Motorola 49901 Software Release Notes - Page 11

K Frame, W Packet, Vanguard 7300 Series Software Performance - Annex G, Recommended, Window Settings

Get Motorola 49901 - Vanguard 340 Router PDF manuals and user guides
UPC - 786523499018
View all Motorola 49901 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 11 highlights

New Features Part No. T0001-42, Rev C October, 2002 Page 11 of 103 Vanguard 7300 Series Software Performance - Annex G Annex G performance can be increased by 40 percent with proper tuning. Release 6.1 and greater includes a new parameter called Window Subtractor. The window subtractor parameter changes the point in the receive window that the layer 3 acknowledgment is to be sent when there are not any packets to send in the reverse direction. The acknowledgment is sent when the number of packets equivalent to the W Packet Window minus the Window Subtractor has been received. If the W packet Window is 32 and the window subtractor is 8, the layer 3 acknowledgment is sent once 24 packets have been received. Setting the Window Subtractor to a non-zero value when INL or INL+INLB are set has no impact on the functionality of the routing loop detection feature of INL. It only effects functionality when the layer 3 acknowledgment is sent. If INL is specified and the subtractor is zero, the router uses the previous setting of 2. If INL+ INLB is specified and the subtractor is zero, the router will send an Acknowledgment for every packet received. This is also what occurs if INL or INLB are not specified and the subtractor is zero. You should increase the value of the subtractor when you are using high speed end-to-end connections or when path delays are unusually high. This sends the acknowledgments sooner so the remote window stays open and the remote node can continue to send data without being stopped (waiting for an acknowledgment). The "Window Subtractor" Value is dependent on the "W" (packet) window setting and interacts with many other settings and factors such as the speed of the line, the "K" (frame) window setting, circuit propagation delay, etc. Tuning can result in CPU utilization savings and higher throughput. Recommended Window Settings Annex G/X.25 Window Guidelines Link Description Recommended Window Settings Recommended Window Subtractor K (Frame) W (Packet) 8 Mbps Serial 63 30 25 4 Bps Serial 30 20 15 2 Mbps Serial 30 20 15 E1 30 20 15 1536 Kbps Serial 25 15 10 T1 30 20 15 512 Kbps 15 10 6 256 Kbps 10 7 4 128 Kbps 10 7 4 64 Kbps 10 7 4 64 Kbps 10 7 4

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
Part No. T0001-42, Rev C
October, 2002
New Features
Page 11 of 103
Vanguard 7300 Series Software Performance - Annex G
Annex G performance can be increased by 40 percent with proper tuning. Release
6.1 and greater includes a new parameter called Window Subtractor. The window
subtractor parameter changes the point in the receive window that the layer 3
acknowledgment is to be sent when there are not any packets to send in the reverse
direction. The acknowledgment is sent when the number of packets equivalent to the
W Packet Window minus the Window Subtractor has been received. If the W packet
Window is 32 and the window subtractor is 8, the layer 3 acknowledgment is sent
once 24 packets have been received.
Setting the Window Subtractor to a non-zero value when INL or INL+INLB are set
has no impact on the functionality of the routing loop detection feature of INL. It
only effects functionality when the layer 3 acknowledgment is sent. If INL is
specified and the subtractor is zero, the router uses the previous setting of 2. If INL+
INLB is specified and the subtractor is zero, the router will send an
Acknowledgment for every packet received. This is also what occurs if INL or INLB
are not specified and the subtractor is zero.
You should increase the value of the subtractor when you are using high speed
end-to-end connections or when path delays are unusually high. This sends the
acknowledgments sooner so the remote window stays open and the remote node can
continue to send data without being stopped (waiting for an acknowledgment).
The "Window Subtractor" Value is dependent on the "W" (packet) window setting
and interacts with many other settings and factors such as the speed of the line, the
"K" (frame) window setting, circuit propagation delay, etc. Tuning can result in CPU
utilization savings and higher throughput.
Recommended
Window Settings
Annex G/X.25 Window Guidelines
Link Description
Recommended Window Settings
Recommended
Window
Subtractor
K (Frame)
W (Packet)
8 Mbps Serial
63
30
25
4 Bps Serial
30
20
15
2 Mbps Serial
30
20
15
E1
30
20
15
1536 Kbps Serial
25
15
10
T1
30
20
15
512 Kbps
15
10
6
256 Kbps
10
7
4
128 Kbps
10
7
4
64 Kbps
10
7
4
64 Kbps
10
7
4