d******i
发帖数: 7160 | 1 非要发明这么Fancy的名字，
华硕做market的辛苦了！
不太懂都有线连接了，
还要Mesh干绳么？
而且先要凑近无线加成node，
弄远了再拉上线backhual。
完全理解不了意义在哪儿，
除了忽悠得好听点儿。 | f******o
发帖数: 2469 | 2 lol
https://www.smallnetbuilder.com/wireless/wireless-howto/33185-wi-fi-mesh-
system-secrets
【在 d******i 的大作中提到】
: 非要发明这么Fancy的名字，
: 华硕做market的辛苦了！
: 不太懂都有线连接了，
: 还要Mesh干绳么？
: 而且先要凑近无线加成node，
: 弄远了再拉上线backhual。
: 完全理解不了意义在哪儿，
: 除了忽悠得好听点儿。
| d******i
发帖数: 7160 | | p***o
发帖数: 1252 | 4 roaming，里面有个帖子提到了。你要是自己刷ddwrt之类的AP没这功能。
via-
【在 d******i 的大作中提到】
: 这里有讨论
: 看来质疑很valid
: https://www.snbforums.com/threads/why-use-aimesh-if-you-can-connect-aps-via-
: ethernet.48537/
| a*o
发帖数: 19981 | 5 其实早年的router也可以用wds实现roaming，效果也许差些不过该roam的时候还是能实
现的。
现在的wifi industry基本上就是加个速度boost几个参数就号称新一代产品，又能撸一
批羊毛，没啥新意。
: roaming，里面有个帖子提到了。你要是自己刷ddwrt之类的AP没这功能。
: via-
【在 p***o 的大作中提到】
: roaming，里面有个帖子提到了。你要是自己刷ddwrt之类的AP没这功能。
:
: via-
| f******o
发帖数: 2469 | 6 你们老婆6了没 谈什么mesh 搞不懂 买两个发糕霸王蟹先吧 两个现在要10000人刀了吧 | s*****a
发帖数: 1269 | 7 Same SSID, same channel, central management.
Roaming的问题就是，如果你拔插错的路由有电脑连着，这些电脑会暂时断网。 | f******o
发帖数: 2469 | 8 WiFi Fast Roaming, Simplified
Facebook
Twitter
LinkedIn
A primer on the 802.11 wireless protocol and when to implement it.
Jason Hintersteiner
MAY 23, 2016
For some reason, all descriptions of 802.11r spectacularly fail to provide a
simple explanation of the WiFi fast roaming protocol. Most of them are too
high level and are effectively useless, or they tend to quickly get lost in
the technical weeds. This blog post attempts to bridge that gap and provide
a reasonably simple but thorough explanation.
What is fast roaming?
Fast roaming, also known as IEEE 802.11r or Fast BSS Transition (FT), allows
a client device to roam quickly in environments implementing WPA2
Enterprise security, by ensuring that the client device does not need to re-
authenticate to the RADIUS server every time it roams from one access point
to another. This is accomplished by actually altering the standard
authentication, association, and four-way handshake processes used when a
device roams (i.e., re-associates) to a new WiFi access point.
The simplest explanation is that, after a client connects to the first AP on
the network, the client is "vouched for." When a client device roams to a
new AP, information from the original association is passed to the new AP to
provide the client with credentials. The new AP therefore knows that this
client has already been approved by the authentication server, and thus need
not repeat the whole 802.1X/EAP exchange again.
Fast roaming also introduces efficiencies into the process of establishing
the new encryption key between the new AP and the client device, which
benefits both WPA2 Personal (a.k.a. pre-shared key or passphrase) and WPA2
Enterprise (a.k.a. 802.1X or EAP). Support for 802.11r is advertised in the
AP beacon and probe response frames.
The regular association process
Here are the normal, or pre 802.11r, steps followed by a client device as
it connects to an access point or roams from one access point to another.
1. Authentication (client)
2. Authentication Response (AP)
3. (Re)Association Request (client)
4. (Re)Association Response (AP)
WPA2 Enterprise 802.1X/EAP (client, AP, and authentication server); skipped
in WPA2 Personal
5. Four-way handshake #1 – AP nonce passed to client (AP)
6. Four-way handshake #2 – Supplicant nonce passed to AP(client)
6.5 Derivation of encryption key (AP & Client independently)
7. Four-way handshake #3 – verification of derived encryption key and
communication of group transient key (AP)
8. Four-way handshake #4 – acknowledgement of successful decryption (
client)
Note, a nonce is a pseudo-random number generated for the purpose of seeding
the encryption algorithm. Both the AP (anonce) and the client supplicant
device (snonce) generate their own nonces as part of the negotiation.
Fast roaming re-association process
The following lists the revised -- 802.11r -- steps followed by a client
device as it uses Fast BSS Transition (FT) to move from one access point to
another.
1. FT authentication; includes PMK seed information from original
association and supplicant nonce (client)
2. FT authentication response – includes PMK seed information and AP nonce
(AP)
2.5 Derivation of encryption key (AP & Client independently)
3. FT re-association request – verification of derived encryption key (
client)
4. FT re-association response – acknowledgement of successful decryption
and Group Transient Key (AP)
This process works for both WPA2 Enterprise and WPA2 Personal re-
associations. In both cases, the eight messages passed between an AP and a
client device for authentication, association, and the four-way handshake
are reduced to four messages.
Note that there is an alternative method called over-the-DS fast BSS
transition, where the credentials are passed from one AP to the others on
the network via FT action management frames over the wired Ethernet network
that interconnects them. This is usually one of those details that muddies
the waters of the 802.11r story. The essential point remains the same: The
first AP "vouches" for the client device to the other APs, so that the
remaining APs need not re-verify that the client device is allowed to
connect to the network.
When should you use fast roaming?
The human brain generally cannot perceive an event that occurs faster than
about 100 milliseconds. An interruption in voice or video service during a
roam that occurs faster than this will therefore not be observed by the user
. The typical target roam time for a client is half of this value, or 50 ms,
and in most well-designed Wi-Fi networks, the eight messages that make up
the authentication, association, and four-way handshake collectively will
take on the order of 40 ms to 50 ms. Thus, in a network using WPA2 Personal
security, shrinking the number of messages from eight to four is naturally
helpful for efficient airtime utilization, but is really unimportant to the
roaming process from a perceived service-quality perspective.
WiFi.jpg
WiFi
The real benefit of 802.11r comes from not having to do the 802.1X/EAP
exchange when using WPA2 Enterprise security. Even with a local RADIUS
server, this exchange can easily take several hundred milliseconds, and far
longer if your RADIUS server is not on your LAN, but requires access over
the Internet. Thus, fast roaming should ALWAYS be enabled when you are using
WPA2 Enterprise security.
One of the issues with 802.11r is that many older client devices don’t have
drivers that support it, and in fact even have trouble properly detecting
and associating to networks with 802.11r enabled. While adding new
information elements to beacon frames is a scalable part of the 802.11
protocol since the early days of WiFi -- and is an essential element in
backwards compatibility of new APs with older client devices -- many older
client drivers cannot read and interpret the new FT information element in
the beacon frames properly so they see the beacons as corrupted frames.
Therefore, to ensure maximum client compatibility, the common recommendation
is to disable fast roaming when using WPA2 Personal, and only use it for
WPA2 Enterprise networks.
来来来 学点文化 | c********n
发帖数: 1577 | 9 确实需要mesh这个功能的，mesh断流可能最多几秒
没mesh纯手动的ap,一样的频道一样的名字是可以，可是会断流，client端是不会自动
更改的用最近的ap的，还得手动连一次。这很麻烦啊？ | c*****h
发帖数: 14923 | 10 嗯，实测如此。mesh之后wifi list里只有一个ssid，就算后台断了，手机和平板也几
乎感受不出。比以前用ap体验好很多，不会被全家人骂了。
【在 c********n 的大作中提到】
: 确实需要mesh这个功能的，mesh断流可能最多几秒
: 没mesh纯手动的ap,一样的频道一样的名字是可以，可是会断流，client端是不会自动
: 更改的用最近的ap的，还得手动连一次。这很麻烦啊？
|
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