Руководство По Проектированию для Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter
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Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 8 Cisco Wireless Mesh Networking
Design Details
Choosing the Best Mesh Parent
The OPS algorithm is implemented in the Seek state of the AWPP state machine. The basic steps of the
parent selection algorithm in the AWPP (for both a RAP and MAP with radio backhaul) is as follows:
parent selection algorithm in the AWPP (for both a RAP and MAP with radio backhaul) is as follows:
•
A list of channels with neighbors is generated by passive scanning in the Scan state, which is a
subset of all backhaul channels.
subset of all backhaul channels.
•
The channels with neighbors present are actively scanned in the Seek state and the backhaul channel
is changed to the channel with the best neighbor ease.
is changed to the channel with the best neighbor ease.
•
The parent is set to the best neighbor and the parent-child handshake is completed in Seek state.
•
Parent maintenance and optimization occurs in the Maintain state.
This algorithm is run at startup and whenever a parent is lost and no other potential parent exists, usually
followed by an LWAPP network and controller discovery. All neighbor protocol frames carry the channel
information. Both parent maintenance and optimization techniques remain unchanged, as described in
the following:
followed by an LWAPP network and controller discovery. All neighbor protocol frames carry the channel
information. Both parent maintenance and optimization techniques remain unchanged, as described in
the following:
•
Parent maintenance occurs by the child node sending a directed NEIGHBOR_REQUEST to the
parent and the parent responding with a NEIGHBOR_RESPONSE.
parent and the parent responding with a NEIGHBOR_RESPONSE.
•
Parent optimization and refresh occurs by the child node sending a NEIGHBOR_REQUEST
broadcast on the same channel as that of its parent and evaluating all responses from neighboring
nodes on this channel. In most practical mesh networks, only a single channel backhaul is designed.
broadcast on the same channel as that of its parent and evaluating all responses from neighboring
nodes on this channel. In most practical mesh networks, only a single channel backhaul is designed.
•
A parent MAP is the MAP that has the best path back to a RAP. AWPP uses ease to determine the
best path. Ease can be considered the opposite of cost and the preferred path is the path with the
higher ease.
best path. Ease can be considered the opposite of cost and the preferred path is the path with the
higher ease.
Routing Around an Interface
This feature is optional and is user configurable via Controller CLI only. If this feature is enabled, it
transmits packets on secondary backhaul (b/g radio) when there is transient interference on the primary
backhaul (A radio).
transmits packets on secondary backhaul (b/g radio) when there is transient interference on the primary
backhaul (A radio).
There are two modes of operation for Routing Around an Interface (RAI):
•
Config mesh secondary-backhaul enable—This enables RAI globally on all APs. In order for RAI
to work properly, the user has to configure the same “b/g” channel on all APs beyond the first HOP
to the one that is being used on the first HOP “b/g” radio. If RRM (auto-rf) is enabled, then it
changes the channels on APs and RAI will not work.
to work properly, the user has to configure the same “b/g” channel on all APs beyond the first HOP
to the one that is being used on the first HOP “b/g” radio. If RRM (auto-rf) is enabled, then it
changes the channels on APs and RAI will not work.
•
Config mesh secondary-backhaul enable force-same-secondary-channel—This forces the whole
subtree rooted at one hop MAPs to have the same secondary channel. Ignore RRM or manually
assigned for MAPs at two hops and deeper.
subtree rooted at one hop MAPs to have the same secondary channel. Ignore RRM or manually
assigned for MAPs at two hops and deeper.
Design Details
Each outdoor wireless mesh deployment is unique, with its own challenges regarding locations,
obstructions, and network infrastructure availability. Such challenges must typically be addressed in
addition to design requirements that are based on users, traffic, and availability. This section discusses
important design considerations and provides an example of a wireless mesh design.
obstructions, and network infrastructure availability. Such challenges must typically be addressed in
addition to design requirements that are based on users, traffic, and availability. This section discusses
important design considerations and provides an example of a wireless mesh design.