x*********n
发帖数: 28013 | 1 这个面试等了1年多了，石沉大海不知为啥就找我了。感谢chee的题目，题目有些相似。
我把全过程写一下，面的优点压力山大啊。
介绍你的daily duty，design什么，那个project最复杂，最难，遇到什么问题。
技术开始
1.single mode vs multimode
我说length，价格
MM的length value是啥？我说400，但是不同vendor不一样的，他说他们looking for
300 meters，你说的也算对。不同vendor不一样的。
2.Circuit CRC value, how do they work
瞎扯了一下，我说看看CPU，看看有没有什么broadcast storm，sh in transceiver看
看信号lost多少
3.circuit is not up, what will you check,
瞎说，真心不太懂。扯了一点transitmitter，smartjack，interface。
4.HSRP vs GLBP
又准备
5.OSPF LSA types,
又准备
6.how LSA 5 to reach LSA 4,
这个问题纠缠了很久，我一直不能蒙混过去。他给我解释了一遍，我现在还是不太懂。
7.OSPF neighbor was down what you would check,
area ID hello interval dead interval 我还扯了一点MTU，还扯了一点network type
他说对，你把我下面的问题都回答了。
8.他说时间不多了，我们加速。how BGP anti-loop
9.what is concept of confederation,
10.RR should treat client as eBGP, right?
我说 yes，
11.will client send routes to client?
我说yes，其实不太确定。
12.what will you do to affect outbound
我说了3个，展开扯了一点。
local preference
AS-path prepend
MED
13.any other way?
我实在想不出来，他告诉我weight，我说，对的，但是juniper人家不支持的，他说我
们假设都是cisco的。
14.MED compare 是都要compare的吗？by default?
NO，但是你有command alway compare 让它比。
15.what will be the issue
我又不明白了，扯了一点IGP会受影响，eBGP AD是20，IGP比他们大，所以我们要
backdoor，他说我的意思是2个不同的protocol，OSPF，EIGRP可能会有不同的metric。
16.How to control inbound traffic
我想来想去想不到常用的，说了一个MED有时候也可以的，他说对，还有些别的吗？要3
种。我其实是不知道，压根没想到community，又开始扯了点origin
17.他说are you familiar with RFC 1998?
完全晕了。。。只好sorry了。
18.他说应该是community，我说对，community很popular的，然后我bla bla又扯了一
点。
这个时候，关键来了，面试人说，既然你连RFC1998都不熟悉，下面的问题你会非常
difficult，我看也算了别问了。
又说了2句：我会给你second chance，你熟悉我们的hiring process吗？
我说大概是这2个面试1个onsite。
他说大致1-2天就会有通知会不会2面。意思说等2天没戏就别等了。
完了。
我觉得看完我和chee的这2个帖子，A家的电面基本覆盖的差不多了。 | s*****g
发帖数: 1055 | 2 Comment on RFC1998, I think this is a stupid question, I never heard of this
RFC (and I did a search of NANOG mailing list, there is no single match),
So I googled this RFC, it turns out it is a very old RFC, what was
recommended by this RFC is a common practice for service providers.
If the interviewer asked you how can you control inbound/outbound traffic
beyond manipulating local-pref, MED, AS-prepending etc when multiple ASes
are involved, that would be a more appropriate question, who the fuck is
going to memorize the actual RFC number? besides this whole RFC1998 thing is
just an idea, each provider will use its own community strings. | x*********n
发帖数: 28013 | 3 我觉得他可能是提醒我还有community。我确实今天忘了这个这么重要的attribute，可
能他们家就是喜欢community-list吧，他是想说community-list优于as-path。
大侠，能给我解释一下这个问题吗？OSPF我还是不太懂，有什么可以看看的吗？
6.how LSA 5 to reach LSA 4,
this
is
【在 s*****g 的大作中提到】
: Comment on RFC1998, I think this is a stupid question, I never heard of this
: RFC (and I did a search of NANOG mailing list, there is no single match),
: So I googled this RFC, it turns out it is a very old RFC, what was
: recommended by this RFC is a common practice for service providers.
: If the interviewer asked you how can you control inbound/outbound traffic
: beyond manipulating local-pref, MED, AS-prepending etc when multiple ASes
: are involved, that would be a more appropriate question, who the fuck is
: going to memorize the actual RFC number? besides this whole RFC1998 thing is
: just an idea, each provider will use its own community strings.
| s*****g
发帖数: 1055 | 4 community-list is used by service providers not customers (typically), I
assume if Apple has a huge internal transit network (its own or via MPLS-VPN
), then it will use this RFC1998 thing heavily.
I don't know what you mean by "community-list优于as-path", community string
itself has no meaning in BGP decision process (except those well-known ones)
it is just used as a language that translates customers (or providers') BGP
needs to actionable BGP attributes, i.e. local-preference, as-path pre-
pending etc.
I don't fully understand what "how LSA 5 to reach LSA 4" means, I suppose it
means how a router in a regular area can reach a LSA5 prefix? I will just
say LSA5 has ASBR information flooded to the whole OSPF domain, ABR
generates LSA4 for this ASBR and floods this LSA to this router, then this
router will know how to reach LSA5 prefix? No idea. | x*********n
发帖数: 28013 | 5 谢谢谢谢，，学习了。。
VPN
string
ones)
BGP
it
【在 s*****g 的大作中提到】
: community-list is used by service providers not customers (typically), I
: assume if Apple has a huge internal transit network (its own or via MPLS-VPN
: ), then it will use this RFC1998 thing heavily.
: I don't know what you mean by "community-list优于as-path", community string
: itself has no meaning in BGP decision process (except those well-known ones)
: it is just used as a language that translates customers (or providers') BGP
: needs to actionable BGP attributes, i.e. local-preference, as-path pre-
: pending etc.
: I don't fully understand what "how LSA 5 to reach LSA 4" means, I suppose it
: means how a router in a regular area can reach a LSA5 prefix? I will just
| r********t
发帖数: 338 | 6 和这种鸟共事，不去也罢。
似。
【在 x*********n 的大作中提到】
: 这个面试等了1年多了，石沉大海不知为啥就找我了。感谢chee的题目，题目有些相似。
: 我把全过程写一下，面的优点压力山大啊。
: 介绍你的daily duty，design什么，那个project最复杂，最难，遇到什么问题。
: 技术开始
: 1.single mode vs multimode
: 我说length，价格
: MM的length value是啥？我说400，但是不同vendor不一样的，他说他们looking for
: 300 meters，你说的也算对。不同vendor不一样的。
: 2.Circuit CRC value, how do they work
: 瞎扯了一下，我说看看CPU，看看有没有什么broadcast storm，sh in transceiver看
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