Hi Tao,
check out this section of the code in the file "ath/if_ath.c":

static int
ath_tx_start(struct net_device *dev, struct ieee80211_node *ni, struct ath_buf *bf, struct sk_buff *skb, int nextfraglen)
{
...
        case IEEE80211_FC0_TYPE_DATA:
                atype = HAL_PKT_TYPE_NORMAL;            /* default */

                if (ismcast) {
                        rix = ath_tx_findindex(rt, vap->iv_mcast_rate);
                        txrate = rt->info[rix].rateCode;
                        if (shortPreamble)
                                txrate |= rt->info[rix].shortPreamble;
                        /*
                         * ATH_TXMAXTRY disables Multi-rate retries, which
                         * isn't applicable to mcast packets and overrides
                         * the desired transmission rate for mcast traffic.
                         */
                        try0 = ATH_TXMAXTRY;
                } else {
...
}

Here you can modify the rate in which you want to send the multicast/broadcast packets.

good luck,
david

Tao wrote:
Hi:

we know that broadcast packets use low rate to sending packets (6M/s in 
802.11a  2M/s in 802.11b) 

can i modify the madwifi to broadcast packets on a multirate (9M/s ,12M/s)?

if i can which file should i modify?



Thanks

Regards
Tao


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-- 
========================================================================
  0 0 0  David Fusté i Vilella       |    Dept. of Comp. Architecture
  0 0 0  Ph.D. Student               |    UPC-Campus Nord, D6-001
  0 0 0  email: dfuste@ac.upc.edu    |    C/ Jordi Girona, 1-3
  U P C  phone: 0034 93 401 67 83    |    08034 Barcelona - SPAIN
                www: http://personals.ac.upc.edu/dfuste/
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