Ubigate iBG2016 Configuration Guide/Ed.00
© SAMSUNG Electronics Co., Ltd.
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The trTCM (Two Rate Three Color Marker)
The trTCM algorithm uses two rates CIR and PIR, and two burst sizes, CBS
and PBS. The trTCM is typically implemented using two token buckets, Tc of
size CBS, and Tp of size PBS. A packet is marked red if it exceeds PBS,
yellow if it exceeds CBS but not PBS, otherwise it is green. Coloring is just a
means to convey the conformance level of packets. An action can be
configured for each color. Supported actions include Permit, Mark-DSCP and
Drop.
Let the token buckets be represented by Tc(t) whose maximum capacity is
CBS bytes, and Tp(t) whose maximum capacity is PBS bytes. One token is the
equivalent of one byte. The Tc(0) is equal to CBS, and Tp(0) is equal to PBS.
Thereafter, tokens are replenished as follows. If Tc < CBS then Tc is
incremented by CIR bytes-per-second up to CBS, and if Tp < PBS then Tp is
incremented by PIR bytes-per-second up to PBS.
When packet of size B bytes arrives for policing, if Tp(t)-B < 0, then the
packet is marked red else, if Tc(t)-B < 0 then the packet is marked yellow and
Tp is decremented by B else the packet is marked green and both Tc and Tp
are decremented by B. This mode of operation is the default mode and is
known as color-blind mode.
In the color aware mode, packet is assumed to be pre-colored. In this case
when packet of size B bytes arrives for policing, if Tp(t)-B < 0 and packet
color is green or yellow, then the packet marked red else if Tc(t)-B < 0 and
packet color green then the packet marked yellow and Tp is decremented by B
else packet’s color is unchanged and both Tc and Tp are decremented by B.
Summary of Contents for Ubigate iBG2016
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Page 16: ...INTRODUCTION XIV SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
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Page 62: ...CHAPTER 4 System Logging 28 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
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Page 140: ...CHAPTER 4 RIP 104 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
Page 156: ...CHAPTER 6 BGP 120 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
Page 180: ...CHAPTER 8 VRRP 144 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
Page 264: ...CHAPTER 10 QoS 228 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
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Page 298: ...CHAPTER 3 Firewall NAT 248 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
Page 356: ...CHAPTER 5 IPSEC 306 SAMSUNG Electronics Co Ltd This page is intentionally left blank ...
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