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

d) VS/VD Control: The switch may segment the ABR control loop using a
virtual source and destination.
2. A switch may generate a backward RM-cell. The rate of these backward RM-
cells (including both in-rate and out-of-rate) shall be limited to 10 cells/second,
per connections. When a switch generates an RM-cell it shall set either CI=1
or NI=1, shall set BN=1, and shall set the direction to backward. The switch
shall assign values to the various RM-cell elds as speci ed for switch-generated
cells in Table 5-4.
3. RM-cells may be transmitted out of sequence with respect to data cells. Se-
quence integrity within the RM-cell stream must be maintained.
4. For RM-cells that transit a switch (i.e., are received and then forwarded), the
values of the various elds before the CRC-10 shall be unchanged except:
a) CI,NI and ER may bemodi ed as noted in #1 above
a) RA, QL and SN shall be set in accordance with ITU-T Recommendation
I.371-draft
MCR may be corrected to the connection's MCR if the incoming MCR value
is incorrect.
5. The switch may implement a use-it-or-lose it policy to reduce an ACR to a
value which approximates the actual cell transmission rate from the source.
Use-it-or-lose-it policies are discussed in Appendix I.8.
Notes-
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