Download - v1.0 - 20050426
v1.0 - 20050426
Document Cover Sheet
Project Number PN-3-0062-RV2
Document Title TIA921B Algorithm – An Update
Source Telchemy
Contact Name: Alan Clark Complete Address: 2905 Premiere Parkway, Suite 280 Duluth, GA 30097
Phone: +1-678-387-3000 Fax: +1-678-387-3008 Email: [email protected]
Distribution TR-30.3
For Incorporation Into TIA Publication X For Information
Intended Purpose of Document (Select one) Other (describe) -
The document to which this cover statement is attached is submitted to a Formulating Group or sub-element thereof of the Telecommunications Industry Association (TIA) in accordance with the provisions of Sections 6.4.1–6.4.6 inclusive of the TIA Engineering Manual dated March 2005, all of which provisions are hereby incorporated by reference.
Abstract
TIA921B Algorithm – An Update
Telecommunications Industry Association TR-30.3/08-12-017Lake Buena Vista, FL December 8 - 9, 2008
TIA921B Algorithm – An Update
Alan Clark
Interfering Source Model
2
1No packets
Packet Parameters:- p12, p21 = Transition probabilities (forward)- p12, p21 = Transition probabilities (reverse)- k = MM update frequency
Low value of k, low value of p21 … e.g. VoIP
High value of k, high value of p21 … e.g. TCP
Interfering Source Model
• Model reverse flow– TCP – assume model generates primary packet
stream• estimate packet volume in reverse direction for normal
ACKs
– VoIP – assume symmetric packet flow– IPTV – assume unidirectional packet flow
Base Model - 1
EstimatedQueuing
Delay
InterferingSource
InterferingSource
Stream
Limits for queuing delay in each directionAND common delay (i.e. shared queue)
Overflow model (i.e. queue length limit)
LossModel
Base Model - 2
At time t:For each interfering source
Probability of being in packet burst = p(b)Decide on a packet burst lengthDecide on the position within the packet burstCompute contribution that preceding part of packet
burst added to queuing delay
Issue 1
If next “t” is close to previous then both events could have occurredin the same packet burst
Add:if t within previous estimate of packet burst length then
use previously calculated burst parameters
Issue 2
If multiple test stream packets are closely spaced they will add to the queuing delay (i.e. self congestion)
Add:incorporate contribution of this packet to queuing delay
Model
+ QueueLimit
InterferingSourceInterfering
SourceInterferingSourceInterfering
Source
TestStream
+ QueueLimit
InterferingSource
InterferingSource
InterferingSource
InterferingSource
TestStream
Model
+ QueueLimit
InterferingSource
InterferingSource
InterferingSource
InterferingSource
TestStream