An OSPF Issue

Cisco introduced an non-RFC-defined OSPF feature called "OSPF throttle timer". You can use CLI to define the SLA generation delay and SPF calculation delay.

The problem is that if there's an OSPF adjacency flapping shorter than 500ms (which is also the default value of OSPF SLA generation delay timer) or the SLA generation delay you configured, NO SLA will be generated therefore no SPF recalculation will be scheduled. On the other hand, the OSPF routes were removed from routing table due to next-hop unreachable. As a result, the OSPF routes were not injected back to the routing table after the flapping.

There are two known workarounds. One is to increase the carrier delay to ignore the brief link interruption. The trade-off will be some packet loss. The other one is to reduce the SLA throttle timer, this will allow the router to generate SLA as soon as there's a topology change and bypass the issue. The trade-off will be increased router CPU load, especially in a large-scale SP network.

The descriptions bove are shown in below picture. Click to zoom.

Joining the Dots

Heraton Park Lane Piccadilly is a very old hotel but its position is very good for touring and the price is very reasonable.

the small bath room

Heraton Park Lane Hotel, Piccadilly

Lobby, Heraton

BT "Joining the Dots" Team Challenge

a BT Cat

-----------From BT intranet, the cat looks pretty similar with mine.

Jolyon, a service solutions manager with BT Global Services in Cambridge, said: there has been a lot of comment and discussion about the replacement of the 'free shares' with 'free BT broadband'.
When my free broadband was activated, one member of our feline family, six-month-old Amber, was very pleased with the change.
Amber loves boxes and bags, and within seconds of the hub being taken out of the box, she claimed ownership, and has been using it ever since.
However, as she is rapidly growing (as kittens do), it is a bit on the small side now, although she does persevere. I think she is as pleased with the box as we are with getting 8meg broadband. It also shows we do our bit for recycling.
We have five cats in total: Amber (six months), Jack and Lois (five years), Belle (seven years) and Rose (eight years), plus two dogs, George, a Cocker Spaniel who is five years old and Max, a Cairn terrier who is 11 years old.

One Sentence to Describe Each Telco (in their own words)

Submitted by Michael Morris on http://www.networkworld.com

AT&T - "We're the biggest, we're the best, and you will enjoy paying for that!"

BT - "AT&T, European-style...."

Verizon - "Global network, got it; great technology, got it; customer service ---- DOH...forget that one every time."

Sprint - "You want some wireless with that?"

Nextel - "Why, oh why, did we let Sprint buy us?"

Quest - "Never mind that whole money meltdown thingy, we're so much more honest now even the US government buys from us".

NTT - "We're great in Asia!"

China Telecom - "It's great to be a monopoly, especially with communism backing you up."

Telmex - "Yeah, we're still a monopoly."

Deutsche Telecom - "I need to finish my beer before troubleshooting that E-1."

And finally, any state-owned international PTT - "Whoa, it's 5 PM, I'll be leaving now, we'll fix that critical backbone OC-12 in the morning."

Now Exposed

BT is to increase its presence in China by opening a global research and development centre in Shanghai. The UK’s leading telecommunications group is to spend $70m (£35m) on the Chinese initiatives, hiring about 75 staff initially. The decision will bolster the capabilities of BT Global Services, the division that has become the company’s growth engine by serving the telecommunications and information technology needs of multinationals. Ben Verwaayen, BT chief executive, said the $70m investment in China could become “much bigger than that”.

Shanghai will be the location of BT’s fourth research centre. BT is also to open a technology and service centre in Dalian.

From: http://uk.biz.yahoo.com/06092007/399/bt-bolsters-china-presence.html

OMD I

OMD I = the 1st Oriental Manhattan Dinner.

Last Friday the boss - captain Richard held a team building dinner in oriental manhattan. The initial members of the organization didn't work in the afternoon and went grocery shopping. Everyone was distributed a shopping list according to the dinner menu and gathered to deliver all kinds of materials like beef, shrimp, pan and bowl to the apartment.

In the evening when all the guys were back from sports, the team (except me, of course) cooked some very good dishes and enjoyed some beer and Chinese wine. It's very interesting and I think we will have such a dinner every time when there are a batch of recruits.

Powered On

Busy like hell on my first project in BT in the past three weeks. Worked for more than 12 hours per day including weekends.

Do I like it? Of course not. I don't think anyone really like being always busy. But I like my job as it can get the best out of myself. It's pretty interesting that you can dedicate yourself to the job and really enjoy it. I'm jealous of this opportunity and the short-term goal for me is to be one of the top 100 engineers in this field in China.

Everyone should have a dream, but not only dream.

===================================

Recently I have a few "major life changing" items going on: new apartment fit-up, wedding arrangement and job change. Thanks to Anita and her Mum, who gave me a lot of help.

Various Pseudowire Emulation Comparison

(click the picture to enlarge)

Reference:
Nadim Constantine. Overlay Service PWE Transport

Inter-AS MPLS VPN Options Comparison

(click the picture to enlarge)

Reference:
Nadim Constantine. BGP/MPLS Layer 3 VPN Services Part II: MPLS-VPN Routing and Label Switching

Rather Burn Out than Rust Out

这是一直以来MSN的personal message。

或许骨子里还是一个喜欢变化的人，毕业四年跳槽四次了，现在终于有了一点感觉。以前的每一次跳槽都很清楚只是一个新的跳板，而不是自己最终想要的，这次或许不同了，作为国内第一个SP的此类facility，现在有一个机会去做特别一些的事情。几个月内可能就要做有几年甚至十几年经验的美国team的工作，还可能要带新人，压力和挑战都很大。但这也是我喜欢的，有这样的机会去努力去超越自己，是很令人兴奋的。

Be Eager... Be Passionate... Be Proud... Always...

1st Day in BT

来自六个地方，六个公司的六个人组成了这个新的机构。

第一天的感觉是完全不同的，不同于以前的SI，也不同于HSBC，这里的感觉既有SI的人人平等，又有HSBC的正规大气，而且多了灵活，乐趣；此外做为第一批员工的一员，对将来也可以充满憧憬。自己工作起来有了积极性，自信也更多了。

或许是我比较乐观，或许是我比较容易接受新事物，在BT的第一天感觉很好。接下来两个月是两只美国大牛的培训以及on-the-job training，希望自己快点变得更强。

Move On

在HSBC这个复杂而庞大的公司整整两年了，搬过七次office，换过七次老板，有苦有乐有收获，尤其是有了在压力下处理很多技术以外事情的经验，虽然两年前进来的时候就估计到HSBC只是一个跳板，技术上不会有大的提高，但当今天要走出去的时候，依然觉得这段经历非常值得，也非常难得。

新的雇主是SP，名字我很喜欢，一个新的机构，工作以技术为主，合同从现在的终身员工变为了两年一签的合同工，薪水多了一些，但也不如从前稳定，进去之后要不断学习技术，总体来看符合我的长远规划，希望将来当我回头再看这段新的经历，依然觉得做了对的选择。