l**********g
发帖数: 503 | 1 昨天BFD排队付钱，有一个外F女排在我后面，搂着一白人，时不时的大声乱笑，引得周
围人侧目观赏。 |
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m*****d
发帖数: 13718 | 5 百度来的
“A=180-B-C
B=180-A-C
C=180-A-B
因为DEF是正三角形
所以
DEF=EFD=FDE=60
所以
ADE+BDF=120
AED+CEF=120
BFD+CFE=120
设角ADE是X度
BDF=120-X
设角EFC是Y度
DFB=120-60-Y
所以
角B=180-(120-X)-(120-Y)
设FEC是Z度
所以
C=180-Y-Z
AED=180-DEF-Z
AED=120-Z
A=180-B-C
代入上面B C
A=180-(180-(120-X)-(120-Y))-(180-Y-Z)
A=180-(180-120+x-120+y)-180+y+z
A=180-180+120-x+120-y-180+y+z
A=180-180+120+120-180-x-y+x+y
A=60
下来继续
A+X+AED=180
代入一下上面证明的
60+X+120-Z=180
X-Z=0
这样X=Z 有问题么？
下面还用我继续推下去吗？” |
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B********r
发帖数: 397 | 6 我来个终结的：
角BFD=a1,CFE=b1,B=r1; BDF=b2,EDA=a2,A=r2; DEA=b3, FEC=a3, C=r3;
画辅助线： DE 交 BC。 so： b1+r3-b3=60degree
and a1+b1=a2+b2=a3+b3 ------带入
b1+r3=60+b3=180-a3
b2，b3 照推，带入 那个等式，b1=b2=b3.
接下来不用我说了。 |
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c***t
发帖数: 324 | 7 假设角A >= B >= C
如果A＝B,那么三角形ADE和BFD全等，AE=BD, AB=AC, 角C＝B＝A，ABC是等边三角形。
如果A>B, 做辅助线BM使角FBM=A,以FD为半径画园交于M，FD=FM，那么三角形ADE和BFM
全等，AE=BM;
三角形BDM中角BMD>BDM,那么BD>BM=AE, 那么AB>AC, 那么角C>B, 与B >= C矛盾，所以A
>B不成立
所以只能A＝B，ABC是等边三角形。 |
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a***y
发帖数: 19743 | 11 ☆─────────────────────────────────────☆
wavelets (Stay hungry, stay foolish) 于 (Sat Nov 20 21:15:38 2010, 美东) 提到:
两年后，拿到Nook Color 再看一下， 当年的没事事儿把图片改失真了的毛病还没有改。
touch 的反应还是贼慢，
天天花劲头去光贴市场占有率高了的新闻有个屁用，用户体验上怎么就那么差？？
有得害老子去退一趟。 NND
估计三爽的tab后天到了也得去退了。
android真是烂泥扶不上墙
☆─────────────────────────────────────☆
tyning (全副*你上过了么？) 于 (Sat Nov 20 21:22:47 2010, 美东) 提到:
Nook color的硬件很垃圾的。而且Android 2.2/2.3并不适合平板机。
android阵营真正出来有竞争力的平板估计得明年下半年大量基于Android 3.0的机器上
市。
另外，对Nook color不看好。$250我宁愿去买7"的sony er... 阅读全帖 |
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t*******r
发帖数: 3271 | 12 application protocols? 我不太明白这个, 能解释一下吗? |
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s*****g
发帖数: 1055 | 13 Huh? Huh? In order to maintain/operate a good network, you not only need to know how to configure network devices, but also need to understand the reasons why various technologies are used and for what purposes. |
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t*******r
发帖数: 3271 | 14 我觉得你应该认识我的好多同事, 甚至是同一个TEAM的 |
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t*******r
发帖数: 3271 | 15 加精了?
zher不错~
继续灌~ 要不然那我老得输入验证码, shit~ |
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t*******r
发帖数: 3271 | 16 我彻底不懂你的意思, 而且我想你是搞错了我要表达的意思了.
to know
how to configure network devices, but also need to understand the reasons
why various
technologies are used and for what purposes. |
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z**r
发帖数: 17771 | 17 my understanding is both link protection and node protection use the same
methods to detect failure, say BFD.
link protection creates a next hop (NHOP) backup tunnel, and node proection
creates a next-next hop (NNHOP) backup tunnel, which means the MP is the
router behind the protected router.
IP |
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z**r
发帖数: 17771 | 18 要求英语好, CCIE level of OSPF, BGP, BFD, QoS, MPLS, IPv6, IOS, IOS XR
good pay, either in Middletown, NJ or RTP, NC, long term contract, I'd say
at least 24m+
感兴趣的请联系。 |
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z**r
发帖数: 17771 | 20 没办法，BFD echo, preemptive, scalability这些，问了几个了，都不行 |
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z**r
发帖数: 17771 | 21 是不好比啊，所以问问你，看你们有没有这方面的testing results。
现在的OSPF有大约500个neighbor，总共30k routes，大约200k LSA，主要是type 3.如
果光这点东西，没有问题，问题是这个router还有很多其他的东西，比如ISIS, BFD,
Mcast, IPv6, BGP等等，这样一搞，就不行了。
OSPF在这里肯定是不scalable的，所以想转一些到BGP，知道会省一些CPU，但是从来没
有人测试过到底能省多少。看看能不能有个大概的数字 |
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s******v
发帖数: 4495 | 22 最讨厌的是scale，开上bfd，dampening, soft-reconfigure, aggregate, switchover
然后再来个soft clear之类的，可能1M条pfx里面少个2条， |
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s*****g
发帖数: 1055 | 23 Data center ToR/Leaf/Spine, No layer 2, IP-fabric. HA on box level is
expensive and buggy, you move the redundancy from box level to network level
to achieve HA, such that any box's failure will not affect applications,
our applications do not need sub-second failover, if we do
need faster convergence, fast BFD timer will be more than enough.
Every vendor has its own definition of SDN, in case of Cumulus, since it is
an open OS, you can write your own software (whether it is a simple shell
scrip... 阅读全帖 |
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f*****m
发帖数: 416 | 24 单从control plane而言,你需要BFD
data plane上, 你需要FRR
take |
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b***p
发帖数: 700 | 25 from your prev post, you have ONE router facing SP network. If the BFD
detects other side is down and notify the BGP, this bgp will withdraw all
prefix and re-advertise the ones from backup SP. I am not sure if this is
what you are asking.
Above it is the fast failure detection between your network and SP.
Fulcrum's idea IP FRR is to fast-reroute your internal networks, if one node
/link is down on the path, the router can switch to pre-calculated path
during the IGP working on the new path. But... 阅读全帖 |
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L******t
发帖数: 1985 | 26 As LZ mentioned 2 BGP sessions, I suppose it's multihoming.
BFD is definitely the way to go. Once link failure detected, LZ's router
will start to reroute through 2nd link per routes already available.
Unless LZ's router is doing transit, no route to withdraw from backup SP.
Correct me if I'm wrong.
node |
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u*****e
发帖数: 47 | 27 先感谢大家的热心回复。我简单的 说一下我的网络结构吧。
(router1)-------(router2)
每个router都连有两个isp，都做了bgp， 两个router之间我还配置了ibgp. 所有的
bgp都接受全网路由。 这样做的目的就是为了在其中一根线断了之后，数据流可以尽快
的切换到其他线上去（不管是去自己路由器的另外一根线，或者是另外一台路由器。不
过我估计他会优先选择本机的另外一根线把。。。。）。
现在基本可以确定，bfd会是我的一个必要选择。但是请问，基于我现在的结构，ip
frr，有需要吗？ |
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b***p
发帖数: 700 | 28 From a quick google, IP FRR is to target 50-ms level traffic convergence. If
I was you, I will leave it to 2nd phase after some experiment and tests,
because your bfd consideration is 1-sec level convergence. you can try some
tech to tune your IGP to have a fast convergence at seconds level. |
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c*****i
发帖数: 631 | 29 其实如果和isp连，isp多半不support bfd的，更没ip frr啥事情 |
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L******t
发帖数: 1985 | 31 Someone please confirm if ISP do not let customers enjoy BFD?
I thought money talks, and in most cases this won't affect ISP's stability?
Good knowledge that you can't learn from books.. |
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s*****g
发帖数: 1055 | 32 Like what upstairs said, if you are a small customer, ISPs won't bird you,
but if you are a big customer, they will so whatever you want them to do. I
am not sure you can achieve milli-second ISP fail-over, most BFD
implementations only support longer than 10-ms hellos, so typically longer
than 30
milli-second fail detection. IP/MPLS FRR is for a totally different
fail scenario.
Did you check with your ISP? they might be able to accommodate, you first
need to check with your ISP's account person... 阅读全帖 |
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i*********5
发帖数: 19210 | 33 Bigfuzzydoug’s Ten Points to Swimming:
http://www.beginnertriathlete.com/discussion/forums/thread-view
The key to swimming is reducing drag, not endurance or powering through the
water. This is not just my opinion; it is the law of physics. I’ll
explain it in a simple way: When you bike, you have to push air in front of
you out of the way. The bigger the frontal section of your body and bike,
the more air you have to move. What’s worse is that it’s not a one to one
relationship. An increas... 阅读全帖 |
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c***z
发帖数: 6348 | 34 http://www.quora.com/How-long-will-coders-salaries-remain-as-hi
与数据科学的关系不大，与数据科学家的关系比较大。文章分析了一直困扰我的一个问
题：为什么老板都是外行？答案是：我们被外行殖民了。
This is an odd question, because software engineers' salaries aren't that
high. I wrote a blog post on this, here: Software engineer salaries aren't
inflated-- at least, not for the 99%. Relatedly, I wrote a Quora answer on
the topic: see Michael O. Church's answer to Why do software engineers make
so much?
That said, I certainly have no illusions about the impossibili... 阅读全帖 |
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i*********5
发帖数: 19210 | 35 Bigfuzzydoug’s Ten Points to Swimming:
http://www.beginnertriathlete.com/discussion/forums/thread-view
The key to swimming is reducing drag, not endurance or powering through the
water. This is not just my opinion; it is the law of physics. I’ll
explain it in a simple way: When you bike, you have to push air in front of
you out of the way. The bigger the frontal section of your body and bike,
the more air you have to move. What’s worse is that it’s not a one to one
relationship. An increas... 阅读全帖 |
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i*********5
发帖数: 19210 | 36 Bigfuzzydoug’s Ten Points to Swimming:
http://www.beginnertriathlete.com/discussion/forums/thread-view
The key to swimming is reducing drag, not endurance or powering through the
water. This is not just my opinion; it is the law of physics. I’ll
explain it in a simple way: When you bike, you have to push air in front of
you out of the way. The bigger the frontal section of your body and bike,
the more air you have to move. What’s worse is that it’s not a one to one
relationship. An increas... 阅读全帖 |
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