Table 10: Tcp-Friendly One-Rate Rate-Limit Profile Algorithms - Juniper POLICY MANAGEMENT - CONFIGURATION GUIDE V11.1.X Configuration Manual

Multiplying the committed rate by 1.0 seconds converts the rate to bits, then
multiplying the number of bits by 1/8 converts the value to bytes.
Excess burst is 1,000,000 x 1.5 x 1/8 + 125,000 = 312,500 bytes
Multiplying the committed rate by 1.5 converts the rate to bits, then multiplying
the number of bits by 1/8 converts the value to bytes.
TCP-friendly rate limits have only one token bucket, but they also maintain a
cumulative debt counter that represents how much traffic above the committed rate
has recently been seen. This cumulative debt increases until it reaches the extended
burst value; at that point the cumulative debt is reset to 0, but the offending packet
is marked red. The cumulative debt increases faster than just by the packet size, so
if the TCP source does not respond to TCP flow control and more of its packets are
dropped.
Table 10 on page 85 presents equations that can also represent the algorithm for
the TCP-friendly one-rate rate limit profile when using hierarchical rate limiting,
where:
B = size of packet in bytes
CD = cumulative debt
t = time
T(t) = number of tokens in token bucket at time t

Table 10: TCP-Friendly One-Rate Rate-Limit Profile Algorithms

Step
If not color aware, use green as the
incoming packet color, otherwise use the
actual packet color
If incoming packet color is green
If T(t) > = B
If T(t) < B and CD is incremented by
B – T(t)
If CD < Extended Burst and T(t) < B
If CD > = Extended Burst B and T(t) <
B
If incoming packet color is (only occurs in
color-aware operation)
If T(t) < B and CD is incremented
by B– T(t)
Chapter 5: Creating Rate-Limit Profiles
Result
–
–
Packet is colored
T(t) is decremented by B
–
Packet is colored
T(t) is decremented by B (allow T(t) < 0, if
necessary)
Packet is colored
CD is reset to 0
–
–
Configuring a TCP-Friendly One-Rate Rate-Limit Profile
85