Hi, Thanks. Still one thing not sure. CIL.
On Sat, Feb 20, 2010 at 6:28 PM, Omprakash Gnawali <[email protected]>wrote: > On Fri, Feb 19, 2010 at 10:15 PM, <[email protected]> wrote: > > Hi, > > > > Please help me understand the following uncertainties regarding 4 bit > link > > estimation (4bitle): > > 1) 4bitle is using both data-driven and beacon approach to estimate link > > qualities in terms of ETX. Data-driven is estimating bidirectional link > > quality since it leverages ACK, whilst beacon is only measuring inbound > link > > quality. Is it problematic to combine these two estimated ETX into a > single > > ETX? What does this single ETX mean? Inbound link quality, or > bidirectional? > > Bi-directional. Beacons are only used for bootstrapping. > But beacons can be sent throughout the running lifetime of the protocol, such as in CTP. In the long run, isn't this going to interfere w/ the accuracy of the bi-directional ETX measured via data-driven approach by mingling it w/ inbound-only ETX? > > > 2) In beacon based link estimation of 4bitle, each packet from upper > layer > > is slapped with a header containing sequence number information needed to > > compute link quality prior to transmission. However, the sequence number > has > > only 8 bits (see below). Is this sufficient for beacons more than 255? > > typedef nx_struct linkest_header { > > nx_uint8_t flags; > > nx_uint8_t seq; > > } linkest_header_t; > > You need to detect and handle sequence number wrap-around. > > - om_p > -- -Xiaohui Liu
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