User's Manual Part 1

Release8OverviewofCycloneNetworks
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Issue2,November2007 Draft5forRegulatoryReview 81
7 CYCLONELINKCHARACTERISTICS
7.1 UNDERSTANDINGBANDWIDTHMANAGEMENT
7.1.1 DownlinkFrameContents
The AP broadcasts downlink frames that contain control information, allocating slots in
succeeding or future uplink frames to SMs that have requested service. The downlink
frame also contains a beacon frame, control information, and data that specific SMs have
requested. Each SM
• examines the downlink frame to distinguish whether data is addressed to
that SM.
• retrieves data addressed to that SM.
• directs such data to the appropriate end user.
7.1.2 UplinkFrameContents
Uplink frames contain control information from each SM that request service on
succeeding uplink frames. SMs insert data into the uplink frames in an amount that the
AP has established.
Optionally, you can configure the AP to change the source MAC address in every packet
it receives from its SMs to the MAC address of the SM that bridged the packet, before
forwarding the packet toward the public network. If you do, then
◦ not more than 10 IP devices at any time are valid to send data to the AP from
behind the SM.
◦ the AP populates the Translation Table tab of its Statistics web page, displaying
the MAC address and IP address of all the valid connected devices.
◦ each entry in the Translation Table is associated with the number of minutes that
have elapsed since the last packet transfer between the connected device and
the SM.
◦ if 10 are connected, and another attempts to connect
• and no Translation Table entry is older than 255 minutes, the attempt is
ignored.
• and an entry is older than 255 minutes, the oldest entry is removed and the
attempt is successful.
◦ the Send Untranslated ARP parameter in the General tab of the Configuration
page can be
• disabled, so that the AP will overwrite the MAC address in Address
Resolution Protocol (ARP) packets before forwarding them.
• enabled, so that the AP will forward ARP packets regardless of whether it
has overwritten the MAC address.
This is the Translation Bridging feature, which you can enable in the General tab of the
Configuration web page in the AP. When this feature is disabled, the setting of the Send
Untranslated ARP parameter has no effect, because all packets are forwarded
untranslated (with the source MAC address intact).