Traffic Management for the Available Bit Rate (ABR) Service in ...

1. A switch queueing point is a point of resource contention where cells may be
potentially delayed or lost. A switch may contain multiple queueing points.
2. Some example switch mechanisms are presented in Appendix I.5.
3. The implications of combinations of the above methods is beyond the scope of
this speci cation.
5.10.7 Virtual Source and Virtual Destination Behavior
VS/VD behavior divides an ABR connection into two or more separately con-
trolled ABR segments. The coupling between adjacent ABR control segments asso-
ciated with an ABR connection is implementation speci c.
The following applies to VS/VD behavior:
1. Each ABR control segment, except the rst, is sources by a virtual source. A
virtual source assumes the behavior of an ABR source end point. Backward
RM-cells received by a virtual source are removed from the connection.
2. Each ABR control segment, except the last, is terminated by a virtual des-
tination. A virtual destination assumes the behavior of an ABR destination
end point. Forward RM-cells received by a virtual destination shall be turned
around as de ned in destination behavior #2, and shall not be forwarded to
the next segment of the connection.
3. The coupling between two adjacent ABR control segments associated with an
ABR connection is implementation speci c.
4. MCR shall be conveyed across VS/VD boundaries.
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