入主軸去看WB or 考古題,我個人的建議是不要急躁,因為你會因此而常常回頭看基礎理論反而更沒效率…

1. Cisco Press - MPLS Configuration on Cisco IOS Software *
2. Cisco Press - MPLS and VPN Architectures Vol.I & II
3. Cisco Press - MPLS Fundamentals *
4. Cisco Press - Routing TCP/IP Volume I & II *
5. Cisco Press - Advanced MPLS Design and Implementation
6. Cisco Press - Traffic Engineering with MPLS
7. Cisco Press - BGP Design and Implementa…