Rate limiting CrashPlan

ratelimit.sh

#!/bin/sh

# The network device used for backups
dev=p10p1

# The remove address of the CrashPlanserver
crashplan_addr=50.93.246.1

# The port
crashplan_port=443

# The rate limit. See tc(8) for acceptable syntax.
crashplan_limit=2mbit

if [ "$1" = "enable" ]; then
    #
    # This creates and activates the traffic shaper
    # configuration.
    #
    logger -s -t ratelimit -p user.notice "enabling rate limits"
    tc qdisc del dev $dev root > /dev/null 2>&1
    tc qdisc add dev $dev root handle 1: htb
    tc class add dev $dev parent 1: classid 1:10 htb rate $crashplan_limit
    tc filter add dev $dev parent 1: prio 0 protocol ip handle 10 fw flowid 1:10
    iptables -t mangle -A OUTPUT -d $crashplan_addr -p tcp --dport $crashplan_port -j MARK --set-mark 10
elif [ "$1" = "disable" ]; then
    #
    # This removes the traffic shaper 
    # configuration.
    #
    logger -s -t ratelimit -p user.notice "disabling rate limits"
    tc qdisc del dev $dev root > /dev/null 2>&1
    iptables -t mangle -D OUTPUT -d $crashplan_addr -p tcp --dport $crashplan_port -j MARK --set-mark 10
elif [ "$1" = "show" ]; then
    #
    # Shows the current traffic shaper configuration.
    #
    tc qdisc show dev $dev
    tc class show dev $dev
    tc filter show dev $dev
    iptables -t mangle -vnL OUTPUT
fi

Hi lars:

I have doubts on this snippet and I have asked a question on serverfault in detailed, Can you explain my doubts?

Thanks.