Case Studies案例研究 / Latest Case最新案例 A 1000 Mbps Telstra Plan Testing Under 100 Mbps on a Cable: the One Printed CAT7 Was the Bottleneck (Adelaide)
1000兆的Telstra套餐，有线只跑不到100兆：印着CAT7的那根网线才是瓶颈（阿德莱德）
Student · Adelaide学生 · 阿德莱德Telstra 1000 MbpsTelstra 1000兆Fibre connection光纤入网Netcomm routerNetcomm路由器House · two switchesHouse户型 · 两台交换机80-minute remote video session线上视频指导80分钟
When this came in online it read like a straightforward speed complaint, the sort of thing that is usually one setting or one port. It was not. It took 80 minutes of remote video guidance, and the reason is that the house was wired throughout — two switches in different rooms and dozens of cables, any one of which could have been the weak link. The two that were had one thing in common: what was printed on the jacket did not match what the cable actually carried.
这一单在线上找过来的时候，看起来就是个很直白的网速诉求，通常一个设置或者一个接口就能解决。结果不是。最后花了 80 分钟线上视频指导，原因在于这是一套全屋走网线的 house——两台交换机分处不同位置，几十根网线，任何一根都可能是最弱的一环。而真正出问题的那两根有个共同点：外皮上印的类别，和它实际能跑的速度对不上。
Where the speed was actually going
速度到底掉在了哪里
Wired test · before vs after有线测速 · 处理前 vs 处理后
2cables replaced — the plan, the provider and the router all stayed the same.根网线——套餐、运营商、路由器全都没换。
The reported figures were the useful part: under 200 Mbps over WiFi standing right next to the router, and under 100 Mbps on a cable. On a 1000 Mbps plan both of those are wrong, but the wired number is the one that matters most, because a cable takes almost every variable out of the picture. If a wired test cannot clear 100 Mbps on a gigabit service, the problem is very unlikely to be WiFi coverage, walls or interference.
这位同学反馈的数字本身就很有价值：站在路由器旁边用 WiFi 测不到 200 兆，插网线测不到 100 兆。在 1000 兆的套餐上，这两个数都不对，但更关键的是有线那个数，因为网线几乎把所有变量都排除掉了。如果在千兆服务上，有线测速连 100 兆都过不去，那问题基本不可能是 WiFi 覆盖、墙体或者干扰。
Why this took 80 minutes instead of 10
为什么这一单花了80分钟，而不是10分钟
Four things stacked up, and they are worth naming because they apply to a lot of remote jobs.
- Nobody was on site. Every observation had to be described, framed on camera and confirmed, which costs time on each loop.
- Limited spare gear. With few known-good parts on hand, each test-and-verify cycle takes far longer than swapping a part and moving on.
- A complex environment. Two switches in different rooms and dozens of cables, so the number of candidate weak links was large.
- A house wired end to end. Devices talked to each other through cabling rather than WiFi, which is normally the good news — until the cabling itself is the thing that is wrong.
The student made the difference here: they drew the home network layout out by hand, and once there was a diagram to point at, the session stopped being a guessing game and became a list of segments to test in order.
有四件事叠在了一起，值得单独点出来，因为它们在很多线上处理的单子里都成立。
- 人不在现场。每一个观察都要靠描述、对着镜头确认一遍，每一轮都要花时间。
- 设备条件不足。手上没有多少已知没问题的备件，每一次测试验证的耗时都比直接换件走人长得多。
- 网络环境复杂。两台交换机分处不同位置、几十根网线，可疑的薄弱环节数量很大。
- 全屋靠网线布线的 house。设备之间走的是网线而不是 WiFi——这本来是好事，直到出问题的正好是布线本身。
真正拉开差距的是这位同学：她把家里的网络布局图手画了出来。有了这张图可以指着说话，整个过程就不再是猜谜，而变成一份按顺序逐段测试的清单。
The two cables
那两根网线
Two weak links on one wired house全屋走网线的房子里，两个最弱的环节
Telstra fibre serviceTelstra光纤服务
1000
→
Cable printed CAT5E印着CAT5E的那根
under spec / 不达标
Bottleneck瓶颈
→
Netcomm routerNetcomm路由器
OK
→
Cable printed CAT7 between switches两台交换机之间印着CAT7的那根
under spec / 不达标
Bottleneck瓶颈
→
Devices on the far switch远端交换机上的设备
slow / 慢
A wired house is a chain of cables, and a chain runs at the speed of its weakest link. Here there were two weak links in series, which is why replacing only one of them would not have looked like a fix. The second one is the nastier of the pair: the jacket said CAT7, which is a higher category than the job needed, and it still measured under spec — so it survived every visual check.全屋走网线的房子就是一串网线接力，而一条链路的速度等于最慢那一环。这里是两个薄弱环节串在一起，所以只换掉其中一根，看起来根本不像修好了。第二根更阴险：外皮上印的是 CAT7，类别比这活儿需要的还高，实测却不达标——所以它能躲过所有靠眼睛做的检查。
Step by step over video
视频里一步步怎么走的
An 80-minute remote session, step by step80分钟线上视频指导，一步一步走
1
Started from the reported numbers, not from guesses从反馈到的实测数字出发，而不是靠猜
WiFi under 200, wired under 100WiFi不到200，有线不到100
2
Student drew the home network layout on paper同学把家里的网络布局画在纸上
House wired via two switchesHouse户型，两台交换机
3
Worked the run from the NBN box to the router first先处理NBN箱到路由器这一段
One cable printed CAT5E其中一根印着CAT5E
4
Swapped that run to CAT6 and retested这一段换成CAT6后重测
Router speed up noticeably路由器侧速度明显提升
5
Moved to the cable between the two switches再处理两台交换机之间的那根网线
Printed CAT7, measured under spec印着CAT7，实测不达标
6
Replaced it with CAT6 and retested end to end换成CAT6后端到端重测
Wired and WiFi both up to plan有线与WiFi都达到套餐水平
Printed category vs measured throughput
外皮印的类别 vs 实测吞吐
What the cable said vs what it delivered网线上印的 vs 网线实际跑出来的
| Printed on the jacket外皮上印的 | What it measured实测结果 | After swapping to CAT6换成CAT6之后 |
|---|
| NBN box → routerNBN箱到路由器 | CAT5ECAT5E | Under spec for the plan跑不到套餐标称 | Noticeable jump at the router路由器侧提升明显 |
| Switch → switch交换机到交换机 | CAT7CAT7 | Looked fine, tested under spec外观正常，实测不达标 | Speed met the target速度达标 |
| What changed改动了什么 | Nothing else in the house屋里其他什么都没动 | Same plan, same router同套餐、同路由器 | 1000 Mbps plan met达到1000兆套餐水平 |
This is the part most people will not expect. A cable that is physically intact, plugged in firmly at both ends, with a category printed on it that is more than good enough for the job, can still be the reason a gigabit plan behaves like a 100 Mbps one. Nothing about it looks wrong. It only shows up when you test that one segment on its own, or swap it and watch the number move.
If you have a wired house and your speeds are short of what you pay for, the practical version of this case is: stop trusting the label, start testing segment by segment, and keep a couple of known-good CAT6 leads around to swap in. That is the whole method.
这部分是大多数人想不到的：一根外观完好、两头都插紧、外皮上印的类别甚至绰绰有余的网线，依然可能是千兆套餐跑成百兆的原因。它看上去没有任何不对的地方，只有在你单独测这一段、或者把它换掉看数字变不变的时候才会露馅。
如果你家是全屋走网线、而速度长期达不到你付费的那个档位，这一单的实用版结论是：别再相信外皮上印的字，改成一段一段地测，并且常备两根已知没问题的 CAT6 网线用来对比替换。方法就这么简单。
If you are troubleshooting this yourself
如果你打算自己排查
- Test on a cable first, right at the router. It removes WiFi from the equation and tells you whether you are chasing a coverage problem or a wiring one.
- Draw the layout. Boxes and lines on paper beat a verbal description every time, and it is what made this session workable at all.
- Change one thing at a time and retest immediately, so you know which change produced which number.
- Treat the printing on a cable as a claim, not a fact. The one marked CAT7 here was the slower of the two problems.
- Remote video guidance genuinely works for this class of problem when someone at the property can move cables and read numbers off a screen. We use it for addresses outside Sydney, and this Adelaide job is a fair example of what it can and cannot do.
- 先在路由器旁边插网线测。这一步把 WiFi 从等式里去掉，直接告诉你在追的是覆盖问题还是布线问题。
- 把布局画出来。纸上的方块和连线永远好过口头描述，这一单能做下去靠的就是这张图。
- 一次只改一个变量，改完立刻重测，这样你才知道是哪一次改动带来了哪一个数字。
- 把网线上印的字当成一种声称，而不是事实。这一单里标着 CAT7 的那根，反而是两个问题中更慢的一个。
- 对这一类问题，线上视频指导是真的能解决的——前提是屋里有人能动手插拔网线、能把屏幕上的数字念出来。我们对悉尼以外的地址就用这种方式，这一单阿德莱德的案例，比较公道地展示了它能做到什么、做不到什么。
Result最终结果
Two cables were replaced and nothing else in the house changed. The run from the NBN box to the router was printed CAT5E; swapping it to CAT6 lifted the speed at the router noticeably. The cable between the two switches was printed CAT7, looked perfectly fine and measured under spec; replacing it with CAT6 brought that segment up to target. Wireless and wired speeds both improved substantially, to what the Telstra 1000 Mbps plan should test at.
换了两根网线，屋里其他什么都没动。NBN 箱到路由器这一段原本是印着 CAT5E 的网线，换成 CAT6 后路由器侧速度提升明显；两台交换机之间那根印着 CAT7、外观完全正常的网线实测不达标，换成 CAT6 后这一段速度达标。最终无线和有线速度都有较大提升，达到了 Telstra 1000 兆套餐应有的测速水平。